This past weekend my Dad and I went to a Chevy/GMC show 32 miles away. After the engine warmed up and we were climbing hills (pretty steep and long), the engine began to make some strange noises. Kind of a clattering, knocking almost over-revving noise under load. Lift off the gas and the noise quieted down right away. Any thoughts on where to look first? Connecting rods? How noisy are these engines in general? I realize that's an impossible question to answer, but how do you determine when a noise is a problem and when it's just a noise? Finally, everyone seems to like the Woodie. Took a 1/2 hour to gas up...Thanks, -dave

if "over-revving" means an increase in engine speed, could it be that the clutch disc was slipping under load?..

or, if engine noise, could be pre-ignition or "knocking" from load & engine temperature from "pretty steep & long" hill climb?..what was the engine and ambient air temperatures?..


epi

It will be helpful if you can provide some background on the engine's history - if it's been rebuilt or still original; how many miles on it (original or rebuilt); and similar.

The engine is, as far as I know, original and untouched--with approximately 45,000 miles. This is only a guess as everything came in boxes with the engine and chassis. I can't swear that the speedometer I got was ever part of the chassis I got. The widow I bought it from knew nothing about it. I rebuilt the fuel pump, carb, water pump. It has a brand new radiator from the filling station. Sunday was a hot day, around 85 and a bit on the humid side. The coolant reached 210 at the top of the longest hill. This particular hill took us about 5 minutes to drive up--speeds from 20-35mph. I don't believe the clutch is slipping--it just sounds like it's over-revving. Thanks.

29 woody, i have a '30 coupe, 42xxx mi. when we drive about in the hills here in the seattle area, i find that "modern time" is not of the essence. long uphill streches have never been a problem ie: over heating or excessive noise, if we take these challenges in 2nd gear and run around 15 to 20 mph. a horse can't do that. 5 miles down hill, well that is another matter.
ps, chevy 6s normally to caletter a bit. probably oght to double check your timing too.

jf, you are right about the time thing--it's a whole different experience driving this car. Makes my Jeep seem like a road hugging sports car. It seems like the noises only start after the car has warmed up and under load, whether I'm going up a steep hill or just trying to make 40mph. I'll recheck the timing and keep my ears peeled.

I asked about age and condition in part to see if there might be a possibility of something rendered loose or worn from age. I figured the oldtimers in this group might toss out some ideas based on the age and condition.

The easiest fix I can think of might be to check the clearances to the rocker arms. The tougher one might be a need to check the clearances on the rod bearings. The rod bearing on the number six piston in my '32 had worn to the point where I used to get noticable knocking under load or going up hills, even after I tried removing the shims. That seems similar to what you're relating. I finally caved in last year to pull all the rods out and get them rebabbited, which cleared it up.

Ed,
Thanks for the suggestion about the rocker arms. I think what I'll do is start at the top and, taking my time, check everything and work my way down.
I guy at work thought that maybe sludge/oil from the car sitting so long damaged the bearings. When I got it I drained the oil, which was more like a sludge. I thought I got it all out. I changed it after idling for a total of about 5 hours over a month or so(before it was road ready) and it seemed ok. It very clear now with no grit. Is this a possibility?

Possibly. Someone else will need to back me up here regarding a '29 - were shims installed to set the rod bearing clearances in that year?

The original rods had 0.008" of shims installed in each rod to allow for adjustment. Most rebabbitted rods do not have shims installed when redone.