383 grind rods down to clear?
08-08-2014, 10:37 AM
#1
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383 grind rods down to clear? A friend of mine took his LT1 to a machine shop and they ordered a (PMB maybe) crank, used stock rods, and a keith black economy piston. Well the machine shop grinded down the rods and part of the rod bolt in order to clear the cam they say. I personally have never heard of this and they did not balance it after the grinding. I haven't seen the rods my self but he said part of the rod bolt has been ground to. Is this normal for these?
08-08-2014, 11:09 AM
#3
I have seen rod bolts ground a bit to clear, but they should not be grinding on the rods.
My oversized rod bolts were ground down slightly on the far edge of each one, but nowhere near the middle of the bolt and none of the rods were touched...and that is using massive L19s with Eagle H-beams that are also fairly poor clearance with our blocks. ARP2000s with a Compstar I-beam would probably clear with zero grinding.
When I first got the shortblock, I did not like how much the previous shop ground down the rod bolts so I had my shop replace them and grind the block more so the bolts only needed a tiny bit of grinding.
I would be leary of that shop and that mix of parts.
My oversized rod bolts were ground down slightly on the far edge of each one, but nowhere near the middle of the bolt and none of the rods were touched...and that is using massive L19s with Eagle H-beams that are also fairly poor clearance with our blocks. ARP2000s with a Compstar I-beam would probably clear with zero grinding.
When I first got the shortblock, I did not like how much the previous shop ground down the rod bolts so I had my shop replace them and grind the block more so the bolts only needed a tiny bit of grinding.
I would be leary of that shop and that mix of parts.
08-08-2014, 12:07 PM
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I have a 6" rod 383. I see NO REASON you would ever grind a rod or a rod bolt. Block yes. Rod no. What length rod is he running where it would hit the cam? I'd run from that machine shop.
08-08-2014, 02:34 PM
#7
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From my understanding talking to him, it is a 3.75 stroke (PMB?) crank, using stock rods (two of which are a odd ball aftermarket stock replacement) and by that I mean 6 are stock rods from his engine and two other different style rods, and a set of keith black (claimer) pistons. It all sounded like a mess to me. He said they told him they had to grind the rod and bolt to clear the cam. I have heard of grinding the block but never a rod. That was with stock rod bolts. I believe he plans to toss it all and start over. I just wanted to touch base on it. None of this was even attempted to be balanced either.
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08-08-2014, 06:18 PM
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WOW... just wow.....
2 rods not like the other 6 in an attempted unbalanced motor with a PMB (whoever the fukk that is) crank and some keith black pistons....
uhhhhhh my humble opinion says that the second it fires (IF it fires) it's going to run like a cement mixer with midgets and ball bearings in the hopper then promptly explode due to vibrating the bearings right out of the main caps....
but at least those rod bolts will clear...
2 rods not like the other 6 in an attempted unbalanced motor with a PMB (whoever the fukk that is) crank and some keith black pistons....
uhhhhhh my humble opinion says that the second it fires (IF it fires) it's going to run like a cement mixer with midgets and ball bearings in the hopper then promptly explode due to vibrating the bearings right out of the main caps....
but at least those rod bolts will clear...
08-08-2014, 07:39 PM
#10
From my understanding talking to him, it is a 3.75 stroke (PMB?) crank, using stock rods (two of which are a odd ball aftermarket stock replacement) and by that I mean 6 are stock rods from his engine and two other different style rods, and a set of keith black (claimer) pistons. It all sounded like a mess to me. He said they told him they had to grind the rod and bolt to clear the cam. I have heard of grinding the block but never a rod. That was with stock rod bolts. I believe he plans to toss it all and start over. I just wanted to touch base on it. None of this was even attempted to be balanced either.
Good idea to junk it and start over, that build was a train wreck.
08-08-2014, 10:25 PM
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As far as clearancing goes, I just had my 3.875" crank installed with 6" compstars and literally almost no clearancing was done. Just a little bit on the bottom of each cyl to get the counterweight to clear. Not even any into the panrail. I know this is a much different setup, but a 3.875" is a full 1/8" larger, you only need a few thousandths. As for taking the material off the rods....let me ask this, and feel free to ask your "builder". are you more comfortable with material coming out of a stationary hunk of iron (clearancing the block) or a chunk of already fucked up mismatched, unbalanced rotating mass? We all know what it takes to dump one of these things in and out (I just did it tonight, 5hrs if you care to know), its not a good time. Do you want to install one intentionally knowing its coming out in a short time? Scrap those parts and tell that "builder" he should be ashamed to be categorizing himself with someone who has a clue.
08-09-2014, 08:53 AM
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A friend of mine took his LT1 to a machine shop and they ordered a (PMB maybe) crank, used stock rods, and a keith black economy piston. Well the machine shop grinded down the rods and part of the rod bolt in order to clear the cam they say. I personally have never heard of this and they did not balance it after the grinding. I haven't seen the rods my self but he said part of the rod bolt has been ground to. Is this normal for these?
08-12-2014, 07:56 PM
#19
Launching!
partially his fault for trying to throw pos parts together in the first place
Maybe he didnt know any better
Using Manley H beams 3.75stroke std base circle cam works just fine with minor block clearancing
Maybe he didnt know any better
Using Manley H beams 3.75stroke std base circle cam works just fine with minor block clearancing
08-13-2014, 09:24 AM
#20
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He just gave full trust in the machine shop. Something I never do. I've talked to at least 5 machine shops locally before I found one that I felt remotely comfortable with. I'll never use this one again. I haven't talked to him in a few days but I don't think hes even going to attempt it.