Liners and pistons

[Mac944]

Hi All,

Happy New Year!

I'm in the process of rebuilding an S2 engine for racing in just a few months time. The original plan was to have the block re-nikasiled (due to wear to the bores) but this is proving frustrating due to delays and setbacks with the firm offering the service, however as a plan B I thought sleeving the block and running performance pistons might be a good alternative.

Can anyone recommend any particular brand of steel liners and pistons as a good combination?

Can the liners be installed by any engine machine shop or would it need to go to a specialist?

Thanks in advance!

 

[944 man]

The high silicon content of the blocks makes machining difficult and theres only one engineering firm that Id use. They changed their name and now Im struggling to remember either, but Jon Mitchell will be able to tell you and offer useful advice too.

 

[Ex Skyline]

"Capricorn Engineering". Used to be called "Perfect Bore" Simon. []

 

[Neil Haughey]

I am sure that is the outfit he was thinking of, they do some very swanky stuff if one has the money.

 

[Neil Haughey]

OP whilst on the subject EMC have been rebuilding NA 944 and 968 race engines for many years with steel liners and race pistons.

 

[944 man]

Spot on re Capricorn. I had intended to mention EMC: as Neil says, theyve been doing this for years and Id talk to them, at the very least.

 

[Mac944]

Hi guys, thanks for your replies.

I was dealing with Capricorn who I was going to get the block re-nikasiled with, unfortunately due to a contract they have with a German firm, any German engines now have to go via them. Capricorn still do the work but the paperwork and money is dealt with by some German company. Unfortunately I haven't made any progress with this and have been chasing for the past four weeks. I've been told there is a 6 week wait even when the process has been agreed and the block delivered. Racing season starts in April which means Capricorn is no longer a viable option which is really disappointing.

I called Capricorn again today and am awaiting a call back regarding steel liners. I think they can supply without any problems but if I have them fitted it might have to go via the German company :-(

I will contact EMC. From a previous conversation I had with them I believe I can run JE pistons and steel liners although I'm unsure as to whether there is a particular type/brand of liners I would need to run and whether there is likely to be any cooling issues etc. Or whether I could run the original conrods or whether they would need to be replaced as well.

 

[944 man]

What sort of revs are you aiming for (or maybe, aiming to survive)?

 

[George Elliott]

I know Capricorn are good, but sounds complicated to deal with

Darton Sleeves are an option (usually USA) I have heard of but I do not take that as a recommendation, again Jon at JMG is a good place to enquire.

Good luck
George
944t

 

[MarkK]

If you are going to race it I would speak to Kevin or Alex at EMC,like has been said they do this regularly to engines that get used in the way you are looking to.Capricorn is meant to be superb but£££££.

 

[Mac944]

Thanks again for your replies.

944 man - revs will be around 6,800-7,000 probably.

George Elliot - I have looked at Darton Sleeves which look amazing but seem very expensive compared to standard steel liners I'm sure there's a good reason but they are a bit over my budget at the moment.

MarkK - I've been in touch with Kevin at EMC and steel liners are fine with the original pistons and rods. Liners don't appear to be any special type.

EMC can offer Alusil liners but Capricorn plate and supply with EMC fitting them but Kevin did mention Capricorn do take a while to turn things around.

The price I was originally quoted by Capricorn to plate the block was £750+VAT which I thought was pretty reasonable (and comparable to steel lining), although that price is likely to change now there is a middle man.

--

Steel liners is the way to go I think and I may upgrade the pistons as well given the additional revs, reprofiled cam and ITBs.

 

[Neil Haughey]

Definitely look into the other components if you need and want the revs. The 944 engine is not really made for it, the 968 bottom end a bit better in this regard, again EMC have a lot of experience here. I had to retire from a race 3 years back after breaking the valve springs on a couple of valves, this happened right up at the rev limiter (6800), the car ran like a bag-o-bolts and eventually conked out on the inside of luffield. Top end rebuild fixed it all up but it was something like £1600+. Talking to Kevin it always seems to be at high rpm when 944 engines fail in race cars, supposedly the crank, rods and pistons whilst being incredibly strong don't like high rpm.

