Another BBC rod question.
Thread Starter
Safety Car
Joined: Oct 2000
Posts: 4,282
Likes: 172
From: Lake Wylie, South Carolina
Another BBC rod question.
If you have a new crank that is std\std and install new rod bolts in the connecting rods. From what I have read both on hear and in books you need to have the big end of the rods resized. So what does this do from a bearing stand point? Are you still using std rod bearings?
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: Another BBC rod question. (BlackRat)
When you remove and replace the bolts in a connecting rod you distort the big end rod bore so it is no longer perfectly round. If the bore is not resized then the bearing will become distorted and you will not get even bearing clearences around the crank journal. After putting in new bolts you will resize the rod by honing the rod bore back to original size. (2.325 on a big block chevy) Then you will use the bearings to get the clearances you want.
Pro
Joined: Mar 2001
Posts: 500
Likes: 0
From: Michigan
Re: Another BBC rod question. (Pete79L82)
When you remove and replace the bolts in a connecting rod you distort the big end rod bore so it is no longer perfectly round. If the bore is not resized then the bearing will become distorted and you will not get even bearing clearences around the crank journal. After putting in new bolts you will resize the rod by honing the rod bore back to original size. (2.325 on a big block chevy) Then you will use the bearings to get the clearances you want.
Dwayne
:cheers:
[Modified by BigBlockVette, 10:27 PM 11/21/2003]
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Re: Another BBC rod question. (BigBlockVette)
Plastigagues are not bad, they will get you in the general ball park. If you have mics, that is the way to go..assemble the rod w/bearing, mike the inside, mike the crank, the difference is your clearance. Every good home garage should have a set of micrometers....they are just as important as a good set of sockets and box wrenches.
Thread Starter
Safety Car
Joined: Oct 2000
Posts: 4,282
Likes: 172
From: Lake Wylie, South Carolina
Re: Another BBC rod question. (GDaina)
Every good home garage should have a set of micrometers....they are just as important as a good set of sockets and box wrenches.
Thanks
Wade
Instructor
Joined: Dec 2002
Posts: 222
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From: Leander TX
Re: Another BBC rod question. (BlackRat)
I bought a set of mics from harbor freight for $39 including a 1, 2 and 3 in. They have carbide faces, but do not read down to the tenths of one thousandth like a Starret or Mitutoyo would. They also came with calibration gauges. Checked them against my brothers Starret set to make sure and they where almost dead on. (You have to eyeball the tenths spot) I'm not sure how they'd last after years of continuous use, but for an occasional engine rebuild they are fine. Digitals are nice, easy to read but for occasional use that battery may be dead when you want go to use it, not to mention the expense. :)
Instructor
Joined: Dec 2002
Posts: 222
Likes: 0
From: Leander TX
Re: Another BBC rod question. (BlackRat)
I also bought a mag base from Harbor for my indicators for less than $20. It works fine. I would also recommend a 6 or 8 in dial caliper. (remember digital = dead battery for the average user.) As log as you know your mic gauges as accurate, you could use them to check any caliper you might buy.
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Instructor
Joined: Dec 2002
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From: Leander TX
Re: Another BBC rod question. (Pete79L82)
I just got my rods back after having a machine shop install arp rod bolts and recut the rods. The bit of advise he gave me is, "Once you put these back together with assembly lube and turn the crank over a few times, you should be able to move one rod side to side on the crank journal (within the clearence) and have the adjacent rod move with it stuck by only the assembly lube.
Le Mans Master
Joined: Mar 1999
Posts: 6,744
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From: delmont pa
Cruise-In I Veteran
Cruise-In II Veteran
Re: Another BBC rod question. (BlackRat)
if you install a tight fitting mandrel in the big end of the rod to hold every thing in place while you change one bolt at a time the rods does not change shape. i have done this many times and then checked the big end with a dial gauge and found no change in shape or size.
