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Success Rate for Valve seat staking
Posted by: Layton Curtis ()
Date: November 22, 2017 09:38AM

I had a valve seat that came loose recently on my 110, I shut it down in time and it did not shatter. The hole is 1.425 dia and the seat is 1.428 dia. just the way GM did them. (I believe) What luck would I have putting it back in and staking it really well? Of course I know it must be heated.

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Re: Success Rate for Valve seat staking
Posted by: davemotohead ()
Date: November 22, 2017 09:52AM

No luck at all, it will fall out again most likely when you start the engine the first time, Fix it right with a new deep seat installed.





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)




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[motoheadmall.com]
-----------------------------------
Rust Free Lancaster Ca

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Re: Success Rate for Valve seat staking
Posted by: jjohnsonjo ()
Date: November 22, 2017 10:19AM

[corvaircenter.com]

Works for me and many, many others. Some will disagree, Have never had one fall out after doing this.

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: Success Rate for Valve seat staking
Posted by: davemotohead ()
Date: November 22, 2017 10:24AM

That is set screwing not staking, and you did not set screw one back into place after it fell out already, if he puts it back in the hole and stakes it, it will fall right back out.





Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)




Sign my guest book!
[motoheadmall.com]
-----------------------------------
Rust Free Lancaster Ca

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Re: Success Rate for Valve seat staking
Posted by: jjohnsonjo ()
Date: November 22, 2017 11:11AM

Yes I did Dave, not on this set, but on older set. He will have to heat the head or freeze the seat to get it back in, If his measurements are correct.

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: Success Rate for Valve seat staking
Posted by: gnvair ()
Date: November 22, 2017 11:52AM

Amazing how many people like to jury rig things rather than repairing them properly. If the seat already came out then the seat bore us already oversized. I would not depend on set screwing. Doing so always comes back to bite on that deserted road somewhere when you don't expect it. I would never do it on my own car or a customer's car. Working in the field I would not consider it a proper repair.

Lee J

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Re: Success Rate for Valve seat staking
Posted by: BobV66Vair ()
Date: November 22, 2017 12:07PM

Either do it right or park the car until you can. Staking is a terrible idea. All it does is introduce more weakness into the seat area. The seat fell out for a reason, usually overheating the head. Other seats may be ready to go or damaged. Just do a valve job and install deep seats. There are sizes available that are larger than the stock OD. They can be installed using heat/freezing to get an absolute fit that won't come out. One and done. Do all the seats and consider the other head as well since it underwent the same heating and wear. Once you do it, you won't need to worry about the heads for years.

While your at it, pull the top shroud and see if there is junk in the fins. Airflow may have become blocked, leading to overheating.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Success Rate for Valve seat staking
Posted by: thewolfe ()
Date: November 22, 2017 12:17PM

^^words of wisdom. I went a few years running heads that had been overheated. Each time I dropped a valve seat I would pull the head and get a new, larger o.d. seat installed then put it back together. Then a few months later another would drop and so forth. After the fourth seat falling out I gave up on those heads and had another set built with deep seats. Zero problems since. I would never stake a valve seat either, especially one that dropped already.

Nate Wolfe
Portland OR
65 Corsa 180

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Re: Success Rate for Valve seat staking
Posted by: Bob Helt ()
Date: November 22, 2017 12:18PM

Entirely possible, but Mackerly has shown data that definitely proves that aluminum looses strength while doing heat-cooling cycles. I would suggest that you have the valve seat holes bored out and then built up by welding in new material. And if one dropped out, then the rest are ready to go too.

Bob Helt

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Re: Success Rate for Valve seat staking
Posted by: Layton Curtis ()
Date: November 22, 2017 06:13PM

If I could find some replacement seats that are 1.430 OD I would do it and heat the head and take the chance as is. But-Clarks sells some +.005 oversize and that will be .008 interference and that one will not go in regardless of how much you heat the head. so I'll probably forget it until I ever need it. I have several vintage heads that I know have never been overheated because I have owned them for 40 years. Besides, I have been driving many Vairs for 54 years and I have been all over the Eastern half of the U S with no so called reworked heads and only dropped one seat recently after a run of very hard driving. (Shouldn't have using a head I had no History of) Those of us that have a Corvair history with plenty of parts have a huge advantage. By the way I grind my own valves with an old Thor grinder.
Thanks to everyone who posted as I was curious to hear about your views. One never knows when his situation will change.

