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Looking for 1979 Mack engine head


RS Disposal

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1 hour ago, JoeH said:

I've only had to do a head on these once, I did it by the book.  Torque to 200, drive around got an hour, retorque.  Its a pain to have to deal with all the intake tubing, and those valve covers are horrible to seal. Gotta do them dry and do not go above torque spec.

To many guys try to use silicone and squeezes the gasket out.    terry:MackLogo:

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small center punch make random divots on bottom side of valve covers ; using light film of high tack between valve cover and rubber gasket  held gasket in place, NOT silicone  but high tack(if it's still manufacture). with the small punch marks on cover the gasket didn't have a 100% smooth surface to slide out.

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4 hours ago, mechohaulic said:

small center punch make random divots on bottom side of valve covers ; using light film of high tack between valve cover and rubber gasket  held gasket in place, NOT silicone  but high tack(if it's still manufacture). with the small punch marks on cover the gasket didn't have a 100% smooth surface to slide out.

It does look like Permatex does still offer "high tack"

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1 hour ago, RS Disposal said:

It does look like Permatex does still offer "high tack"

Trust me. Absolutely nothing. Don't use hi tack, don't use silicone, don't use anything. Check the valve covers for "straight" sides, the mating surface bows outwards when you over tighten. Wipe the mating surfaces down real well so there's no oil residue or anything else on them, put the gasket down, cover on, make sure the gasket is sitting right under the covers, then torque them up.  

High tack and rtv silicone and anything else will lubricate the gasket and it will squeeze out. You will never get them to seal properly for any length of time unless you do them dry. Our '79 endt676 we could never get to seal up. We tried high tack and rtv and it always leaked. Then we did it dry once and we've been leak free for years now.

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if you have the old gray rubber gaskets or the black ones that are attached at the business end, , you can re-use them..  you will see how the crush on them makes them just a tick wider at the mating side..  You can flip them over, they will fit snug in the valve cover groove..  the cover bolts are shouldered so they will only go down so far before they stop...  to me this is not a crappy way to do this,  its just using both sides of them..  of course, you have to determine if they are to far gone for re-use...  

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While I've only had to replace one head on these engines, we've had the valve covers off plenty of times. Last time was to delete the jake brake, we have a weak valve springs on one cylinder and the disk on top of the valve stem that the jake actuator pushes on kept popping out, so after the 2nd time it popped out we pulled the plug on the jake.

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1 minute ago, Joey Mack said:

if you have the old gray rubber gaskets or the black ones that are attached at the business end, , you can re-use them..  you will see how the crush on them makes them just a tick wider at the mating side..  You can flip them over, they will fit snug in the valve cover groove..  the cover bolts are shouldered so they will only go down so far before they stop...  to me this is not a crappy way to do this,  its just using both sides of them..  of course, you have to determine if they are to far gone for re-use...  

These don't have a valve cover groove.

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4 minutes ago, Joey Mack said:

if you have the old gray rubber gaskets or the black ones that are attached at the business end, , you can re-use them..  you will see how the crush on them makes them just a tick wider at the mating side..  You can flip them over, they will fit snug in the valve cover groove..  the cover bolts are shouldered so they will only go down so far before they stop...  to me this is not a crappy way to do this,  its just using both sides of them..  of course, you have to determine if they are to far gone for re-use...  

I actually have 2 sets of new gaskets

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New gaskets are a must. This is an ENDTB, so it has Dynatard not jake brake? Does the Dynatard use a riser under the valve cover? The Jake does, so you need 2 valve cover gaskets per head, one for the riser and one for the valve cover. I've never had a Dynatard so I don't know how they're set up.

Edited by JoeH
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9 minutes ago, JoeH said:

New gaskets are a must. This is an ENDTB, so it has Dynatard not jake brake? Does the Dynatard use a riser under the valve cover? The Jake does, so you need 2 valve cover gaskets per head, one for the riser and one for the valve cover. I've never had a Dynatard so I don't know how they're set up.

yes, it is a dynatard. Wish it was the jake brake.  About the only thing it is good for is to help with the shifting of the 5 speed.  No where near a good as the jake on my other truck when coming down canyon.  And no, there is no riser

 

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2 hours ago, JoeH said:

What's your other truck? The Jake brake on these isn't much use for anything other than shifting, but it makes a world of difference as a shift aid.

My other truck is an Autocar with a Cummins N14. Unfortunately that one has transmission problems that I really should of fixed before now but life just keeps getting in the way.  LOL

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  • 3 weeks later...

I did get my truck running, but locating a rebuilt turbo is getting impossible.  Does any of you guys hjave a source to try or a source for a seal kit for this 4LE-303 turbo.  This one leaks oil out the exhaust side

 

Can anybody tell me what the difference is between the 4LE-303 and the 4LE-292 or 4LE-556.  The pictures I am seeing they look similar

Edited by RS Disposal
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Sorry to confuse you with yet another turbo model added to the possibilities. Just rechecked, you're running an ENDTB 675 which will be the 237hp variant! Sorry this turbo is for the 283hp variant! 

I do have a 237 endt-675 sitting outside my garage, I'll see if it has a tag on it tomorrow!

Edited by JoeH
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