Crankshaft align hone?
Racer
Joined: Aug 2011
Posts: 493
Likes: 217
Racer
Joined: Aug 2011
Posts: 493
Likes: 217
Align honing does not require machining the caps. It is a HONE, to get everything straight and to the appropriate size. Align boring involves cutting the caps first (to undersize the mains) and then bore back to the correct main size for straightness and uniformity.
As pointed out already, honing is common, boring less-so and more expensive.
"Undersize" (actually, oversized/thicker) bearings are to tighten clearances. Standard .010 or .020 under bearings are to accommodate crank undersize (NOT oversized mains - the O.D. of the bearings should be standard). Cranks are commonly ground at 10 or 20 under to clean up. In my case I used 0.001" undersize bearings on a standard crank to tighten my oil clearances after crank polishing and align honing.
There would need to be a major amount of change in the crank centerline to cause excess slack in a timing chain. I would question whether that's even a possible cause with the small dimensions we're talking about. A change of 0.020" is only 0.010" on a side. There is slack designed in the chain set to begin with, so how much slack do you have? Have you tried a different timing set? Maybe it's the tolerances in whatever set you're using.
As pointed out already, honing is common, boring less-so and more expensive.
"Undersize" (actually, oversized/thicker) bearings are to tighten clearances. Standard .010 or .020 under bearings are to accommodate crank undersize (NOT oversized mains - the O.D. of the bearings should be standard). Cranks are commonly ground at 10 or 20 under to clean up. In my case I used 0.001" undersize bearings on a standard crank to tighten my oil clearances after crank polishing and align honing.
There would need to be a major amount of change in the crank centerline to cause excess slack in a timing chain. I would question whether that's even a possible cause with the small dimensions we're talking about. A change of 0.020" is only 0.010" on a side. There is slack designed in the chain set to begin with, so how much slack do you have? Have you tried a different timing set? Maybe it's the tolerances in whatever set you're using.
"Align honing does not require machining the cap"
That is wrong. It requires machining the cap two different ways when using a conventional bearing.
Melting Slicks
Joined: May 2007
Posts: 2,415
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I have seen them for cracked cap PM connecting rods so they can be reconditioned but not mains.
Last edited by PAmotorman; Nov 24, 2017 at 09:31 AM.
Racer
Joined: Aug 2011
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The engine remanufactures had these outside diameter bearings made, they are not available to the public.
Last edited by Vortecpro; Nov 24, 2017 at 09:46 AM.
Melting Slicks
Joined: May 2007
Posts: 2,415
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Ever had a dial bore gauge in the torqued up mains of L31 roller 350 one piece block? If the housing bore was found to be .002 bigger (which is very common) than the high side of the factory spec, how did the assembly line deal with that?
The engine remanufactures had these outside diameter bearings made, they are not available to the public.
The engine remanufactures had these outside diameter bearings made, they are not available to the public.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
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From: Cool Northern Michigan
Racer
Joined: Aug 2011
Posts: 493
Likes: 217
I see over size housing bores from the factory often in BBC and SBC that's why they get lined honed. The bearings are coded, but not available.
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Racer
Joined: Aug 2011
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I thought the same thing, upper gear is bigger, but I do believe the lower gear remains the same size. The sets I've seen the upper gear is marked with the lower gear with no marking-.005 or .010. I do understand your point though.
Last edited by Vortecpro; Nov 24, 2017 at 10:34 AM.
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
A old worn out chain likely has an quarter inch lateral play or more. What would that be equal to on the main bearing vertical clearances?
Last edited by HeadsU.P.; Nov 24, 2017 at 11:53 AM.
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
Summit Racing, Cloyes # 9-130-5 SBC, timing chain only, no sprockets, 0.005" shorter. For use on align bore blocks. $56
Last edited by HeadsU.P.; Nov 26, 2017 at 10:08 AM.
Thread Starter
Parts Sherpa
Joined: Feb 2017
Posts: 520
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From: ICE boneyard, Pa
New set to this motor pink "O" rods with ARP bolts & resized
New set L2304 + 0.030 domed pistons
Rotating assembly balanced to new components
Align hone recommended to create tight true clearances crankshaft rotating assembly
I have no issues with the cloyes double roller I am installing. My initial question was referring to another thread where excessive chain play had developed and the question was asked if the block had a previous line bore or hone.
My question as a result was...When, how much how do you know when a shorter chain or different timing chain is required. I am just looking to better understand what variables this introduces. This is a new topic for me that I had not previously encountered.
Thank you all for the responses
Last edited by EarlyC34me; Nov 24, 2017 at 07:53 PM.
Race Director
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I had a Pinto in high school (don't laugh---it ran 14.60's in those days spanking new Z-28's/Trans Am's all day- in fact I still have it!). Anyway, the 2.0L engine had oversized O/D mains from the factory. In fact it had one piston and rod that looked completely different than the other 3 and had a slightly shorter deck height. I was there the day my Dad bought it new with like 5 miles on it...so it came that way from factory. Weird POS but was a running ****!!
JIM
JIM
Le Mans Master
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From: Sarver Pa
2021 C1 of the Year Finalist - Modified
Sounds like your engine builder knows what he's doing. Line hone in my neck of the woods runs about $175, good for peace of mind. I wouldn't worry too much about the chain but check it during cam degreeing.
Thread Starter
Parts Sherpa
Joined: Feb 2017
Posts: 520
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From: ICE boneyard, Pa
Thread Starter
Parts Sherpa
Joined: Feb 2017
Posts: 520
Likes: 98
From: ICE boneyard, Pa
I had a Pinto in high school (don't laugh---it ran 14.60's in those days spanking new Z-28's/Trans Am's all day- in fact I still have it!). Anyway, the 2.0L engine had oversized O/D mains from the factory. In fact it had one piston and rod that looked completely different than the other 3 and had a slightly shorter deck height. I was there the day my Dad bought it new with like 5 miles on it...so it came that way from factory. Weird POS but was a running ****!!
JIM
JIM