2. Oliver Nuthall Presents Bristol Engine Developments

uh, unfortunately, none of these are for sale, right? He has counted them and wants them back. Many of them are in poor condition, because of the way he tried to build them. I have to say you are a pretty intimidating audience. There's a lot of practical knowledge here you know, and I'm only 36 so I'm way behind most of you, just a kid, yeah I'm just a kid, my dad really should have given this talk, but he's testing. at Silverson today um so you have me because I've been delegated to come and talk to you so I thought what could I bring that probably not everyone has seen before because most of you own very nice Bristols some of you. more than one and thought I'd start with the 85 series head, the earliest head now.

I don't actually have a very early head. I heard some of you correct me saying that Bristol used two different castings at the beginning and the first heads weren't very good and most of them corroded. Andy is right, so I have never seen a very early head, presumably they are all gone. The number of 400 heads that the factory had to change. Yes, the first year or two, even yes, and the first head we have here is an h5a head. This carburetor here was made is a double choke solx um solex, solex uh 30p a AI or sometimes known as A A pii. it was used in a Ford V8 pilot after the war, uh and the pilot, the largest

engine

that the pilot had was a three .6 L V8.

The same car in a Bristol produced 75 horsepower. The same

engine

, the Ford V8, which had side valves, produced about 80 horsepower. So that shows you how good the Bristol engine was right away, it's much more efficient, a much more efficient engine, um, yeah, I'd never seen that setup, that intake manifold until I started digging through the boxes at the auction. by Brian Mag, showing bidding hands. Something on Brian Mays, did anyone see it was for sale? No, it was at the bottom of a box, it was just a pile of junk, and at the bottom was that manifold and that carburetor, and I thought I'd never seen one of them. those just in a book I think I think Chris Bala's book has a picture of an 85 per block with a head with one of those carbs with one of those manifolds 85 simple yes, sorry technically 85 yes, mine is that the Yours did it.

Where was the photo? fabulous, um, in the backyard, in your back, so you still have, you still have one of those, and you also have the special air filter cleaner setup on top of it. Yes, it is the standard collector. but you have a square, yeah, on the top and that's because the cast magnesium is aluminum, so I've never seen one of those either. I only saw one at a concore many years ago, well you were my inspiration for buying that primary. so there's just a g on the bottom of these boxes very smoothly, is that right?

Yeah, I'd love to drive, try it one day with a car with one of those I've never driven one, um, that collector has a date, uh, six of the six 47. stamped on it, so presumably that's when it passed inspection. in Bristol. Bristol was very interested because aircraft manufacturers inspected each item and almost all aluminum items have an inspection stamp that is very small. this big and it says bacd um, you'll see it on some of the heads when we turn some heads in a moment, uh, when at lunch you can wander around a little bit because Bristol, when they inspected each cylinder, they put a seal on each one. on each one to show that they inspected it, yes, you'll see them here, that they're actually there, so you have 1 2 3 4 5 6 and then you stamp next to each cylinder to show that it's been inspected, so that's cool.

There is actually someone here who has driven one of these CU setups. I don't have what's very interesting about this is there's a restrictor plate, yours has Chris in it, there's a restrictor plate here on the manifold, no I don't think it has well we'll take it we should take it apart you and I in wait uh and it actually has this shape and it's very restrictive I don't think I just don't remember it I wonder if I wonder if that was a later mod or something, Tri maybe um let's just remove the collector because uh I just put it on slightly so everyone can take a look, so this is a h5a head that Tony Bford and Rod Mcferson kindly lent me.

It is, but I don't actually have it, we'll take it off and it will suddenly become an h5a with a Balan tube. Strictly, these carbs should have been on this head, but I'm running out of time, eh, sure, everyone can have a nice Look at it later, so 85 heads, all with the Balance shoe for the Su. I quite like the setup on the Su, it seems a little crazy, uh, this whole choke system, so you have a manual choke and also this solenoid operated choke, so everyone. 400 has that uh carburetor switch on the dash um which obviously not many people use anymore because a lot of them have soxes so the h5a head doesn't have very big valves so 36 mil intake valves uh and this one It's a pretty flat head we were.

Speaking of flat heads earlier, when you start to lose all the detail, under the stock, is when they start to get quite flat, although it can be really misleading because some of the heads, when they were cast, look like they were cast on a slant. , but they are not if you check the depths of the real combustion chambers and our depth expert of cheap combustion chambers of combustion is in contact with the first in the back, who knows them all, tells you rodnie so that Can Rony tell us the depth of uh, a new 885a combustion chamber and how it's different from, say, 100d depth.

