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Trial Assembly of Case
Posted by: Frog ()
Date: March 20, 2017 07:28AM

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: Trial Assembly of Case
Posted by: cnicol ()
Date: March 20, 2017 07:58AM

My version of "trial assembly"

Set 1/2 of crankcase horizontally on the engine stand.
Set Install bearing halves in both case halves.
Set crank into case half.
Plastigage on each main journal.
Set other crankcase half onto first half.
Torque bolts in three steps.

Hold that process for now and...

Install testing tube washer and nut on crankcase stud. Torque to 35# to test stud.
Repeat all studs on the top crankcase half. Flip engine over. Repeat on the other crankcase studs. Flip engine back to original position...

Loosen and remove crankcase bolts.
Remove upper crankcase half.
Measure plastigage widths and compare to specs.

Remove crankshaft.
Suspend crankshaft horizontally between bench vice and another support of the same height. (I use a large scissors jack and a vee-block.)
Hang each connecting rod/piston assembly onto its journal with a piece of plastigage in the lower bearing half.
Install and tighten connecting rod cap to torque.
Remove cap and measure plastigage width.

You can check the cam bearing clearance during the first step if you want but that's mostly so you can learn how far out of spec it is. The engines I've built over the last 25 years were all out of spec but that caused no issue.

I've attached a photo of the rod clearance testing but I'm still looking for a shot of one engine case attached horizontally to the engine stand.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe project
65 White 4-dr 110/AC/PG (parts)
66 Sprint Corsa convt - First car! Re-purchased 43 years later

+18 Tons of parts

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Re: Trial Assembly of Case
Posted by: steve c goodman ()
Date: March 20, 2017 08:00AM

Do you belong to a local club? Sometimes the clubs do tech sessions about some of your questions. OR help you assem the eng.

Where are you? A local shop like myself often helps with assembly or at least visits with you for questions etc.

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo 1965 Crown V8
1967 monza 110/4 1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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Re: Trial Assembly of Case
Posted by: cnicol ()
Date: March 20, 2017 08:46AM

Found the picture of how I do my trial case assembly...

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe project
65 White 4-dr 110/AC/PG (parts)
66 Sprint Corsa convt - First car! Re-purchased 43 years later

+18 Tons of parts

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Re: Trial Assembly of Case
Posted by: davemotohead ()
Date: March 20, 2017 08:55AM

cnicol Wrote:
-------------------------------------------------------
> You can check the cam bearing clearance during the
> first step if you want but that's mostly so you
> can learn how far out of spec it is. The engines
> I've built over the last 25 years were all out of
> spec but that caused no issue.
-------------------------------------------------------
Really Craig? Every Engine I have built all the cam journals were still in spec,I always check the mains and Cam at the same time just to see, but they always turn out in spec, I must have low mileage cases.

Also once you are ready for final assembly, make sure you put a little sealer like Gaskachinch in the 3 exposed case locations circled in red so you wont have a leak. thumbs up



Email me at: Dave Motohead

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Re: Trial Assembly of Case
Posted by: tboltkc ()
Date: March 20, 2017 09:24AM

Also make sure the crank and cam do not turn at all and the rods don't move if you do those or the plastigauge can get smeared and not give the measurement you want.

-Travis


'65 Corsa; '63 Convertible; '62 Wagon; '65 4 Door
Heart of America Corvair Owners Assocation (Kansas City, MO)

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Re: Trial Assembly of Case
Posted by: Frog ()
Date: March 20, 2017 11:21AM

Outstanding. That's exactly what I needed. And I was wondering how to check the rod bearings without installing the pistons.

Craig, I have a question. I don't understand what you mean by:

Hold that process for now and...

Install testing tube washer and nut on crankcase stud. Torque to 35# to test stud.
Repeat all studs on the top crankcase half. Flip engine over. Repeat on the other crankcase studs.


Steve, Dave, and Travis, thanks for your inputs.

I live in the extreme northeast part Georgia seven miles between the North Carolina border and the South Carolina border.

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Re: Trial Assembly of Case
Posted by: Frog ()
Date: March 20, 2017 11:34AM

Never mind, Craig. I was just reviewing Bob Helt's book The Classic Corvair, Tenth Edition, and on page 154 I see what you're talking about. You're talking about testing the cylinder-head studs to make sure they don't pull out of the case.

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Re: Trial Assembly of Case
Posted by: jcorvair ()
Date: March 20, 2017 11:35AM

Yes, to check head studs you will need a "Test Tube" of some sort to bridge the gap to the block so you can pre-check that studs won't oull out if torqued to around 30 ft-lbs. Maybe Craig can share what type of tube he uses.

Good luck with the build.

James
Maple Ridge, BC

1965 Monza Coupe 140/4spd, Factory '66 headrests, rear antenna
2013 Hyundai Santa Fe Turbo
2013 Hyundai Elantra (daughter's future car)
2009 Silverado HD Crew Cab 4x4 (for haulin cars, trailers, fifth wheels, quads, etc.)
2013 Victory Car Hauler (enclosed)
2015 Polaris 570 EPS
2016 Polaris 570 SP



Edited 2 time(s). Last edit at 03/20/2017 11:36AM by jcorvair.

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Re: Trial Assembly of Case
Posted by: jjohnsonjo ()
Date: March 20, 2017 11:37AM

""Hold that process for now and...

Install testing tube washer and nut on crankcase stud. Torque to 35# to test stud.
Repeat all studs on the top crankcase half. Flip engine over. Repeat on the other crankcase studs.""

What you are doing with this process is checking the integrity of the head studs at the block. The tube simulates the barrel and head in length. If you do have a loose or weak stud, this is when you want to find out, not during the final stages of assembly. I go higher than 35, but that's me. I had one begin to pull many years ago during final torqueing. You instantly get a not so good feeling in your stomach. I don't want to go through it again if it can be prevented.

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: Trial Assembly of Case
Posted by: Frog ()
Date: March 20, 2017 11:55AM

Thank you.

Bob Helt's book says to use a 5/8" outside-diameter cast-iron pipe with an inside diameter to just fit over the head studs with washers above and below. He says go to 40 lb-ft.

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Re: Trial Assembly of Case
Posted by: davemotohead ()
Date: March 20, 2017 12:13PM

Test at 35 ft lbs and Torque them at 30 ft lbs when assembling.



Email me at: Dave Motohead

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[motoheadmall.com]
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