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AQ130crebore one cylinder or all

L

lodochnik

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"I have an engine where all cy

"I have an engine where all cylinders were rebored to +.020" some years ago. Today, 3 cylinders show little wear (bore gage shows +.0205" in some spots), the 4th needs to be rebored due to rust caused by a bad manifold elbow. Is it necessary to rebore all cylinders to the same diameter? Thanks for any help.
George"
 
"Over-sizing one cylinder only

"Over-sizing one cylinder only was routinely done in the old days!

However, the purist will tell you that all cylinders should be re-sized. Balancing for weight and power will be the issue.

The realists will tell you that you could likely get by with this, but may advise that you match the weight of the newly over-sized piston with the existing and then make it work.
I highly doubt that one cylinder being slightly over-sized would cause any problems.
If you are .020"+ over now, and .030" over will clean up this one cylinder, that is a diameter increase of only .010"..... or, .005" off the wall.
That is not much!
Will that even clean it up?

You will at least want to hone and re-ring the three existing along with the new, and you will no doubt do all new bearings and will want do the valves. You may even have # 4 exhaust port damage that needs to be addressed. (quite common on these engines)

It's your call..... these are just suggestions!

."
 
"Ricardo, thanks for the respo

"Ricardo, thanks for the response. I will examine exhaust port #4. I honed #4 cylinder to see the high/low spots, and I think a .040 over rebore will be required to clean up. Considering that I have to replace 2 pistons already (#1 and #4 both badly scuffed), I might as well bite the bullet and rebore all cylinders, provided I can find +.040 pistons with 22mm wrist pin bores."
 
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