One of the cheapest and easiest ways to increase compression on the Bristol was to simply stroke the heads more. You know, it's more expensive to have many different piston designs. um, so, yeah, h5a head, uh, yeah, pretty high, pretty high efficiency, um, no, no, no, no, no, huge, cool, uh, breakthrough in BMW's pre-war design, although, um, BMW before the war, in their racing engines, they were already getting 130 horsepower in the M meu. engines um and they already tried larger valves than this so that's pretty interesting. Maximum power um around 42 to four and a half. This head has actually already been converted to work with solet carburetors, so I believe Bristol did this at the factory and it.

You could correct me, they put a sleeve here to get rid of the balance. Tuesday, so you can no longer get your, you no longer get the balance tube. I stuck my finger there and here, but not here to run, it was the balance tube. more for the vacuum to balance the vacuum or do you think it was a mix. I think the mix could have been everything, it could have been a little bit of both, although yes, to me, if you think about BMW before the war, they didn't put a balance tube in, but they had it between the intake manifolds, so that's how they did it, they did it a little different.

I really like the 34. They look a little modern, the only problem with them is that they have to fix the choke on the Webers. So when you buy the bodies, they're 25, 27 or 29 mil chokes, whereas obviously with the solexes you can take the chokes off and chase them around for whatever you want, although you can't get more than 29 in um, you don't. I'd like to, uh Mo, most of the race cars that we drive have 27 or 28 million jokes, so we'll return this one that was the h5a thank you bar for lending that one. He's had a bit of a difficult life.

So this is actually a totally different 100 and um casting, but before we get into this we should talk about the 85 uh B and C uh, the early 85 C engines in the 401s. I think I'm right in saying that they obviously had quite a few. These molds were left over, so they holstered them and all the first 40 would have had a head that looks like this with the sleeve on with the socks on, although a little more power, 85 horsepower, I think like this, um, yeah, so yes, they had to use. I guess they made 450 400, something like that.

Someone will know the exact number and then they sold over 600 401's so I think all the first 401's would have had this type and then went on to not have it. not having the balance, it should be placed in um, you can see, maybe see that the intake manifolds, the intakes are quite placed, uh, like this and I think that helps turn, I think that was that good, it did deliberately, um, they only have one shot. on the front here, which could have been used for vacuum, but they obviously weren't equipped with Servo, so I think that's what this tube was for, to go there.

The later heads differ in that they all have flats, the more recent heads of like the entire 110 series, all the 100 d2s almost all have Flats here, um, which you'll see on that head and those Flats were used on the 110 series for the servo for servo vacuum, that's one way to spot the 10 series head from A w from a mile away is that each of those heads is drilled and tapped so you can see the floor. It's going to be hard to see from the back, but there's a floor there, there's a floor there and a floor there and this.

It just has the front drilled and tapped because it was off a 100 D head, one of the early 100d heads, um, but yeah, 110 series, all of those now. I'm pretty sure the 110 series had, yeah, yeah, but everyone can have a milling round. After all, I'm pretty sure the casting was exactly the same for the 110 series, just the machine is different. That's the same for us in racing. We get these castings and we're developing them. We have developed a 2.4 engine, using the same. casting so it's the same casting as the 2 ler uh and all we do is machine it differently so we offset the combustion chamber so this chamber is like this it's like this the spark plug and the valve stay exactly the same place, um, but there's enough. meat here to do that and it gives you 2,452 CC which is pretty interesting the BS on the block are obviously offset and we don't use liners on the block um because of modern metal you can basically line up the blocks if you want um and actually, if they did wear out, that would be the best thing to do, it would just be overdoing it and a line of them, um, no, not for the 2.4 engine, which is for the 2 liter blocks, so yeah, this has been something we've made.

I've spent years developing now, what size do the valves end up being? Obviously, it is a cast part and has not yet been machined at all. Good question, obviously Bristol used a 39 mil valve and sometimes a little over 39 mil I don't think. they were ever at 40 39 points something like that for the intakes uh our biggest valves are 41.8 mil for the intakes um it's also a lightened valve so it has a thinner stem um we lightened the valve train to get more RPM , but that's all. The main reason the light has a light drive train, valve train, sorry, higher RPMs you get more power.

