Paul Gardner Racing Engines

[cain-it]

Hi guys
Anyone used this company for their Duratec needs? Feedback would be welcome.

I've spoke to Paul & Leon today, both very helpful & enthusiastic. Offered some good ideas & options regards my 2.5 Duratec build & seemed competitive, but yet to get a full quote. They're happy to supply a base engine, tuning parts or a fully built / dyno'ed engine... depending on budget.

One thing that I'd not heard of before, was to used the 2.5 short block mated to a 2.0/2.3 high port cylinder head. Apparently all their 2.5's are built this way and in top spec they're getting approx 300 bhp / 240 lb ft out of them, with 200 lb ft from 3000 revs. They felt this combo gives better low / mid range torque & a wider (and cheaper) range of tuning parts.

I always thought that one of the advantages of the 2.5 head was the bigger ports i.e. more flow more power. I haven't noticed a huge difference in 2.5 tuning components Vs 2.0/2.3 either....

If you have a view on the 2.5 / 2.0 hybrid, I'd be glad to hear it, as its decision time for me.
Cheers Sean

[Forest_rallying]

I have had dealings with Paul Gardener for over 30 years and his workmanship is to a very high standard.

I have bought a Duratec 2.5 donor engine off him, forged pistons and steel rods. I intend to fit the 2.0 high port ST cylinder head. Apparently the inlet ports are too big on the 2.5 head to keep the air speed fast.

At the moment all the parts are in the bottom draw awaiting me stripping the donor engine and sending it to Paul.

[Fridgeman]

only ever heard very good feedback from this very professional company.

[Lmr025]

While I was at auto sport show this year there was two 2.5 duratec engines there one boasting 325 hp and the other was 313hp both had 2.5 head on , one was from omex other for the bac mono if the ports are too big where's them figures coming from ?

[cain-it]

This is a key question for me too.
When I've spoke to Raceline (OMEX's partner) they use the 2.5 head & still have to CNC the ports / fit larger valves to achieve north of 260-270 BHP.
Thats why it was new to me to use the 2.0/2.3 high port head with the 2.5 block. I know some builders did this in the early days of 2.5 due to lack of tuning options, but now you can get dedicated ITBs suitable for the larger ports of the 2.5 head.

Maybe I should clarify. I'm not shooting for the stars regards power, but want the extra torque of the 2.5. I'm putting the Duratec in my '98 Elise, so will always have less than ideal intake / exhaust lengths compared to a Caterham or Escort say. So somewhere in the region of 250-270 BHP will be fine for me. Happy to clean-up the ports by hand, but don't want to go to a CNC or big valve head.

[katana]

Big holes make big power BUT at the expense of torque and flexibility! If the engine is going to live at peak rpm / WOT for long periods allied to a close ratio box and they work great. But its well known that if the ports in any engine are too big then infilling with epoxy and then porting that to improve port shape / flow whilst reducing the cross section will pick up torque and lose minimal power at the big end. If done carefully the gas speed can be enhanced to the point where cylinder filling is in excess of 100% ie. a degree of supercharging whilst N/A.

[cain-it]

I have a high port 2.0 head already, hand ported really to go...

So given a clean sheet, would it be better to buy a short block 2.5 (which will be refreshed with bearings / steel rods / forged pistons etc) or buy the complete 2.5 long block, retain the larger port head and uprated that ?

My car is fundamentally road use with some track days, so low / mid torque is useful, pure top-end power not so.

[katana]

Personally - for your intended use - i'd stick with what you have. Buying in a 2.5, then porting it out and then finding its not very usable / nice everyday could cost! Think carbs - 48's sound great and will flow loads but be a pig round town when 45's nearly make as much but are tractable - win win!

[Forest_rallying]

The engine that's built by Paul Gardner that gives 300bhp and 240 lb of torque is a Rally engine and not in Race spec. The cylinder head has 1mm oversize valves. The cylinder head will be ported but only around the valve throats and not right through to the inlet manifold. If large inlet ports were the answer everyone would be boring Pinto inlets to 50mm.

