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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: cnicol ()
Date: January 28, 2015 02:24PM

If you make sure there are no nicks, sealer or other impediment to proper mating of the crankcase halves, you'll probably pick up enough to get it in spec. Gently test all crankcase-half mating surfaces for raised edges using a fine file. You might be surprised.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later

+17 Tons of parts

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: jjohnsonjo ()
Date: January 28, 2015 02:32PM

If it were my engine I would take my bearings, my crankcase halves, my crank, my plastic guage, then torque the whole thing to a full 55 ft lb pulland double check it myself. Also would check the cam jourals at the same time. Then I know for sure.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: red monza ()
Date: January 28, 2015 04:02PM

I looked up the bearing clearances on my 66 110...all of yours was in spec...the max in the book was .0027.

The one that is .0030, after re checking all the clearances...I would give it another 5 lb of torque if you get .0030 again.

Thats just me and what I would do.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: Ratt643 ()
Date: January 28, 2015 07:27PM

jjohnsonjo Wrote:
-------------------------------------------------------
> If it were my engine I would take my bearings, my
> crankcase halves, my crank, my plastic guage, then
> torque the whole thing to a full 55 ft lb pulland
> double check it myself. Also would check the cam
> jourals at the same time. Then I know for sure.


This is what I did this time around. I ordered .010/.010 bearings since I knew I was going to have it reground. Installed the bearings into the block, making sure to install the bearings with red dye in #4 position. Torqued the block together and off to the machine shop the block and crank went. He measured both the bearings and the crank and after machining, everything came out with .002 clearance, in spec my the manual.


1964 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: 63ConDan ()
Date: January 29, 2015 06:04AM

Hi Ratt643 yes what you propose is the solution my machine shop had suggested and it is a very good solution but with a good in spec nitrated treated crank and the std bearing in hand, and per several confirming options from this forum, the slightly excessive clearances out weigh the cost and time to purchase new .010 US bearing, regrind the crank and a nitrated treatment. And then I have a reground crank, with the possibility of additional unknowns.

So I am happy with the decision, and I will keep posting progress update.

All the best

Dan Central MN

1966 Sport Coupe 140 3spd,

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1966 CHEVROLET CORVAIR 140 Engine rebuild: update with questions
Posted by: 63ConDan ()
Date: February 20, 2015 07:29PM

Hi as the progress goes new challenges surface.
So here is what happened:

Got the lower end sorted out and moving out with pistons and heads. It turns out the + 45 year old TWR forged pistons are +.60 over, so re-bored +.30 barrels to match, so OK with that although I have no where else to go except new barrels for a future rebuild. IOf anyone has thought as to what is a fair price for the re-bore work it would be appreciated?

Then I find one of the compression rings is broke, so ordered a single to replace + $20.00 also found 3 valves were too worn 2 Ex 1 intake to continue so sourced them +$45.00. got the package with valves late yesterday and today found 2 ex vales are incorrect. I order C3023P and received C3022P. Thought I messed the order but the packing slip noted what I ordered P3023P But the size did not match. Confused but after closer review the packaging that contained the valve was marked C3022P. So got the replacement going on that today. At Clarks what would be the usual course of remedy for something like that?

Later next week when all is sorted out to the heads there I'll post photos.

As always any input and/or support offered would be appreciated.

Thanks a bunch.

Dan Central MN

1966 Sport Coupe 140 3spd,

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Re: 1966 CHEVROLET CORVAIR 140 Engine rebuild: update with questions
Posted by: MattNall ()
Date: February 20, 2015 07:36PM

Call Clarks and they usually send them right out when a mistake has been made..





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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: 63ConDan ()
Date: February 21, 2015 06:46AM

Thank you Matt, the correct valves are on the way.

Again if anyone has a comment or suggestion to improve the motor as this is assembled I would appreciate any feedback it very much.

Thank you.

Dan Central MN

1966 Sport Coupe 140 3spd,

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Valve Seat Question on 1966 CHEVROLET CORVAIR 140 Engine rebuild:
Posted by: 63ConDan ()
Date: February 25, 2015 03:58PM

Should I replace the valve seats as I re build the 1966 140 motor?

i'm about to that point now.

Never ran the motor so do know of any problems, but would like to run pump Unleaded fuel and do not want any problems.

Any information is welcome

Dan Central MN

1966 Sport Coupe 140 3spd,

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: thewolfe ()
Date: February 25, 2015 04:10PM

It certainly wouldn't hurt to have deep seats installed so you don't ever have to worry about them falling out. Regular unleaded fuel has always been fine for corvair valve seats - they're hardened steel.


Nate Wolfe
Portland OR
65 Corsa 180

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: 63ConDan ()
Date: February 26, 2015 05:03AM

Any recommendations on to have deep seats installed?

Dan Central MN

1966 Sport Coupe 140 3spd,

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: JimBrandberg ()
Date: February 26, 2015 05:32AM

Last set of deep seats I had done by Ken Hand in Michigan who does nice work and is set up properly.
My local machinist in Bethel has expressed interest in doing them but it's an investment for him and I'm a little apprehensive. I've already got him set up with provision for boring cylinders torqued down and set up for flycutting head gasket surfaces. He also Magnafluxes rods and reconditions them if necessary for me.
I prefer a machine shop in Lester Prairie for crankshaft work and usually bring them several at a time.
If doing deep seats be prepared to spend some serious money.
I will not let just any machine shop who thinks they can do Corvair work. I switched from a guy in Wayzata I'd used for 20 years and interviewed half a dozen before deciding on my guy in Bethel. I would ship to Corvair guys if I weren't doing so many.
I can Plastigauge your crankcase while you wait and help if desired.
Jim Brandberg
Isanti, MN
CorvairRepair.com

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Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Heads
Posted by: 63ConDan ()
Date: February 28, 2015 11:07AM

Hi Attached are photos of the combustion chamber of the heads. My concern is the area where the barrel meets the head. There is an indentation in the head where the barrel met the head, cause by the barrel .

