No fix last forever................................head gasket problem.

[Freightrain]

It was just two years ago Labor day I popped a rear head bolt coming home from a race. I limped it along for 2 hrs and made it home. Was told by a few people just stick a new bolt in and it will be fine. I did and was pleasantly surprised it was good. Well, sorta.

Step up to yesterday, I was on my way to a race, had just pulled a grade going about 55 mph, holding about 1800 rpm. Just as I was going to roll over the top and dump it back into OD, it acquired a ticking noise. Slow, rythmic, only under heavy throttle. Oh crap. Wasn't heavy enough for bottom end, didn't make sense for valvetrain. It has apparently blow out the head gasket in the back where I put that new stud in.

I was able to limp it home, though it was midnight when I left, I told my traveling buddies to just head out and I'll just take it easy. It was chirping pretty bad when I first left. It some how got quieter as I got on the highway. Once I made it home, it was really quiet compared to when I left. Not that it's fixed, but strange how it is not as bad???

Anyway, seems like I get to pull the back head and put a gasket on it. Not looking forward to it. Likely remove the hood to make room. I think I'll drop the exhaust manifold off fully, so I can get the rear head off without taking front head too. I'm torn from doing both anyway? just because it's apart anyhow? I'd like to find a full set of studs to replace them all. It is just a matter of time til another goes??

I've got til Sept 1st to have it roadworthy as I have a double points race.

[theakerstwo]

Let me tell you what i would do. This is the way we did them back when thoses trucks was on the road ever day. You should replace both gaskests any ay. Remove hood and cross bars from hood to rad cowl. Now dont remove the exhaust or intake manifold and pull both to together.A small chain attached to the middle rocker hold bolt on each head will balance good.And remove each stud and clean and then screw in hand tight only.When you tighten the head bolts then loosen the exhaust stud so it will not put the manifold in a bind.

[Freightrain]

Thanks for the input Glenn. My only problem is lifting the heads off together. I do still have my buddies Bobcat, so maybe I can use the forks and rig up a way to lift them? The bobcat isn't too gentle when it comes agility. Kinda all or nothing if you don't work it very, very slowly.

Going over some ideas in my head, this might work. I might work on getting the exhuast nuts loose before putting the head back on(much easier to work on the floor then over the fender. I'll snug them to pick up the head and put it on the block, then loosen them to torque bolts.

Not sure if new studs are available? Should I look at getting new ones if I can?

My only other trick is getting valves readjusted. Not that I don't know how, it's just doing it. It's not a typical V8 that you can simply bar over with the plugs out.

[Mike]

Man what a bummer. Larry, i'm trying to understand how you can leave manifolds attached and pick them up enough to get the gaskets out from under the heads. I'm not questioning Glenn, but in my mind I just can't figure how without detaching the heads etc. etc. and possibly using the forklift, unless you find a steal plate and mount it to the forks so you can slide the heads onto the plate, put the gaskets on lift up a couple of inches then slide heads over onto the gaskets. Just my 1/2 cents worth.

mike

[Maddog13407]

you take take the head and intake and exhaust all off at once and set it on the floor. then clean and put new gaskets on the deck. id use new studs if they are available. adjusting the valves isnt that hard either and it will probably run better after. my END707 skipped when we got it but was a recent rebuild. then the back head gasket started leaking, pulled the heads one by one, replaced the gasket and found a push rod was bent. readjusted the valves and it ran 100% better than before. mine has the maxidyne thin head gaskets on it with the fire rings tho, not the old style copper gaskets like most of the 673's and older 711's.

[220cummins]

Likewise I would replace both. If the studs are pitted or worn thin like a 711 I took apart I'd replace them. I'd start at Mack or pai. I'd be surprised if an arp or other stud mfg has them. When I did head gaskets on my 673 I had a hard time figuring out which ones I needed because I couldn't identify which 673 I had. The numbers where ground off on the block. After some matching up with gaskets that watts we figured It out. I took my manifold and turbo off because the manifold had a crack in it. Then I took one head at a time which I could man handle off the truck. Set the valves Cold to spec with a filler gauge. I have old started button rigged up to with leads hooked to the started to bump the motor over on fire order.

[Freightrain]

Well, things aren't so bad. After going out this morning and poking around....................I found another broken stud. Rear head, front left corner. Nut was laying down in nook of intake.

I wasn't able to spin stud out, so I welded a nut to the top and used a rachet to spin it out. Stud looked pretty beat. 9/16" stud, so going to check R/R Mack in Akron as it's close by and the parts guy knows me from getting B model stuff over the years. Guessing, like the rear one 2 yrs ago I should be able to torque it back down and be okay. I didn't run it hard so I got my fingers crossed.

Hopefully dodge another bullet?

Gotta say, no matter the ol dog does get me home everytime.

[220cummins]

That's good. How does the truck ride since the re-bush on the neway? How did you end up repairing the transverse beam pin where the bushing sits? We just got one set of (both right and left equalizing beam) welded up and ground to diameter. The axle pivot bushing came out with slight ease. We made up puller out of 7/8"x14 all tread and tapped the old bushing to 7/8"x14...seen an OTC Hendrickson axle bushing sevice kit that was pretty much the same thing including the tap. It worked fairly good.