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Re: Success Rate for Valve seat staking
Posted by: Wagon Master ()
Date: November 22, 2017 06:38PM

What is the generally excepted consensus on the property press fit on a table seat?

'64 Monza Coupe 140 4 speed
'61 700 Lakewood 95 4 speed
'69 Monza Convert. 140 Auto.

Been aircooled since 1973
Northwest Ohio

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Re: Success Rate for Valve seat staking
Posted by: Wagon Master ()
Date: November 22, 2017 06:50PM

How about on a valve seat.

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Re: Success Rate for Valve seat staking
Posted by: Bob Helt ()
Date: November 23, 2017 08:07AM

Wagon Master Wrote:
-------------------------------------------------------
> What is the generally excepted consensus on the
> property press fit on a table seat?


I don't understand. What is a property press fit?

But anyhow, You don't have a press fit for valve seats, if that is what you mean. Valve seats are installed with a zero press fit or maybe just a slight one. You heat the head to get the hole to expand and cool the seat to shrink its diam. Valve seats have an interference fit that occurs after the head and seat return to room temp.

Bob Helt

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Re: Success Rate for Valve seat staking
Posted by: 66vairman ()
Date: November 23, 2017 10:46AM

As Bob said it's an interference fit AND NO MATTER how tight you get the fit (heating head, cooling seat) after a few normal engine heat/cooling cycles the aluminum around the seat will "give" and that's going to be the interference fit between the head area and seat (dissimilar metal expansion rates). Of course overheating a head will cause the aluminum to "give" more and when things cool down the interference fit is inadequate to hold the seat in.

The ONLY way to increase the friction between seat and the head is to INCREASE the contact area between seat and head, or deep seats.

Staking increases tension between the head and seat ONLY in small areas and experience indicates it's not a reliable fix on Corvair heads.

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Re: Success Rate for Valve seat staking
Posted by: v8vair ()
Date: November 23, 2017 12:34PM

Waste of time

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Re: Success Rate for Valve seat staking
Posted by: Wagon Master ()
Date: November 23, 2017 02:36PM

OK. So maybe I used the wrong term. It's not a press fit. It's a interference fit. The original poster states he had what measured to be a .003 factory interference fit. Is this exceptable for deep seat too? Since it's not the fit but the extra surface area that holds the seat in. Also are Clark's replacement seats deeper or just a larger o.d.?

'64 Monza Coupe 140 4 speed
'61 700 Lakewood 95 4 speed
'69 Monza Convert. 140 Auto.

Been aircooled since 1973
Northwest Ohio

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Re: Success Rate for Valve seat staking
Posted by: Mel ()
Date: November 23, 2017 03:37PM

Do the deep seats and be done with it.

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Re: Success Rate for Valve seat staking
Posted by: martyscarr ()
Date: November 23, 2017 05:31PM

Wagon Master Wrote:
-------------------------------------------------------
> What is the generally accepted consensus on the
> proper press fit on a valve seat?


THIS ARTICLE has some good info, but doesn't make a distinction between water cooled and air cooled aluminum heads. The gist of the article is "whatever the manufacturer recommends" but also says a rule of thumb to use is .007 minimum press fit.

The chart below is what Durabond (a manufacturer) recommends for their valve seat. They recommend a larger interference fit for larger seats, but they also don't address air cooled heads. I do agree that a larger seat needs a larger interference fit, I know some of the performance VW guys are using .010 for their intake seats.

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Re: Success Rate for Valve seat staking
Posted by: martyscarr ()
Date: November 23, 2017 05:39PM

Wagon Master Wrote:
-------------------------------------------------------
> .....are Clark's replacement seats deeper or just a larger o.d.?

They are a just a larger OD

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Re: Success Rate for Valve seat staking
Posted by: vairmech ()
Date: November 24, 2017 06:59AM

There are many places that have and sell deep seats, including me. My seats are larger in OD and way deeper as I showed in a past post about deep seats. The average interference fit I use is about .007". Any more and the head just relieves it's self as the two parts normalize temps to about the .007" interference.
(My post of the valve seats sizing will not show up because of photobucket.

An oversize stock seat will not stay in.Why? Unless you clean the carbon from the ID of the head the new seat WILL slip out eventually!

I also posted a video here of installing deep seats!

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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