LS1TECH - Camaro and Firebird Forum Discussion

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-   -   Need help arp studs now crank won't spin (https://ls1tech.com/forums/generation-iii-internal-engine/1984805-need-help-arp-studs-now-crank-wont-spin.html)

Thillroman May 10, 2026 05:07 PM

Need help arp studs now crank won't spin
 
Hi I'm putting together my first motor and I got all new bearings standard size and replaced the main studs with arp and after I tighten it down the crank won't spin my buddy says it might be becuase he lubes the crap out of the bearings before I set the crank down with sticky lube but he said to ask a form before slapping it all together and hoping the starter spins it any help would be great

RollingDumpster May 10, 2026 05:26 PM

The block needs to be lined honed with the new studs torqued. They distort the block slightly which is why they require a trip to the machine shop. The crank should spin by hand freely. You need to disassemble and go back to bolts or take it to a machine shop. Your crank is bound up assuming its not also incorrect bearing size.

Che70velle May 11, 2026 09:17 PM

Since it’s your first rodeo here, make sure your main cap orientation is correct….they are all in the correct spot…#1 is front and #5 is rear. Make sure they are turned the correct direction. If you didn’t mark them to indicate forward direction, then you might have one or two…or more facing the wrong direction which will affect tunnel alignment greatly. This is easy to do as a novice, trust me. Also as mentioned by RD, your bearing clearances must be checked in this situation, to eliminate possibilities. As a builder I’ll suggest to you that you make very sure that everything is clean, and then wash it again….and again. You can’t get everything clean enough. Make sure the backs of your bearings are dry. Bearings are a press fit. The only thing keeping them from spinning in the bores is their press fit. Oil behind them is bad. Your main bolts torque in a sequence. You can find the sequence on many websites…look it up. That’s important here also. Hit us back with any more questions.
​​​​​​…edit…and because the ARP main fasteners have more clamping force, they do have the possibility of distorting your main caps. I’ve posted pics here many times of a line hone after ARP main stud installs, to illustrate just how much the caps and block distorts. I didn’t want you to think I was overriding what RD mentioned about distortion here…I was simply throwing out things to try before you have to take it to a shop. I DO a see guys installing ARP main studs and not having to line hone, but it’s few and far between.

1FastBrick May 13, 2026 05:14 PM

This is the Main cap orientation Che70velle is referring to. 1-4 go one way while the 5th cap is reversed. This very common issue for a first time build.

https://cimg0.ibsrv.net/gimg/ls1tech...69eb1e1a8c.jpg

Utinator May 17, 2026 10:04 AM

Before you lube the crap out of it, you need to check the bearing gaps. You can either do that with plasti-gauge or a calibrated dial bore gauge. In either case, the bearings need to be dry. Do this before trying to spin the crank. Checking the bearing gap will tell you if the bearings are the correct size for your crank or not.


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