Daimler 250 V8 engine mods
Discussion
Hey.... you're not the first person to say that (or words similar) but although classics interest me obviously, I've always had a 'thing' for custom cars. Have you never bought a car and said to yourself..... yep... I really like this car BUT..... it would look better if........ 
Hi, I just thought you might like to know that I raced a Daimler SP250 in club races in the 70's and 80's using an engine that had been bored out 156 thou and utilising special forged pistons. It gave me no problems and after the last rebuild it ran for four years before finally becoming rather tired so I retired it and myself. I currently have an SP on the road using standard Bonnie plus 20 pistons. I am pretty sure you can also use the High compression ones and these are available up to plus 60. The problem with the engine in the saloon as it gets older is cooling, in that as there is not much room around the engine it does not get sufficient cooling causing hot spots. This shows itself with the skirt dropping off one or more of the pistons at the rear of the engine. Unfortunately Jaguar did not help by using a piston with an oil groove that is machined with three long slots whereas Dimler used a piston with an oil groove that was drilled with many holes. The latter never breaks.
Someone earlier on in the thread said that the 2.5 engine had a strong 'bottom end' - I thought that the reverse was the case! I had my last Daimler 2.5 some 30 odd years ago and believed that the bottom-end and 'oiling' of the engine was its limiting factor - mine eventually threw a 'rod' - not surprising with 20 lbs oil pressure at best! We know of the drag racers that have done good thing with these, but didn't the Yanks use these with bottom-end girdles for midget racing, I seem to remember an article in Hot Rod magazine about rpm's of 9000 or so? It seems to me that the other limiting factor of this engine is that it is only 2.5 litre, fine for a lightweight Dart or rod but no good for a heavy car. Why not 'lift' the engine and drop-in a Chevy small block or better still a Ford small block - its about the same or lighter in weight, it has dollar for dollar the best potential for power output of any USA engine, you can get injected versions - downside, it doen't look as pretty as a Daimler Hemi. There was a Ford Sierra Estate 'knocking around' SE Essex for many years with a 'blown. Daimler Hemi - and quick it certainly was!
Evening all,
For my sins,I've just bought a couple of 250 saloons(and all of the associated rust) down here in sunny Queensland.
I stumbled on this forum whilst looking for ANY info on the hemi.
Has Mr Carpenter ever put anything in writing? I understand that he recommends a few mods,can anyone point me in the right direction? I'm sure that I can get any amount of machining done around here and I'm keen to make the lump as reliable as possible, once i get the $$$$$ body fixed up!
Even some more personal experiences( similar to what's posted above) will help.
Any takers?
Cheers,
Brian Gilmartin (complete newbie)
For my sins,I've just bought a couple of 250 saloons(and all of the associated rust) down here in sunny Queensland.
I stumbled on this forum whilst looking for ANY info on the hemi.
Has Mr Carpenter ever put anything in writing? I understand that he recommends a few mods,can anyone point me in the right direction? I'm sure that I can get any amount of machining done around here and I'm keen to make the lump as reliable as possible, once i get the $$$$$ body fixed up!
Even some more personal experiences( similar to what's posted above) will help.
Any takers?
Cheers,
Brian Gilmartin (complete newbie)
Hi, just logged on and was interested in the Daimler V8 subject, i've been a fan of these engines for many many years and as far as i remember, the designer, Edward Turner worked for Triumph motorcycles for many years and used his experience in this field when designing the V8, it is rumoured that during development, the engine was fitted with eight Amal bike carbs, it revved to 9000 rpm and produced 400 bhp. It is a very strong engine. I remember reading an article in Custom Car magazine back in the early 80's about drag racing using a Daimler V8 and the use of Triumph Bonneville pistons goes somthing like this. The Triumph came with 'standard' compression at about 8.5 to 1 or 'high' compression which was about 10.5 to 1. The gudgeon pins were the same size as the Daimler and the design of the combustion chamber was the same, why change an excellent design? The problem with using Bonneville high comp pistons is the bore size of a standard Daimler engine is slightly too big, so you have to use oversize Bonneville pistons, but the next size up is then too big for the standard Daimler bore so you end up boring out the Daimler block and using +25 or +50 Triumph Bonneville High compression pistons. There will obviously be a performance gain from the higher compression but alternative fueling and exhaust systems will bring extra power as well. As a Triumph Stag owner i could never understand why the factory didnt use the Daimler engine, seeing as it was designed by a Triumph man, this would have eliminated much development time and cost, and with a little more fettling would easily have put out as much if not more power than the stag unit.
Hope this helps a little.
Steve Hill
Hope this helps a little.
