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Cometic Head Gasket Question

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Question, How many times can I crush a Cometic Multi Layer Steel head gasket using Copper Spray Gasket.
We've run into some issues and I'm up to about 4 or 5 now.

Thanks!
 
Do NOT use spray copper on any Cometic gasket!!! Also, you can only use a Cometic gasket once.
 
Call cometic, don’t take out word for it. But the instructions state to use them dry when I bought them.
 
I installed mine dry the first time, and re-used them with copper coat the second time. Only re-used 2 or 3 times. I'm not sure I would go past 3 times?
 
has the engine been ran since the gaskets were torqued? they can be torqued as many times as needed if they haven’t’ been ran
to the point of being seated by engine heat.
I read this statement from cometic on a gasket comparison write up. And you really
shouldn’t use any type of sealer on them
unless of course your doing a hemi.
I would never put a gasket and head on a hemi without using a bit of sealer around the water jacket ports.
 
Do NOT use spray copper on any Cometic gasket!!! Also, you can only use a Cometic gasket once.

May have to agree here... Google "retorque or reuse Cometic gaskets".... there sure is an awful lot of chatter about on racing sites, car forums, engine blogs, etc. Nary a peep from Cometic, as far as I can find anyway... I did see where Cometic does say, install them dry tho, and the reason is because they are already coated, and anything further could hinder the seal. HTH, Lefty71
 
Basically, there are bends in the steel layers that flatten out to complete the seal. Once the bolts are loosened, you will NOT achieve the same crush, and therefore, will have a gasket that will leak and fail. One tighten, one use, and never apply any extra sealer as they are already coated with a layer of rubber.
 
Basically, there are bends in the steel layers that flatten out to complete the seal. Once the bolts are loosened, you will NOT achieve the same crush, and therefore, will have a gasket that will leak and fail. One tighten, one use, and never apply any extra sealer as they are already coated with a layer of rubber.

Maybe read this write up still no reply to if this engine has been fired up yet.
https://www.dragzine.com/news/gasket-science-can-you-reuse-an-mls-head-gasket/
 
The article answers your question in the first paragraph, "... but just because you hear something is true doesn’t mean it is...". This is from the next paragraph, "...reusing MLS head gaskets and the success of the practice, its failure rate is much higher after reuse...". Here is the next paragraph, "...Now, if you’re in a total bind at the track and need to reuse a gasket for only a handful of runs it’s not ideal, but it can be done. If you’re trying to reuse a head gasket as a long-term solution, that’s opening a dangerous door to many problems. The risks involved with not using a fresh MLS head gasket far outweigh the benefits enough to make it a good idea to keep a spare set on hand at all times...".

They are basically saying that it is NOT a good practice, and it is certainly not advisable once the engine has run, but in a pinch, you might get away with it at the track. So, with all of this maybe and probably, I still refuse to risk a customers engine and my reputation to maybe's. I will always err on the side of caution, and suggest to not reuse a Cometic gasket.
 
The article answers your question in the first paragraph, "... but just because you hear something is true doesn’t mean it is...". This is from the next paragraph, "...reusing MLS head gaskets and the success of the practice, its failure rate is much higher after reuse...". Here is the next paragraph, "...Now, if you’re in a total bind at the track and need to reuse a gasket for only a handful of runs it’s not ideal, but it can be done. If you’re trying to reuse a head gasket as a long-term solution, that’s opening a dangerous door to many problems. The risks involved with not using a fresh MLS head gasket far outweigh the benefits enough to make it a good idea to keep a spare set on hand at all times...".

They are basically saying that it is NOT a good practice, and it is certainly not advisable once the engine has run, but in a pinch, you might get away with it at the track. So, with all of this maybe and probably, I still refuse to risk a customers engine and my reputation to maybe's. I will always err on the side of caution, and suggest to not reuse a Cometic gasket.

so you chose to leave this part out for what reason?

According to Hale, the myth of being able to reuse a MLS head gasket has been around for a while, but it’s a bit misguided.

