Turbo Engine Rebuild

[scam75]

Well AMAC got a hold of Wossner today, nothing they can do for us although they apologised for their mistake with the incorrect pistons. 2 options now, get JE to make a set, AMAC have sent a sample across to them today, or I found a set of old stock NLA Mahle Power Pak pistons with a US vendor. Would need to ascertain coatings etc and most probably they are designed for Alusil. So bespoke from JE looks like the plan, no doubt at least a month before they are made! My mechanic friend is delighted my Porsche ornament is taking up space in his garage for eternity, not!!

Have also had the head tapped for a steam vent kit and Eldavo has supplied me with all the bits and bobs to purchase to make up the kit. Change out of £40 for the lot. Cheers again Dave!

Stuart

 

[blade7]

Got some original Porsche 2.7 pistons that look in good shape, came out of unmarked bores. Take your liners out to 104mm for a capacity increase. Cheap too []. Not saying they're the same but someone on Rennlist had a big problem with Mahle Motorsport pistons for alusil. It's a bit of a minefield.

 

[scam75]

Thanks Blade! Yes it is a minefield. Anyway we now have a plan. Cambridge Motorsport are making me a bespoke set of uncoated JE forged pistons, with offset pins to reduce slap, suitable for an aluminium block with dry iron liners. They have one of my original pistons to work from. They will be ready on or before 1st Feb and cost is £730 which is £90 more than the Wossners were. However this now sounds absolutely the way to go and seems a good price to safely get exactly what we need for my application. All going well the engine should be returned complete mid Feb. So possibly by March she may be back on the road.

Just need to tell my mate now that the Porsche ornament in the corner will be an ornament for at least another 2 months!!

Stuart

 

[blade7]

Did you try EMC, they've built and raced with JE's and should know their stuff. And may have some pistons in stock. AFAIK JE 944 pistons are a modified yank V8 blank, so technically bespoke. I'm not sure offsetting the pins stops all the slap, Cosworth did that when they updated the 88 Saph Cosworth pistons, so it's nothing new. The slap is supposedly caused by the extra cold clearance forged pistons need. What alloy are the pistons Cambridge Motorsport are supplying made from?

 

[scam75]

Didn't try EMC, yeah the offsetting will reduce but not stop slap. I've no idea what alloy they are using. All I know is the pistons are being made size wise to perfectly suit the properties of the ali block with iron liners and that both Cambridge and my engineer seem pretty switched on and have had a decent chat about what's required and have a plan. I place my trust in them!

Stuart

 

[blade7]

Buchannen motors in Oz have good experience building 944 turbo road and race engines. They kindly sent me a piston drawing a few years ago, unfortunately it was on an old laptop that crashed though.

 

[scam75]

Cheers Blade!

Well there probably won't be much in the way of excitement now till the pistons are ready. Today the T-Piece for my steam vent kit arrived, first of 5 deliveries that will complete the kit and match up to the hole that's been tapped in the head. Quite a clever idea whoever came up with that and the shiny AN06 braided hose will look lovely in my engine bay! Fuel lines will be next for the braided treatment and probably do this when bolting it all back together.

As an aside on the topic of fuel hoses, why on earth do the 3 bar FPR's not come with a threaded connector like the standard turbo one? Always thought it was sacrilege hacking off the threaded end of the hose to fit a 3 bar FPR with a jubilee clip!

Stuart

 

[blade7]

Are JE machining them for you?

 

[Eldavo]

Stuart - there’s a reason I sent you the link to the nylon braided hose rather than the metal braided hose - maybe just my paranoia but I didn’t like the idea of the metal braided hose running alongside electrical cables, etc. and the potential (albeit small) of it rubbing and causing damage over time.

 

[scam75]

Are JE machining them for you?

Yeah. They have one of my pistons for reference. They should be ready 1st Feb.

 

[scam75]

Stuart - there’s a reason I sent you the link to the nylon braided hose rather than the metal braided hose - maybe just my paranoia but I didn’t like the idea of the metal braided hose running alongside electrical cables, etc. and the potential (albeit small) of it rubbing and causing damage over time.

