I don't know how that gouge happened, but the corrosion is a function of the coolant and aluminum head getting jiggy-with-it.

Thats repairable Andrew - I had much worse from corrosion and a scratch that was caused by Fed ex. Asswipes.

I have PMed you with more info.

 

That is easily repairable. Just had worse GTS heads done. They welded material to all low spots and then milled them straight. Result looks like new and head thickness should be within spec.

 

like Vilhuer said. Just make sure you order the new thicker head gasket. I think that you need to make sure that you do both sides so they are equal IIRC. The corrosion is a factor of the incorrect coolant type/ concentration. May be the reason for the head gasket failure as well.

 

I think it's either-or on the head gaskets matching for both sides. Either both heads get machined/repaired to the same deck height, or the one gets fixed, is lower, and needs the thicker gasket to get it back to the proper compression level, while the other head only needs the stock-height gasket because that head wasn't machined as much. Make sense?

I think the head gasket failed because of predetonation caused by running super-heated compressed air through a previously non-SC'd engine. With Andrew's exhaust, he'd never hear the pre-det (sounds like really loud rice krispies in your engine).

 

Thanks guys. I've received a few PM's onthis as well confirming the concensus here that they are indeed repairable. I havent' looked at the other head yet, but obviously I will... and I will also have both heads decked/shaved to ensure equality between both sides.

When I bought the car 2 (or was it 3?) years ago, it had green antifreeze which I immediately changed. I don't know how long it had been in there or if it was the universal green stuff - but probably not based on these pics.

For a few hours last night I was thinking $$$$$, but now I'm down to $$$. Whew!

 

Andrew, did I read in one of your posts that you had a pre-det. problem for quite a while before alleviating it?

 

Yep... but I don't think that's what caused this. I believe this is more of a corrosion issue with the GREEN antifreeze that was in the car when I bought it, but of course I cannot be 100% sure. The detonation certainly didn't help things, that's for sure, and the boost... well that probably helped to clear the passage for the coolant to enter the combustion chamber.

 

This is from a spare fire damaged motor i bought 4 years ago. Had appx 37,000 miles on it. Doesnt take long for corrosion to set in. My plan is most likely to have it filled and shaved down..only becasue its into the fire ring area.. Tha gsaket shot is of the corresponding mating area.
So far my motor is holding up fine...Ive had no need to build this spare up yet. Although i probably should slowly start accumulating gaskets at stuff.

 

Andrew..............do some research on 'magnaflux".

IIRC they shoot the metal with dye and perform some sort of x-ray to ensure the damage isn't beyond what you can see with the naked eye.

All well you build up the missing material, shave 100% flat and rebuild.

 

Well, I got a good look at the passeger head tonight. No drama. A little corrosion, but no giant gaping pits or gouges.

Passenger head:

 

Hey Andrew,
Sorry about your engine, that really bites, I know. Your head doesn't look too good with the corrosion on the fire ring , its hard to tell from the picture, but it could be too deep for machining to take care of (which I hope not). As Tony points out in his pictures, he ran into the same thing. Page 15-112J, (WSM Vol 1 - Engine), gives you the resurfacing dimensions on the heads. If machining can smooth away the corrosion spots on the fire ring area, then you should be good. It states the wear limit head dimension is 146.6mm (from 147mm), while using the "thicker" 1.4mm head gasket. The 'stock' head gasket is 1.1mm.

I'm sure the head can be machined further, how much? I don't know. When I got my heads back from the machine shop, they measured 146.52 mm, and I'm using the 1.4mm gaskets. Everything runs fine and I had my block machined as well.

Also, carefully inspect both heads around the bolt holes, where the main head bolts go, this is where the S4 heads tend to crack (which is where mine did) and leak coolant into the oil. Although its unlikely since you have the reinforced GT design.

Not to open up another can of worms here, but how do your piston rings look? i.e., did any of them break? Since you have everything out, its not that much more to disassemble the block and know exactly what you have inside (main bearings, rod bearings, piston pin bushings, and rings). I did all mine in the garage on the Koenig motor, its not rocket science.

But whatever route you take, just follow the WSM's and take your time with it!

 

Bill-

Thanks for chiming in. The information on the 1.4 HG is very nice.

The more I look at it, the more I'm beginning to realize that I should probably go ahead and pull the pistons, crack the block, pull the crank, replace the bearings, etc. Damn slippery slope.

 

Andrew, it's wintertime in Michigan now. What else are you going to do?? Take your time, do it right, see you at SITM.

 

Damn Skippy you have to do all that. Now you can surface the block and go with the cometic.

 

Don't forget Andrew that you do not want to buy the cast 944/928 piston rings. You will want to get the 951 rings which have Chromoly rings, and a different oil ring. Much more robust rings for boost.