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Looking for 1979 Mack engine head


RS Disposal

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lightly oil the threads then wipe them off, and the same for the washers and under the heads of the bolts.  no biggie, just dip them in some 30 w and wipe the excess off.  if the threads have too much oil, they will hydraulic lock, thats why we wipe them off..  if not, it will give a false torque when tightening them.  jojo

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pretty sure I know the answer, but have available a head from an engine that is 10 yrs newer than mine.  engine model number EM6-300L

casting number 5311A

also the guy has an engine model number E6-250

Head isn't off the either engine so not really sure what it looks as far as a match

Like I said, pretty sure I know the answer and that it isn't a working match

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Well, I learned my lesson about relying on other people/shops that are regulars in the heavy truck world to see about sourcing parts.  Didn't even have the courtesy of letting me know they didn't have time after telling me the would let me know what they find or can't find.  Hench started my quest for the parts myself.  If I had just started doing it myself I would probably be 2-3 weeks ahead of where I am now.

Every website that said they had a head in stock, once I called they did not have one.  So I have taken the head into my machine shop (this guy went above and beyond communicating and trying to help me source a head locally. Definitely will have any and all future work I might need done.). Guess I'll see what the verdict is as far as any cracks.  Took a jeweler's magnifier eye loop on high power and a real bright light after I cleaned the head and didn't see any possible cracks.  Hopefully when it gets Magnafluxed it will tell me the same thing.  New valves, seals, seats and guides are all repairable.

Have gotten my bottom end parts in so I get to start putting that back together.  My shop manual that came with the truck only shows torques for head bolts (175), exhaust studs (35), intake manifold (33-37) & injector nozzle stud nut (16-18).  Can't seem to find the connecting rod, pan bolts, water manifoild, rocker cover bolts & turbo mounting bolt torques.  Any info in this area is greatly appreciated

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1 hour ago, Joey Mack said:

As far as torque specs.. I have an E-6 book.  I will see what it says and post pictures.. It will be after 4 pm, est.   Jojo

I would very much appreciate that.  Also any words of wisdom you can share as far as anything I should do or be on the look out for as I reassemble this engine.  I will definitely be chasing all threads and bolt holes so I get accurate torque readings

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19 minutes ago, doubleclutchinweasel said:

There are 2 or 3 guys on here regularly who know these things inside and out, and you were talking to one of them above.

They'll steer you right.  Have no fear!

That I have found out and am very appreciative for everyone on this forum

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Another quick question. the old piston had just 2 compression rings and the new piston has 3.  The third just above the oil rings.  I rad that piston weights should all be the same or else it can cause vibration issues.  The new piston is .7 ounces heavier than the old piston with just the top 2 compression rings.  When the third is added the piston is 1.7 ounces heavier.  Is this weight difference going to be a problem and should I leave the third ring off?  Should I maybe remove 1.7 ounces of material from the piston itself?

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I would think the weights should be pretty close

Someone smarter than me will know for sure

I would hunt around a bit more for the correct piston

I don't really think mixing up parts like this on the rotating assembly is a good idea

Just keep on looking for the correct piston is my advice

 

Paul 

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your welcome..   I found this forum 3 1/2 years ago, and knew I was in the right place..  I have received a lot of help here, and trying to help others just come naturally..  good luck, Jojo

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  • 2 weeks later...

Still waiting to hear back from the machine shop, but upon looking closely when I took it in he didn't think he would find any cracks.  But magafluxing will tell for sure.  Going to start putting the bottom end back together.  Should I use any type of thread locker on the connecting rods bolts? What about the head bolts? I know on the head it was said to dip into 30w oil and my thinking is thread locker requires clean threads.  Have to braze the inside of the pan where it appears probably from new, or close to, there is a couple of small holes where the center support bracket was spot welded to the pan.  I could never really find where the oil leak was other than assuming that was where it was coming from.  Once the pan was off and cleaned, I could see where the problem was and when I filled the pan with water and let it sit, it confirmed my assumption.  This has definitely been a journey and learning experience for me and this forum was a huge help.  It has just been frustrating in the sourcing of parts, the head mainly.  My biggest mistake was not starting off right to begin with and doing my due diligence of tracking parts myself rather than inquiring into several different shops that if they could find parts I would bring truck in.  Never heard back from any of them.  Guess since my truck wasn't sitting in their shop taking up paying space they didn't really have the incentive to spend alot of time on my behalf.

 

Also on a previous post I was asking about a small difference in old vs new piston weight, being the new piston was slightly heavier than the old piston.  I had an "awe ha" moment a bit ago that when I weighed the two I failed to take into account the hole and missing material in the old piston.  Pretty sure my weight will be, if not the same, very close to being the same as the old piston before the damage

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Don't know about thread locker on the rod bolts, but on head bolts be sure to run a bottom tap in head bolt holes, and blow out with air, and a die on headbolt threads and , oil threads and washers as you said.    terry:MackLogo: 

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