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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: red monza ()
Date: January 27, 2015 01:48PM

davemotohead Wrote:
-------------------------------------------------------
> I have never had a Machine shop stamp the bearing
> journal sizes on a crank nor would I want them to,
> Every crank I have ever had polished or Turned
> came with a Tag,Not a stamping.

Well, I have never seen anyone stamp bearing journal sizes on a crank either...if you are referring to my post...go back and read it again. Here it is so you can see it without any work.


I think it is customary for the machine shop to stamp the crank as to any change in size....there is usually two markings...one is for the main surface and the other one is for the rod surface...my 49 283 was a 10/10 turn and done down in Charlotte as I had some other work done to the crank.

All the cranks I have installed that were turned...had the turned amount stamped on the crank....I have never seen a crank with a tag on it...I would never want that on my crank as it would be too easy to get lost, break off, etc. I guess things are done different here and I prefer the crank be stamped so it is NEVER is questioned as to size or if it has been turned.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: MattNall ()
Date: January 27, 2015 02:04PM

Must be "zonal"!!


out west all I've ever seen is a tag as well...





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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: Kims65 ()
Date: January 27, 2015 02:19PM

I've had yellow paint pen (like a used parts yard) on the side of a turned crank say "10/10" along with the paper tag here in CA a while ago. The tag only had the company name, my name and work order info. The tag on one side said mag and check. The other side said mag OK and turned 10/10.

Oh and balanced too.

That shop is now gone...sadly as they did good work.

John G.
Mission Viejo, CA



Edited 1 time(s). Last edit at 01/27/2015 02:20PM by Kims65.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: red monza ()
Date: January 27, 2015 03:12PM

I went on line and all I saw was "stamped"...now...there might have been a paper tag attached to the crank with the amount of metal removed from the crank bearing points when I opened the box from Charlotte Crank..I still have the box and I am pretty sure it shows 10 10 on box...but here it is always stamped on the crank itself...usually on the counter balance...what attaches the tag to the crank out there?

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: 66vairman ()
Date: January 27, 2015 03:31PM

A good discussion here. It would be nice if the original poster would supply the mic'd crank numbers. Even with a mic'd crank that is within spec I always plastigauge the crank in the block to make sure there are no issues with the bearings, case halves, etc.

Specifications for the crankshaft journals and the clearances for the journal bearings are two different sets of values.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: red monza ()
Date: January 27, 2015 03:37PM

If you build an older chevy v8, as the bare block is upside down and you are installing the pistons, each piston is marked on the oil pan rail as to a number....that is the number the factory wanted the assembly person to place in the engine in that hole...if you do not bore the engine and try and re use these pistons...they better be the right number matching hole...this was just trivia...don't know about corvairs engines.

When the engine is bored...then this all goes away of course.

My mechanic said once he tore down a toyota engine that was not running right for a friend. He discovered that the bearings I think he said were color coded. There was a non matching color on one piston...changed that and all was good.

As for me...I trust my machine shop to correctly order the correct bearings, etc for my rebuild....the last engine I built has 160lbs on the compression, the little 283 in my 49...none have ever smoked and they all started within seconds on the first firing attempt...can't believe the tv shows that cannot make the engine fire without re-setting the distributor.

I put a piece of waded paper in #1 cyl and turn the engine over...when it pops out( and you think gun shot), I re-align the timing marks to 0, drop in the dist so that the rotor points to #1 wire...how hard is that?

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: red monza ()
Date: January 27, 2015 04:09PM

Here is another thing I do as I am assembling the engine...after each piston is installed, I put a wrench on the crank bolt and turn the engine...if it turns easy and no markings on the bore, I then assemble the next piston and do the same thing.

My friend, who I help build ford engines for all his cars, one day we were putting together his engine...again...did what I stated above. About the 3-4th piston, the engine would not turn but so far and lock up...yep, upon checking the last piston, we had been yaking and laughing and put in a bearing wrong...so it does pay to do what I stated above....had we not done what I suggest, that engine would have been a big paper weight upon starting.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: 63ConDan ()
Date: January 27, 2015 04:40PM

Hi here are the measurement details

The main journals // Clearances
1 2.0983 with flange // .0030
2 2.0985 // .0025
3 2.0987 // .0022
4 2.0984 // .0026

All the rod journal were 1.799 or 1.800

Also it has the & stamp on the flywheel end.

so look like the crank is OK but the clearance are a bit loose

What are your thoughts??

Dan Central MN

1963 vert with '65 110 PG, 1963 Spyder vert 150 turbo,1966 Sport Coupe 140 3spd, 2002 TA WS6 Vert




Edited 2 time(s). Last edit at 01/27/2015 04:48PM by 63ConDan.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: MattNall ()
Date: January 27, 2015 04:51PM

Run it!! it will make good HP and mileage!





