Main Studs Question
Main Studs Question Since I just got my motor bored to 3.905 would it be wise to keep the stock main bolts or upgrade to the ARP main studs? If I decide to upgrade to the ARP main studs then what precautionary measures do I need to make so that my engine balance isn't thrown off?
Thanks!
Thanks!
You should have done this before boring the motor. You need a to line hone the block when you install main studs because they will clamp the main caps to the block differently than a set of bolts will (they also change the patterns of deformation of the main caps). This is important because this determines your bearing clearences as well as a baseline for the rest of the machine work on the motor, including boring the cylinders. Installing main studs is not just a simple swap from the stock hardware.
TECH Apprentice
Joined: Aug 2004
Posts: 321
Likes: 0
From: Buffalo, N.Y.
I didn't know that. If you swapped the OEM main caps for, say, a set of billet main caps, I could see having to do an align hone. I studded my bottom end, and, after plastigaging, all 5 mains came in at .0015". I agree that stud nuts apply a different clamping force than bolts would; the clamping force, or so I've been told, is a "truer", more vertical force than what you'd get using bolts, which apply more of a "twist".
I hope the consistent plastigage readings I got are an indication that studding the bottom end of my engine, without doing an align hone, isn't going to turn into a catastrophic bottom end failure down the road.
I hope the consistent plastigage readings I got are an indication that studding the bottom end of my engine, without doing an align hone, isn't going to turn into a catastrophic bottom end failure down the road.
You should have done this before boring the motor. You need a to line hone the block when you install main studs because they will clamp the main caps to the block differently than a set of bolts will (they also change the patterns of deformation of the main caps). This is important because this determines your bearing clearences as well as a baseline for the rest of the machine work on the motor, including boring the cylinders. Installing main studs is not just a simple swap from the stock hardware.
Excellent point and cant be stressed enough, even if your using OEM, you still want to line hone it. WE have a little trick we do with this as well to ensure results. At least you measured and took precautions where most dont even bother with it, they just slap it together and then wonder why they spin a bearing prematurely.
TECH Apprentice
Joined: Aug 2004
Posts: 321
Likes: 0
From: Buffalo, N.Y.
I originally DID want to align hone (or is "align bore" the more technically correct term?) the main bearing bore before reassembly. The "guru" at the machine shop that did the cylinder wall plateau hone told me that, unless I was having the block resleeved, or was using aftermarket main caps, an align hone would be unnecessary. He did offer to measure the main bearing bore if I brought him all the caps & studs, so I did.
When I picked up the block, the machinist said the main bores were right on the money, and just about dead-on in alignment with the cam bearing bore. I was still kind of pushing for the align hone, and the machinist said that if I insisted, he'd be glad to take my money. He also said that had the bore measurements been suspect, he wouldn't have put his shop's reputation on the line by skipping the procedure.
I already mentioned how consistent the main bearing clearances came out, but I didn't mention how effortlessly the crank spun when I wrenched 'er over a few times....every bit as smoothly as the cam, after I installed the cam bearings. But that may not mean a thing. End play measured .0045". I still don't understand how smacking the crank forward & back "aligns" the thrust bearings, but that's what the instructions said to do, so I did it.
When I picked up the block, the machinist said the main bores were right on the money, and just about dead-on in alignment with the cam bearing bore. I was still kind of pushing for the align hone, and the machinist said that if I insisted, he'd be glad to take my money. He also said that had the bore measurements been suspect, he wouldn't have put his shop's reputation on the line by skipping the procedure.
I already mentioned how consistent the main bearing clearances came out, but I didn't mention how effortlessly the crank spun when I wrenched 'er over a few times....every bit as smoothly as the cam, after I installed the cam bearings. But that may not mean a thing. End play measured .0045". I still don't understand how smacking the crank forward & back "aligns" the thrust bearings, but that's what the instructions said to do, so I did it.
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We dont take chances, we always line hone and yea align hone...LOL
We dont consider it taking anyones money to follow proper procedure on every engine we build. There are lots of experts out there who skips steps.. we dont see a need to. You either do it right or you dont, there is no gray area on skipping steps to save money.
is not good enough for us that's why we always line hone..
We dont consider it taking anyones money to follow proper procedure on every engine we build. There are lots of experts out there who skips steps.. we dont see a need to. You either do it right or you dont, there is no gray area on skipping steps to save money.
just about dead-on in alignment with the cam bearing bore
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Well thanks for that information. I am keeping the main studs and caps the same then just for that reason. I talked to my machinist and another pro guy here locally and they said that main studs aren't necessary for what I'm doing anyhow. So it's better now just to play it safe and keep the existing bolts and caps and torque them to specs. I'm currently file fitting the top and secondary rings for the new pistons and what a major PITA that is. I'll be going .023" top and .025" second rings just because I'll be spraying the motor after I seat the rings. I think it took me somewhere in the neighborhood of an hour just to get 4 rings filed...
You should have done this before boring the motor. You need a to line hone the block when you install main studs because they will clamp the main caps to the block differently than a set of bolts will (they also change the patterns of deformation of the main caps). This is important because this determines your bearing clearences as well as a baseline for the rest of the machine work on the motor, including boring the cylinders. Installing main studs is not just a simple swap from the stock hardware.