Lightening the valve train is very important. We also changed the design of the tweezers so that the tweezers have a slot design, which is a modern design compared to the old one. design that is more of a wedge, two wedges, as Bristol stated and in the correct book it says that this head produced 170 horsepower at 7,000 RPM. Now I have doubts about this because if you accelerate the normal collet design to 7,000 RPM, a valve will fall off, I guarantee it. I grew up watching prime and racing bristles race and uh an idol of mine there and uh Rod never used to exceed Rod 6,000, yeah, and you can have a very reliable racing engine using the original colet design with a 6000 limit, so our modern racing engines can go up to 7000, but that's due to the lighter valves because of the titanium TI valve spring top caps, there's not much more spring pressure, we really don't have. high spring pressures Really high spring pressures will ruin the cam and the cam followers pretty quickly, so not only will they ruin your followers and the cam, but they will also cut power from the engine, so you really want the lightest spring you can get without the valves floating at the RPM you want now I think this engine could have revved to 7000 um the bsx or BC could have read 7000 reliably in the period.

I think that would have been a really cool thing CU breathes a lot Better, very, very well, with this design, it's still a good design, although with the three carbs and now we can get more power out of this than you could get in Period, which which is interesting, in the workshop. over the years I haven't seen many cars with six port heads I have to say uh War Banks is 404 um uh ACA Bristol from Tony Bank uh these heads this is a late 53 head so a six port head from Bristol very early they changed the I designed a few times, they ended up if you got the right book with a single bar going through special Solx carburetors, uh, Sandcast, which I don't have twin chokes, just made for the Lon cars.

It would be nice to get that head together with some of them. but they're like hen's teeth, um, yeah, so we can get a little more power out of this. AreHeads were designed to fill them all to speed through the mson, hour after hour, after hour. They weren't designed to get away from traffic lights, you know, outside of B and Q um Jeff D uh in Australia has created his own six foot head, which is amazing, you know what kind, uh, but he found it, I think he put weers on his He has found that to make it nice on the street you need very small chokes on the Webers because at low RPM you don't have the airspeed with the big chokes and it doesn't want to get away at all so he puts very small chokes on. uh, to me, it kind of negates the fact that you have this head that breathes really freely, um and I think it has 140 horsepower from its 130 something like that, um, but a really cool engineering challenge, uh, and it did it. modifying an original head which is something bobGerald did it in the period um Rod Speed ​​did it in the period maybe Barwell I think it's the right rod yeah I'm getting it and Westlake but I think Harry Weslake had it too something to do with this design, um, Bristol hired him to help get more power.

I think what's also very important for the six port header on the Leemon is that the fuel was garbage on the Lemon, it still is, it's still the only place where we've had a head gasket failure. for years it's on Lamon and you have to use the fuel they provide and the fuel garbage so I think that's why we don't actually run higher compression on these racing heads than Bristle on Period so some of The bs4 heads on Period run at 11 to 1 compression, we don't go any higher than that, um, so the biggest power is in the form of the input tracks which, when Peter designed the head, were slightly different.

Straighter, can everyone see that they are much straighter in this in the new head than they were originally? So maybe not for the purists, but I guess if you're going to go to all the expense and time of designing something, hey, pet, Peter worked. Very closely with COA for many years, Peter J um, when in fact, the last time I went to see him, he was Machining some DF blocks is one of his last jobs, uh, for Richardsons um, so yeah, I think it's a good idea, less swirls like this. um we didn't open the ports too much uh if you open them again you'll understand that you don't speak so well um the car doesn't want to go away you know you don't want a racing engine that only runs between six and six thousand five hundred you want something that be really manageable from something like three at least um three to about we've developed some new cam designs so our latest cam is better from four to six and a half and it starts to kick in a puff after 6,500 so that It's the good thing about having the limit of 7,000 because if you lose a gear you won't go, not all the valves will get the pistons and everything gets very expensive very quickly if you're not careful, start this one, any questions about the new ones, you get the 2.4.

I don't know, Jeffrey is the answer, so I ran it on the engine mount at work and ran it. in a car, uh, last year and we still have to put it. I would like to take it out and send it to a separate Dyno motor. Dyno, that's the best thing to do. I think people who own their own dinosaurs and their own dinosaurs. With your own engines you can make it give you what you want. The thing about a power meter is that the crucial thing about a power meter is that you run it and it records the same thing every day, so it doesn't matter if it records 50 that long. since it clocks in at 50 horsepower every day, and if you make a tweak to the air fuel ratio and get more power, then you get 51, that's cool, isn't it?

