506 block crack questions

[derekja]

First, pictures:

http://img.photobucket.com/albums/v719/derekja/truck/block1.jpg

http://img.photobucket.com/albums/v719/derekja/truck/blockcrack1.jpg

http://img.photobucket.com/albums/v719/derekja/truck/blockcrack2.jpg


Questions:

1) is there any grey area? That one crack is the ONLY one I see, even after looking pretty hard. But I think if I see a crack at all I should not invest in a rebuild, right? I haven't spent any money on block rebuild parts yet...

2) is there any approachable repair? Is splaying the mains an option with a crack already in there? Is that something that could be described fully enough for a local machine shop to get their head around and do successfully?

3) any other recourse, or am I now off to find a new long block?

Sigh. Thanks. This is what I didn't want to find in here... a bunch of cracks would possibly even have been better than a perfect, lovely block with a single fatal flaw.

[ronniejoe]

I know of one crack repaired block with splayed mains that is working well. However, it would always be nagging in the back of my mind that their might be a problem...

[dieseldummy]

That is a pretty bad crack, even if it's the only one... I wouldn't waste any money rebuilding a block in that shape, splayed mains or not. You'll be better off to find a good rebuildable block and using it.

[Slim shady]

I know what you are going through. The repair RJ is talking about is from this company http://www.locknstitch.com.

I have their head repair kit and I have repaired a few 6.2 and 6.5 heads with some serious cracks.

It wouldn't hurt to call them, they are very knowledgeable and honest about what can and can't be repaired. You can send the owner your photo and he will tell you if it is a viable repair. Repair the one crack and put splayed mains on it. This can't cost as much as a new AMG block.

http://www.locknstitch.com

[redbird2]

I don't think I could put money into a block with that bad of crack if I was planing on any towing in the future. I might stick it back togeather as is new gaskets and drive it til it drops. You already need new heads thats now new block or good used block. I think I have a 96 and a 2001 block I know its a GEP engine setting around I will look this weekend.

look at the cost you will have in this bad block might go out and purchase complete engine with warranty cheaper in long run.

testing old heads 100
new cylinderheads 850
rings 120
rods bearings 40
mains 50
gasket set 85
timing chain 50? guessing I put in gear drive
splayed mains 500 if memory is right
cam bearings 25 going to need to clean block to machine
freeze plug set 10
machine work 500 could run more with installing splayed mains
oil pump 125
total 2455 I sure I've missed somthings i was just guessing on these prices if you would have to bore you will have another 120 in machine plus 400 in pistons all in a block that has crack and could start leaking

i see engine on ebay 2900 plus frieght with 500 core unlimited mileage 12 months I have never purchased from them i know nothing about them but you might look around and find a good deal and go with complete engine

best of luck I will let you know if I have a block available

[Slim shady]

Unless you buy one of RJ's blocks or a new AMG block, you run the same risk of main web cracking.

You may get a lot of miles before a failure You may never know if your main webs are cracked on your new block, until the crank ends up in the oil pan.

I would repair the one main web, spend the money on splayed mains and be done with it . If you drill a hole in the crack at the end, it will not travel any further. Repair it with the metal stitching repair and the splayed mains will relieve the stress on the center webs.

At the very least contact the cast iron repair guys and get their opinion. We are not cast iron repair experts, they are.

Get all the information you can and then make YOUR decision. You will spend money either way. Look for the most durable solution not the cheapest.

[Robyn]

Well just my 2 cents worth.
I agree with RJ 100%

A rebuild is too expensive and time consuming to take a chance on losing it.
I would use that block for a door stop or a boat anchor and ferret out another one thats not cracked.

While your serching check out and wash up all the other engine parts.
Get the crank tanked, maged and if good, polished.

Generally get all the rest of the engine parts ready to go.

You have a good several hours work cleaning ring grooves unless you end up with a block that requires a bore job and fresh pistons.

Sorry to hear the sad news.

