Porsche Enthusiasts Club Forum

Perhaps I confused matters by mentioning uprating 928 S4 brakes on a late 944 turbo. I think initially they were talking about supplying new calipers and discs, rather than just adapters. I had a look for A8 D2 calipers, but it seemed there are different versions. Perhaps related to engine size and 2/4wd options?

My mistake , it’s S8 d2 4.2L . They pop up every so often .
Don’t think they have had many dealings with 35 year old porsches , most of it is m3’s or vw’s.

Put in some EV14 Bosch 980cc injectors with adapters yesterday and really impressed . No difference in driveability down low, if not even smoother but gives a bit of extra headroom heading to the rolling road . Best bit is they are less than £40 each .

Which engine is this for?

3.28L 16v turbo . Got most of mapping sorted up to about 4500 rpm but starts to get a bit difficult on the road after that as seem to be travelling rather quickly hence the rolling road . A bit of auto tune and some manual adjustment .

Is this built with Baz's parts, or is that engine going into something else?

And get it dirty ? Got to be joking Paul , build them and wrap them up in cotton wool !

The 968 black cam cover engine is the one with Baz's bits .
I am aiming to swap engines over just after xmas all being well . Main reasons are that the nicosil liners allow a much tighter tolerance on the piston wall clearance and even though it doesn't last long , couple of minutes, there is some piston slap on start up , there is an oil leak I believe is coming from the sump gasket from when I removed the sump with engine in the car and obviously did not reseal it well enough while lying on my back (never doing that again ,ever!) and there is a slight judder changing down from third to second which I think could be a hotspot on the flywheel . Even though it was refaced , I do not think they took enough off to get to the bottom of any existing hotspots on the flywheel. And it's different.
I have attached a few photos, the first shows the nicosil wet liners with the 9/16 head studs the block and head were machined for . I am using a cometic head gasket which is shown against the water ways to the head . As can be seen the wet liners do cut down the flow going to the head which I have also seen on other (darton) wet liners which is one of the reasons to use an electric water pump as you can increase the water flow to some extent.
The crossover has been cut and increased in width to help with any back pressure and coated with creacote, its supposed to lower tempatures 10-15% and looks good for a reasonable price . Originally was going to use the Hy35 as attached at the moment but having seen how well matched the HX35 is in my other car , I have had the hy35 machined and fitted with the hx wheels comp 56/82 , turbine 60/70 with a new forward facing compressor housing. I am using the turbo oil filter housing as the enables an adapters to be used for the oil cooler hoses . I have also used the left hand balance shaft housing to run a hose for crankcase venting as the intake manifold is to tight to get a hose on top of the aos .
Just got the valve timing from piper cams so hope to have it all timed and sealed up by the weekend , then cocooned till xmas

more pics

I thought the tight piston clearances were a possible due to the original Porsche pistons having a similar expansion rate to the Alusil bores. Don't the forged Wossners have a larger expansion rate, and require a larger cold clearance?

Hi Paul , they are aluminium liners with a nicosil coating which I would imagine has similar expansion rates as the pistons .
They are the same style of liners as Baz uses in the 996 engines . When I went up to Hartech , I was bowled over by the sheer quantity of engines they are rebuilding not just for this country but worldwide due to their excellent reputation . He's also a true gentlemen , spending time showing me around and answering my ignorant questions.
Unfortunately they are no longer making these liners for the 944 .

Hi Simon, I seem to recall the original Porsche pistons run something like 0.001" clearance. Though it seems to be a mystery whether they're of forged or cast construction. Cast pistons expand less than forged AFAIK, though forged are more resistant to cracking during minor to detonation. I think Wossner specify 0.003-4" clearance for their forged turbo pistons. I don't know whether that's for iron and/or alloy liners. Though there are stories of Alusil rebuilds going badly wrong on rennlist, when people tried running factory clearances, with aftermarket forged pistons. Did you use an O ring, or some kind of adhesive/sealer between the bottom of the liner and the block?

On the engines with steel sleeves and forged pistons I am using , I allowed .005” wall clearance to be safe .
I believe factory is .008 to .032mm clearance and these were not far of the top end .
The block already had the liners installed which had been prefnished as is the spare I have .

Sorry to prattle on about this engine , but its been quite quiet on the forum recently , I forgot to mention the wills rings fitted to the head ( all done by Barry before I bought it ).
The head has had a fair amount of welding to enable the grooves for these rings to be fitted . These are gas filled rather than solid rings . I realise two school of thoughts of rings and cometic head gasket , but fairly confident it will work especially with the 9/32 head studs meaning we had to wind it up to 104 ft lb to get a bit of stretch on the bolts. This was the minimum amount of torque to get these bolts to stretch , ideally it should have been just under 120 ft lb but it all gets rather tense at these figures in case you start pulling the threads from the block.
The exhaust valves have also been replaced for some sodium filled jobies to deal with the heat .

All interesting stuff. What piston clearance is being used with the alloy liners?