You know it could be 51, it could be below 151, you just need to know if you're going the right way or the wrong way, so we build a lot of engines and obviously a lot of people want an independent valuation. We used RM Wilson in Leicester and Sam and his dad who have been working for many years. famous doing Ferrari Restorations and Ferrari P4 replicas uh, so they independently Dyno our engines um, yeah, so the answer is I don't know, uh, I think the 2.4 will give a lot more to talk about. It may not give much more power, so we'll see, I mean, we see that in the 110 Series in a Bristol, so the 2.2 engine in the Bristol gave the same 105 horsepower as the 100 B2, but the torque was better and with lower RPM, so I got more torque at 3000, while the maximum talk on the um 100 B2 was close to 4 3750.

I think we hope to talk more and, oh, touch wood you have. It has to give more talk, it has bigger pistons, it's just that it's Just how it's going to burn, it's going to be more, it's going to be interesting, um, because it's all offset, um, the piston is nothing fantastic, nothing super fancy, uh, it's a Quite conservative design actually and we haven't gone for high compression, so. I hope to talk a lot more, it would be nice to have 200 horsepower, I've never seen that before, so the biggest thing when seeing a 2L Brussel produce is 185 horsepower at the flywheel, that's really reaching the capabilities of what's possible ,uh.

I think to get a lot more power, what are the cheat options? 67k pistons are an easy way to go, and we didn't really get it done in racing, so there you go, you can't accuse us of cheating. Because we do not have a 67 thousand piston or we manufacture one. The other way is to try to use a 2.2 crank to run it with a 99k stroke, but if you use a 67k piston and a 99k crank, that is exactly the same stroke. since Bristol is used in the 110 series engine you only end up with 2.1, so a little more power, maybe you could go to 180 290.

I don't know, uh, I don't know, you have a very long career in a Bristol versus the um versus the piston width side so no I can't see us getting much more out of them anyway reliably I mean Mike Hawthorne and Leslie Hawthorne their dad got quite a bit of horsepower during the bristling period of operation. Nitro and methanol with Nitro, but I read that Leslie took the engine apart after every race and rebuilt everything, so you need Deep Pockets for something like that. You know our racing engine should easily last three or four seasons. We are not separating them after each race, yes, absolutely not, and I think our customers would if I told them they would have a fit, but yes, I mean, if you look at the mini engines that are now competing.

Nick Swift Mini Motors Brilliant Nick Design amazing motors, but you have to send them back after 10 hours. Now 10 hours isn't a lot of driving, is it a race track, uh, and testing, but they're speeding them up to some kind of I don't know 8 and? half a thousand now or something like that. Silly, yeah, amazing stuff, but you know, with the Bristol engine, the really cool thing is the fact that it should be pretty reliable because it's a road engine turned into a racing engine, it's not a racer, it wasn't built on its own. like a racing engine, um, I think on the road it never makes sense to have more than 100, 140 to 150 horsepower, um, you can't drive at 6,000 RPM all the time, um, and it really is a total waste of time .

The really nice camshaft that we recommend is Bristol's own camshaft, so Bristol made the five, what we call the 590 cam, which is the Bristol Sports cam, which fits the standard on all AC Aces and stuff like that, but it's a good sports cam. and with the electronic ignition you can get it to run really well from about 1500 RPM, um, and that's the smoothest cam that we sell now because it fits inside the standard journals, you don't have to modify your block in any way, the axle journals of cams. uh obviously the fancier cams have higher lift so putting them in requires altering the cam bearings and yeah it starts to get very expensive and most road cars take a total of time.

I wouldn't particularly recommend it. You know, high lift stuff because they're pretty heavy cars, aren't they Bristols? You know no, yeah, you need to get them moving, so you need to talk and you don't want to have to speed up. Stop um Tove, how are you? Yes, between 175 and 185, that's standard, everything yes, yes, yes, for three or four. Yeah, you can't, you can't build one for one client better than another. You know they're all pretty similar, obviously, us. We're always trying to make them a little bit faster, and a lot of that is small advances, and a lot of them aren't really worth it.

