Whats the limit on stock head gaskets...

[bandit67]

In one of Nick latest dyno run videos , a 360 magnum , they blowout a stock head gasket somewhere around 5200. I did not hear at what compression ratio the engine was built to, but a compression check showed about 190 on one cylinder.

Most rebuilds for me were mostly stockers and I would just use the supplied Felpro head gasket in a standard rebuild kit with no problems so far. But, I recently put together a 68 440 that has a ratio around 10.24 for a pump gas motor that may be too much. And I used stock gaskets. So, what is the cutoff in compression or cylinder pressure check that calls for stepping up to a performance gasket. thanks.....

 

[4406bbl]

You are fine with steel or felpro as long as everything was clean when you assembled it, big blocks also have a way better head bolt pattern. Hard to say on the 360 magnum, magnum blocks have a real smooth deck surface, I always used mopar gaskets or cometic with aluminum heads, never had an issue with a magnum at 10 to1.

 

[dvw]

I've run a 340 with 12lbs of boost using Felpro's
Doug

 

[451Mopar]

I don't think that was a Fel-Pro gasket? The Fel-Pro gaskets usually are blue or blue striped.
Not sure what brand it was? Maybe a McCord?

 

[RemCharger]

It was a shitty stock graphite one I think.

 

[451Mopar]

Happens when building a high performance engine with low performance parts.
It's a lesson many of us learned the hard way.
I have shot myself in the foot several times trying to use cheap parts, just to have to replace or scrap them later.

At least the engine was not in the car. With the engine mostly torn apart, I would pull the rotating assembly and double check it if they suspect the balance is off.
My 360 was balanced with a new damper and the B&M 360 flex plate to use a neutral balance converter.
On my 500" stroker, the shop that balanced the engine must have mis-calculated the bob weight or had some other error, and overbalanced the engine by about 1 ounce? Had the engine re-balanced by another shop, and they basically removed the weight the other shop added.

 

[Wietse]

How the thin metal gaskets hold up against the paper ones like Felpro?
Are the metal ones supposed to be able to withstand more pressure?
I have a .020" metal gasket in my 440, don't know the brand or whatever as a PO build the engine. But it runs at 10.5:1 and was running close to 200psi with an over advanced cam, which is now installed as intended.
Just wonder now if I was lucky enough not to blow it out.

 

[dvw]

We ran the thin metal in every Hemi back in the 90's. It was all that you could get except copper. They worked fine at 12.5-1
Doug

 

[Don Frelier]

I don't think compression ratio has much to do with the problem.
It's the explosions inside which create the leaks.

 

[440Coronet500]

Typically, Fel-Pro lists the recommended compression ratio for there head gaskets. I have never had an issue with Fel-Pro head gaskets in my builds. I use the Fel-Pro "Perma Torque" 0.039 compressed thickness head gaskets. 440'

 

[Wietse]

CR not by itself no, though its part of the road to your cylinder pressure, then the added "boom" factor of the combustion.
I've seen in Nick's Garage he said he prefers to use the thin metal gaskets, guess it comes down to the "build plan" of the engine if he needs the thin gasket or not.

 

[66Satellite47]

How the thin metal gaskets hold up against the paper ones like Felpro?
Are the metal ones supposed to be able to withstand more pressure?
I have a .020" metal gasket in my 440, don't know the brand or whatever as a PO build the engine. But it runs at 10.5:1 and was running close to 200psi with an over advanced cam, which is now installed as intended.
Just wonder now if I was lucky enough not to blow it out.

I've used both the metal .020 and the Fel Pro .039 blue gaskets. There are two versions of the blue Fel Pro's, a wire reinforced sealing ring style for high CR and a standard style for the lower CR. On my 440 drag motors with 12.2 to 12.5 CR I've run both the metal .020 (both Mopar or Fel Pro) as well as the HP Fel Pro style (1009 or it's predecessor). I've used the Fel Pro 8519 on lower CR 383/400/440's. Even finished a race season with a 906 head/.020 metal gskt on one side & 915 head/.039 Fel Pro on other side. The CR was within .1 CR. Not a recommended practice.

 

[IQ52]

In one of Nick latest dyno run videos , a 360 magnum , they blowout a stock head gasket somewhere around 5200. I did not hear at what compression ratio the engine was built to, but a compression check showed about 190 on one cylinder.

Most rebuilds for me were mostly stockers and I would just use the supplied Felpro head gasket in a standard rebuild kit with no problems so far. But, I recently put together a 68 440 that has a ratio around 10.24 for a pump gas motor that may be too much. And I used stock gaskets. So, what is the cutoff in compression or cylinder pressure check that calls for stepping up to a performance gasket. thanks.....

"And I used stock gaskets." ?

What was the 'stock gasket' you used?

If it was the FelPro 8519PT1 out of the FelPro gasket kit you're fine. I've used those in normally aspirated, pump gas engines without a failure at nearly 12:1 and over 700 HP.

 

[4406bbl]

How the thin metal gaskets hold up against the paper ones like Felpro?
Are the metal ones supposed to be able to withstand more pressure?
I have a .020" metal gasket in my 440, don't know the brand or whatever as a PO build the engine. But it runs at 10.5:1 and was running close to 200psi with an over advanced cam, which is now installed as intended.
Just wonder now if I was lucky enough not to blow it out.

No need to worry, the steel gaskets will hold 11-1 and a 500hp nitrous shot. As long as everything is wiped with lacquar thinner, and the bolts are not over oiled they are solid. I coppercoat mine but it really is not needed.

 

[bandit67]

I've seen in Nick's Garage he said he prefers to use the thin metal gaskets, guess it comes down to the "build plan" of the engine if he needs the thin gasket or not.

I think Nicks apprentice built and picked the parts used in that 360. Nick was just doing the dyno run and had already made a pass to 4000. Next pull was going to 5500, but the gasket spit out a chunk at 5200. Nick found the piece when they pulled a valve cover.

I do not know the part number Felpro head gasket I used, I will need to look back at which Felpro kit I used back then. I have not fired that motor yet. thanks guys....

 

[1967coronet]

No need to worry, the steel gaskets will hold 11-1 and a 500hp nitrous shot. As long as everything is wiped with lacquar thinner, and the bolts are not over oiled they are solid. I coppercoat mine but it really is not needed.

A 500 shot damn .

 

[66Satellite47]

I think Nicks apprentice built and picked the parts used in that 360. Nick was just doing the dyno run and had already made a pass to 4000. Next pull was going to 5500, but the gasket spit out a chunk at 5200. Nick found the piece when they pulled a valve cover.

I do not know the part number Felpro head gasket I used, I will need to look back at which Felpro kit I used back then. I have not fired that motor yet. thanks guys....

Small blocks were always a little hard on head gaskets with only 4 bolts around each cylinder. Proper torque is a key.

 

[Gunner1]

Don’t forget the brittle oil filter gasket. Looks like some very old stock stuff. I used a regular Felpro blue set on a 427 Chevy with an 8-71 making 10 psi and 822hp on 91 pump. No problems. I think it was some very old product the kid bought somewhere.

 

[Geoff 2]

Nicks 360.
Built by a beginner, so were the head bolts torqued correctly?
Very poor gasket design, compounded by 4 bolts per cyl. The gasket blew at the weakest point, right in the middle of the span where the gasket was not very wide. There was room to make the gasket 1/4" wider, might have held.
That is the risk with composition gaskets. Two or more separate pieces, does not have the same strength of a single piece gasket.