hacker-pschorr

If Audi can design a car with a quick change rear end / transmission - anything is possible

When did you buy that cometic gasket? Year / month if you have those records.

928SS

might solve my pinging issue w/91 OCT fuel on a hot day too, if I slip in a slightly thicker gasket.... currently it's a .043", and the fact has one that's 1.5mm, so I've got a ways to go w/out exceeding fact squench limits. I did want to go as far/close to the comp limit as poss.. but I don't want to cut back on my timing too much beyond stock settings to keep throttle response quick...
and it might be time for a super MAF and shark tune WYIT....

I must admit - greg did such an awesome job w/all new fasteners, perfect resto, that I"m hesitant to touch it... on the other hand, it should be easy to work on cause everything is new/clean....

back at ya! loved your motor and your shark looked great!

dangblerb: cometic makes a custom thickness 104mm bore 928 gasket w/RMR construction... just finding a 104mm 928 headgasket is a bitch, let alone something in custom thicknesses - although I must admit I"m not impressed w/mine... I'd be open to an alternate vendor for sure, if they looked decent/had references. $230 for a headgasket that leaks is a bit disappointing, IMHO.... some guys use 968 gaskets, but they have to be bastardized...

928SS

I'll have to check... got a 2" file of recepts hidden from the wife, hehehe.... iirc, was spring/05...

Iris and Kevin

I got those Cometic gaskets too...never could get the waterfalls turned off.
Took them out and installed stock gaskets and had no more troubles. Definitely not worth the price.

PorKen

Shark Tuning should fix the pinging. For now you could try retarding the valve timing to reduce the compression a tad.

928SS

true, but it's gotta come apart 1st anyway and I'd rather not get to retarded on the timing to keep power up... but I guess I'd have to compare power consequences of changing timing a couple of degrees vs dropping compression a .1 or so... hmmmmm.. where was that power calculator....

marton

Always fancied buying one of those (I mean 2 of those...) Cometic gaskets when the inevitable happens. Surprised by the comments on these.

Anybody got good experiences?

Marton

heinrich

Hey Rob I'm sorry to read this news. But I agree, pull the head first. Look. parts are cheap.
Heinrich

dr bob

Rob--

I've seen hydro'd engines with bent rods just from starter motor torque. This is one time when you hope that you had a leak big enough for half a cylinder overnight. That's the point where the starter has the least chance of 'compressing' a rod I think. No matter, you will certainly want to peek up the skirts, so to speak, and make sure that the rods are still straight. Here's hoping!

RyanPerrella

Rob,

What crappy news! Dont you dare get rid of that car and engine though! You need to get 200K miles on the engine before you dare part with it, i am suprised isses with only 4500 miles coming from what i have been told is the west coast 928 engine guru. I would assume its your gaskets as you already suspect. I dont know much about hydro locked, not up on the principle, how why it happens but i would think the stuff you have in the lump under the hood should be tough as ...something really strong. It must be some inferior part, and as you suspect head gaskets thats probably the best place to start.

It is allot more fun taking these things apart when they are clean, thats for sure. Thats funny you said you gave Greg a basket case. That sounds like a mess especially when you didnt label what cylinder they came from of which of the 32 valves the springs and tappets went to. BAD!

Pulling the heads has got to be a bitch with the block in the car. But if you know what your doing i think it is possible, just probably very frusterating. There has got to be another supplier to make gaskets for you though, although they probably cost an arm and a leg.

Again sorry to hear about your lock up, but hopefully its something realtively minor, such as i said one inferior part. I would think there is nothing wrong in the assembly of the engine just something non porsche that let go.(although most of your internals are probably non-porsche)

928SS

always happy to peek up a skirt, and not get disappointed (or beaten) I've seen some pretty twisted stuff in boats that ingested water too... that's why I stopped messing w/it as soon as it stopped turning... it didn't get up to speed during the start cycle, so I suspect the bottom is fine, but will have to ck everything to be sure... based on how much water it drank the night before (about a quart), it's possible more than 1 cyl got pretty filled up...

hey ryan I'm certian it's nothing to do w/the builder - I supplied the cometics, rods, pistons, heads, crank, etc and when it started leaking - I made the choice to leave'em in when the leak appeared to "magically" stop... I was impatient, and thought I'd roll the dice/see if they held.... and they did for a while. but I think if one is counting on "magic", one shouldn't be too surprised if the poop hits the fan, in retrospect

I think the colder temps now (40F at night) may have pushed them over the edge as the problem seemed to be worse when the motor was cold before... short of moving to baja, MX, I suppose now I'll have to do what I should've done before... if I'm lucky enough to not have done any other damage I'll be happy - keep those candles burning!!

928SS

tim murphy has had good luck w/his boosted stuff, so far.... I know some drag racer guys that swear by them too... I think this was just a bad batch and I was too impatient to mess w/them after they seemed to settle down...

Tom. M

Adam B put a 2mm cometic gasket in the rebuilt 9:1 cr rear turbo motor recently finished. It is running fine and has about 2000 miles on it now with no coolant leakage. The car is being fitted with another rear turbo and should be on the road shortly (after sharktuning).....

Later,
Tom
89GT

P.S. Doesn't GM have a coolant additive that seems to cure the leaking gaskets?..supposedly put in the northstar caddy motors?

hacker-pschorr

Todd had issues with the first batch he tried - reason why I asked what year you purchased yours. He went as far as to add more embossing to the middle layer. The Cometic in Tim's current car is 100% stock from Cometic.

For his bigger bore engines Todd buys blanks - embosses them himself.

hacker-pschorr

Per a reliable source, GM pours their own house brand Bars Leak into every new car that rolls off the line.

I could share where this came from, but then I would have to kill you