CUCV 1986 M1008 - In a Real Pickle - Bad Heads - Need Advice

[Commander5993]

Hello All!

Been a while since I have posted anything, but I am around from time to time, just been sooooo busy, just haven't had much time.
But, something happened recently that made me "take some time"... my 1986 M1008 with the 6.2L diesel - 3 speed trans 4x4, blew a head gasket a couple weeks ago...

Long story short, got the top end of the engine tore down, got the heads off, bought all new gaskets for everything, new head bolts, etc.
Decided we needed to send the heads out, have the magnafluxed (to check for cracks), milled, and a full valve job....
Just got a call a few minuets ago with some really bad news... they said they just got them fluxed, and quote "...the heads are riddled with cracks..."

So... what to do...

I need some advice. What is the best route to take at this point??
Should I (or are we even able?) to buy new heads for these engines?
But would that be the best option? Both in reliability and price wise?

A little background: We've owned this truck for going on 6 years now, when we first got it, my father and I went through it bumper to bumper, as far as all maintenance and any other issues we could find. I re-did a lot of the electrical especially in the engine compartment, a little inside the cab. Whoever had screwed with the wiring had no idea what they were doing... or they just didn't care. We replaced all belts, filters, and much other on the engine. Changed all fluids throughout. A lot of other too, but we did not tear into the internals of the engine or transmission, as it was running seemingly fine other than a small oil leak out one valve cover.
After we got this truck done and "up to date", we moved from where we lived in Indiana and were on the road for about 18 months. We drove all the way up to far NW Montana. During that time we put approx 5,000 miles on this truck (as well as our deuce and another truck).
We finally ended up here in Missouri, where we have been for the last 3 years, during which time we've put another 7,000 miles or so on the truck. The truck currently shows around 22,000 miles on the odometer, but if that is what is on the engine is anyone's guess.

We haven't had any issues with in during these last 6 years, other than the starter dying. We replaced the starter with a new Wilson starter about a year ago, when the "original" one died. We had the original starter rebuilt, but found out that it was not even the correct starter. In fact someone had stuck a 12v starter on it. How the solenoid had held up all that time, I don't know. But the guy I had rebuilt it put a 24v solenoid on it, and we kept it for an "emergency backup" anyway.

Back some months ago, we had noticed when we would first start the truck, a little "puff" of white smoke, but only out of one tail pipe, the other pipe was always clear. Which I knew (but wanted to believe other wise) that meant water. It didn't seem to get any worse, so I just kept it in mind. Then back a few weeks ago, we saw that it was starting to very lightly smoke while running.... Then the last day I drove it I was up in the little town not far from here, and it started to really smoke a lot out the one tailpipe. Didn't make it home before the temp light came on, so we pulled into the driveway of someone we knew. They let me leave it there overnight as it was already late, and we towed it one home the next day. And you know the rest from the first paragraph above.

The point being, this truck has been our "daily driver", and we need it to be dependable.
So what would be my best option??
*Get Quality Rebuilt Heads?? (not the reman's with cheap chinese junk valves etc) And then also rebuild the engine?
**Or get a whole a new engine??

If a new engine, whats the likelyhood of finding the same 6.2L in fully rebuilt condition, Done Right?
I don't want to just put in a used "unknown" engine in it, and be right back at the same place 6 months down the road. I need something that I can trust, and I really don't want to do this but one time.

If I can't find a 6.2L... then what would be the options in changing to a different type engine, even if it is changed to gas? I would expect that the transmission would have to be changed out then as well? Although we've never had any issues with this 3 speed transmission, I don't know the actual condition of it.

Basically, what new or good remanufactured engine and (4 wheel drive) transmission would fit and work in this truck?

Any Help and Advice is MUCH Appreciated!
~Thanks
Warren

 

[richingalveston]

pm me if you need a good 6.2 I pulled mine for a 6.5 with some banks parts (turbo never installed on motor)
To change the motor you don't have to change tranny but possibly torque converter if you go gas

The only direct swap in another 6.2 or a 6.5 if you do not get a Navistar 6.5 I would probably stick with a 6.2
you can get heads for a 6.5 and put on your 6.2 if the bottom end is in good shape. aftermarket heads are a crapshoot also.

changing to another engine cost a lot more because other parts have to change.

 

[scottladdy]

Assuming from your post that this truck has value, utility and meaning to you that warrants an investment.

A few things that will help us if you don't mind:

1. Sounds like you have the necessary equipment and means to swap an engine yourself. Please confirm if not.
2. What is your budget?

