Truck#1 96 or97 (I can never remember) 3500 HD
Broke crank block is probably junked. Turbo is 6 months old. This is the truck I have to get going.

Truck#2 1994 3500 HD
Has at least one cracked head but was running, #3 piston looked like it was just barely touching the head. Crank appears good. Both trucks are F motors

I also have a block and crank in unknown but assumed good condition that orginally came from truck #1.

I am thinking the newer block would be better to rebuild the motor with? What casting numbers are good or bad.

Same with crank and heads,newer is better or not?
Machine shop says they can sleeve the heads to fix the cracks. Any one had this done.

Can a good machine shop check the blocks and cranks for cracks or is it just a visual inspection/crap shoot.

What would you guys recomend as far as problems to watch out for? And which of my available parts to use if they are good?

Off the top of my head I am thinking Pistons,bearings,harmonic balancer valve job and seals, cam bearings,rebuild/replace injectors,glo plugs,etc.

Thanks
Gary

Truck#1 96 or97 (I can never remember) 3500 HD
Broke crank block is probably junked. Turbo is 6 months old. This is the truck I have to get going.

Truck#2 1994 3500 HD
Has at least one cracked head but was running, #3 piston looked like it was just barely touching the head. Crank appears good.

I also have a block and crank in unknown but assumed good condition that orginally came from truck #1.

I am thinking the newer block would be better to rebuild the motor with? What casting numbers are good or bad.

Same with crank and heads,newer is better or not?
Machine shop says they can sleeve the heads to fix the cracks. Any one had this done.

Can a good machine shop check the blocks and cranks for cracks or is it just a visual inspection/crap shoot.

What would you guys recomend as far as problems to watch out for? And which of my available parts to use if they are good?

Off the top of my head I am thinking Pistons,bearings,harmonic balancer valve job and seals, cam bearings,rebuild/replace injectors,glo plugs,etc.

Thanks
Gary

Yes a good machine shop can do more than a visual inspection for cracks, i think its called magnafluxing? As far as casting numbers and whats good whats bad, i know nothing and if someone replies with some answers ill probably be crawling around the engine bay of my truck later on looking for the numbers :rolleyes:

#3 piston looked like it was just barely touching the head.

Machine shop says they can sleeve the heads to fix the cracks. Any one had this done.

Can a good machine shop check the blocks and cranks for cracks or is it just a visual inspection/crap shoot.

What would you guys recomend as far as problems to watch out for?



I can answer these ones:

First thing is mark that connecting rod (#3). If you end up using this rod make sure you check it for cracks and bends. It is unlikely there is a problem with it but you better check that one first anyway. A close measurment of roundness (rods should be re-sized anyway). If it has excessive oval shape to the big end of the rod throw it away. Also check the bushing in the small end of the rod. You should really try and find ut why this piston was touching the head.

The question about sleeving the heads. Yes I have done it myself on many engines. We generally used the rule that if they were previously cracked but not leaking yet we would sleeve them. If they were cracked and leaking we would try and persuade the customer to get new or exchange the heads. It works very well either way, we were just concerned about comebacks / warrenty which never ended up being an issue. I have also used many heads that had the cracks welded (by a shop with a pre-heating furnace and spray or submerged arc welder) and had 100% success with them. New heads are getting cheaper all the time so price around. The repairs / rebuilding may cost more than new heads once you put sleeves in and rebuild them properly.

A machine shop can clean the block and magnaflux it. A clean and dry block, crankshaft and heads are needed to do a good magnaflux. Most machine shops will know where to check which brings this up:

The biggest problems are the main web cracks and head cracks. The main web cracks occur on the three center main webs. Once the main caps are off they are usually fairly obvious. The often crack and get worse over time, yes they survive for a period and most never blow right apart. You would be nuts to put one back together with the cracks in there. Cheap insurance to prevent them on a good block would be main cap girdles from a vendor here such as John Kennedy. The heads are not as expensive or as much of an issue but again they should not be used without a repair of some sort. Many 6.5 heads crack on the valve cover side of the heads too and are often overlooked by mechanics and machine shops. Make sure they are checked, it should not cost you any more if they are magnafluxing anyway.

Thanks.

I got the other block out of storage probably tear it apart tonite to see what it looks like.

Gary