Engine builders and machinists?
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,103
Likes: 4,465
From: Marlton NJ
Mis-labeled bearings! Phew... You dodged a bullet there!
I was just at my machinst buddy's and he was straightening out a rather new low mile 4 cylinder aluminum block that always ran hot. (Mfgr unknown)
#1 (or #5) main bearing cap was almost 1 thou tighter than all the rest! Since new! Duh!
Ever tried align honing just ONE main cap? Without ruining the other four? That was interesting...... It was a PITA!
Align honing and cap skimming effects all the caps equally.....
His specs go to the 1/tenth-thousandths...this was one thousandth off....
I was just at my machinst buddy's and he was straightening out a rather new low mile 4 cylinder aluminum block that always ran hot. (Mfgr unknown)
#1 (or #5) main bearing cap was almost 1 thou tighter than all the rest! Since new! Duh!
Ever tried align honing just ONE main cap? Without ruining the other four? That was interesting...... It was a PITA!
Align honing and cap skimming effects all the caps equally.....
His specs go to the 1/tenth-thousandths...this was one thousandth off....
Last edited by leigh1322; Aug 25, 2020 at 09:44 PM.
Burning Brakes
Joined: Feb 2014
Posts: 1,045
Likes: 226
From: Cape Neddick Maine
2020 C3 of the Year Finalist - Modified
It sounds like from reading Gkulls post that the Main Caps for #2 & #3 got installed incorrectly. When it was originally machined the arrow on the Main Cap was pointing towards the rear of the block instead of forward. When it was at the machine shop getting rebuilt they noticed it and engraved the two caps.
Gkulls pulls it apart to assemble it never noticed it until he was putting the crank in. I have seen this a few times.
Putting a set of rods together I got called off and when I got back I put a rod on backwards. Frigging damn engine would not spin
Gkulls pulls it apart to assemble it never noticed it until he was putting the crank in. I have seen this a few times.
Putting a set of rods together I got called off and when I got back I put a rod on backwards. Frigging damn engine would not spin
Thread Starter
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Thread Starter
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Burning Brakes
Joined: Jun 2020
Posts: 881
Likes: 113
rods & mains tang-to-tang, triple T, TTT
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Auto machine shops are not where journeyman machinists get the wages they can get elsewhere. So what I'm saying is the most labor is done by the newest hire in the shop and whatever machines he has learned enough to about to use. The tech honing my Pontiac block back in the '80s was a guitar player in a band when he wasn't honing and boring blocks.
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Le Mans Master
Joined: Apr 2015
Posts: 9,433
Likes: 124
It spins free with # 1 (front) and #5 Rear main caps installed. Add # 2 it gets rotating resistance. Add # 3 or 4 and you can't rotate it by hand even with the old used main bearings. It's going to the shop today. This Motown block has had a tough life. It was originally a Bill Mitchel Hard core racing 625 hp crate motor. It was a H-roller. It suffered valve train failure snapping off and pounding two intake through the valve seats sideways. AFR did a beautiful job of welding the heads back to what appeared to be brand new. It got a couple of pistons, balanced and I went to a solid roller 252/256 .685/.714 Then back to Road racing and driving at the max.
Within a year I was running it through the gears and actually had let off when I heard/felt something. It was the crankshaft breaking in the #4 rear main. I just stabbed in the clutch and put it in "N" and coasted off a return exit road because I was going about 120 mph. So much for a scat 4340 forged crank.
It was a 350 mains lighter crank. It damaged the block in the #4 main. So they bored the mains to 400 crank diameter and I bought this super Callies crank. The 1.5 mm racing rings only seem to last about 5000 miles. Every year or two I was reringing it. This was just another time,
http://www.superchevy.com/how-to/010...block-solution
Within a year I was running it through the gears and actually had let off when I heard/felt something. It was the crankshaft breaking in the #4 rear main. I just stabbed in the clutch and put it in "N" and coasted off a return exit road because I was going about 120 mph. So much for a scat 4340 forged crank.
It was a 350 mains lighter crank. It damaged the block in the #4 main. So they bored the mains to 400 crank diameter and I bought this super Callies crank. The 1.5 mm racing rings only seem to last about 5000 miles. Every year or two I was reringing it. This was just another time,
http://www.superchevy.com/how-to/010...block-solution
Edit I guess i'm late to the party
Last edited by centuryoldracer; Aug 28, 2020 at 12:33 AM.
