How to fix a cracked 6.5 block

[JetBoater]

I am the owner of 3 cracked 6.5 turbo diesel blocks.

One of these blocks had been checked by a machine shop and certified "crack free". At that time, I was doing a motor project and was ecstatic about having a "599" block to work with... so off it went for boring, align honing, decking, etc...

I spent $1000 on machining the block and then threw several thousand more dollars into parts for my build. ARP head studs and a bottom end girdle were purchased to suck everything into the block.

I had the heads machined, including all the crack fixes done. This included the installation of intersecting Mac hardened valve seats.

Everything was ready for assembly so I took out my camera before we got started, and noticed a fatal crack on the 2nd main web.



OK... that was 6 months ago. Many of you know I went out and purchased the P400 and ended that nightmare.

I am back on this build after finding a reputable shop who repairs cracked 6.5 TD blocks. Guaranteed!

Here is the same bolt crack after it was repaired.



The shop machines in steel inserts which draws/pulls in the surrounding metal with spiral hooked threads. The inserts can withstand 3000 psi hydraulic pressure. Enough of the sales pitch.. which I'm not that good at anyway.

This shop (its a machine shop) has been repairing diesel blocks for the last 4 years and guarantees their work. They had to opportunity to tear down 2 blocks last year due to "Chinese heads" with porosity issues... This gave them a chance to review previously repaired cracks/inserts for stability. NO ISSUES. Ya... no issues.

I had all 3 of the 3 cracks repaired... here are the other 2.




The shop usually does all 6 outer bolt holes on the inner 3 main webs. They do this even if they are not cracked as a preventative measure. This is not cheap... at $100 per hole.

They finish off with align honing to ensure everything rotates straight.

I will be building the engine and selling it to recoup some of my $,$$$. I am happy to provide any info to those who are in need of this type of repair... I am a believer !

The product is a LOCK-N-STITCH product and the inserts are called Full-Torque... apparently well known in the cast iron repair field.

Caution: you can possess the right product to fix a crack, but you still require a skilled shop to ensure you end up with a stable repair.

[More Power]

We did a story a few years ago, written by Andy Ashwill, who repaired a 2000 506 block using the Lock-n-Stitch method (which was explained in the article). As far as I know it's still on the road.

Personally, I would rather not spend money on a cracked block, but there are extenuating circumstances (like yours).

I'd be inclined (if I had to use a cracked block) to repair the crack, then install splayed mains. This should move the stresses away from the failure point.

Jim

[JetBoater]

I didn't search out TDP for the fix... rats! There is just a wealth of knowledge buried here.

I did research the splayed main caps before the fix... I didn't/don't have the $1,200+ dollars to spend there.

The machine shop doing these repairs have reliably been repairing and building these diesel engines without any aftermarket products. They have instilled me with confidence in this 599 block... and perhaps the other 2 dead projects sitting in my garage.

Thanks for the input Jim.

[JetBoater]

I should mention that this method does use the lock-n-stitch pin, the same method used to pull cracks together.

The bolt holes were fixed using the full torque insert... shown here





You can see how the pipe style threads are cupped, to pull metal towards it when torqued into position.

[jerry598]

The shop usually does all 6 outer bolt holes on the inner 3 main webs. They do this even if they are not cracked as a preventative measure. This is not cheap... at $100 per hole.

They finish off with align honing to ensure everything rotates straight.

I will be building the engine and selling it to recoup some of my $,$$$. I am happy to provide any info to those who are in need of this type of repair... I am a believer !

The product is a LOCK-N-STITCH product and the inserts are called Full-Torque... apparently well known in the cast iron repair field.

Caution: you can possess the right product to fix a crack, but you still require a skilled shop to ensure you end up with a stable repair.

My shop charged me $40 per bolt hole to do this fix. But, it was only the second time they had ever done it. I'm no machinist and I can't be sure about the quality of their work. The only concern I had was that one bolt threaded into it's hole with some difficulty, that is, it required a wrench to get it seated in the last few turns. I tapped the hole once to clean it up but that did not help much with the threading. Don't know if that's a sign of poor workmanship or not. I'm just now ready to put it back in the truck and fire it up. Just in time for the Israelis to bomb Iran and diesel will go to $10 a gallon.

[nodd89]

hey i live in vic what do u want for the blocks a peice if u have one left?

[JetBoater]

I sold that project and all my 6.5 diesel parts to a guy in Surrey this past July.

You can try contacting Garrett Engines in Kamloops BC... talk to Eric Garrett.
He can repair your block or supply a repaired core. He can machine to your needs and do the short or long block. He stands behind his work and warranties fully assembled units only.

Good luck

[Robyn]

I bought the tooling a couple yeqars back and do the inserts here.

This is a 100% great fix.

As long as the cracks are not out of the bolt hole or are not at the register cut, your set.

I usually do all six center holes (outers) but on occasion some customers will only pay to have the cracked ones fixed.

I would never toss out a block that has short cracks in the center mains.

If the cracks are already below the holes depth , then its too late for that one..

The best part of the insert is that once the block is done its better than it was when new.

I am still not a fan of the 506 squirt block, and personally would never use one no matter what. **UNLESS** it was a real late AMG 506 block.

The early squirters would crack through the squirt holes and up into water.

Another important step is to totally debur the bottom end on these engines.
This includes lightly chamfering all the holes in the bottom end.
Breaking all sharp edges on the webs as well.

These block have more damned stress risers in them than I care to think about.

Missy

[Greg@Lloyd]

Does anyone know the part number for the correct full torque inserts to repair the 6.5 outer main bolt cracks.
Not sure which ones to order and don't want to drill the holes any deeper than original if possible.
Any help would be greatly appreciated.

[Robyn]

Does your block have 10mm outer bolts or 12mm ???

The threads must allow the insert to be flush with the block surface.

Use a steel plate and a mag drill (Or get the block in a mill or large drill press)
The hole must be straight....

Debur and roughness where the drill breaks through the web....Smooth...no stress risers (Sharp edges)