Mike Simard

In my case the gaskets need to have a bigger bore than is available with stock gaskets, stock ones, even 968's aren't an option, well not in their stock configuration anyway. I also have had good experience with Cometic gaskets on aluminum block engines with cylinder liners. I don't understand why some have never had them work while others have had good luck. I personally won't rule out Cometics until I get more details about the variables of a failed installation from a source I can trust.

The studs in my case are to solve block strength concerns, I'm concerned with the main studs, nobody has ever addressed block strength seriously so I'm "solving" that. The head studs in my case just follow because I'm already making studs and will be testing their properties and I'm able to control the material, heat treat and hold the thread clearance closer to the actual block threads.
I agree that the stock gaskets and head studs would be good if they could be used but I believe that big horsepower engines aren't going to stay together reliably without the bottom end modifications I'm doing and the main studs are the most important single modification IMHO.

atb

I also went with the Cometics also out of neccesity. The RMT motor used Chevy slugs, so the bores were 101.6mm. The fire rings on the S4 gasket were too small, with the interior circumference sitting over the opening of the cylinder tower. The 968's were too big, exposing a part of the cylinder top.


Downtown wrote:

This is what I was referring to when I posted this in post #4:


It was as if the black bonding material actually permeated the metal. I used a little scotch brite on one part of the head and you could actually see the aluminum "underneath" start to polish yet it was still "covered" with the black stuff.

BC

At least you're consistent Marc. Always trying to make sure you post something that makes others think this is rocket science, and that they need to be a metalurgist JUST to do some engine work.

Oh, and to be sure, as I mentioned earlier, there is no new ground being broken. Are you really trying to say that ARP head studs and an MLS gasket design is new ground? Amazing.

BC

Thought so.

hacker-pschorr

I forgot, the Cometic gaskets in Tim's 88 @ 17psi is the "original" design, not the improved one Todd was working on.

GregBBRD

Also well said.

Look Brendan. Having a discussion with you is about the same as "drop kicking a wounded humminbird." There isn't much challenge or point. It seems that it one either agrees with you or you get offended and personally attack the individual....and it's not just me! Looking back at your stuff you pretty much lash out at everyone. You don't seem to attack the thoughts, you attack the person.....which seems to be a bit childish and not very intelligent....to me. I'm not here to fight with anyone. If you don't like what I think or do, fine, I can live with that. If you think I'm an idiot, fine, I can live with that. If you think I should not be on this Forum, put up a post about who likes what I say and who thinks I'm an idiot and I'll just bow out if the majority dislikes me....I really don't need this, so it is no skin off my back....I'm here to help people with my experiences, not fight with the "unarmed".

I have no idea who you are or what you do...I'm going to assume that you aren't a engineer or a professional mechanic. I'm also going to assume that you work for someone and are not self-employed. I also assume that you keep poking yourself in the hand with the wrong end of the screwdriver.

I personally think that the posts by Danglerb were better than most of your stuff. At least when he asked and posted a stupid thought, he was able to laugh at himself and poke fun at the question. At least he listened to what others said. At least he had a sense of humor. Discussing things with you is like going out back and talking to my fence. Therefore, I'm going to put you officially on "Ignore". I hope others that feel the way I do about your crap do the same. Seems like the fastest way to solve the problem! You can have discussions all by yourself and then no one will have a different view and you can put your stuff together knowing that you have the best ideas!

Give it up and get off my ***!

gb

BC

No Need Hero. You win. You can hold court here with your Ego and groupies all you wish. Have fun with all the posts about where to drink beer and what the best wax is. Yours and Marc's brand of advice will make damn sure thats the only exploration that happens with this model.

Btw, the screwdriver joke is old, you need new material. By about 25 years or so, same as where the 928 is going to stay in development if you and yours continue to run out the open-source type people like me. The fact that you don't probably know what I mean is proof in itself.

Have fun everyone.

928SS

damn, I go to work and miss all the fun.

fwiw, I called cometic about my leaking issue and they said, "you need an RA50 finish on the block and heads & we do NOT recommend the use of any sealers". no secret there, it's also on their website in black & white: Install Dry.

we followed those instructions and they leaked on my car. 1st on the outside like a waterfall, but after a dozen or so heat cycles they seemed to dry up. then they leaked internally and forced me to have another rebuild after my motor hydro locked on 2 cyls. clearly, others have put stuff on in spite of the OEM recommendations and they have worked. but IMO, if I can't install a product to OEM specs to make it work, then I don't want to use it cause if it fails the 1st thing they will do is claim it wasn't installed properly.

all I can say is,"F that shyt". so I don't care if some folks make them seal by having hookers sleep w/them - I went w/the old 968 doc brown specials and they haven't leaked a drop since. (no issues w/the hookers either, hahaha)

after this and the MANY bad experiences of other 928 owners/builders, I'll never touch another cometic - although I've had great luck w/other ML gaskets on other motors (plane, boats, built mopar motorhome, race bikes, etc)

there are also a LOT of other gasket makers that will make any custom gasket you want. w/"the google" I'm sure we can solve any problem w/an alternative.

BC

I was not going to come back to this thread, for concern of what kind of trouble Mr. Brown may get himself into with more personal insults, from the mere inquiry for some out-side-the box thinking, but I see your info and raise you this:

Are you sure it was 50RA or smoother? The scale goes down, and 50RA is a "minimum" smoothness, as in they may actually want like 30, but are afraid of scaring away customers with this requirement, which most engine shops would never do.

But you make a good point - custom gaskets in the MLS design from SOMEBODY else, Felrpro for example, may be a good option if its COMETIC and not the MLS, which does work much better as an inherent design.

928SS

beats me... but if someone clearly states a spec and expects folks to deviate, it seems to me they shouldn't state the spec. kinda like sayin you can have sex, and then putting qualifiers on it after you buy dinner - and we all know that sucks. (or doesn't, so to speak hahaha)

also iirc, in my case the gaskets actually leaked BETWEEN the layers.. so surface prep didn't seem to be the issue. course, leaking should best be analyzed on a case by case basis I suppose as there could be a variety of reasons something can fail - like bore wobble, torque stress/procedure, surfacing, etc, etc.. maybe there's a special torque sequence or assembly temp range that cometic likes but only a few have stumbled upon or the 928 is just fickle/wasn't designed w/a ML gasket in mind??

I just said "enough" cause if I have a problem w/something 1x it's shame on them. but if I do the same exact thing again, it's shame on me and I didn't want to risk it cause it costs me a small fortune every time I have to do an OH (and I'd rather spend $$ on tires and tickets )

I'd guess from here folks might want to experiment w/some alternative ML gasket compounds and brands/see what works best for most folks, etc... it'll just take time & $$$

Randy V

Making more friends I see, eh Brendan.

BC

Most people seem to have the ability to be civil. But I have plenty of friends, and only some are stuffed animals.

Susan K Thomas

Mike,
No stud configuration will prevent the cracks that i have seen.

If I can locate another "good" failed cracked block, block still intact, need more data points, I might have a solution.

Brendon, why do you insult AynRand and all she stood for.....that actually "hurts" more than actually being in agreement with Greg

Atlas Shrugged is a landmark book for those who spend the time and energy to actually "know" and produce value, rather than leaching off those who produce with no value to offer in return.

out of here...

marc