[Mike]

Larry if they have some studs available, can I get the phone number and see if they can get me some for my project? I'm having liners made at this time and will soon need studs.

mike

[b61mack]

Well, things aren't so bad. After going out this morning and poking around....................I found another broken stud. Rear head, front left corner. Nut was laying down in nook of intake.

I wasn't able to spin stud out, so I welded a nut to the top and used a rachet to spin it out. Stud looked pretty beat. 9/16" stud, so going to check R/R Mack in Akron as it's close by and the parts guy knows me from getting B model stuff over the years. Guessing, like the rear one 2 yrs ago I should be able to torque it back down and be okay. I didn't run it hard so I got my fingers crossed.

Hopefully dodge another bullet?

Gotta say, no matter the ol dog does get me home everytime.

Larry i have a few studs from a 237 and 285 if you need some you can have them, i replaced my studs with bolts. if you need them i will send them to you. Ron

[41chevy]

Hope you make out okay! If not you can put a come a long on the Bobcat bucket to get the heads on and off and the bobcat to lift and move. I used the same set up to pull my AC engine out of the chassis. the Come a Long gives you the "gentle touch to R and R it. Paul

[Lmackattack]

I also recall that there was a stud update but it may have been for the 711 only? Glen may know for sure? Something about thicker or stronger updated studs? If you can't find replacements I guess it's just time for an E9???

[Freightrain]

Pretty sure the updated motors(711) got 5/8" studs in the corners. I've only broken two, both in the corners.

I'll be checking into new 9/16" studs tomorrow, I'll post back Mike.

Ron, are they 9/16"? If things go awry I might take you up on the offer.

I'm also going to check into maybe ARP fasteners. Might be pretty pricey for all, but maybe at least for the corners.

[theakerstwo]

Larry i have a few studs from a 237 and 285 if you need some you can have them, i replaced my studs with bolts. if you need them i will send them to you. Ron

The head bolts or studs in the 237 and 285 will be 5/8 studs.

[theakerstwo]

The first 711 had 3/4 in the corner and later had 20 5/8 in all

[theakerstwo]

Those studs or any studs can nbe custom built but only thing is i have forgot were. I guess you could goggle for studs. Be care with what kind of stud you come up with some of them may want to move in with you and stay with your GF.

[rsb502]

Likewise I would replace both. If the studs are pitted or worn thin like a 711 I took apart I'd replace them. I'd start at Mack or pai. I'd be surprised if an arp or other stud mfg has them. When I did head gaskets on my 673 I had a hard time figuring out which ones I needed because I couldn't identify which 673 I had. The numbers where ground off on the block. After some matching up with gaskets that watts we figured It out. I took my manifold and turbo off because the manifold had a crack in it. Then I took one head at a time which I could man handle off the truck. Set the valves Cold to spec with a filler gauge. I have old started button rigged up to with leads hooked to the started to bump the motor over on fire order.

ARP probably does actually they make a lot more than whats advertised in Summit Racing, they probably wont be sold as Mack replacement studs but they probably have the right length and thread and if not they will make them for you for not much more than their off the shelf studs and bolts.

[b61mack]

The head bolts or studs in the 237 and 285 will be 5/8 studs.

I coudnt remember what size they were, but it is a 237 and took a 3/4 socket. Ron

[Freightrain]

Don't worry Glenn, I'm the ONLY stud she can handle LMAO!!!!

Talking with my motor machine shop owner yersterday, he was stating that likely an A460 head stud would work(it's 9/16"), but not sure lenghts yet. Mack part calls for 6 3/4"

Just talked with R&R Mack, Jeff did some soul searching and came up with a pair of part numbers. One for $10, the other was $44? WTH? The cheap one was for 36 bolts, the other was 32 bolts. Mine has all 9/16, so we're thinking it would be the cheap one. The 32 count would likely be for the bigger 5/8" in the corners. He also has my axle seal in stock(ouch, $167).

Mike, I'll confirm part number and let you know the damage. Not sure if you want all of them? Likely not enough around, as he checked parts availability and only few here/there in system. Might need to look into ARP if you want all? ($44x32= $1496 yowza, where 36x$10=$360)

BTW, on the air ride. I was able to weld and grind the rear crossbeam pins and get that fixed up last winter. I was able to get the front arm bushings out pretty easy. The RF was toast and that was the reason for the looseness. I was able to just torch the rubber out and cleaned the hole with a cup wheel on air motor. I then used the long mount bolt to install the new bushings. Was pretty simple actually. Couple big washers, some never seize and lube for the bushing. Couple seconds with 3/4" impact and the bushings were in. All in all, it rides better. The bad shake is gone. I then readjusted the toe-in and that helped with the shake in the steering wheel. Still not 100% perfect, but much, much better.

[Freightrain]

Got some studs coming. Hope to have them first of the week. I'll take'r for a little spin to make sure all is okay.

Bought a couple extra for the next time around LOL!!

[Freightrain]

Well, one day and I had 3 NOS studs/nuts/washers in my hand. Got it put in Saturday afternoon. Got it out today and went for a quick spin with the trailer. Nice and quiet!! We're good to go(for another year or so). Got spares for when it does it again.

[mackdaddytruckfixer]

I have worked at columbus truck and equipment mack deal rumpkey waste ect 15 yrs at it and the first thing i would do is send the head to be checked or you are wasting your time