The Stovebolt Site Forums The Shop Area Engine Shop Chevy 230 Running Very Poorly

Hey guys, I just introduced myself earlier today on this forum and I am just getting into a this project, so please excuse any dumb questions. I am kind of new to bigger gas engines (lots of experience with Diesels and motorcycle engines), so I thought I would reach out for some advice.

I picked up a 66 C10 pickup last weekend and I am just getting into the engine to see if I can get it to run correctly. It's a 230 (not sure if it's original to the truck) with the Granny 4 speed. It's got a Carter YF carb and the rest seems pretty standard.

I took the carb apart and sprayed it well with carb cleaner (while rebuild kit is en route) and it seems to be working alright.

The issue that I'm worried about is that when I start it, I get a bunch of exhaust coming out of the vent on the valve cover. It's pretty bad. I am thinking that this is due to worn/broken/non-existant piston rings. Anything else that this can be caused by? I am thinking that my next verification step is to test compression. Is this right?

Also, I put a timing light on, and the engine was runing at ~20 degrees advanced. I adjusted this closer to the factory (4 degrees, I beleive) mark, but the motor really does not like that. I settled on about 14 degrees or so and tightened it back on. Is this anywhere near normal?

Try a vacuum gauge on the intake to see if there's s big fluctuation. If a cylinder is missing, or there's a big compression difference, it will show up as a rythmic dip in vacuum as the bad cylinder tries to fire. If you're getting a lot of blowby from the crankcase, your suspicion about broken or stuck piston rings is probably correct. Do a compression test, or a cylinder leakdown test to confirm the problem. With the crankshaft locked and a cylinder at top dead center on the compression stroke, put air pressure into the cylinder through the spark plug hole. listen at the intake, exhaust, and crankcase filler for air leaks. Repeat for all the cylinders to isolate the problem hole.
Jerry

As for the timing being off, I suspect the outer ring on the dampener has slipped. Does have have a wobble to it or part of the rubber squeezed out?

Joe

Hey Lincoln, I'll try that. I will pick up a compression tester on my next trip to Harbor Freight.

Joe, the pulley with the timing mark does have a significant wobble. What dampener and how can I correct this?

The front crankshaft hub is a 2-piece item bonded together with a strip of rubber. The timing mark is on the outer ring. Once the parts slip in relation to each other, there's not much way to fix it- - - -just replace it. The 230/250 engines are still pretty common in the wrecking yards, so a good-condition used balancer might be an option. A new one isn't terribly expensive, however. There's a center bolt with a big flat washer, but the hub is also a press fit. You'll need a 3-prong puller that bolts to the center hub to remove it, not the hook-type puller that grabs the outer ring.
Jerry

Ok, thanks for the info. I think I may be into rebuild territory here in which case, I will probably be looking to put a 350 in this.