Main cap cut for studs

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amc fan
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Main cap cut for studs

Post by amc fan »

How much does the main bore change when you install studs?
How much do you have to cut the cap to re line bore it round?
AMC engine almost same size as BB Mopar uses the same studs as 318-440 Mopar
I cannot picture in my head the bore of main changing.
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modok
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Re: Main cap cut for studs

Post by modok »

-If you tighten the bolts or studs to a higher clamp force it will distort the bore more. Does not matter if it is a stud or screw.
-.000-.004
-ok
- try harder

When rebuilding engines most use a bore gauge to measure bores instead of using an imagination.
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Re: Main cap cut for studs

Post by modok »

What it all means is the engine is old enough it should be checked anyway. And you can find out the answer yourself in just a few minutes more.
But as a general rule for ANY split bearing housing, increasing the clamp force does tend to decrease the chances it will be in spec.
Over time the bolt stretches and the housing gets smooshed from that force.......so you retorque the bolt what happens? It gets smaller. That's what they all do. Imagine that
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Re: Main cap cut for studs

Post by modok »

So then what if we make the housing huge and use a small bolt......that would solve it right? Nope. Does not work well. It can't flex at all without stretching the bolt or fretting. Quite counter intuitive.
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Re: Main cap cut for studs

Post by amc fan »

Modock thanks for the reply.
Block was line honed caps were cut 20 years ago 2nd time(dusted) and was used in trailered car briefly than pulled and exchanged for a stroker motor. I have Mitutoyo and Peacock dial bore gauges. I will have to put it on a stand and pull the crank and torque to spec and see if there is a difference between the ARP studs and Fasteners.
I was concerned with timing chain slop after cutting caps again and re Aline honing the main bearing saddles.
Block is squared decked, plate honed, line honed was run for a couple months than pulled. just needs to be cleaned and refreshed after setting a long time.
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Re: Main cap cut for studs

Post by rebelyell »

the better timing set makers offer reduced-distance sets specifically for that.
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