Short Version: Coolant just came pouring out of one of the #3 exhaust manifold bolt holes when I rolled the engine over on the stand - obviously with the passenger's side down. So, are these engines like B-block Chryslers and the bolts go into the cooling passage? Or, as I suspect, is this head cracked?

Long Version: Bought a truck with a "built" 351M that does indeed run. Swapping engines between that truck and Dad's since his 351M runs like the original '81 M's ran - sluggishly. But, while this one is out I am fixing some oil leaks so put it on the stand to do the work. Wanted to figure out what cam is in it so put the degree wheel on it and had the dial indicator in #1 to find true TDC. Got the dial indicator's extension caught between the piston and the spark plug hole and the threads snapped and dropped into the cylinder.

So, I rolled the engine over hoping the extension would drop out and got a shower of coolant. Given that I'm thinking the good Lord was telling me I needed to pull that head and somehow I was missing it. Maybe now it is a given?

Thanks, in advance, for your expert opinions. I won't shoot the messenger as I'm pretty sure I know the answer.

 

Yeah, you're sure of the answer, there shouldn't be any coolant there....

 

As you know, Chris, I wasn't looking for a vote of confidence. I was begging, pleading maybe, for someone to say "actually, that's not too uncommon, and all you have to do is make sure the bolt has PTFE on it". I do know some engines are actually designed that way, such as the 383 in the Bee behind me. So, maybe this has been seen before and isn't terminal - for the head.

Ok guys, 6 others have read this besides Chris. No comments?

 

I'm thinking the guy who built your heads got a bit too close to the water jacket.

Give it some time (maybe 24 hours) this forum doesn't normally see but a trickle of traffic per week.

 

I don't think these heads have had any porting done. And, even if so he wouldn't have been working in either the bolt hole or the cooling passage. It is as if a long bolt was put in that punched through.

But, I can wait to let others see this thread. We are going to be busy for the next couple of days so there is plenty of time.

And, as I just posted in Dad's Truck Build, my leak-down testing shows #2's exhaust valve has a bit of a leak. So, I'm betting I'll get to fix that.

 

Probably drilled out a broken bolt, but went a bit too deep........

 

Gary, I just took a look at my heads, and there definitely should not be any coolant coming out of the EM bolt holes. Shine a flashlight down the suspected thread hole and look closely. On my heads, you can see the end of the hole on each and every EM bolt hole. If the hole is hollow, you have issues.

 

I'll look to see if I can tell. But, if he did go "a bit too deep" I would have though he would have used thread sealer on the bolt, and there was no indication of any. If I knew that was the case I might put sealer on the threads and go for it. On the other hand, it is out so......

 

Shaun - I'll do that in a day or two as we'll be busy tomorrow if not Sunday. But, that's a good idea - maybe a way to tell if it is drilled or cracked.

 

I could clearly see the shiny tapered end of the hole, so if you see darkness....



If you seal that bolt up really well, maybe you could get away with it, just as long as there isn't anything else wrong with the heads.

 

My thoughts exactly. If it looks like it was drilled maybe I can seal it and be fine - after all, it wasn't leaking before I pulled it and there was no sealer on the bolt. But, if it wasn't drilled, meaning it has cracked, it really needs to come off as there's no telling what else is wrong.

 

That sounds a little suspicious Gary. I dont think the wheezer heads have through passages either where the EM bolts up. If the threads are tight as in not stripped out I couldnt imagine why thread sealer wouldnt work. Some of the head bolts on the wheezer go through the coolant passages and they require thread sealant. They seal up just fine.

I hope the head isnt cracked. However, if it is I believe I saw a truck or two with the M in them at Plainview. I dont know if they would make you buy the entire motor. Suppose they did I couldnt imagine them wanting more than a couple hundred for it. Then again I bet a machine shop around town would have a head.

Then again if Kris was farther into his job he would have enough money to build a wheezer for Rusty and that would leave both M's for the picking.

 

How much further into his job? Maybe I put this on the back burner and bring the machine work for the ZF5 transformation forward?

 

He only has about half of what the truck costs now. It will probably take him another 2 weeks to get the rest of that. Then more than likely it will take 3 or 4 weeks to save up enough for the rest of the goodies like machine work,engine parts and tranny parts.

So I dont know if it is possible to do it in any amount of time thats reasonable.

 

Lemme think on that.