In a mock-up situation, it is perfectly acceptable to install, check clearances and reuse the gasket. Once heat is put to the gaskets, the ‘spring’ is gone and since the embossment is the sealing area, there is a greater chance of a coolant or compression leak.”

this part confirms what I stated in my very first post here MLS head gasket can be torqued more than once if not heat cycled.
 
so you chose to leave this part out for what reason?

According to Hale, the myth of being able to reuse a MLS head gasket has been around for a while, but it’s a bit misguided.

“While we see it on forums and message boards all the time about reusing MLS head gaskets and the success of the practice, its failure rate is much higher after reuse. The reason behind this is: once the gasket is heat cycled, the embossments will not spring back to where they were originally. In a mock-up situation, it is perfectly acceptable to install, check clearances and reuse the gasket. Once heat is put to the gaskets, the ‘spring’ is gone and since the embossment is the sealing area, there is a greater chance of a coolant or compression leak.”

Because, it isn't a myth. The article even says that you shouldn't reuse them, but in a pinch, you might have to try to, but it still isn't recommended. Look, if you do it on your own engine, that is fine with me, but I refuse to do it on a customers engine, or my own for that matter. And, whenever a person asks me, I will always advise against it. Why take a chance when you have the option of only having to do it once.
 
I agree it’s not a myth it’s perfectly acceptable to torque a MLS head gasket more than once if it hasn’t been heat cycled
 
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I'd love to have new head gaskets every time, but at about $100 each, they are not cheap.
I'm also sure the Cometic would love to sell you more gaskets too.
Installing dry is correct for the first use.
The coating is not the same after use, so the copper gasket coating helps seal the gasket when using after the first use.
As I said, I haven't tried to use the MLS gaskets more than 3 times, but they seem to work for me so far.
 
Sorry for the delay, been working and been in the shop.

So, to answer Beekeeper's question. Yes it had been run on the Dyno. It got to temp. and 1 5k pull and that was it. Had some issues going on with cam walk.

So took the motor apart and found an oiling issue also.
Long store short, the head gaskets have been torqued 2 times since for various reasons like re-honing and when we put the motor back together we primed it with the intake off and found where our oiling issue was coming from. SO we had to take the heads back off.

Now on our old motor I've have had numerous experience with re using Cometic MLS gaskets with Copper Spray Gasket with ZERO issues. And most engine builders will tell you the same thing. BUT I've never done it more than once or twice. I was wondering if anyone has had any experience with it.

Like 451 Mopar said... these things are $100.00 each, I'm not putting a new gasket on every time I have to pull a head. If that's the case then I'm going to Fel Pro.

Thanks again for your help guys.
 
Do NOT use spray copper on any Cometic gasket!!! Also, you can only use a Cometic gasket once.
Really? I've used mine on a 15-1 motor 3 times with no issues ever. And when they were used they were used both without and then with spray. My experience. I'd use these in question in a heartbeat.
Doug
 
Thanks Doug, so my 12.5-1 motor should be fine.
My issue is not only the fact that I don't want to fork out another $200.00 but it's also trying to find them.
Summit is out, can't get them direct I'm hearing, I was trying to call Todd Marsh today but he must be out of the office.

SO...I'm just going to spray it and put it back together.

Thanks again for all the input guys I do appreciate it.... I'll let you know if it leaks. LOL
 
No problem on the 500" stroker, 12.4:1 compression, been ran to 7,000 RPM several times.
Hughes CNC ported Victor MW heads (around 400 cfm), and custom comp solid roller with HXL lobes, I think around 272 or 274 @ 0.050" intake duration, 0.726" lift.
 
Thanks Doug, so my 12.5-1 motor should be fine.
My issue is not only the fact that I don't want to fork out another $200.00 but it's also trying to find them.
Summit is out, can't get them direct I'm hearing, I was trying to call Todd Marsh today but he must be out of the office.

SO...I'm just going to spray it and put it back together.

Thanks again for all the input guys I do appreciate it.... I'll let you know if it leaks. LOL
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I’ve re-used the Cometic MLS head gaskets in the past without a problem. DVW shared his torquing procedure, which I use. Definitely helps. The wait/ship date for cometic head gaskets is crazy these days. Summit says ship date for cometic head gaskets is mid August if ordered today.
 
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