Best of luck on the search for a block

OH if you agree to buy a used engine for the block be sure and get it in writing that the block is guaranteed to be crack free as well as the crank.

I bought a 6.5 (506) block and it was junk but I had insisted on a written guarantee of NO CRACKS and as it turned out that paid off.

Robyn

[Robyn]

Just a thought here.

I see this is an oil spray block.
I would hunt down a non spray 506 of better yet a 599 block.
Now they all can crack but the chances of keeping it together are far better with a none spray block.

92-93 and early 94 used the 599 block.

My 94 has 250K on it and is crack free.

Robyn

[Slim shady]

If we all kept doing the accepted. Then none of us would be here playing with injectors, pumps, lower compression pistons and the like.

I have talked with the guys at Lock and Stitch about a block I lost and want to repair. I will repair it with their system as the one guy did and then install splayed mains. His is still running as far as we know.

I am not an engineer but have spoken with my brother who is a mechanical engineer (I am sure we have a few here also) and has given me a complete engineering run down on the subject with terms and language I have no clue about.

That being said, as far as the cast iron repair, he likes to fix the cause of the problem rather than repair an inherent design flaw. Thus the splayed mains, to transfer the cycle loading out to a more stable mass. (I think that is what he was talking about). Oh and by the way, on the lower end stud girdle, he thinks that it is a feel good product and won't do much good.

This is my two cents worth, it is just hard to get new ideas accepted. There may come a time when purchasing a good used block for GOOD MONEY is not a viable option.

Maybe we should see if they (Lock and Stitch) would like to repair a block for the forum and we could do splayed mains and see if it lives or not. I for one would put some money up for the project.

[Slim shady]

By the way why don't we see if we can get this block fixed and then splayed mains put in. We can see if it lives. I will chip in for some of the repair just to find out. Let me know what others think, it would be much cheaper as a group than having one person pay for it.

[derekja]

I'm looking forward with interest to the response I get from B&G Machine in Seattle. They are who Gary Reed, the LocknStitch CEO, pointed me to in the Seattle area after looking at my pictures.

"
http://img.photobucket.com/albums/v719/derekja/truck/blockcrack2.jpg
http://img.photobucket.com/albums/v719/derekja/truck/blockcrack1.jpg


Please see the thread below for a block crack that the locknstitch
guys sent me your way as a repair possibility. In addition to
repairing the webbing crack I am looking for someone to rebore the
main caps with a splayed outer bolt. The repair seems to distribute
stresses better and prevent further cracking. It is described here:
http://www.kennedydiesel.com/detail.cfm?ID=267

So I guess the full work list on this engine looks like this:
--clean and mag block
--evaluate deck flatness
--cylinder hone (or rebore if necessary)
--locknstitch weld repair
--fill bolt holes and rebore new splayed mains

An idea of what your time requirements are and a cost estimate would be great.

Thanks!"

[Slim shady]

Keep me informed. I told you the owner would talk with you, not some tech sales person. I liked his product and have purchased and used the head repair kit along with the kit to install the water passage sleeve between the valves in the 6.2 and 6.5 heads.

Since you only have one main crack it shouldn't be that expensive to repair. Let me know, send me a private message if you want.

Maybe we can get JK to sell you a set of splayed mains at a project price. Then we can do a test on how the repaired lower end lives.

[gmctd]

IMO, that crack is way too deep to salvage - it appears to be well past the bottom of the bolt-hole.

Look at it on the opposite side, in the area of major undercutting.

1/2" or so could possibly survive with splayed bolts anchored into the area above the rails.

[derekja]

Feasibility of a repair is looking poor. I spoke with b&G machine in Seattle and they don't tend to repair small diesels using that technique. They will locknstitch weld big engines, but sent me to Action Machine shop for smaller engine work like this. Action was very reluctant to take this on, they said that the welding in the mainline of the block like that tends to heat up and distort the block. They quoted me about $200 on the weld, but said that it would likely run to double that or more to correct any block distortion that might be caused. They recommended buying a new block. Of course, this was sight unseen based on a verbal description of the crack, but they didn't say anything encouraging enough for me to pursue it by taking the block down there.