Most people can't tell the 10 to 10 horsepower difference between one engine and another. I can't tell the difference driving the car I can't tell the difference, you know, you need to be like Nikki stronger to tell the difference. 10 horsepower difference. What we're trying to do is have something that's very tractable and doesn't just run at high RPM. You have a lot of dead center with these carbs, although with our race cams we alter the carburetors a lot, the Soxers are modified a lot to try to make them work. better, but they don't, they don't make a big difference, we already know Trump and we integrate chokes and another big thing is to make sure that if they flood, they flood into the car and not out of the carburetor because some people used to develop funnels that They covered that and then they caught fire a lot.

You know. I think being a Bristol owner, everyone will tell me that the first thing they do after leaving it for the winter is check it out. to make sure there's no fuel leaks in those banjos Cu uh the fiber washers dry out and then they want to catch on fire so that's something I check on every car I get in we often take them off but and we have a feed for Each car feeds each carburetor separately, which I think for full race cars it's worth it, because then obviously the fuel doesn't have to go from one to the next, but again for radical cars, no absolutely. no and and and the fuel pump the standard fuel pump is more than enough man for uh you know electric fuel pumps I think electric fuel pumps often create more problems than they actually solve um because you can have too much fuel then and it's It's easy to flood it and blah, blah, blah.

I think mechanical fuel pumps, as long as one of you knows it's been rebuilt really well, is a good thing. The interesting thing about the fuel pumps is that the 2.2 pump is different from the 2L pump, which is unusual, it has a different arm, presumably to pump a little more fuel, so there is more leverage, but that was another thing I bought at Bri's auction. I was trying to find one of those pumps because they are hard to find but if you are going to build a 110 series engine you need one of those really yes any questions about how to make the bristles go fast or race them or why Bristol switched from the Su to the higher power.

I think so, they were looking for more power, yes. I think that's the main reason these are only an inch and eight, so they're not very big, by the way, you rarely see these cars, if ever. Try and buy some Auto Jumes, they are specially made downdraft Their so called D2, they have this little oiler on the top, they actually give it away, they were fitted to quite a few cars before the war, like singers, not a standard though Austin feels like I spent. years trying to buy a kit, uh, for a car, yes, it was done by Western Services on Kingsland Road, true, they were involved in the development of the sex adjustment, but they never told me why, I think it was more power.

The only thing I can think of is: what are you doing? Yes, I put ngks in my 405. Yes, I must admit they burned the oil poorly at first, but I found it works better with an old set of kgs I bought at Bristol cars. in 1973 what ngks were you using because there are many different ngks you can put on a Bristol? I don't remember well, which of the problems with the plugs was that they couldn't work in a wide temperature range? In the '80s, '70s, and '80s, you would start the car with a C plug and race it with another set of plugs, but there are so many spark plugs and ngks for road cars that we usually recommend C5 or C6 HSA, um, them.

They are a really good plug and cheap to buy, plus very cheap to make sure you leave it. When I go to the local motorcycle dealer to buy a set of six, I get a lot of respect and they wonder what I am, yes what. are you going to put them, what exactly are you going to put them on? Yeah, the only annoying thing about modern sockets is that you can't use your lovely Bristol socket wrench on them without modifying them, going back to the early days, um, of course. We, we only had pool gas, well, every 400 would have worked and given their performance numbers on pool gas and a lot of 401s, because when did it, um, when was p p, when did P gas end, it was 52 53, someone knows?

Yeah, maybe 54 could be getting those performance figures at 80 incredible octaves, yeah, yeah, H, hence the low, hence the low compression of s and a half, yeah, uh, and then 8 and a half and then in the 100 d, uh, 9 and a half, uh, to one, yes, modern fuel. Again, apart from the drill bit sideethanol, it's much better, so if for fast highway use we usually have 10 to one compression and it's absolutely fine to fill it with a pump, I mean I recommend just using 99 octane with the E5 um for race cars at 11 to 1 uh we tend to use 105 octane racing fuel, a terribly expensive leaded racing fuel, from Sonico, so yeah, again, not necessary, just regular Super Leed, absolutely fine and there it is where the performance lies.

Profits come um so if you take a tired 100d engine you know when it was new it was meant to make 125 or 128 horsepower something like that um but they were made on a budget 100d engines you know they were made for AC cars were not like BS engines, they were a kind of cheap copy of a BS engine, so they were not all hand finished in the ports and, well, they were just assembled, for the reason that they had more compression . they just rub the heads a little bit more, um, yeah, so they weren't, they weren't, people think the 100d engine is the one to have, but, you know, on any of the 100 series heads. you can put 39 mil valves in, so 100 a The head, you know, to me it's ENT just as good as a 100 D head.

