Line boring

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street demon

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I have just installed some 4 bolt splay main caps on a 360 and noticed that one side overhangs the main journal some but the other side is back away from the journal about .004-.006. Will the line bore take that out or should I just throw the caps on the mill and take .010-.015 off the surface? Also one of the legs where the splay bolts are there is a .002 gap between the cap and the block after the caps were torqued. I plan on milling the main cap surface just a hair to take out the slack. Does this sound normal for installing the caps? Oh the caps are old RAM but the look identical to Pro Gram caps. Thanks for the help.
 
Not a machinist here. However. Any time a cap/caps are replaced align honing is an absolute must. The aftermarket caps are made with that very need in mind. Find yourself a competent shop.
 
I know a very good shop close to me that does my machine work but I like to have most of the stuff prepped before I take it to him. All the aftermarket caps I've seen have overhang but these go the other way on the one side. Plus I like to do most of the work myself(if I can) including drilling and tapping the 6 holes for the main caps.
 
I would take it to the machinist!Get his opinion.If he says you can mill it off then go for it.But it is still going to need line bored !
 
Yes I know lined boring is all part of it and have always considered that part of the build but I'm just trying to find out if a line bore with even clean these up. Thanks for the input.

This is a pic of the first one installed. I'm going to use studs but used the OEM bolts with the thicker part just under the head to locate the cap. Also will be going to ARP bolts for the outside. This is a junk block that I'm using to trail fit the caps and get some practice with drilling the holes. Before anyone says it I'm not going to mill the caps UNTIL I mount them on the block I will be using and take some measurements.

1226071228a[1].jpg
 
STOP! you cannot fit caps to a block. The shop needs the exact block you're using, and the caps, and the exact hardware. You shouldnt sneeze near them. Don't mill, dont clearance, don't deburr. Bring them your parts, and pay them to do it. You run a very good chance of destroying the caps, and truthfully, if they were fitted to a different block, you should have bought new caps. Because of the compound angles on splayed versions, the more the cap mating surfaces on the caps are milled, the harder it gets to have everything work right after. You should be charged for fitting the caps, which usually means minor milling on cap and block in a couple spots, then align boring, which removes a bit of material from the cap, and a small amount fromt eh block, then align honing, which sets the final torqued dimension and may or may not be included in the Align Boring operation charge. You cant do one and not the other....lol. BTW, main studs will deform the cap and block differently, so dont bother trying to do anything with stock bolts.
 
These caps are old but new. I don't plan on milling these caps to fit this junk block just was trail fitting them since I plan to put them on the block I'm going to use. Yes I agree with you on a machine shop putting them on but I want to learn and again yes it will be line bored and honed with studs after the block filler has a few months to cure. I used the OEM bolts to locate the caps in to place to drill the outer holes. Also I've been sick so the sneezing has already occurred.
 
You know they have to be fitted before the bloc is filled, right? So the mains can be torqued and the block stressed...Also, bolts may not fit the holes as tight as studs.. They may not be the best alignment dowels if you are using studs to hold the caps.
 
Yes they will have studs in them before I pour the block filler. From what I know the OEM bolts are suppose to locate the caps better. I've heard of some people havig to drill the cap holes out to a hair larger size to make the caps fit right(with studs) but that was suppose to only happen if the holes drilled in the block were alittle off from factory. Also there is some play with the outer bolt holes compared to the bolts that go threw them so I will have alittle play room if I don't get it exact. Thanks for all the input.
 
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