So, my options:
1)--local 1993 engine with 160,000 miles on it. Individual is selling it whole and wants $1500, then I'd still have to rebuild. It has a new IP, but I'm not sure a 1993 IP would fit up with my 1998 wiring. Anyone know when the 599 block was produced? This truck was built in oct of '93.
2)--1800 or so for a bare block guaranteed crack free, then ~1500 for heads and rebuild parts
3)--3K or so for a scary reman
4)--5K or so for a good reman on a new block and heads
5)--9K or so and a 3 month wait for the best engine ever


I'm wavering between option 1 and option 4, I believe. I may go up to look at this 1993 on Wednesday and if I can do a driver side compression test and it looks good and then drop the pan look for webbing cracks then I might take it. Ideally I'd like to break it down and magnaflux it and all before buying it, but that's hard.

I still need to ponder this some. Option 4 is the logical one, except for it's impact on the bank account, I think.

[Slim shady]

I understand your plight. I tried to find a good 6.5 block here in Michigan and it was almost impossible.

I had a good 6.2 block and used that. The rebuild still cost me a small fortune. I spent almost as much as I paid for the truck. It was heart breaking to dig into the wallet for that kind of cash on a motor that might (probably) will crack again.

[Kennedy]

I know what you are going through. The repair RJ is talking about is from this company http://www.locknstitch.com.

I have their head repair kit and I have repaired a few 6.2 and 6.5 heads with some serious cracks.

It wouldn't hurt to call them, they are very knowledgeable and honest about what can and can't be repaired. You can send the owner your photo and he will tell you if it is a viable repair. Repair the one crack and put splayed mains on it. This can't cost as much as a new AMG block.

http://www.locknstitch.com


This is what Mark Bajus did to his 93 several years back and then topped off with splayed mains. He runs pretty stout fueling and boost on it too, but it's also 18:1.

[Slim shady]

I would fix the crack with the lock and stitch yourself if you are able to. Call the owner of Lock and Stitch and ask him for another opinion. He will also guide you through the process if you are so inclined.

The process is not difficult you just have to be patient and thorough. The one crack shouldn't take you that much time to repair. If I remember right they have fixes for the outer main bolt holes also. If you fix it right this time and put splayed mains on it you will be done.

If you decide to scrap your block let me know I may be interested if I can get it here reasonable. I would like to repair one with only one crack and do the splayed mains myself.

Mine has all three mains cracked almost to the center of the block.

The weld repair the one machine shop is talking about sounds like an oven repair. They heat the whole block to 500 degrees and keep it at that temperature,weld it and then cool it over several hours in a oven which lowers the temperature and a controlled rate, this produces the warping they are talking about). This is an accepted repair on cast iron. The lock and Stitch doesn't require heating of any kind.

The company that does the big engines could do yours without any problem. Take it down and sell them on the idea of fixing it as a forum project. They could get a potential windfall of business from this site alone.

[ronniejoe]

Actually, the oven process minimizes warping by minimizing the thermal gradients. Warping is caused by thermal stresses caused by high thermal gradients from the welding process on a cold block.

Many precision aerospace parts are welded in this manner specifically to eliminate heat distortion.

[Slim shady]

I agree, you are correct. The rate at which the piece is brought down in temperature effects the amount of warping.

I have had a few pieces oven welded, my brother has also, he is an aerospace engineer. He and I have had many discussions on different subjects especially the GM 6.5 diesel.

I am not an engineer: sometimes he rattles off things that don't mean anything to me. I know how to fix broken items, not make and design new things that require complex equations. I respect him and his opinion though.

Do you have an opinion on the repair? I know you sell engines, but not everyone can afford a Cadillac, some have to settle for a Pinto (showing my age).