Time to replace the valves in the '54 302 The intake valves still have a part number 2193984 back on the this was a good part, not so today. The exhaust valve use a round horse shoe keeper and a cap on top of the valve? Hoping there a modern style valve that I can use, The exhaust are in decent shape, but I lost one of the keepers during disassembly,
Dave
Last edited by Gdads51; 03/24/202612:52 AM. Reason: add detail to title
Dave - here's what I found searching GM Partswiki in the screenshot below reference your intake valve # 2193984. It lists your number as fitting 1955 (Y code) 302's and there is another 302 intake valve # 2304149 that fits 1956-59 302's (STX codes). Not sure if that might be a suitable replacement for your valve needs or not?
I did find that the "round horse shoe keeper" you are missing is listed as GM# 2192706. You can acquire a replacement (or more) from Olds Obsolete as they show having some in stock. Picture of that piece also below.
Hope ths might be of some help.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
With all the "almost fit" aftermarket parts that are available out there, why should we bow down and worship a part number that was used 70 years ago, like Moses brough it down from Mt. Sinai chiseled in stone? If I can make a part that's similar to original equipment work with minor modifications, I'm going to do it, especially if it happens to be readily available at a fraction of the price of a scarce original. I'm going to be looking at the brown side of the grass by the time some other machinist has to try to sort out what I've done, anyway! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Jerry, I see your point, regarding “modern” replacement valves, which style fit into the 302 head without a lot of work? This truck is not going racing, it isn’t even going to work for a living.
I haven't done much research on the GMC engines. Right now I'm working on a way to replace the long-stem Chevy stovebolt intake valves with ones for a Pontiac 455 V8, by extending the length of the stems with a screw-on extension. From 1950 to 53, Chevy engines used with Powerglide automatic transmissions had 1.94" diameter intake valves. Those valves can be fitted to any Chevy stovebolt head, but they're getting VERY hard to find. The Pontiac uses a 1.96" valve with the same stem diameter, but the stem is too short. I'm working on adapting the stem length by threading the top of the stem and fabricating an extension made of stainless steel, attached permanently with red LocTite. I'm still in the development stages right now, but I'm sure something similar could be accomplished with GMC valves- - - - -probably easier, since those engines don't use long-stem intakes. Find a valve with a similar head diameter, stem diameter, and stem length, and adapt it as necessary. I've been doing similar stuff on round track racing engines for 50+ years. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
When the machine shop overhauled my 302 head they used small block Chevy V8 valves. New intake valves measured 1.841" (original was 1.856") and 1.60" exhaust (original was 1.565"). I don't remember what they used for guides. Valve springs are spec’d by GMC at 53-63 pounds of pressure on-seat. The machine shop found some proper diameter springs that measured 65 pounds at installed height. They also supplied the caps and the keepers. Sorry, I don't have part numbers.
Last edited by Bill Hanlon; 03/24/20265:22 PM.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
Good info, Bill! There's also a 1.94" small block V8 intake valve that could probably be used, along with a little pocket porting. Putting a 60 degree cone shape under the valve tulip with a carbide cutter aids in gas flow. That's a trick we have used for several decades on race engines. Those spring pressure specs are minimum- - - -it doesn't hurt to go a little heavier. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
GMC used both conventional and rotating or free valves. Back when we ran our GMC's wide open all day we used rotating valves. But for normal driving rotating valves aren't necessary. As soon as I get my fleet of trucks auctioned off I am going to build some GMC engines when I have the shop to myself. I'm not going to mess with rotating valves. The valve with the taper in the stem is for a rotating cap. The others are conventional valves. Y-Blocks use the same stem diameter as GMC and I will have to figure what is what.
