Head Off - AGAIN

[Mark Halligan]

Unlike the two pistons that clearly showed something dramatic had happened with the colour differences on the ceramic coating, the combustion chambers are all the same with no signs of anything nasty happening.

[audiman]

Doug, i would be interested to see how your rings have bedded in. Cant beleive there are no honing marks?? I hope it doesnt perform like last time too, as that turbo is making your/my car almost undriveable. I was gonna take it off today, but couldnt be arsed. Will do it soon tho. What you gonna do about headgasket then?? Just fit both gaskets or remove the rivets and make a custom multi-layer one?? Thats what I would be tempted to do. I must do that oneday when i have some more cash.

[Doug_RS2]

Tom - the honing marks are still there - they are not as visible asd the first timr I took the head off so I think the drive it hard to bed in method must work really well.

No hurry for getting that turbo off - hopefully get the new turbo built next week though.

I have made a thicker headgasket using the 2 internal layers of a second headgasket. The CR will be low now! I reckon 8.0 (maybe lower):1 - who cares what off boost is like! It is on the car now anyway. Just need to get all the new bits plumbed in adn that PS pump relocated.

[Pisobiker]

Mark, that's great news dude!
This means your problem only was the pistons sharp edges and the knock Mihnea heard wouldn't have done any damage at all if the pistons didn't have that problem.
This is very important, 'cause if for any reason it will happen you hear some knock again, you know that if it isn't so severe and you lift off the throttle whitin few seconds, your engine will be totally fine.



Marco

[Audi_CQ]

Could the oil jets on cyl. 1 and 5 be blocked and cause higher temp on those pistons?

Cheers,
Roger

[Beetie]

I hope it doesn't perform like before - it will perform a lot better this time - lots more advance (lower CR) and more lower down torque (changing turbo coldside).

In the way of reliablity i meant!

[Mark Halligan]

Could the oil jets on cyl. 1 and 5 be blocked and cause higher temp on those pistons?

Cheers,
Roger

Roger,

I did wonder about that, but didn't check them yet, I would have thought that I would see evidence on the undersides of the pistons, and possibly top of the rods, of overheating. But there was none they looked like new all heat damage on the top.
I can check them easily enough though, I am getting good at stripping the engine .

Doug, not meaning to hijack your thread either, will keep quite now

[audiman]

Thats it, im taking my head off now and gonna fit a custom headgakset, also do the ARP stud thing too

Should have done all this when i rebuilt it, but didnt have the money then

[Doug_RS2]

Thats it, im taking my head off now and gonna fit a custom headgakset, also do the ARP stud thing too

try and keep up!

I am hoping th elow CR means loads of advance.

[audiman]

Keep up. Pah. I wont be content with just 'keeping up'. It needs to put me in the back of my seat and hold me there.

[auditude]

Stroker report

P.S. If you guys have a little bit of patience I'll soon edit a detailed report of the stroker building.

I'm interested to read your report. I now actually have in my possession an AAF 2.5l block. I plan to change the pistons and conrods, but use the block and crank.

So far I'm aware of some of the issues involved, at least with my block. Looking at the block and a 10vt MC headgasket, I can see that one of the oil return holes needs to be blocked by welding or plugging, and another part of the block needs to have some material added because a passage in the gasket hangs over the edge of the deck. Another important thing that's missing is the hole for the timing pin sensor. All this in addition to having to add the oil squirters. And the 20v head needs larger headbolt holes put in. But at least one of the hard parts is done, I actually have the block and crank!

Cheers,

Ken