You can make them go just as fast, so yeah, it's not something. I mean, the one that is a little more complicated is the 110 series because it is very deep and they are so wide to accept the 69 thousand piston, that is a little difficult because you can't get 69 mil pistons anymore. 69 mil so we normally weld the heads to accept a 67 mil piston or if we rub them quite a bit the landings between the um between the combustion chambers gets thicker and then you can put a two L head gasket on and if has already cut the engine with six seven mil pistons, oh wow, and six six mil pistons for the original Conrads are available through Rod Cosworth loves lovely pistons, lovely Forge pistons, yeah, I mean, I remember a time when I had never seen a 110 series engine come into the shop and then three or four years ago three or four came in all at once to be rebuilt, so, yeah, that.

I think the next thing we really need to do is have 2L two point head gaskets made new because I don't know if they are available right now. Ktic made some. there was something left over, something old, it's paying, paying, yes, paying, but there aren't any anymore that I know of, which is not good for the people who own the original 2. Tws, you know, so, yeah, we should invest in doing more. I invested quite a bit. When doing the 2.4 you can't just order 10 together, you know. I think I had to order 50 or 100. There is only one engine of this engine running in the world, same with the pistons.

I think I ordered 30 or 40 odd pistons and again there's only six in a car so it's a big investment for the business uh yeah we'll see we'll see how it goes I mean I think it should go well but if they have more questions guys yeah go for it. T exhaust on yes, yes, well, something that c, almost all CP bristles are like that, so you have three in one, two, three in one and they never come together, um, yes, so effectively, using a V8 exhaust system on a six-cylinder, uh, yeah. Do you remember the 450 450 uh they tried a lot of similar things like that? um they tried two in two in one and then they didn't come together, but in the end at 55 they put them all in one and got eight more horsepower, the back pressure is affected. um the other thing was if anyone read Jennings' book uh R Jennings wrote a fabulous book about his time working at fras and Ash afn Limited in 51 if anyone can get it if anyone never read it they should try to get a copy. because it's him, he was a fascinating guy, he hit the engine brake on afn Limited and he didn't have very good things to say about the Bristol Sports Department, you know, he thought they were a bunch of cowboys and he did, yeah.

He didn't rate his work at all and he used to rebuild the engines before they turned to ashes, um, so yeah, yeah, there's a copy on eBay, you should go find it, get it, um, I have some copies too . I probably could, if anyone wants one, I think Rod has some copies too, but yeah, they tried a lot of different exhaust systems. Jennings estimated at 51 that they could use a much longer primary, so he said he said that. They were working very hard, no, no one noticed, but he discovered that the main length needed to be doubled or tripled compared to what it already was.

This is one of the limitations: escaping is a big limitation for a standard. Bristol 2 L because you have the collectors that are three in one and those primaries are not very long, not very long, um and it was the same on a BMW 328 because they had a collector similar to the three in one. and then those two became one and how that happens can make a big difference in power, so what we see with the exhaust is that you can give an engine maybe 10 to one that has 130 horsepower, if you like. you give 11 to 1 compression, it will win.

You won't necessarily have more horsepower if you don't modify the exhaust system, if it can't draw well you won't get more power, so the exhaust is key, long primaries also give you more torque, um, so the end of last week. The racing bristle engines came in first and third in the Pell Cup, which is good for the Bristols, I guess, in line with the Bristols, uh, and yeah, and both engines have what you described, Chris, so, uh, three in one with fairly long primaries and then, then there are individual tubes of equal length that end in front of the rear wheel.

Is there a payer? No, no, no, you win with T, you actually win everywhere and another thing you win is if you don't. does it have any mufflers, um, so on an ACA, uh, Bristol, uh, we took a muffler off of one recently and gained seven more horsepower at Rolling Road right away, so that's a lot of horsepower, is it? Isn't it just for one? So you think about removing the muffler, removing the fan from the front of the water pump. You know that's half a horsepower or something. You remove the fuel pump. You know there are many ways to try these. marginal gains add up to more power um Bristol, famous for cutting the butterflies inside the solexes and inside the engines uh lamon too um we don't do that uh because for several reasons, one of them, those butterflies are a good 8 degrees um on them and it seals very well uh without that they don't seal very well and you get a nasty idle, plus if you cut them with a knife, they can start to get into the castings, which is not good, uh, you know, that's the guy.

