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Head stud interference problem?
Posted by: Tramp61 ()
Date: January 18, 2023 01:57PM

I’m taking down my 61 80 hp FC engine due to marginal compression and low compression in #1 cylinder. Found most of the issues and planning to clearance the case for a 164 ci crank. One of the upper head studs on #1 cylinder is protruding inside the case. Turning the crank while it was still assembled showed about 1/8” clearance between this stud and the connecting rod bolt. The case is going to be relieved for the 164 crank. I’m guessing that this bolt is going to cause interference with the longer throw of the 164 case and bigger rods.

My question is what to do about it? I could do a quick hack job and just grind the end of the bolt off. Common sense tells me otherwise. I have tried soaking the area with penetrating oil and use the double nut method on the head end to get it to turn in either direction. It doesn’t budge with a breaker bar. The studs have not been torque tested yet, but a few turned a little on head nut removal. These will be dealt with. This one didn’t move.

I’ve thought about taking the impact wrench to drive the nut through the case. I think the stud thread pitch taper will make that very difficult. I don’t care if the threads in the case get ruined. That is repairable. I’m not sure how effective heat will be with the aluminum, or maybe do more harm than good.

I’m open to suggestions or different ideas. I’d rather deal with this now than wait to see if there might be a problem during assembly. Thanks to all who respond.

Craig T
Central NY
1961 Tramp (truck with a ramp)

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Re: Head stud interference problem?
Posted by: cnicol ()
Date: January 18, 2023 02:05PM

I would torque-test the stud using a pipe spacer to fill the distance to the nut. If the stud passes the torque-test, it is well and properly seated and I would certainly not disturb it.

Grinding off the protruding end would be the way to maintain the happily seated stud while allowing room for the rod nut. As I recall, the protruding stud that causes problems in on the driver's side, just forward of the middle.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
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+17 Tons of parts

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Re: Head stud interference problem?
Posted by: Tramp61 ()
Date: January 18, 2023 02:23PM

Thank you Craig! This Craig appreciates your advice.

Craig T
Central NY
1961 Tramp (truck with a ramp)

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Re: Head stud interference problem?
Posted by: 63turbo ()
Date: January 18, 2023 04:56PM

cnicol is giving you very good advice. 20 years ago, I decided to replace all of the head studs with new. It was an AWFUL job! one or 2 of the studs refused to come out without using a lot of heat, penetrating oil and many vise grips all at the same time. They finally came out but it wasn't worth it!!

------------------------------------

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Friday Harbor Washington
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Re: Head stud interference problem?
Posted by: Frank DuVal ()
Date: January 18, 2023 07:13PM

Yes! To what Craig and Kevin said.smileys with beer

Frank DuVal

Fredericksburg, VA

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Re: Head stud interference problem?
Posted by: Tramp61 ()
Date: January 18, 2023 07:35PM

Thank you everyone for your responses. Will torque test and grind as necessary. I believe the breaker bar was the torque test, but for thoroughness I am doing all the studs anyway.

Craig T
Central NY
1961 Tramp (truck with a ramp)

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Re: Head stud interference problem?
Posted by: Tramp61 ()
Date: January 22, 2023 09:19AM

Following up on my earlier post. The head stud in question was tested at 35# and held. Ground off the threads protruding into the case. About half of the head studs unthreaded after testing, so threads were cleaned up and put back in at 15# with blue loctite. I’m torn about re testing them, if they did not pull out the threads at 35# before, they should hold again. Don’t want to cause further erosion of material if they unthread again. There is no way to keep the stud from unthreading when testing with pipe on the studs.

I have to heli coil one stud because of my own screw up. Put loctite on and cross threaded the stud on the way in. Destroyed the aluminum threads getting it back out. That hole was somewhat loose after cleaning up anyway, so probably better off with a heli coil in it. Ordered a “good quality” die from McMaster-Carr to cut the stud thread taper for the heli coil. I sure hope it’s good for $28.00.

The block was also relieved with a 60 grit flap wheel on the angle grinder to make room for the longer throw of the 164 crank and rods that will be going in. I’ve sweated in anticipation about having to do this for months. Turns out it’s much easier than I expected. It’s not precise machine work that I’m familiar with, but it’s not a hack job either. I put the old main bearings in place and covered the sensitive areas with gorilla tape to protect the block from me. Over prepared, but mostly safe from me screwing it up. Took about 5 minutes or so per cylinder location to get to 5/32” depth. I chose this because 1/8” didn’t seem like enough and 1/4” seemed like too much. Very scientific. I’m not good enough at math to calculate the exact depth needed, so I approximated. If I have to adjust the depth later I will have learned that 5/32 isn’t enough. Don’t have the crank and rods on hand, so final results will have to wait.

Craig T
Central NY
1961 Tramp (truck with a ramp)

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Re: Head stud interference problem?
Posted by: RexJohnson ()
Date: January 22, 2023 09:54AM

If you have a long-stroke block to compare it to you can use calipers to measure from the outside where the barrels sit to see if you are deep enough. I always use a long-stroke barrel to mark the outline of what needs grinding.

RJ tools
Salem,Oregon

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Re: Head stud interference problem?
Posted by: Tramp61 ()
Date: January 22, 2023 10:00AM

Rex: That’s what I would have done if had either of those here to go by. I need to get the block finished up with a couple more cleaning passes. It is taking forever. Figured I would get the grinding out of the way before final cleanup.

Craig T
Central NY
1961 Tramp (truck with a ramp)

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Re: Head stud interference problem?
Posted by: Frank DuVal ()
Date: January 22, 2023 10:10AM

I know McMaster is in your backyard so to speak, but so is MSC (the old Manhattan Supply Co.). They are also good for quality machining tooling/tools/supplies.

Frank DuVal

Fredericksburg, VA

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Re: Head stud interference problem?
Posted by: Tramp61 ()
Date: January 23, 2023 07:01AM

Frank: Thanks for the tip!

Craig T
Central NY
1961 Tramp (truck with a ramp)

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