 

[Mac944]

ORIGINAL: Neil Haughey

Definitely look into the other components if you need and want the revs. The 944 engine is not really made for it, the 968 bottom end a bit better in this regard, again EMC have a lot of experience here. I had to retire from a race 3 years back after breaking the valve springs on a couple of valves, this happened right up at the rev limiter (6800), the car ran like a bag-o-bolts and eventually conked out on the inside of luffield. Top end rebuild fixed it all up but it was something like £1600+. Talking to Kevin it always seems to be at high rpm when 944 engines fail in race cars, supposedly the crank, rods and pistons whilst being incredibly strong don't like high rpm.

Thanks for your reply Neil.

I was under the impression the S2 engine was fairly conservative at its standard 6400 rpm and that squeezing out another 400 or 500 rpm with a chip or aftermarket ECU was reasonably safe particularly on a fresh build?

The cams are being sent to Piper next week. I have discussed with them profiling without the need for modifications to the head. I've looked at numerous profiles from suppliers in the states and at around 6800 is indeed where valve springs need upgrading and beyond that lifters and valves too but Piper seem confident they can create a profile (based on the US profiles I've seen) that keeps it within the limits of the standard head components, therefore the final profile may be a little less than 6800.

The head is currently being refreshed but have been told the condition is absolutely fine, the exhaust valve guides were replaced as a precautionary measure.

Did you make any mods to your engine to run at 6800?
What was the engines lifespan before it let go?

 

[Ex Skyline]

jonmilledgeengineering.com. Try these guys. I'm going to. Jon' Mitchell rates them highly. Iv'e decided to swerve Capricorn now that they have taken on a factoring partner. Too much fcuking about plus, they want mega bucks! Give Jon Milledge a shout.

 

[944 man]

Far from easy to deal with.

 

[Neil Haughey]

Mac the limiter is at 6750 - 6800 something like that its well into the red. I tend to rev the nuts of mine as it has a weak mid range only just scraping over 200 lb/ft at something like 4750 but has a nice 220+ Bhp around 6300 rpm or so. I think its because my head was skimmed it tends to retard the timing. Its something I am looking to improve for the coming season, as my peak torque is coming in way way to high for one of these engines, it means the car tends to bog coming out of corners but conversely sings really nicely on the straights.

My bottom end now has 170+ k miles on it, the engine was completely original when I started racing it so its likely some of the valve springs had age hardened. That is testament I guess to how unbelievably tough these engines are.

 

[Mac944]

ORIGINAL: Ex Skyline

jonmilledgeengineering.com. Try these guys. I'm going to. Jon' Mitchell rates them highly. Iv'e decided to swerve Capricorn now that they have taken on a factoring partner. Too much fcuking about plus, they want mega bucks! Give Jon Milledge a shout.

JME are based in the states so that's a no go unfortunately.

 

[Mac944]

ORIGINAL: Neil Haughey

Mac the limiter is at 6750 - 6800 something like that its well into the red. I tend to rev the nuts of mine as it has a weak mid range only just scraping over 200 lb/ft at something like 4750 but has a nice 220+ Bhp around 6300 rpm or so. I think its because my head was skimmed it tends to retard the timing. Its something I am looking to improve for the coming season, as my peak torque is coming in way way to high for one of these engines, it means the car tends to bog coming out of corners but conversely sings really nicely on the straights.

My bottom end now has 170+ k miles on it, the engine was completely original when I started racing it so its likely some of the valve springs had age hardened. That is testament I guess to how unbelievably tough these engines are.

The engine I have has done over 150k miles but after a full rebuild including full bearing sets, pistons rings, gaskets, seals etc and now a steel lined block I was hoping that would be sufficient to cope with the additional stresses of the modifications. Maybe I should just bite the bullet and go with turbo valve springs at least.

If the head has been skimmed that much did the change in compression contribute to the head letting go?

Did you do anything to the cams?

Were you running a chip or aftermarket ECU?

 

[Neil Haughey]

No skim was part of the head rebuild, but it actually restored about 10 lb/ft as the old head was probably leaking through the valves. Never came across race cams for this engine, if you manage to get some it will be interesting to see what the results are like. I have always run a chip, first a Promax one which I still have in my 'spare' ECU and later a smoother custom program that was originally done for another racer by some outfit up in Sunderland ISTR. I can't run aftermarket ECU as the car was built to comply with the club's championship and also now this new Dunlop Porsche Cup. Note of course that the goal of the custom program was to maximise power under the curve whilst keeping under regs required 221 Bhp. I am sure I am way way down on the torque produced by some other cars out there.

 

[Mac944]

With a stock engine and chip it sounds like you're running conservatively, almost stock. I'm a bit surprised the head let go and now slightly concerned for my build, eek.