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-   -   sbc wont move freely after rebuild rebuild. (http://www.hotrodders.com/forum/sbc-wont-move-freely-after-rebuild-rebuild-227011.html)

nskeeter99 12-10-2012 06:35 AM

sbc wont move freely after rebuild rebuild.
 
A buddy of mine brought me a crate engine from jaspers that was very difficult to turn over. He told me he traded for it. The guy he got it from took it apart a few years ago but did not mark anything. Then put it back together.I loosened all the rod bolts, and got it to turn. So I started tightening on rod at a time and checking to see if i could turn it. if it turn i went to the next one if not i tried swapping some around. I have the front 4 good. I can get 1 of the last 4 by itself but can get all 4 at once. Do any of ya ll have a secret to help fix this are do i have to just keep moving caps till i get it?

dogwater 12-10-2012 07:33 AM

I would of started with the crank first and took a look at all of the bearing then checked with plastagauge. One thing I read was that you should be able to turn the crank without the rods on it with 3 fingers. Then look at all of the rod bearings an plastagauge them.Make sure all the notches on the pistons face the front.Install one rod at a time then rotate the crank one whole turn,do that with each rod an piston.

C-10 12-10-2012 08:59 AM

Another thing to check,

The big end of the rods have a chamfer. The rod bearing is also offset away from this chamfer slightly. The chamfer always goes toward the 'fillet' of the crank. It could be a few of the pistons are installed backwards and the rods are binding because of this.

Put a GOOD straight edge on the crank webs in the block too.

V-block the crank and check run-out.

Mic each bearing and journal.. As mentioned, plasti-gauge..

Etc etc..

lmsport 12-10-2012 09:12 AM

Quote:

Originally Posted by nskeeter99 (Post 1621150)
A buddy of mine brought me a crate engine from jaspers that was very difficult to turn over. He told me he traded for it. The guy he got it from took it apart a few years ago but did not mark anything. Then put it back together.I loosened all the rod bolts, and got it to turn. So I started tightening on rod at a time and checking to see if i could turn it. if it turn i went to the next one if not i tried swapping some around. I have the front 4 good. I can get 1 of the last 4 by itself but can get all 4 at once. Do any of ya ll have a secret to help fix this are do i have to just keep moving caps till i get it?

Each rod and rod cap assembly is unique once it is machined. Randomly moving the caps around and having the engine run is impossible. The rods were probably marked at one time.
Do you see any markings on the rods or the caps?

This is also true for the main bearing caps on the block. They too are usually marked and install in a particular direction also.

vinniekq2 12-10-2012 09:35 AM

sounds like you might have to take it apart,resize all the rods and check all clearances.

38Sedan 12-10-2012 01:12 PM

Quote:

Originally Posted by lmsport (Post 1621199)
Each rod and rod cap assembly is unique once it is machined. Randomly moving the caps around and having the engine run is impossible. The rods were probably marked at one time.
Do you see any markings on the rods or the caps?

This is also true for the main bearing caps on the block. They too are usually marked and install in a particular direction also.


This is correct, trying to randomly move things to get it to turn is not the way to go. You need to measure, measure, measure rods and bearings.

BOBCRMAN@aol.com 12-10-2012 03:36 PM

It is too bad that you have a Jasper rebuild.

Take the rods to a machine shop and have them checked. But, don't be surprised if they tell you that the rods can't be sized to standard.. A common problem with Jasper rebuilds. They are built to Jasper specs. NOT OEM specifications.

Jasper uses almost every core they get. That means some rods are bored oversize in the rod journals big end which require an oversized OD and an undersized ID bearing. Not common to the aftermkt retailers. You have to be real careful and have good measuring tools. When building one of their products. They use some real odd ball stuff compared with what the average enthusiast is used to.

The same goes for main bearings and cam bearings. Very common to encounter +.020 oversized OD/.020 undersized ID.main bearings and .020 OS cam bearings.

BOBCRMAN@aol.com 12-10-2012 03:42 PM

Sorry computer probs. BOB

nskeeter99 12-10-2012 06:21 PM

So reading what you guys are saying, it seems the easiest and cheapest would be to just buy a new set of rods?

BOBCRMAN@aol.com 12-10-2012 06:37 PM

Depends on where you take the rods and what their shop rate is.

I get $40.00 to place the correct cap on rod and torque/check rod dimension for eight rods. Most shops around here get $8-10.00 per each to re-size rods.

A new set of rods will also require removal and install on piston. Another charge.


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