Steve Hill
tevie54 said:
Hi, just logged on and was interested in the Daimler V8 subject, i've been a fan of these engines for many many years and as far as i remember, the designer, Edward Turner worked for Triumph motorcycles for many years and used his experience in this field when designing the V8, it is rumoured that during development, the engine was fitted with eight Amal bike carbs, it revved to 9000 rpm and produced 400 bhp. It is a very strong engine. I remember reading an article in Custom Car magazine back in the early 80's about drag racing using a Daimler V8 and the use of Triumph Bonneville pistons goes somthing like this. The Triumph came with 'standard' compression at about 8.5 to 1 or 'high' compression which was about 10.5 to 1. The gudgeon pins were the same size as the Daimler and the design of the combustion chamber was the same, why change an excellent design? The problem with using Bonneville high comp pistons is the bore size of a standard Daimler engine is slightly too big, so you have to use oversize Bonneville pistons, but the next size up is then too big for the standard Daimler bore so you end up boring out the Daimler block and using +25 or +50 Triumph Bonneville High compression pistons. There will obviously be a performance gain from the higher compression but alternative fueling and exhaust systems will bring extra power as well. As a Triumph Stag owner i could never understand why the factory didnt use the Daimler engine, seeing as it was designed by a Triumph man, this would have eliminated much development time and cost, and with a little more fettling would easily have put out as much if not more power than the stag unit.
Hope this helps a little.
Steve Hill
Hope this helps a little.
Steve Hill
Thanks for that Steve,
I'm still scratching my head on this one but want to make a start after Easter when I will have more time on my hands (65 on 5th April!) and will have sold a house so have some cash to play with!
If you read the full thread, you will note all sorts of advice as to what I might do. One idea was to increase the capacity to ideally 3 litres by boring and sleeving. But a look at the drawings would seem to indicate there isnt enough meat in the block to do this - would mean breaking right into the waterways and, even if the new liners could be sealed, cooling flow would be reduced and general block strength compromised. Has anyone any experience of this type of thing? Also, what pistons could I possibly use? Have searched in vain for anything standard with a pent top and the right gudgeon pin position - or even close to modify.
As for the up-sized Bonny racing pistons, these sound a good idea if I stick to circa 2.5 litres but again, are these still available?
This whole thread started because I wanted to increase the power of my Daimler 250V8 manual by adding fuel injection for a serious road car I'm restoring (dont want dragster performance or anything too silly!). I'd like to stay true to the Daimler heritage but would like to end up with maybe 250 bhp. Have considered but rejected fitting the 4.5 Daimler V8 and now even looking at a modern Jag 3.2/4.0 litre V8. Will be chucking the original manual box for something more appropriate.
My quest goes on!
Thanks for that Steve,
I'm still scratching my head on this one but want to make a start after Easter when I will have more time on my hands (65 on 5th April!) and will have sold a house so have some cash to play with!
If you read the full thread, you will note all sorts of advice as to what I might do. One idea was to increase the capacity to ideally 3 litres by boring and sleeving. But a look at the drawings would seem to indicate there isnt enough meat in the block to do this - would mean breaking right into the waterways and, even if the new liners could be sealed, cooling flow would be reduced and general block strength compromised. Has anyone any experience of this type of thing? Also, what pistons could I possibly use? Have searched in vain for anything standard with a pent top and the right gudgeon pin position - or even close to modify.
As for the up-sized Bonny racing pistons, these sound a good idea if I stick to circa 2.5 litres but again, are these still available?
This whole thread started because I wanted to increase the power of my Daimler 250V8 manual by adding fuel injection for a serious road car I'm restoring (dont want dragster performance or anything too silly!). I'd like to stay true to the Daimler heritage but would like to end up with maybe 250 bhp. Have considered but rejected fitting the 4.5 Daimler V8 and now even looking at a modern Jag 3.2/4.0 litre V8. Will be chucking the original manual box for something more appropriate.
My quest goes on!
[/quote]
Thanks for the call John. Will be in touch soonest!
I'm still scratching my head on this one but want to make a start after Easter when I will have more time on my hands (65 on 5th April!) and will have sold a house so have some cash to play with!
If you read the full thread, you will note all sorts of advice as to what I might do. One idea was to increase the capacity to ideally 3 litres by boring and sleeving. But a look at the drawings would seem to indicate there isnt enough meat in the block to do this - would mean breaking right into the waterways and, even if the new liners could be sealed, cooling flow would be reduced and general block strength compromised. Has anyone any experience of this type of thing? Also, what pistons could I possibly use? Have searched in vain for anything standard with a pent top and the right gudgeon pin position - or even close to modify.
As for the up-sized Bonny racing pistons, these sound a good idea if I stick to circa 2.5 litres but again, are these still available?
This whole thread started because I wanted to increase the power of my Daimler 250V8 manual by adding fuel injection for a serious road car I'm restoring (dont want dragster performance or anything too silly!). I'd like to stay true to the Daimler heritage but would like to end up with maybe 250 bhp. Have considered but rejected fitting the 4.5 Daimler V8 and now even looking at a modern Jag 3.2/4.0 litre V8. Will be chucking the original manual box for something more appropriate.
My quest goes on!
