6 bolt short block advice needed

[Aphix]

Story goes I spun a rod bearing on my 7 bolt so I'm keeping my freshly hot tanked and resurfaced head with new valve seals in favor of velocity, and intending to put it on a 6 bolt short block. I was lucky enough to pick up a 6 bolt hidden inside a totaled 2g at the local you pull it yard for a smokin 60 bucks. Brought it home, got the pan off and found myself with about 3/8" or so of end play in the crank, I haven't had a chance to get real numbers.

Now half of me is thinking CW and the other half is thinking worn or loose crank pulley. Just because I can't imagine this guy was driving it with 3/8" of end play in the crank. But I'm no wiseman. Like I said I really haven't had a chance to look at it too closely.

I know this is a dead horse that has been beaten but I have spent about two days trying to find a straight answer and it hasn't came to me yet.

1. Say this is CW, is it even worth trying to salvage the block, or should I just keep hunting for a engine in better condition? I don't live in a area with a lot of DSM enthusiasts.

2. Say this is worn or loose crank pulley, will there still be damage sustained to the block?

3. Even if I try to repair it, I hear the odds of being able to reassemble a low end to be reliable on the long term are slim.

 

[bryanwheat]

If the whole crank is moving than it is a work thrust bearing/crank aka crankwalk. If just the pulley is moving than it is a problem with the pulley or bolt. If it actually has 3/8 of an inch of play than there is some serious carnage in there . The thrust bearing would have to be non existent and the crank thrust surface would have to be seriously damaged. Pull the middle bearing cap and check to see if it is spun, damaged or what is going on.

If the bearing is spun in the block than i would just find another, if it is just worn than i'd have it line bored and it will be just fine with a good crank.

 

[BogusSVO]

Pull the oil pan.

If you have anything close to 3/8 (.375) worth of crank end play, you will know soon as the pan is off.

The thrust bearing will be totaly gone, its what maybe .125 thick, the crank thurst surface will have a huge gouge in it.

The small ends of the con rod will have gone into the inside of the alum pistons.

 

[V12 Killa]

Like everyone stated you will know if it CW'd after popping the pan. If it indeed walk, I would look for another block to swap/rebuild. I've read endless stories of people rebuilding CW'd blocks just to have them do it again.

My rebuilt 7 walked after 1000 miles so I decided to toss it and not risk it. I also decided to keep the 2g head & go with a 2g Head/ 6 bolt block combo. But from living in Omaha, I know how hard it is to find a DSM engine period . Just keep searching. Tuners & CL are your best friends

 

[Aphix]

Ok thanks for the replys guys, school has been hectic but I finally found time to get to my dads shop to look at everything going on. The crank has probably 5mm of end play, I didn't have a guage present to get a real reading, but I popped all the bearings on the crank and saw some pretty bad scoring, however nothing was spun.

So, obviously crank is shot, thrust bearing is way out of whack. Haven't had a chance to pop the main caps.