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bjautos7 04-03-2013 03:45 PM

main caps need help
 
ok i got a 87 roller block , this has been strip down by the last owner. now heres a photo of the older of how i remove the main caps

http://i1352.photobucket.com/albums/...pscc81b394.jpg

now the top numbers on the caps are casting numbers , what is the second number for. is this for the older the caps should go on the block. lowest number being cap 1 and highest cap 4 . looks like the last cap is in the wrong place.

http://i1352.photobucket.com/albums/...psf05fbd76.jpg

in this photo cap 4 is in the front and cap 1 at the back.if you look at the bottom of the caps you can see the front one has a diferent foot to the second one, like as if its for the front of the block no 1. the rest of the main caps are the same as the second one at the feet. now do you think that this cap number 4 was put in the wrong place. should it be at numer one as it also has the lowest number too.

BOBCRMAN@aol.com 04-03-2013 04:04 PM

The cast numbers have nothing to do with position. The small stamped numbers determine where the cap fits. If cap fits tight in register, then it most likely the correct one.

Install cap in marked position and physically look at the cross hatch pattern and any hangover into the bore. If you can feel the cap hangover into the bore, something is wrong. If the cross hatch doesn't match it's wrong. No. 4 is never in front position.

cdminter59 04-04-2013 06:02 AM

main caps need help
 
If your engine has never been rebuilt or taken apart most likely you will have to number the main caps and the connecting rods. Use an electric engraver that you can pick up cheap. This is not done by the manufacturer. When purchasing new main bearing caps 1-4 are the same part number. When installing the new ones they have to be align bored and honed. If you get yours mixed up you might be able to take it to a machine shop for them to mic the caps and the block to get the caps back in the right position. If they can't the block will need to be align honed after the caps are installed.

Mr. P-Body 04-04-2013 07:18 AM

It's true, most small block Chevy engines have no markings from the factory. SOMETIMES, there's a number stamped into the cap on the bolt "flat".

If they are truly the original caps from that block, it takes about 15 minutes for a machinist to "sort it out". Not complicated, but helpful to have the correct measuring tools, in this case, a bore gage, set to the housing bore size. If all the visual indicators that Bob mentions are "there", making sure everything is "round and straight" will take care of it.

Jim

oldbogie 04-04-2013 10:10 AM

Quote:

Originally Posted by bjautos7 (Post 1662904)
ok i got a 87 roller block , this has been strip down by the last owner. now heres a photo of the older of how i remove the main caps

http://i1352.photobucket.com/albums/...pscc81b394.jpg

now the top numbers on the caps are casting numbers , what is the second number for. is this for the older the caps should go on the block. lowest number being cap 1 and highest cap 4 . looks like the last cap is in the wrong place.

http://i1352.photobucket.com/albums/...psf05fbd76.jpg

in this photo cap 4 is in the front and cap 1 at the back.if you look at the bottom of the caps you can see the front one has a diferent foot to the second one, like as if its for the front of the block no 1. the rest of the main caps are the same as the second one at the feet. now do you think that this cap number 4 was put in the wrong place. should it be at numer one as it also has the lowest number too.

First number is the casing number the second number is the mold number that it was cast in. The important thing is fit with the block the slight difference of foot contour from mold to mold is not important. But knowing where they came from and which way they point (the F) for forward mark and the arrow are important. The same must be said for rod caps, cap and shank are a matched set and are directional with each other and with orientaion to the crankshaft. The tang slots will on the same mating side but at opposite edges to each other. There are two chamfers on the big end, the larger radius chamfer always faces to the outside of the journal to provide relief for the cheek to journal blend radius.

Bogie


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