Raceline engines are built more for circuit racing in light weight cars so it's not always a good comparison to make. I made an inquiry with a company called AP Racing about the price of a CNC cylinder head, he quoted me for the 2.0 high port and the 2.5. His words were, we would have to sleeve the inlet ports down if you wanted to use the 2.5 cylinder head. Big is always not the best!

Paul Gardner told me how they had tried a set of 52mm throttle bodies on a 2.3 engine on the Dyno, they lost bags of mid range torque when tested back to back against 48 bodies.

[capri dave]

Big holes make big power BUT at the expense of torque and flexibility! If the engine is going to live at peak rpm / WOT for long periods allied to a close ratio box and they work great. But its well known that if the ports in any engine are too big then infilling with epoxy and then porting that to improve port shape / flow whilst reducing the cross section will pick up torque and lose minimal power at the big end. If done carefully the gas speed can be enhanced to the point where cylinder filling is in excess of 100% ie. a degree of supercharging whilst N/A.

I once heard a nice little quote years ago which explains port velocity...

imagine the speed a pea shoots out of a pea shooter using the velocity of your breath.... now trying blowing the same pea through a drain pipe

[cain-it]

The engine that's built by Paul Gardner that gives 300bhp and 240 lb of torque is a Rally engine and not in Race spec. The cylinder head has 1mm oversize valves. The cylinder head will be ported but only around the valve throats and not right through to the inlet manifold. If large inlet ports were the answer everyone would be boring Pinto inlets to 50mm.

Raceline engines are built more for circuit racing in light weight cars so it's not always a good comparison to make. I made an inquiry with a company called AP Racing about the price of a CNC cylinder head, he quoted me for the 2.0 high port and the 2.5. His words were, we would have to sleeve the inlet ports down if you wanted to use the 2.5 cylinder head. Big is always not the best!

Paul Gardner told me how they had tried a set of 52mm throttle bodies on a 2.3 engine on the Dyno, they lost bags of mid range torque when tested back to back against 48 bodies.

Could you explain a bit more regards Rally spec Vs Circuit Racing spec?
Would Rally have more torque across the rev range (do to ever changing conditions) whereas the Circuit spec, for a light weight car, be tuned for more top-end BHP, with less concern over torque, due to the layout being known, so you can always be in the right gear towards peak revs ?

If so, sounds like rally spec would be better for my road based needs....

[alladdin]

Correct


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[Forest_rallying]

For a fast road engine you certainly don't want it built to race specification. The Rally spec 2.5 would be much better for your needs, 200 lb ft torque at 3000 rpm is a massive amount of torque for a NA engine.

The best thing to do is speak to Paul and tell him what you require the engine for for, he then can tailor it to your needs. He'll explain about the different cylinder heads and compressions between the two.

Are you intending to fit a dry sump system? I know all the Gardner engines are built with a dry sump, he doesn't like wet sump engines for competition.

I wish I could be more of a help regarding your engine but mine has yet to be built, I am still gathering all the parts required for the project.

[cain-it]

For a fast road engine you certainly don't want it built to race specification. The Rally spec 2.5 would be much better for your needs, 200 lb ft torque at 3000 rpm is a massive amount of torque for a NA engine.

The best thing to do is speak to Paul and tell him what you require the engine for for, he then can tailor it to your needs. He'll explain about the different cylinder heads and compressions between the two.

Are you intending to fit a dry sump system? I know all the Gardner engines are built with a dry sump, he doesn't like wet sump engines for competition.

I wish I could be more of a help regarding your engine but mine has yet to be built, I am still gathering all the parts required for the project.

You've very helpful. Thank you. Yes, I will call Paul / Leon again, but would rather do it with researched questions, I guess they get overloaded otherwise.

I'm not building a race car, so intend using the Raceline baffled sump, which Paul mentioned he uses too for some applications.

I note on their FB page they had a 'Duratec Road Rally' engine (2.0 or 2.5) with a Cosworth inlet mani & single T/B... I'll ask what power that makes & if suitable for my needs... like I say, space is very tight in the Elise engine bay, as ITBs & long air horns will be tricky to pack-in