I decided a long time ago for my own trucks that if the (apparently) original blocks became damaged I would swap in new long blocks. More than likely optimizers. I would keep the old school mechanically controlled engines which, while no power houses, are fuel efficient and relatively cheap to maintain. This is in contrast to putting in a D'Max which requires electronic controls and has a much higher TCO.

New heads would depend on how solid the bottom end is at the time. You also need to ensure there are no cracks in the block. Clean the old head gasket material off the deck carefully and look for any signs of cracks. No sense in putting new or reman'd heads on a bad block. For all you know the cracks the machine shop found in your heads, though likely, may not be the cause of your coolant leak.

 

[Commander5993]

pm me if you need a good 6.2 I pulled mine for a 6.5 with some banks parts (turbo never installed on motor)

To change the motor you don't have to change tranny but possibly torque converter if you go gas

The only direct swap in another 6.2 or a 6.5 if you do not get a Navistar 6.5 I would probably stick with a 6.2
you can get heads for a 6.5 and put on your 6.2 if the bottom end is in good shape. aftermarket heads are a crapshoot also.

changing to another engine cost a lot more because other parts have to change.

Hi richingalveston, Ok, so even with a transmission change, it would still take more part changes to swap in a different type engine/transmission then?
I kind of figured that, but wasn't sure, exactly why I wanted to ask. And of course the more parts you have to change the more cost. So I guess I don't want to go that route.

Is the bottom end in good shape... well that is a good question at this point. Up until now, I thought the engine was good, but after removing the heads I'm not so sure.
I was going to put in my original post, that when I removed the exhaust manifolds, I found that neither one had any exhaust manifold gaskets. Further, the valve covers didn't have gaskets either, just some gasket sealer.
So what shape is the rest of the engine.... I have no idea at this point.

 

[Commander5993]

Assuming from your post that this truck has value, utility and meaning to you that warrants an investment.

A few things that will help us if you don't mind:

1. Sounds like you have the necessary equipment and means to swap an engine yourself. Please confirm if not.
2. What is your budget?

I decided a long time ago for my own trucks that if the (apparently) original blocks became damaged I would swap in new long blocks. More than likely optimizers. I would keep the old school mechanically controlled engines which, while no power houses, are fuel efficient and relatively cheap to maintain. This is in contrast to putting in a D'Max which requires electronic controls and has a much higher TCO.

New heads would depend on how solid the bottom end is at the time. You also need to ensure there are no cracks in the block. Clean the old head gasket material off the deck carefully and look for any signs of cracks. No sense in putting new or reman'd heads on a bad block. For all you know the cracks the machine shop found in your heads, though likely, may not be the cause of your coolant leak.

Hi scottladdy,
Well, we paid $7800 for the truck 6 years ago. I took a train to new mexico, and a rental car on over to arizona to pick up the truck, and drove it back to indiana.

The body of the truck is in great shape, very solid, no rust.
The 4 wheel drive works perfectly.
We put an all aluminum extra extra tall... "camper shell" for lack of a better word, on the bed. So the bed is totally enclosed with a door operated by a shock cylinder that raises up.
We use this truck litterally all the time.

One of the reasons we bought this truck is specifically because it did not have any computers or other "required" electronics. We wanted a simple straight truck that we could fix if needed.
So I'm right with you there on the mechanically controlled engines, and yes this 6.2 has been very fuel efficient.

To answer your questions:
Sounds like you have the necessary equipment and means to swap an engine yourself. Please confirm if not.
I don't have a cherry picker, but yes I do have the equipment needed to pull an engine. And for the first time, I have a shop to work inside of... I just had to take everything else outside to make room for the truck


What is your budget?
Well..... what will it take to fix it right?
I don't have deep pockets, but if needed I would rather take a bit of time to get the cash required to fix it the right way, rather than just throw some money at it to try to "patch it up".


I'm not looking to "upgrade" to a power house engine or anything, I'd be just fine staying with a 6.2 or a 6.5, if I can get the needed parts, and I can do it "the right way".
Although its been a while (uhmm.... 16 years or so?) since I've rebuilt a motor. If I have to pull this engine, and rebuild the entire lower, and buy new heads, if the parts are available I can do the work. From what I had tried to look up thus far, I just wasn't sure if the parts were even going to be available. As I have yet to find any place that lists the heads for this motor. I guess I'm just not looking in the right places.

