Head gasket thickness

[Eli77]

Hi. Bought a 6.5td from gov plant and it was missing the intake bridge I should have known better. But I still bought it and I guess some water went in and set there. short story we ended up removing the heads and cleaning the engine and it looks like this engine was rebuilt before by the mc based on the paper work that was attached. Now what we trying to find out is what thickness of gasket to use. Since there are so many I am assuming it is critical. Any idea what gasket thickness will be the safe way?
thank you

 

[MarkM]

You have to see just what shape the cylinder walls are after you clean them. Is the engine frozen? Hopefully the rings are not frozen in place. Not sure if those cylinder walls are OK.

Mark

 

[Eli77]

You have to see just what shape the cylinder walls are after you clean them. Is the engine frozen? Hopefully the rings are not frozen in place. Not sure if those cylinder walls are OK.

Mark

I posted a picture of the engine cleand ! Not frozen everything looks ok

 

[MarkM]

Oh sorry didn't see that pic. No pitting on the walls? Damn she might be a runner.

Mark

 

[Eli77]

Oh sorry didn't see that pic. No pitting on the walls? Damn she might be a runner.

Mark

Yes now the question is. What thickness of gasket ?

 

[mgFray]

As far as I know, there is only one standard thickness for the head gasket on these things. The military doesn't deck the heads or the block, if they are out of tolerance they get replaced. I'm not sure what the standard thickness is, but gaskets I used were the standard military ones from MacMotors.

 

[87cr250r]

0.040" is standard thickness. You need to measure your deck height to determine if the block has been decked. If so, you'll want to run the thicker gasket. It usually takes about 0.010" to clean up a deck.

I see you're looking at Cometic gaskets. They require a much smoother sealing surface and the factory finish doesn't meet this requirement. With that said, I have Cometic gaskets at 0.051" with 10 thou shaved off the deck. I haven't run it enough to give any reports on durability.

 

[Mogman]

I posted a picture of the engine cleand ! Not frozen everything looks ok

Nice work!
Did the OEM gasket have a number??
If you are thinking of raising the boost .010 over may not be a bad idea.

 

[mgFray]

Nice work!
Did the OEM gasket have a number??
If you are thinking of raising the boost .010 over may not be a bad idea.

I just looked up the part number in the manual and ordered it from Mac. Unfortunately my rig and everything is still at the repair shop, so I don't have an easy way to check. The head gasket came as part of a full kit though. (I have no desire to boost my engine, with the three speed transmission boost just sounds like a great way to blow it up quicker.)

 

[Eli77]

Nice work!
Did the OEM gasket have a number??
If you are thinking of raising the boost .010 over may not be a bad idea.

Unfortunately I don’t have the old one anymore. Didn’t realize it will be that difficult to get a replacement

 

[Eli77]

0.040" is standard thickness. You need to measure your deck height to determine if the block has been decked. If so, you'll want to run the thicker gasket. It usually takes about 0.010" to clean up a deck.

I see you're looking at Cometic gaskets. They require a much smoother sealing surface and the factory finish doesn't meet this requirement. With that said, I have Cometic gaskets at 0.051" with 10 thou shaved off the deck. I haven't run it enough to give any reports on durability.

The cometic is the only one that fit, anything else that sell looks like it made for different heads. just attached them both that you can see the difference. That is another thing I didn’t expect, two different kind of gaskets

 

[mgFray]

Found it, the part I put on my engine, search MacMotors for P/N 5714842.

It's listed as 6.5L TD, but it's the same head gasket for the 6.5L NA.

 

[Eli77]

Found it, the part I put on my engine, search MacMotors for P/N 5714842.

It's listed as 6.5L TD, but it's the same head gasket for the 6.5L NA.

Seems like my heads are different

 

[mgFray]

Looks the same as my engine and it definitely works with the military gasket I mentioned above

 

[Mogman]

All the 6.5L engines are the same, there are not two different heads/blocks.

 

[mgFray]

All the 6.5L engines are the same, there are not two different heads/blocks.

Yup, and the only difference in the standard heads are the angle of the intake runner bolts. (Cause I bought the wrong heads the first time and had to return them..)

 

[Eli77]

All the 6.5L engines are the same, there are not two different heads/blocks.

I meant two different kind of gaskets

 

[mgFray]

Different manufacturers may have different shape gaskets, but they should all be compatible. Other then shape there is thickness of course. For the stock thickness gaskets, both of your pictures are probably fine, based on the block and heads only having one pattern.

 

[87cr250r]

Do know that if you go the Cometic route that there are in fact two different gaskets as they are different for left and right bank.

 

[Eli77]

I ended up ordering the stock once. From hummer parts guy and ordered a set of arp from jegs