1570 Motor Lower Case

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vmax_nc

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Looks like the lower case in the 1570 motor is trashed. You can see the abrasion on the mating surface near the main case bolt holes. This case has been squirming for a long time.
 

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I wonder if there's a way to pin the mains like they do on car engines? Seems like it would help the walking effect...

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That’s a good point but don’t know if there is enough material there to do that. Someone else will have to answer that one.
 
Yea after looking at the one picture it looks like its pretty thin down there, also I've never had the crank out on one of these things but it looks cracked like a very small piece broke off by the bearing tang? Gotta be a way to make it stronger but these things were never designed to make the kind of power your making and I hope to make on my next one...

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I've got a girdle setup that John could look at adding for you. Not sure if it will help the crank walk but shouldn't hurt either. I think pics are in the "engine" album on facebook. Maybe you can send a picture of that back to him.

The upper case is what keeps the crank from walking around so it will be in worse shape then the lower. Other then the broken chunk near the bearing shell and the chain gouges I didn't see a lot of issues?
 
Sean, When I talked to John he said the upper case was in good shape and didn't see anything wrong w/ it just looking at it. I wish I had it in front of me to were I could see it.
 
The upper case controls crankshaft walk. The lower case only has one indexing pin from the factory though there are provisions for 2. Not sure why they didn't use both? Of course the trans bearings, main bearings, and countershaft all pass through that half and will help maintain alignment.

Do you need just a good lower half? I've got a stack of lowers I could send him to pick from to get best bearing alignment.

Sean
 
The upper case controls crankshaft walk. The lower case only has one indexing pin from the factory though there are provisions for 2. Not sure why they didn't use both? Of course the trans bearings, main bearings, and countershaft all pass through that half and will help maintain alignment.

Do you need just a good lower half? I've got a stack of lowers I could send him to pick from to get best bearing alignment.

Sean

Sean, I thought you had to use cases in pairs to ensure you didn't have problems with the reciprocating clearances. When they align-bore the cases, doesn't that pretty-much 'marry' those two? It seems like the machining required to make two dissimilar cases work would be cost-prohibitive over just buying a good used pair and making any machining needed.
 
Normally YES, you don't want to swap case halves. However, with the investment that's into this case already I would see if we can get lucky and swap over a lower case and get one that's close enough to work. It's been done before with success but not sure about one with this much output. I could crate up probably 20 lowers though shipping would be rude. I suspect John at PCW should have a few junk uppers he can steal a lower from.

Sean
 
I know of a couple here I. Houston that were mismatched without even paying one but of attention to bearing sizing, just swapped one lower for another.

Guys had no problems with it at all.
 
Thanks for the offer on the lower cases Sean but I think I'm going to go w/ a 1500 case that's already setup for a chain drive and put all my goodies into that block. with the longer rods and the stage 5 heads it still should be a beast. I think this will be more practical.
 
No problem. I do have one of the fastest 1500 blocks sitting here complete. Ran 8.30's and PCW should have the history. That was with some work on the heads but nothing like what you had.

Sean
 
Make sure you have the crank checked!!!!! It could be bent causing the movement on the halves> I got recipe chillers i rebuild and they got to be at .000 dead on> They fail at .001 John should know what it should dial in at. You got a nice set up but a 1500 tourmaster with a 40 to 50 shot of nos is bullet proof. Reliable as well. Good luck
 
Make sure you have the crank checked!!!!! It could be bent causing the movement on the halves> I got recipe chillers i rebuild and they got to be at .000 dead on> They fail at .001 John should know what it should dial in at. You got a nice set up but a 1500 tourmaster with a 40 to 50 shot of nos is bullet proof. Reliable as well. Good luck

Very good advice, I was just gonna say the same thing... Also the 1500 tourmaster with a shot of juice is exactly the route I'm taking once funds allow...

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