With that said, if I pull this motor, and I can buy a long block like you mentioned, that may just be the best way to go.
Especially as I mentioned in my last post, that when I removed the exhaust manifolds, I found that neither one had any exhaust manifold gaskets. Further, the valve covers didn't have gaskets either, just some gasket sealer.
So what shape is the rest of the engine.... I have no idea at this point.

Also a long block would obviously be faster to get it done as well, which thankfully I'm not having to rent a car or anything... although that would be a good reason to drive the deuce but right now my cousin left his "extra" truck here, so we're driving it.

So what would your suggestion be?
Get a long block? If so, where would be the best source?

 

[corelokt]

Check the mains for cracks. If good, get some 6.5 heads and I'd go arp studs. I don't have a good reason as you don't have a turbo tho. If the bottom end is good, you might consider the Ford pinto head studs in the mains to take some stress off the webs. It's excessive, but...

 

[ken]

They don't come with from the factory or need exaust manifold gaskets. And the RTV silicone on the valve covers is typical of military repairs. The valve covers and oil pan leaks fairly easily.

 

[98G]

I would think that new-in-the-can 6.2 motors would be readily available. Maybe Warthog still has one rattling around somewhere.....

 

[snowtrac nome]

I would look for a good 6.5 with low miles, you may have swap out the mechanical pump for the electronic pump, also the serpentine belt system. and waterpumps would also have to be changed. along with the flexplate. yours has the 2 piece rope seal crank and the newer 6.2 and 6.5 engines have a full circle rear main. the reason for a 6.5 swap is simple, 6.2 parts are hard to come by I have a gen1 6.2 in a chevy truck I rebuilt, with a reman crank and all. it broke a journal inside a main I cant find another crank, my suppliers are saying that its an obsolete part. good luck those old v8 chevys weren't power houses but they were easy on fuel and reliable also I have never driven a truck that handled snow and ice like ,my diesel square body

 

[scottladdy]

Not an endorsement as I have never worked with them, but others here have: http://leroydiesel.com/

 

[cucvrus]

I went thru 3 sets of heads before I found a good un-cracked set. I would say just put a good set of heads on the bottom end and call it a day. The head gaskets on most of these trucks are in bad shape if you still have the original ones. Time and wear have contributed to the head gasket leaking. I would not worry about doing anything else. The original motor has black silicone valve cover sealant with no gaskets. Check out a few of my threads. I have been changing head gaskets and having heads redone on CUCV's as regular maintenance items the past 3 years. Even good running supposedly nothing wrong with them had bad gaskets when I pulled the heads. 30 years and acidic antifreeze have that tendency.This is a head gasket that was NOT leaking. I removed the heads just to change the gaskets as a maintenance item while I was rebuilding the truck. Glad I did. Look at the corrosion in the gaskets at the water passages. All I did was send the heads out and it took 3 sets to get a good set. I bought a complete gasket set and changed the head bolts. It has worked for me on everyone I worked on so far. I have not had any bottom end problems with any 6.2 even a few with over 200K on them. I have sold a few with over 150K and as far as I know they are running fine never been apart. Other then an injection pump or 2. My vote would be just change the heads and fix the problem. keep it with in budget. You know what you have fix what is wrong with it and move on. I just find pulling the engine and working on it on the floor is much easier. Disassemble it reseal it clean it paint it and reinstall it. that easy. Don't buy any unknown engines. they may have bad head gasket very soon just like yours. IMHO fix yours.

 

[Tinstar]

How was that thing still running?!

 

[Commander5993]

Not an endorsement as I have never worked with them, but others here have: http://leroydiesel.com/

Wow..... these new upgraded long blocks are a lot higher than I imagined. Would love to have one, but don't think I can swing $7k+

Looks like $2k for two new heads... if I want hardened valve seats... not sure why I would want "NON hardened valve seats"....
I was hoping to avoid have to get a new set when I sent the heads out to the machine shop, but since those are cracked, going to have to go with new one's.