Hi Dave

I ordered from the link you sent me! Nylon braided hose arrived yesterday. All the bits have arrived now except the 2 x 90 degree elbows.

Cheers

Stuart

 

[blade7]

Are JE machining them for you?

Yeah. They have one of my pistons for reference. They should be ready 1st Feb.

I hope this works out well, but you do seem to be going around the houses to source the pistons. Lindsey Racing must have ordered plenty of sets from JE. And closer to home, EMC too.

 

[scam75]

Are JE machining them for you?

Yeah. They have one of my pistons for reference. They should be ready 1st Feb.

I hope this works out well, but you do seem to be going around the houses to source the pistons. Lindsey Racing must have ordered plenty of sets from JE. And closer to home, EMC too.

I hope so too! AMAC have done a few 944 engines and seem very knowledgeable and they have had a good chat with the piston supplier to ensure we get what we need. I put my trust in them. Had we went to them first instead of Wossner the car would be back on the road. Wossner are the reason for going round the houses as they got it wrong twice, then went missing in action, then faffed about and eventually apologised for getting it wrong and telling us they could not supply a piston set for my application. I checked out other options in this time, Mahle were a non-starter JE seemed the best way to go. Not a lot else I could have done. For a company of Wossner's stature they were nothing short of a total joke and have put months onto this build!

But yeah, I do hope it works out well!

Stuart

 

[blade7]

I was mucked around a few times, when I wanted to buy 3.0 turbo Alusil pistons. 3 or 4 years ago, Wossner told their US dealers not to supply custom pistons to Europe, in case it upset their European dealers. Another time the Yanks wouldn't ship Wossners direct to me from Germany, insisting they were shipped to the US first, and then back to me here. Incurring big import duties. And another time when I was going to the US, they wouldn't accept my credit card, because the address was different from my Mums address where I was staying. When the Alusil coating started falling off pistons a year or 2 ago, I gave up on aftermarket Alusil pistons.

 

[scam75]

Similar story then! I don't mind the extra time it's taken as the end result is far more important. Probably dodged a bullet with regards to Wossner pistons anyway. Heard a story of another engine go pop after 6 miles on new Wossners to go with the various other horror stories about their coatings. I am getting uncoated ones from JE.

Stuart

 

[blade7]

Nikasil coated cylinders are probably the best option. No pistons issues, but you may need an introduction to Capricorn to go that route.

 

[scam75]

Nikasil coated cylinders are probably the best option. No pistons issues, but you may need an introduction to Capricorn to go that route.

Past that stage now, don't fancy having body parts removed in this climate to pay Capricorn's bill!!

The whole point of this was to build a good, reliable, engine at a good cost, certainly not a no expense spared affair. The car gets used daily and is rarely thrashed and never tracked. Should have change out of £6k all in at current estimate which includes a new clutch with a cup disc, all the parts and engineering work, and the removal and refitting of the engine at my mechanics place, and of course a steam vent kit!

Hopefully a fully rebuilt bottom end with liners and new forged pistons, new oil pump, all new bearings, seals and gaskets, all parts checked, cleaned, polished, replaced as necessary, and a head with new guides, complete with correct width cometic HG, should be more than good enough for years to come.........

Stuart

 

[blade7]

I have everything including the pistons, to build a 3.0. But now I'm just saving it all in case I ever need it, rather than a definite build plan.

 

[blade7]

Nikasil coated cylinders are probably the best option. No pistons issues, but you may need an introduction to Capricorn to go that route.

Past that stage now, don't fancy having body parts removed in this climate to pay Capricorn's bill!!

The whole point of this was to build a good, reliable, engine at a good cost, certainly not a no expense spared affair. The car gets us

On Capricorns website, it looks like they can supply steel or ali nikasil plated dry liners, for around 2 grand.

 

[scam75]

Cheers. It was £220 for my cast iron liners from Westwood. Still a huge difference!