The bottom line is that if you're doing a lot of engine rebuilding, it might be worth doing what we do instead, having a very low profile spindle for racing engines. A very low profile spindle that we make in Nottingham, most of the stuff we make in Nottingham, um, yeah, and that's the only difference with very small special screws to hold it on so we don't cut them, but we have a very low profile and sometimes we also waste the emulsion tube holders. and all kinds of stuff like that to try to get better flow, on full race engines we also run 34k butterflies, not 32k, so we drill out the base of the carbs and run 34k again. this is a waste of time on the highway, really, you know you're just looking at the difference in those carbs, 6.65, so you know a total waste of time, if you're not going to race, you can get 175 horsepower out of the 32 mil butterflies so yeah not again it's not something I recommend it's just the little bits that take a long time and don't really give you much more power um yeah more questions yeah you say you can machine one of your new blocks, yes. for an 11 I understand the camshaft housings on one are offset 100 yes that is correct and the 100 series fuel pump doesn't fit yes how do you fix that?

Yes, so you are absolutely right, so a 2.2 ler Bristol 10. The series uses a unique camera that is not like any other camera. They use different followers and also the easiest, so the casings of the real followers also have a different size. They can also have a different size. They have a different size. Yes you can. The trick is the same as a mini follower of the same size as a mini follower. So with a very light house you can put a lot of followers in a series and all of our camshafts are made by RS. Piper bills the camshafts and Piper sells a follower to match the cam um and they have an oil hole, which is nice, it's nice to have an oil hole in them um and that's what I do if I'm trying to rebuild 110 can't get that original cam so we normally put in a 2 ler cam so we put in a new C two L cam and then we do what I just described yeah yeah you're a series uh yeah , you could do it that way yeah yeah it won't fit no it's the AR the arm isn't the arm is different on the pump I think the location too um I think I had a new one I don't think so I have two series motors 110 uh I sat on a bench at work and I think it's in the same place but the lobe may be different on the cam and the arm is different for sure on the AC Delco lift pump and I think it was to give more fuel , if you remember the VES. air filters Rod MC first did some testing with the VES air filters and there is a specific height for the air filter and he found that the 2.2 liter required a taller VES filter to move it because it was basically sucking in more air and if you use a standard VES height that limited 2.2 RPM higher, so yes they are a little different and they are rare, they didn't make many of the 2.2 engines therefore we rarely see them but they are a good thing I think, since you know, in the period they had a bit of a reputation for having problems with head gaskets and things like that, but if they landed so TI because the lands were so exactly, they were so small and what is.

The interesting thing about us doing 2.4 is that we didn't want small lands between the I have my finger traps, there we go, so we've kept The Landings in 2.4 exactly the same as 2 L. um, because we didn't want to have these problems with the head gasket, so by moving the balls we managed to keep it exactly the same size as the 2 L in our 2.4, yes, and with modern head gaskets, modern composite head gaskets like you. we can get from Spencer Lane Jones stock a good one we stock a good one um very exact identical price to each other but they are just as good um with good modern composite head gaskets um and with good head bolts, so the Bristol Head studs, you can get much better quality studs now that they've stretched a bit and the nuts used to crack the nuts are made like they're made of cheese you take them off and on multiple times so yeah we used a motorcycle nut on the our. and I'm sorry, no, no, they're not.

The workshops went up to 13 thousand, it was a hassle because you had to do it, so we didn't worry. I'm selling the wrench, so ours are half inch AF with a 12o knot, uh, yeah, with a 12 with a 12p tip knot and obviously all threaded right into the block. The bolts are made in the UK and are rolled. They are made of aircraft-spec steel, which makes them expensive, but they are. really good and again you fit them and that's it, you forget that they fit and you forget that they last the rest of the life of the engine, so, yes, I think so, with good bolts and a good head gasket, you know, problems with the head gasket.

They are like eliminated with bristle motors, can I say thank you very much for an extraordinary and erudite talk? Fab and can or during lunch, feel free to touch and poke all these things that are here, good luck, convert them. On the other hand, yes, our sandwiches are waiting for us out there, fruit and various things, tea and coffee are available here for free and, um, let's keep joking and going. Technical discussions over lunch and we'll start again. Don't know. o'clock something like that um so bravo