sherry66

Hi, I have a scored block 3 litre block and hope to have it bored and honed ( I realise it is Alusil). I have also got a set of 104.5 JE pistons which are coated. Could anyone advise on the piston clearances for these pistons with an Alusil block ? Also using Total Seal rings and again any advice welcome on gaping these to suit. The car is biased towards track use.
Thanks simon

blade7

Probably best to search, personally with those pistons I'd be thinking about plated cylinders or iron liners.

Van

I found total seal rings are not compatible with aluminum blocks - they tore mine up.

My engine is sleeved now.

Tom M'Guinn

I'd find a shop with a solid record of success building 944 engines, and ask for their input on parts and machine clearances. There are too many unknowns for anyone to throw out a clearance number that would be useful to you, and the parts you've listed may not work well together. I've not heard of a coating for the JE pistons that have a solid track record of success. The ones I've seen are dry film lubricants (unlike the iron-based Mahle coatings), that reduce but don't eliminate the chance of galling in Alusil. They also come in different material with different expansion rates, and therefore different clearance needs. For what it's worth, there was a machine shop near me that did race motors using coated JE pistons in Alusil. They used a much bigger piston-wall clearance than you'd want to run on a street motor to help avoid galling (noisy when cold), but they rebuilt after each season.

sherry66

Thank you for the replys. I have just finished another build using JE pistons in a sleeved block allowing .0055" as clearance. Should sound like a tractor till it warms up!
With all the parts I had left over I thought i would put another engine together and would try and utalise these pistons I had. Originally the pistons and rings come from Lindsey racing and according to the Lindsey spec sheet are Alusil compatible. Just wanted to hear of other peoples experiences using these pistons in Alusil block.

333pg333

Let us know how that other build you mention goes. Be interested how it goes.

sherry66

Hi Patrick,
Yes, I will. At the moment the engine is fully built up sat on an engine stand at the back of the garage. Still running in the original 3ltT thats in the car at the moment and managing to scare myself with how quick that is on the public road.
Because of this I am considering put the new engine into a 931 shell (aka GTR) that is available and making a full on track car , maybe have a go in some non contact competition. I think a 3 lt 16valve turbo in the lighter shell should be fun .

blade7

Who supplied and fitted the liners in this engine ?

sherry66

Hi. I used a local engineering company, ATK Engineering, to me in Fareham , Hampshire. The sole employe/owner, Ian should have retired a while back but enjoys his work to much. His main work is building pre war Aston Martin engines for race cars and when I saw him casting and machining bearings for these engines which are no longer available, I had no doubts about him putting some liners in ! £800 supply and fit flanged liners.

blade7

Thanks for the info, I've got a 2.7 block that I'm going to use for a 3.0 conversion at some point. Do ATK heat the block and chill the liners to install them, and can he have the liners plated ?