Hoping some Karma pays off here.... Issue is 350 sbc in my 64 c10 daily driver. two days ago coming home from work noticed a bit of an extra noise from the p*** side. got home and noticed the weeds under the right muffler were moving quite a bit, figure it finally rusted through. then yesterday morning started up and suddenly the idle is really rough. not quite like a miss, but more of a shake to the whole truck. late to work so drove in, above idle it seemed to disappear. but if in gear and let of the gas (manual), the truck surges almost like it is missing a cylinder. never acted like that before. listening to the idle with the hood open there is some additional noise, but I can't locate it. still accelerates fine, but I'm really worried something else might be off, and I can't afford to screw this thing up right now. so far i've checked plugs, wires, timing and tightened exh. manifolds for any leaks. I don't know if the previous increase in noise is related since the mufflers have been slowly going out anyways, but thought it may be a clue. DETAILS: mid 70s 350, edelbrock 600 cfm carb (3 mo old), GM HEI ignition, manual transmission, around 40k on rebuild by p.o. oil pressure 25 psi at idle and moves with rpm. throw me what you've got. thanks in advance jon
how good are your plug wires..? maybe a cross fire? #5 and 7? 3 month old carb?..mm mm? check for vac. leaks!
replaced two years ago when the engine was yanked for paint. all bolted up tight, but left side seems to have a little separation on the top. jon
Do a compression check on all cylinders; if they all read good, it eliminates a lot of pointless screwing around. I've seen sbcs wear one of the valve guides to the point that exhaust will come up through it and make a strange sound that is hard to find if you don't know where to look.
plug wires are about 3yrs. seem to be in good shape. have to check the resistance... all in order on the cap and plugs. sprayed carb cleaner around carb and manifold base with engine running, idle picked up a touch (?!). any other issue with this engine has been at higher rpms (fouled plugs, bad carb tune, bad wires, etc). why is the idle ****ing up? ran great until wed afternoon. jon
Spray bottle with water and cold motor. Spray the manifolds til the're wet then fire it up and watch for which port takes longer to burn the water off. Little harder with manifolds,but should still give you an indication of a weak/dead cylinder. A place to start looking anyhow
ya this happined to a buddy of mine, broken spring, replaced a 2 weeks later wiped his cam out, now he has to rebuild the whole thing, took crank out now from wiping the cam
no, really, that is not the advice i'm looking for! but that should be an easy visual sight with the valve covers off, right? can't find my compression gauge and it's gotten miserably hot for the day. try some more later tonight. thanks for all the help. jon
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