VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Valve replacement on '32 ?

I'm looking at a full replacement of intakes and exhaust valves for my 194. It's in the shop now for a rebuild. It's been recommended I go with a SS alloy type for the exhaust as opposed to a stock OEM replacement.
I'm looking for a few opinions of the advantages of SS not just for the exhaust but for the intake in SS as well ? Better heat tolerance ? Better with crappy modern gas ? I'm not second guessing the pro at the shop, just wanted to hear from the folks that actually drive these cars. I intend to drive mine regularly, weather permitting of course
Thanks guys !

That is a new one on me, never heard of anyone doing SS valves in a Vintage Chevrolet

I know TFS sells replacement valves, as well as Vintage Auto Parts

in general SS is Softer than Steel, usually use Steel and harden it to ensure it last and does not bend break. ALSO SS valves are usually used for high performance engines spinning fast, hard, and hot, also go up to Titanium for weight, as well as inconel for hardness. main use in race engines, turbo charges, super charged, nitro.

Good little article: Guide To Performance Valves

I would say it is kind of an overkill unless your planning on putting another 30,000 miles on the engine. If they are not too expensive just do it. You don't need hard valve seats because the regular grade on gas in the 1930's didn't contain expensive lead and there were no problems.
Yes, just for the exhaust because of the heat.

It seems that there are two schools of thought on hardened valve seats. One says, no--not needed, the other says you have to have them due to today's lead-free gasoline.

What I've determined through my own experience is that it depends on what kind of service the car is in. I have a 37 Chev 1/2 ton pickup, a 40 Chev 1/2 ton pickup, and a 36 Pontiac Deluxe 8 business coupe, all with their original, factory-installed engines, which I have rebuilt. My interest in these vintage cars is driving them, and 90% of the miles I have put on these cars is at highway speeds, with the engine turning over at 2500 to 3000 RPM, sometimes for 15 hours straight, often in 90 to 100 degree ambient temperatures. On all three of these engines, I have experienced severe pitting of the exhaust valves, and to a lesser extent, the exhaust valve seats. In each case, the engines had NORS Norris valves. The Pontiac valves went sour really soon after the rebuild, and I have subsequently installed hardened exhaust valve seats and stainless steel exhaust valves. So far, after around 7500 miles, the engine compression remains good, and no valve recession has been noted.

The valves in the 40 pickup also did not last long, so I had hardened exhaust valve seats installed, although I did not use stainless steel valves, but rather another set of Norris after market valves. So far, with maybe 15,000 miles on it, that engine seems to be holding up OK, with no exhaust valve recession noted yet.

I rebuilt the engine in the 37 pickup using NORS valves and drove to Flint, MI and back for the 50th anniversary meet, a trip of about 5,000 miles. The engine ran great, with no problems, but a few months after returning home, the camshaft timing gear let go during a casual Sunday drive. On disassembling the motor, I found the exhaust valves and seats badly pitted. On reassembly, I did not install hardened seats or special alloy valves, and after several thousand miles, that engine continues to be the sweetest running of all three engines.

I'd like to take all three engines apart and look at the valves, but I don't have the energy to do that just to satisfy my curiosity as to how the valves are holding up. The two engines with the hardened seats are still running well, but so is the one without hardened seats.

Based on what I've experienced, I'd say if you plan to drive your car long distances at high rpm, you might want to consider hardened exhaust valve seats and stainless steel exhaust valves. The intake valves generally do not deteriorate like the exhaust valves because they are operating at much cooler temperatures than the exhaust valves.

If you just plan to drive your car in parades or shows with occasional moderate speed cruises, your motor will probably be fine without hardened seats or stainless steel valves.

Mark

Interesting stuff. Thanks for the overview with your experience. I'll probably go with the SS on exhaust only. I plan a visit to the shop Thursday when we'll go over everything. The head and block are cleaned up, hot tanked, and ready for surgery. My exhaust valve stems are worn pretty bad.
I see Marx Parts may have what I need.

Regarding your valve stem wear, your guides may be worn also. I've had good luck with bushing the guides with a thin-walled bronze bushing. Your engine rebuilder is probably familiar with this procedure.

Mark

Thanks Mark. Yes he was but I was able to locate a full set of guides, valves from Marx Parts. SS alloy on the exhaust and NORS on the intakes

Go with the SS valves they may cost more but you will be able to use the gas of today, with out no problems

What is the difference between the gas of today and the gas avalable in 1932 other than the octane?

The short answer is the composition of the hydrocarbon blends used in the two periods and the addition of an oxygenating agent (ethanol) in modern gasoline.

I was looking for "the gas in 1932 contained lead"
The regular grade of gas in 1932 that Chevrolet owners used was unleaded. If you paid 2 cents a gallon more for Ethyl in 1932 (to raise the octane about 10 percent) the gas contained tetraethyl lead.
The tetraethyl lead was added as a cheap was to raise the octane level for the then high compression engines that required a fuel with more than 60 octane. Had nothing to do with valves.
The ethyl gas contained a red coloring as a warning it was a poison.

I figured that was likely what you were asking. In fact the composition of gas in 1932 was a wide range of hydrocarbon mixtures depending on the refinery feedstock, equipment used and which refinery produced what was delivered to the gas station. Might change from load to load.