Is the carb still jetted for high altitude?
CK5
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The Beige Jimmy
- Thread starter regal403
- Start date
I'd say #6&8 are using a little oil. Could be valve stem seals or it could be pushing past the rings.
A compression test might reveal some loss in those cylinders compared to the rest. A leak down test would probably yield more detailed results. If the cylinders are within 10% of the average of all I wouldn't sweat it. Neither test will confirm valve stem seals leakage.
Or you can forgo the compression/leak down and just go straight for the valve stem seals. They are known to leak and an '84 is going to have the cheesy o-ring type seals. Get a set for a later TBI engine that are umbrella type, but don't require machining of the valve guide boss to fit.
A compression test might reveal some loss in those cylinders compared to the rest. A leak down test would probably yield more detailed results. If the cylinders are within 10% of the average of all I wouldn't sweat it. Neither test will confirm valve stem seals leakage.
Or you can forgo the compression/leak down and just go straight for the valve stem seals. They are known to leak and an '84 is going to have the cheesy o-ring type seals. Get a set for a later TBI engine that are umbrella type, but don't require machining of the valve guide boss to fit.
I put the new plugs in but didn't have a chance to drive it until just now. Purrs like a kitten.
I'm not sure what jets are in it, but I haven't changed any since leaving the high country.
It needs to be adjusted for the new elevation you are at for sure, but jetting is not going to cause the plugs fouling on two cylinders only.
Lolz_cats
Uga duga
Where about in Oregon? They have some very well maintained ORV parks. It's a beautiful state.
Valve stem seals are pretty common issue. A lot of times indicated by a white puff of smoke on start up. It will run better now with the new plugs. The plugs foul on my C10 and the first indication is rough running. Clean them up, and it runs fine again until they're fouled up.
Definitely need to re-jet as others have said. Years ago I moved a K10 from Colorado to Virginia and it would knock horribly under load due to being jetted for altitude. I was young and dumb so I never knew why it did that, but now in my wise old age I know what was going on.
Definitely need to re-jet as others have said. Years ago I moved a K10 from Colorado to Virginia and it would knock horribly under load due to being jetted for altitude. I was young and dumb so I never knew why it did that, but now in my wise old age I know what was going on.
I wouldn't jump to change jets until you drive it some. You went down in elevation, right? It may have been too rich in Denver unless you or someone else changed them before you got it.
I have seen trucks with the high altitude package printed on the SPID before.
I'm out in Beaverton. Any recommendations on trails in the area?
Yep, I went from 5280' to 32' above sea level. What jets should I be running in a stock Quadrajet?
It smells rich af, but I need to take a look. Replacing valve stem seals on a stock small block sounds like a tedious, but not an overly difficult, task.
I'm worried about catching maw syndrome if I open things up too much.
I'm not sure what the jetting should be to be optimum for your new elevation. But valve stem seal replacement isn't a hard job. Ideally you would use a hose for a leak-down tester and an air compressor to hold the valve up in the head when the spring is removed. To help, bring the piston up to TDC on the cylinder you are working on so the valve wouldn't have a chance to drop into the cylinder if you lost air pressure. I've also heard of using a chunk of rope to push through the spark plug hole to help hold the valve up when the spring is removed. Just take it slow and you'll get into a rhythm.
.069 main jet primary rods 36b secondary -DR. want to run a little fat, help[ cool the valves
It shouldn't smell rich, it's getting more oxygen now. You will probably get a better idea after driving it and checking the new plugs.
Wes probably has a good idea of what would work. Obviously if you have rods and jets with the same spread with the numbers, it won't matter if you are not identical. Say 72 jets with 39 rods.
I honestly don't remember what will work. Can't even remember what my fat block truck is using.
Wes probably has a good idea of what would work. Obviously if you have rods and jets with the same spread with the numbers, it won't matter if you are not identical. Say 72 jets with 39 rods.
I honestly don't remember what will work. Can't even remember what my fat block truck is using.
It still cleans up pretty good for a 37 year old truck.
I only know Holley stuff for carbs and generally you go down a jet size for every 2000' elevation increase, or in you case it would be up in jet sizes. Not sure how that translates with Qjets.
Lolz_cats
Uga duga
Not too far West of you is Browns camp. I have only done dirt bike riding there but it is a pretty popular place for wheeling as well. Oregon spends a chunk of Money on maintenance for their parks so they are kept quite well. If you travel North into Washington you aren't terribly far from Evens Creek either.
Everyone is assuming the carb was jetted correctly for high elevation. My recommended sizes are factory for 4MV quadrajet. Should run well under 4k elevation. Mine runs rich at 7k, starts alittle rough need to help it with my foot on the gas.
