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Re: Do I really need to degree the cam?
Posted by: Chasgee ()
Date: October 15, 2019 12:47PM

Great discussion. I’m just proud one of my posts got to two pages!

Chuck Gee
Carlsbad, CA

1963 Monza 102 - in the family from new
1966 Corsa 140 Coupe - new project

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Re: Do I really need to degree the cam?
Posted by: Chasgee ()
Date: October 15, 2019 12:48PM

Awesome, my post made it three pages!

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Re: Do I really need to degree the cam?
Posted by: joelsplace ()
Date: October 15, 2019 01:01PM

That's my kind of info Jim. I need to draw that on my wall or do you offer that service?
Does it only work in tandem with a generator?

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: Do I really need to degree the cam?
Posted by: Wagon Master ()
Date: October 20, 2019 07:19AM

What was the final decision,

1. GM advanced the crank gear 4 degrees to retard the cam 2 degrees.

2. GM advanced the crank gear 8 degrees to retard the cam 4 degrees.

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Re: Do I really need to degree the cam?
Posted by: JimBrandberg ()
Date: October 21, 2019 05:33AM

I can't think that hard this morning but I believe the final effect was that in the 140 PG application only, the Intake centerline of the 889 cam was changed from 104 degrees to 108 degrees. I've always looked at it in terms of offsetting the cam gear.

Bob Helt explains the theory well in his book and goes beyond theory with dyno testing. If not for that, it's a little hard to get my mind around a little cam performing well with a big Intake and Exhaust. I think Bob was a little surprised himself.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Do I really need to degree the cam?
Posted by: Wagon Master ()
Date: October 21, 2019 06:17AM

Sorry for my persistence but Bob Helt wrote quite a few books. To which one do you refer?

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Re: Do I really need to degree the cam?
Posted by: JimBrandberg ()
Date: October 21, 2019 06:48AM

I think it's in "Corvair Secrets" but I'm not sure offhand. There's quite a discussion and useful charts on Corvair cams in general and a section on the 140 PG peculiarities.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Do I really need to degree the cam?
Posted by: Wagon Master ()
Date: October 21, 2019 08:24AM

So then, to answer my question, if GM moved the 889 cam intake centerline from 104 degrees to 108 degrees to move the power band higher in the rpm range. Was this 104 to 108 shift in camshaft or crankshaft degrees?

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Re: Do I really need to degree the cam?
Posted by: JimBrandberg ()
Date: October 22, 2019 05:46AM

Crankshaft degrees.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Do I really need to degree the cam?
Posted by: Wagon Master ()
Date: October 22, 2019 08:15AM

Must be why Clark's offers a 2° or a 4° offset key if you want to replicate the factory change. 4° for the crank or 2° for the cam. The cam key being much easier to swap out.

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Re: Do I really need to degree the cam?
Posted by: JimBrandberg ()
Date: October 24, 2019 04:33AM

The force required to remove the crankshaft gear is scary and I haven't done it for a while now. I'd rather move along to a different crankshaft if it's bad but I have a few to choose from.

I have the aforementioned crankshaft here where I discovered the gear had slipped, which I discovered when checking the cam timing. The woodruff key had looked fine when viewed from the end. It had already been Magnafluxed and ground .010/.010 so I have some money in it. I took it to my local Machine Shop guy to remove the gear. He has a mechanical press made from a truck differential where he can get some distance. Even slipped with the woodruff key sheared, he said it sounded like a gun when it came loose. I wanted to have a look at it but instead he went ahead and pressed it back on with a new key.
I've still got it on the shelf, I'm wondering about welding the gear to the crankshaft. I'd use it in my own engine rather than sending it along with a customer.

Jim Brandberg
Isanti, MN
CorvairRepair.com






Edited 1 time(s). Last edit at 10/24/2019 04:34AM by JimBrandberg.

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Re: Do I really need to degree the cam?
Posted by: joelsplace ()
Date: October 24, 2019 11:19AM

Excellent shelving!
Who knew eggs went with Corvair cams?

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: Do I really need to degree the cam?
Posted by: Wagon Master ()
Date: October 24, 2019 12:10PM

12 eggs
12 lifters
It's math.

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Re: Do I really need to degree the cam?
Posted by: joelsplace ()
Date: October 24, 2019 12:49PM

12s go together? Lifters might damage your teeth.

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: Do I really need to degree the cam?
Posted by: jjohnsonjo ()
Date: October 24, 2019 02:24PM

JimBrandberg Wrote:
-------------------------------------------------------
> The force required to remove the crankshaft gear is scary and I haven't done it for a while now. I'd rather move along to a different crankshaft if it's bad but I have a few to choose from.
. I took it to my local Machine Shop guy to remove the gear. He has a mechanical press made from a truck differential where he can get some distance. Even slipped with the woodruff key sheared, he said it sounded like a gun when it came loose.


Jim ya know the drill, no video ???????

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: Do I really need to degree the cam?
Posted by: JimBrandberg ()
Date: October 25, 2019 04:40AM

When assembling an engine all day and counting in 6s and 12s I find myself looking for a 6th finger when washing my hands.

Jim Brandberg
Isanti, MN
CorvairRepair.com



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Re: Do I really need to degree the cam?
Posted by: 66vairman ()
Date: October 25, 2019 09:09AM

JimBrandberg Wrote:
-------------------------------------------------------
> The force required to remove the crankshaft gear is scary and I haven't done it for a while now. I'd rather move along to a different crankshaft if it's bad but I have a few to choose from.
>
> I have the aforementioned crankshaft here where I discovered the gear had slipped, which I discovered when checking the cam timing. The woodruff key had looked fine when viewed from the end. It had already been Magnafluxed and ground .010/.010 so I have some money in it. I took it to my local Machine Shop guy to remove the gear. He has a mechanical press made from a truck differential where he can get some distance. Even slipped with the woodruff key sheared, he said it sounded like a gun when it came loose. I wanted to have a look at it but instead he went ahead and pressed it back on with a new key.
>

I use a machine shop familiar with Corvair engines. I had them remove the gears from two cranks while I waited. Yes it can take a lot of force and makes a loud bang. One crank had a corroded gear and the other crank had the 140 PG retarded gear.

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Re: Do I really need to degree the cam?
Posted by: joelsplace ()
Date: October 25, 2019 09:10AM

How much force? Will 50 ton do it?

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: Do I really need to degree the cam?
Posted by: MattNall ()
Date: October 25, 2019 10:34AM

20 will with difficulty... 50 no brainer! GG

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Do I really need to degree the cam?
Posted by: MattNall ()
Date: October 25, 2019 10:46AM

If I were building an engine...IE: $3k plus... I'dbuy one of the Adjustable cam gears.

Set it as recommended


Drive it 1000 miles..... decide if I wanted more top end or low end.

Pull engine and adjust.... drive another 1000 miles and decide..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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