Anyone one think these are not usable or should be work to smooth that surface? Id like to know your thoughts.

Any difference in depth can be taken up with using gaskets to insure the heads fit correctly. Is that basically correct thinking?





Any and all comments would be welcome.

Thank you.

Dan Central MN

1966 Sport Coupe 140 3spd,

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: Frog ()
Date: March 20, 2017 05:19AM

I'm getting ready to assemble my engine. I want to perform a trial assembly, but I'm not sure of the step-by-step procedure. My machinist told me that my crank journals were in good shape and just needed cleaned up. Because of this he recommended the standard-sized main and rod bearings, which I have from Clark's. What I'd like to do, though, is take the bearing measurements myself, just to be sure everything's within specs. Below, read from a couple of years ago what seems to be what I'm looking for regarding a trial assembly. Am I to understand that I need to put Plastigauge on each of the four main bearings all at once, then torque the case? Now, for the cam journals, same thing? I know it sounds as if I'm simply repeating what it says below, but give me a break. God willing, I'll be 75 next year and I want to put this original-owner Corvair back together properly. I've seen a couple of videos from folks not part of the Corvair Center, and a website of the fellow assembling his engine for use in his airplane, but none have a start-to-finish presentation.

I read this:

Posted by: Ratt643 ()
Date: January 28, 2015 10:27PM

jjohnsonjo Wrote:
-------------------------------------------------------
> If it were my engine I would take my bearings, my
> crankcase halves, my crank, my plastic gauge, then
> torque the whole thing to a full 55 ft lb pull and
> double check it myself. Also would check the cam
> journals at the same time. Then I know for sure.

Also, going through the threads I get two different views on using antiseize where bolts are inserted into aluminum. I also understand that the torque specs change when using antiseize.

Thank you.

Frog

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Trial Assembly of Engine
Posted by: Frog ()
Date: March 20, 2017 07:26AM

I'm getting ready to assemble my engine. I want to perform a trial assembly, but I'm not sure of the step-by-step procedure. My machinist told me that my crank journals were in good shape and just needed cleaned up. Because of this he recommended the standard-sized main and rod bearings, which I have from Clark's. What I'd like to do, though, is take the bearing measurements myself, just to be sure everything's within specs. Below, read from a couple of years ago what seems to be what I'm looking for regarding a trial assembly. Am I to understand that I need to put Plastigauge on each of the four main bearings all at once, then torque the case? Now, for the cam journals, same thing? I know it sounds as if I'm simply repeating what it says below, but give me a break. God willing, I'll be 75 next year and I want to put this original-owner Corvair back together properly. I've seen a couple of videos from folks not part of the Corvair Center, and a website of the fellow assembling his engine for use in his airplane, but none have a start-to-finish presentation.

I read this:

Posted by: Ratt643 ()
Date: January 28, 2015 10:27PM

jjohnsonjo Wrote:
-------------------------------------------------------
> If it were my engine I would take my bearings, my
> crankcase halves, my crank, my plastic gauge, then
> torque the whole thing to a full 55 ft lb pull and
> double check it myself. Also would check the cam
> journals at the same time. Then I know for sure.

Going through the threads I get two different views on using antiseize where bolts are inserted into aluminum. I understand that the torque specs change when using antiseize.

What is the recommended tightening increment for the case bolts and bearing-cap bolts? In the case of the case, in proper sequence do I tighten to say "25," then maybe to "40," and finally the specified 50-55?

Thank you.

Frog

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Heads
Posted by: 66vairman ()
Date: March 20, 2017 09:05AM

63ConDan Wrote:
-------------------------------------------------------
> Hi Attached are photos of the combustion chamber
> of the heads. My concern is the area where the
> barrel meets the head. There is an indentation in
> the head where the barrel met the head, cause by
> the barrel .
>
> Anyone one think these are not usable or should be
> work to smooth that surface? Id like to know your
> thoughts.
>
> Thank you.

If the indentation is slight then it's not a problem IF you use a shop that has the proper tool. Both the gasket surface and quench step can be cut to maintain a proper relationship and compression ration (CC the heads). If the heads were cut once before then the gasket surface may be too close to the spark plug hole!! The indentation is thought to be caused by the steel gaskets installed upside down, or possibly the head was overheated. A good shop will check for head warp and make sure ALL the gasket surfaces are the same height relative to a common plane. If too big a cut has to be made then you get into issues of pushrod/rocker geometry, but usually at that point it's not worth trying to save the heads. While the supply is dwindling, you can still find good used 140HP heads.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Heads
Posted by: Scott V ()
Date: March 21, 2017 09:01PM

66vairman Wrote:
-------------------------------------------------------
> A good shop will check for
> head warp and make sure ALL the gasket surfaces
> are the same height relative to a common plane.

what common plane is used for the measurements?

-Scott V.

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