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Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: davemotohead ()
Date: January 27, 2015 05:25PM

Never had a Machine shop stamp anything on any crank, only a work tag,I have had a lot of Different kinds of cranks magged,turned,polished by different shops and none ever came back stamped that is all I am saying,maybe its a east coast thing?





Email me at: Dave Motohead

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-----------------------------------
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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: jjohnsonjo ()
Date: January 27, 2015 06:07PM

The & stamp indicates factory nitrided, good thing. I'd almost bet it had .001 in from new.

Shop manual clearance 1 and 2 = .0012-.0027 3 and 4 .0007-.0022.

Your about .0003 over, not much. If you already have bearings go stock. If not phone Clarks and see if the have some .001 still around.

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: jjohnsonjo ()
Date: January 27, 2015 06:34PM

Do you have a shop manual????

journal 1 and 2 = 2.0978-2.0988 3 and 4 = 2.0983- 2.0993

your pretty well in there

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: v8vair ()
Date: January 27, 2015 06:46PM

all my race cranks come back with a date stamped and what was done. And these are from pro shops Mike

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: v8vair ()
Date: January 27, 2015 06:49PM

Reeves told me his race motors had to have high volume pumps because he ran such loose clearances. .0025 on the rods and .0030 on the mains.
Mike



Edited 1 time(s). Last edit at 01/27/2015 06:58PM by MattNall.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: vairmech ()
Date: January 28, 2015 02:51AM

With the numbers on your crank you should be able to run the Std. bearings with no problem. The ONLY thing you will see is a little lower than "normal" idle hot oil pressure, you will be down to 10-15 psi, nothing to worry about.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: Spectre ()
Date: January 28, 2015 04:13AM

The last 140 I built had .001 bearings in it. I measured the rod and main journals and it just barely needed those. I could not find that size at the time of the build, so I put standards in it. It ran great and as far as I know, is still making the current owner very happy.

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2013 Mustang GT convertible - 5.0, 6spd auto, Procharger i-1

2003 Miata SE - 6spd manual (wife's toy)

"Victory is mine!" - SG

Warner Robins, GA (15 miles south of Macon)

Click for Warner Robins, GeorgiaForecast


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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: afterdarkgames ()
Date: January 28, 2015 05:58AM

You could use a Honda rebuild trick. Buy the .002 bearings from clarks and use one side of the standard and one side of the .002. It will tighten up your clearance to the middle of the specifications.

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

That was or is a GM trick as well, from new.

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

Image and video hosting by TinyPic

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: red monza ()
Date: January 28, 2015 07:26AM

Clearances look okay to me...I too would build it with those clearances.

I have been having a real problem with my 49 chevy 283...
1. It has had to have 3-4 sets of plugs put in in 2500 miles
2. It starts missing after a road trip out of town...great
3. The plugs are all oil soaked on the threads
4. When you first crank it, and drive it, it backfires thru the carb

I went out to talk to my engine machinist a week or so back about fixing an intake for me. While there mentioned the problems...and finally told him I was running about 100 lbs of oil pressure on start up...THAT IS YOUR PROBLEM. Did you put in a high volume/pressure oil pump...I said no..I would never do that. Then you have a pump with the pressure relief valve stuck...so I took the oil pan off last week and the first thing I see is great big numbers stamped into the crank....10/10...you would have to be blind not to see that.

I took the oil pump out and took it to my mechanic....it took an act of congress to un-stick the pressure relief valve...but we did it. Now, on start up I have about 60 lbs of pressure...much much better.

What was happening, was that that much oil pressure was spraying a mist of oil into the valve covers (edelbrock, not chevy) and the pvc valve was sucking it up and putting it in the carb..then on to the pistons...the back fire was as my great mechanic said....that much pressure is locking the lifters and keeping the intake open...hence the backfiring.

So, all is well now...but lesson learned...I knew I had not put in a HP oil pump...like my mechanic says....have you seen what high pressure does to cutting metal...a swift running stream does to rocks....he is so right always.

Hope this helps someone in the future...again, those big 10 10 numbers stamped on the crank was the first thing I saw when I took the pan off.

If I was going to rebuild an engine and it had 10 10 stamped on the crank, I would be looking for another crank if it too, needed turning one more time...



Edited 1 time(s). Last edit at 01/28/2015 07:36AM by red monza.

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Re: Problem with 1966 CHEVROLET CORVAIR 140 Engine rebuild: Crankshaft Main Bearings
Posted by: 63ConDan ()
Date: January 28, 2015 02:17PM

Hi I have made a decision,spinning smiley sticking its tongue out I'm going with the standard bearing I have. No cost no delay and a small compromise.

A big thank you to everyone on this forum who help in the decision process.

I would have to imagine this will not be the last of my challenges, so you may find me around here more often

Dan Central MN

1963 vert with '65 110 PG, 1963 Spyder vert 150 turbo,1966 Sport Coupe 140 3spd, 2002 TA WS6 Vert

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