 

[Commander5993]

I went thru 3 sets of heads before I found a good un-cracked set. I would say just put a good set of heads on the bottom end and call it a day. The head gaskets on most of these trucks are in bad shape if you still have the original ones. Time and wear have contributed to the head gasket leaking. I would not worry about doing anything else. The original motor has black silicone valve cover sealant with no gaskets. Check out a few of my threads. I have been changing head gaskets and having heads redone on CUCV's as regular maintenance items the past 3 years. Even good running supposedly nothing wrong with them had bad gaskets when I pulled the heads. 30 years and acidic antifreeze have that tendency.View attachment 683221This is a head gasket that was NOT leaking. I removed the heads just to change the gaskets as a maintenance item while I was rebuilding the truck. Glad I did. Look at the corrosion in the gaskets at the water passages. All I did was send the heads out and it took 3 sets to get a good set. I bought a complete gasket set and changed the head bolts. It has worked for me on everyone I worked on so far. I have not had any bottom end problems with any 6.2 even a few with over 200K on them. I have sold a few with over 150K and as far as I know they are running fine never been apart. Other then an injection pump or 2. My vote would be just change the heads and fix the problem. keep it with in budget. You know what you have fix what is wrong with it and move on. I just find pulling the engine and working on it on the floor is much easier. Disassemble it reseal it clean it paint it and reinstall it. that easy. Don't buy any unknown engines. they may have bad head gasket very soon just like yours. IMHO fix yours.

Well, these gaskets weren't quite that bad, but they were in pretty bad shape.

Good to hear that the bottom end is lesser prone to issues. I have read that some of the 6.2's were prone to cracks in the blocks. But you haven't found that to be the case?

Thanks for info!

 

[Commander5993]

Check the mains for cracks. If good, get some 6.5 heads and I'd go arp studs. I don't have a good reason as you don't have a turbo tho. If the bottom end is good, you might consider the Ford pinto head studs in the mains to take some stress off the webs. It's excessive, but...

What is the issue with the webs exactly? I've seen several places mention this, but none of them actually stated what the issue was.
~Thanks

 

[Commander5993]

They don't come with from the factory or need exaust manifold gaskets. And the RTV silicone on the valve covers is typical of military repairs. The valve covers and oil pan leaks fairly easily.

The exhaust gaskets... or lack of... is strange to me... never knew of an engine that didn't need them. I mean I guess it doesn't hurt anything, but would seem to me that it would at least cause more engine noise to escape or something. I could be wrong though.

Yeah, seems like on most GM engines the oil pan and valve covers always leak...

~Thanks

 

[Commander5993]

Check the mains for cracks. If good, get some 6.5 heads and I'd go arp studs. I don't have a good reason as you don't have a turbo tho. If the bottom end is good, you might consider the Ford pinto head studs in the mains to take some stress off the webs. It's excessive, but...

I have already purchased a full set of all felpro gaskets... not sure if that was the best option. I can return them all, as none of them have been used at all yet.
I also ordered new felpro headbolts. But they are still Torque to Yield. Didn't know there was another option. Really like those studs though, I might go with them simply because of the design, even though they are 5 times the cost...

~Thanks for the info!

 

[Commander5993]

I wanted to thank everyone who replied! The information has been a great help!
I'm not sure what I'll do yet... but I am at least considering just putting a new engine in it. Although we would have to sell an all aluminum cargo trailer that we have... or the deuce... maybe both.

Need it to be dependable once I get it back together, but we're not going to jump and get into a rush.
Going to take a bit of time and think about it and see what we can do.

Thanks All!

 

[cucvrus]

No need to use head studs. I look at it this way. They lasted 30+ years with torque to yield bolts. Put new ones in and call it a day. I am not a guy that fixes on the cheap. But I do NOT just buy something and change something because someone else says it's better. I mean 30 years and still going. That has passed my test. I think 2 K is a lot of cash for a set of 6.2 heads. I have a set of GM ones in the crates. I would be tempted to sell them. I also have many that are used and un cracked. I learned a while back that some of the cracks are going to be on any of the heads and never hurt a thing. I was talking to the machine shop guy and he said he just lets people know they are cracked and that I can decide if I want to proceed. Of course I never ran one and over heated it with a bad head gasket. I changed a few just to change them and I had a few that would hold pressure all night long and never had heat in the cab when I slowed down in city traffic. That prompted the head gasket change on them 2. If I could sell you a set of good used ones I would. But getting them checked and shipped to you would not be cost effective. Good Luck. If it were mine I would get a set of good used heads and put it together with the new parts you have. I would install the exhaust gaskets. they seem to work every time that way. I have tried the no gasket on reassembly and had a few leaks. Do as you wish and have a great day.

 

[cucvrus]

How was that thing still running?!

Yes it ran fine. It never missed a beat. I changed the head gaskets because I had the engine out during the restoration of Easter Find M1008. I have been stalling on that project. I have so much other work to do this year. But all is good. A little at a time.