[/quote]
Thanks for the call John. Will be in touch soonest!
dave de roxby said:
As for the up-sized Bonny racing pistons, these sound a good idea if I stick to circa 2.5 litres but again, are these still available?
Plenty of Triumph motorcyle specialists around the country for Bonnie pistons in any flavour.You can still get virtually anything for a Bonnie of any year.
SRM are one of the best for engines etc.,
http://www.srmclassicbikes.com/
I think 100bhp from a 2 valve road engine is a very tall order! It would be interesting - and if the design is as similar to the Triumph as people think then you could probably copy cam profiles, valve sizes and gas flowing from the bikes but then you would run into issues of driveability.
I think a modern engine would be easier, cheaper and better. Assuming you we willing to sacarafice originality. Jags, BMWs and Mercs all have smallish, lightish V8s though I understand that the electronics can be a little complex.
I think a modern engine would be easier, cheaper and better. Assuming you we willing to sacarafice originality. Jags, BMWs and Mercs all have smallish, lightish V8s though I understand that the electronics can be a little complex.
BMWChris said:
I think 100bhp from a 2 valve road engine is a very tall order! It would be interesting - and if the design is as similar to the Triumph as people think then you could probably copy cam profiles, valve sizes and gas flowing from the bikes but then you would run into issues of driveability.
I think a modern engine would be easier, cheaper and better. Assuming you we willing to sacarafice originality. Jags, BMWs and Mercs all have smallish, lightish V8s though I understand that the electronics can be a little complex.
Hi Chris,I think a modern engine would be easier, cheaper and better. Assuming you we willing to sacarafice originality. Jags, BMWs and Mercs all have smallish, lightish V8s though I understand that the electronics can be a little complex.
I'm sure I've read somewhere that the Daimler factory tried a cam based on the Bonny with good results. The challenge I've set myself is really to get the most I can sensibly extract out of the original engine including adding fuel injection of some sort. But if I do eventually go for an engine transplant, I'd want to keep it in the family so would go for the new Jag/Daimler, if it would fit, rather than a BMW etc.
Cheers,
David
aeropilot said:
BMWChris said:
I think 100bhp from a 2 valve road engine is a very tall order!
I pressume you mean 100bhp/litre from a 2 valve per cyl road engine...?Not a problem with a Lotus-Ford Twin Cam
Really? I'd say possible but not as easy as you imply. I know race versions can comfortably exceed 100bhp / litre but a tractable, smooth, tickover at a reasonable speed, normalish sevicing and tuning intervals, suitable for a big saloon, road engine?
dave de roxby said:
BMWChris said:
I think 100bhp from a 2 valve road engine is a very tall order! It would be interesting - and if the design is as similar to the Triumph as people think then you could probably copy cam profiles, valve sizes and gas flowing from the bikes but then you would run into issues of driveability.
I think a modern engine would be easier, cheaper and better. Assuming you we willing to sacarafice originality. Jags, BMWs and Mercs all have smallish, lightish V8s though I understand that the electronics can be a little complex.
Hi Chris,I think a modern engine would be easier, cheaper and better. Assuming you we willing to sacarafice originality. Jags, BMWs and Mercs all have smallish, lightish V8s though I understand that the electronics can be a little complex.
I'm sure I've read somewhere that the Daimler factory tried a cam based on the Bonny with good results. The challenge I've set myself is really to get the most I can sensibly extract out of the original engine including adding fuel injection of some sort. But if I do eventually go for an engine transplant, I'd want to keep it in the family so would go for the new Jag/Daimler, if it would fit, rather than a BMW etc.
Cheers,
David
aeropilot said:
BMWChris said:
I think 100bhp from a 2 valve road engine is a very tall order!
I pressume you mean 100bhp/litre from a 2 valve per cyl road engine...?Not a problem with a Lotus-Ford Twin Cam
Crikey, this thread's really got some good legs...Me, a great fan of Turner's 2.5ltr, and Dave, for sure you could easily go down the injection route. However, what do you want from the engine...extra power and/or extra fuel economy? If economy go for injection. If power and the fun of a modified car/engine, shoe-horn Daimler Majestic engine (if you can find one!!). I have some experience of Daimler and Jaguar engines - personally I'd rebuild the 2.5ltr but really pay attention to balancing, very detailed headwork, perfomance tune the SU's, and really beef-up the ignition system and timing. By doing this you'll be amazed at the results!! You could even weld-up existing sparkplug threads and redrill for install of surface-discharge motorcycle plugs (big efficiency power a.k.a Rob Beere Racing Services). For some good background reading on XK engines and tranferable techniques for your v8 250, read the SpeedPro Power Tune Series by Des Hamill and Dave Pollard's XK Engine. Some of the guys here have mentioned Russ Carpenter - there's not much he doesn't unerstand about Turner's engine see http://www.russcarpenterracing.co.uk. Good luck on your project - have attached pic of my old v8250...wish I'd never sold her 
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