Mack END673 headgasket(s)

[JAKES.]

Hello and happy 2018 to H.E.F. crowd!
I have been tinkering with a 1962 B-61 six wheeler with a quadruplex and END673. This truck has sat idle for around 25 years giving lots of time for the mice to move into the cylinder head and fill it with filth. The original idea (mine) was to clean the top up, pull injectors, put back in rebuilt injectors with fresh copper rings and crank it up. I made the decision to pull the head because the rockers and push rods were so caked with mouse filth I figured the valves should be cleaned too so I took the heads off disassembled and cleaned valves and seats 1 pair at a time which I feel was much needed because there was a lot of loose debris on each valve.I had the heads checked and they are not warped; so I think I am ready to reassemble. A few months of tinkering (this is hobby project for me) off & on weekends; I am still trying to find 2 new head gaskets. Watts claims there are only 15 of the gaskets that exist in the world and want $200 per! So I want to run this by the H.E.F. and see if anyone can shed some additional experience / info on this matter, especially a way to find the correct gasket(18boLt) at a better price. I am a carpenter that plays with wrenches on the weekend and have used this forum to get lots of help in the past. Thank you in advance to anyone that took the time to read my plight!! -Jake

 

[Junkyard]

Checking with the Mack guru. Be back with info shortly. Sounds like bull to me. I don't recall having issues getting them.

*edit*. He's got a felpro number. He just moved so he's gotta find the archive box! Haha

 

[Wytruckwrench]

When I get back to the shop I have the PAI numbers somewhere.

 

[kshansen]

Just in case someone needs to know how many head studs in each head? There are some with 18 head studs and some with 20 head studs. Are they all 5/8 inch? I believe some had one 3/4 inch stud in the corners and some had 2 5/8 inch studs.

Also nothing against this forum but might be worth checking out this other one as well:

https://www.bigmacktrucks.com/

 

[Truck Shop]

Watts sponsors Big Mack Trucks .com

Truck Shop

 

[Junkyard]

Apparently the going rate is about $200 each. Last ones we got were $180 from Shipley Mack in Ft Smith, AR. He said you can take Mack part # to Napa and they can cross to felpro. Not a great answer like I have 12 and I'll send you some for the cost of postage but they're not like hens teeth either!

 

[mitch504]

op said 18 bolt heads

 

[JAKES.]

The head bolts 18 per head = 36 total all of them are 5/8" I gave up on trying to find new ones, I did call around. Fortunately the original bolts appear ok visually so I hope they still hold the desired torque values when I go to bolt down my overpriced gaskets! Not an ideal situation.

 

[JAKES.]

Thanks guys for your assistance so far. I was trying to upload a pic of the old gaskets but unsuccessful for some reason? I tried 3 different computers to upload? I need to start a new thread "how do I post photos to the H.E.F.?" So no pic until I sort that out. Sorry about that.

 

[kshansen]

op said 18 bolt heads

Had to read through it twice and finally spotted the (18boLt) !

Hate to say I probably tossed more than a few of those out over the years as just about every older Mack we had, and we had many, had the 20 bolt heads.

 

[kshansen]

Thanks guys for your assistance so far. I was trying to upload a pic of the old gaskets but unsuccessful for some reason? I tried 3 different computers to upload? I need to start a new thread "how do I post photos to the H.E.F.?" So no pic until I sort that out. Sorry about that.

That's an easy one. In the box where you type the message like I am doing right now there are three blue buttons. One says "Post Reply" the next says "Upload a File" and the last one says "More Options".

If you click on the center one "Upload a File" it "should" take you to a place on you computer from where you can look to find the file you want to upload. Of course you will have to know where on your computer you have saved the file! Anything I plan on up loading I put on desktop to make it easy to find.

After you have selected the file if it is an image, like picture of gasket, you can select to post as a thumbnail of full size image. Either way is fine but I usually go for the full size image.

Note that sometimes an image will show sideways or even upside down. I believe this is much more common with pictures taken with some cell phones. Someone else may be able to explain how that works but for a picture of a gasket it would not be a big deal!

 

[mitch504]

CLICK ON "UPLOAD A FILE" at the bottom, (oops)

 

[JAKES.]

Hi finally getting a pic up.having problems related to my sat internet. I do understand how to upload. Cheers.

 

[Freightrain]

Let me look in my junk box of gaskets I have, maybe by some stroke of luck I have one? two?
If yours aren't damaged, then I'd likely try to reuse them. I have broke a couple head bolts on my 673P and drove for 100+ miles with it chirp'n away. Got old stud out, screwed new on in and continued to run it. Finally upgraded to 237 and sold that motor just a few months ago.

 

[JAKES.]

That would be some luck! Makes me feel better about the head bolts too. thanks Freightrain.

 

[Freightrain]

Well, no good news. Sorry. I got a pile of odd gaskets but no head gaskets.
If your gaskets aren't hurt I would consider reusing them. Just need the rubber o rings.

 

[DMiller]

There is a Fire Ring on the inside bores of the head gasket, crushed once will not re-crush to control combustion pressures, find a pair of NEW head gaskets. As to the studs, CLEAN well the thread bores, Remove ALL of the studs for cleaning the thread bores make certain are CLEAN then lightly lubricate the studs with oil(I used a FILM of 90wt not dipped) then make a stud torque adaptor with a head nut and a NF bolt to set them AT TORQUE in the block. Do it any other way you will be back changing another head gasket. Follow the service manuals on these as to torque values.

 

[Freightrain]

Some early motors(non turbo) didn't have fire rings, thus if you bolt a turbo to them they had a chance of blowing out. I've had two broken studs over the years, drove for hours with it leaking and after installing a new stud, closed it right up. BTW, it broke different stud each time. Snap it right below the nut, right at the surface of the head.

I'm going to recheck my Mack book as I don't recall the stud torquing. I had the heads off mine 237 a couple years ago.

 

[Freightrain]

My book states oil, install finger tight and back off 1\3 turn. Torque nuts in 50 ft/lb increments.

 

[DMiller]

Reason they snap off high is moisture infiltration (corrosion) and heat expansion of the heads. I need to dig my old manuals out, worked at Mack in the 70's and swear we torqued them with a stud adaptor(tall nut will a ball bearing pressed inside).