Cometic Head Gaskets LEAKING!
- Thread starter soontobefastfox
- Start date
xr8d302
I bought a 27" monitor to compensate for my lack o
xr8d302
I bought a 27" monitor to compensate for my lack o
xr8d302 said:
You, back under my desk! I mean um... back over to 94-95!
Back on topic:
I wonder if the issue of leaking between the layers has anything to do with the R&D that Cometic did when they made the gaskets, like they need more torque than a regular head gasket? Say they used a 351 to test them with 1/2" head bolts and 100 lb. ft. of torque, versus the 302's 7/16" bolts and only 85 lb. ft.?
Thanks! Looks like this winter I will betting ARP studs with bushings and Felpro MLS Permatorque gaskets. I'll see if I can send the Cometics back to Cometic and get my money back but we will have to see about that.
Not to bad but still a pain. I'm glad I am still doing a couple other fun mods this winter.
You, back under my desk! I mean um... back over to 94-95!
Back on topic:
I wonder if the issue of leaking between the layers has anything to do with the R&D that Cometic did when they made the gaskets, like they need more torque than a regular head gasket? Say they used a 351 to test them with 1/2" head bolts and 100 lb. ft. of torque, versus the 302's 7/16" bolts and only 85 lb. ft.?
Interesting point. That could be the problem. Couldn't overtorquing 7/16" bolts cause other problems?
gcomfx.com
Founding Member
Yeah, sorry about that guys. I was under the wrong impression about "he was building". It appears to me he "bought" an engine built just like I did. 
Which by the way my engine matched another setup in my engine builders shop. His cometics sealed just fine (with a turbo). Which is why I'm pretty confident in saying I bet it's a quality control issue. I hope to have mine back apart here pretty quick. Once we mill the pistons a little, I'll have more choices for gaskets as we can go thinner. 
soontobefastfox - if you get yours fired up before I do, let me know which route you went and if it was successful or not. I'll do the same. Right now I'm saving up for a few other things while we're doing this all over. With Christmas coming up fast... it may be Jan. 
Good luck! If cometic gives you the run around... send them here. I can find out my engine builders order number to help refresh their memory if they still say they've never had issues.
Oh... almost forgot. I already have one kid. xr8d you know it was Guero. Look at the eyes and hair when it comes out.
Which by the way my engine matched another setup in my engine builders shop. His cometics sealed just fine (with a turbo). Which is why I'm pretty confident in saying I bet it's a quality control issue. I hope to have mine back apart here pretty quick. Once we mill the pistons a little, I'll have more choices for gaskets as we can go thinner. soontobefastfox - if you get yours fired up before I do, let me know which route you went and if it was successful or not.
I'll do the same. Right now I'm saving up for a few other things while we're doing this all over. With Christmas coming up fast... it may be Jan. Good luck! If cometic gives you the run around... send them here. I can find out my engine builders order number to help refresh their memory if they still say they've never had issues.Oh... almost forgot. I already have one kid. xr8d you know it was Guero. Look at the eyes and hair when it comes out.
soontobefastfox - if you get yours fired up before I do, let me know which route you went and if it was successful or not.
Thanks! I may not be until January also, I am very busy at the moment. I talked to a couple engine builders and they do not sell or recommend Cometic for this reason. They said use the MLS Felpro Permatorque gaskets, which is what I am going to do along with head studs.
rd
Founding Member
Some old info on the oil pump seizures.
My first sbf did this, a 260 two barrel back in 1970.
It turns out the oil pump screen was only stretched across the bottom of the pickup where there is a solid metal portion of the bottom of the pickup.
The screen is crimped at the perimeter. This is, I am told, by design, so that if the screen is totally plugged, the suction will lift the rear of the screen and allow oil to flow.
Yep, it took awhile for me to figure out how big chunks of valve stem seal got in the oil pump....
Cleaned it, put in a new pump shaft, and drove the daylights out of that 65 Mustang for 3 years....
My first sbf did this, a 260 two barrel back in 1970.
It turns out the oil pump screen was only stretched across the bottom of the pickup where there is a solid metal portion of the bottom of the pickup.
The screen is crimped at the perimeter. This is, I am told, by design, so that if the screen is totally plugged, the suction will lift the rear of the screen and allow oil to flow.
Yep, it took awhile for me to figure out how big chunks of valve stem seal got in the oil pump....
Cleaned it, put in a new pump shaft, and drove the daylights out of that 65 Mustang for 3 years....
gcomfx.com
Founding Member
Ouch, that's not good. But it's cool the engine kept going once you cleaned it out. BTW - when the shaft broke. Aprox. how long did it run before you caught it and shut it down? Just curious.
A MLS (Multi Layer Steel) style gasket has the best sealing strength and it will take more abuse then a convential gasket. These are perfect for high cylinder pressure car, boost, N2O or high comp NA. They give you a little extra protection if you get greedy, although you can blow them. They are also re-usable, drill out all the rivot but one and clean then very good, coat them with the Chrysler spray I mentioned and you can put them right back on and use them again. Most guys do not use them over but I have done it at the track successfully.
Exactly, I wanted them because of their superior sealing strength. Also I plan to run a procharger in the future and wanted high performance gaskets that could support high cylinder pressures. Another reason was at the time Cometic was the only MLS gasket company I could find (now Felpro has MLS gaskets, which I plan to use).
gcomfx.com
Founding Member
Also, some of us wanted to be cheap and change the gaskets to get the right piston clearance on a decked engine. You need a thicker gasket to try this.
Finally got my stang running. I decided to go with Fel-Pro 1011-1 gaskets because I don't plan on running to much boost (~10-12 psi).
Thanks for all the help guys. Sorry for bring this back from the dead.
Thanks for all the help guys. Sorry for bring this back from the dead.
gcomfx.com
Founding Member
Guess I should follow up as well. I ended up going with a whole new block (properly decked). No more Multi-layer gaskets here. Just a good ole Fel-pro and it seems to be holding just fine.
gcomfx.com
Founding Member
I am still having a few issues with the tune/transmission conflict. We fixed the 3rd gear blow out by going back to stock settings. Now we have to fix the shifts. The car basically cuts out on each shift.
I did run a new best yesterday.
12.58 @ 108 on ET Streets and 3.55 gears. The car stumbles on the shifts and has a weird miss issue in 2nd gear at 5,000 rpm. Definitely more to be had....
Pics and vids soon. I won the burnout contest at the track rental. I finally got my nitto d/r's hot enough to stick!!!!!!
I did run a new best yesterday.
12.58 @ 108 on ET Streets and 3.55 gears. The car stumbles on the shifts and has a weird miss issue in 2nd gear at 5,000 rpm. Definitely more to be had....
Pics and vids soon. I won the burnout contest at the track rental. I finally got my nitto d/r's hot enough to stick!!!!!!
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