The Stovebolt Site Forums The Shop Area Engine Shop What have I done to my engine?!?

I'm baaaack with another escapade that leads to more questions.

My situation: Truck is a 1953 3100, with an engine that does not run and needs replacing. The replacement engine is from a 1961 Impala and is a 235 with hydraulic lifters. I've posted several questions and issues that needed resolving, so there is lots of history here. Long story short, I got the engine running last summer and was hoping to get it into the truck this summer.

Today, I was out in the garage running the engine and I came across an issue that I had not seen before with the engine. I was revving the engine, trying to simulate running through the gears. On my modern cars/trucks, I usually shift gears when the rpm's hit around 3,000 give or take. When I got the 235 on my test stand up to about 2,800, I heard a "tinny sounding" metal on metal sound. I backed off the throttle immediately and it went away. Revved it back up and the metal on metal came right back. Backed off and it went away. I continued to let the engine idle until I drained the small fuel tank and it ran as it has always run. In fact, as the fuel was running out (and presumably the mixture leaned out alot) the engine was running great. After I shut down the engine, I removed the valve cover and found nothing out of the ordinary. I checked the side engine cover and found nothing that jumped out at me (like a bulge in the metal plate), but I did not remove the plate.

My questions: Did I over rev the engine? Any ideas what the metal on metal could have been? If I did over rev the engine what could I have damaged and is there anything specific that I should look for?

I'm really hoping that I didn't bollix up the engine and ruin my plans for getting it into the truck this summer!

As always, any thoughts or suggestions are welcomed.

Thanks!

If the flywheel covers are on it could be coming from one of those.

When the engine was in the Impala, it was hooked up to a cast iron powerglide. When I got it home, I took the powerglide off, but left the adapter plate and flexplate, so that the starter would work. I was planning to swap the clutch assembly when I did the engine swap. So right now, when I run the engine, I can see the flexplate spinning! That doesn't mean that the flexplate wasn't hitting the adapter! I don't know, maybe it was wobbling at the higher RPM's since it wasn't hooked up to the torque converter?

First of all, revving the engine on a stand, will in no way, simulate running down the road. There is no load on the engine. That engine in stock form is only good for around 4500 rpm's. What kind of oil pressure does it have? It could be a lot of different things causing the noise. Lifter, valve spring, piston noise, rod bearing, pushrod hitting the side cover, etc etc. While the engine is out I would think about pulling the pan and checking bearings

If your truck has a standard transmission, make sure you install a pilot shaft bushing in the rear of the crankshaft.

The description "tinny" makes me wonder if any of the sheet metal on the engine, or possibly a bracket, is loose and vibrating. If you run the engine again and get the sound, try touching parts to see if you can feel vibration or if the sound goes away with your fingers providing damping to the part (paying attention to keep fingers away from mooving parts). Is there good clearance to the radiator? Anything on the engine stand that might be looses and making the noise?

The engine actually has good oil pressure. It consistently reads about 30 lbs. I was wondering about the rpms and if I had overstressed the engine since it was not under any load. I had thought about pulling the pan before making the transplant, but didn't want to go down that rabbit hole right now. I know somewhere down the road, the engine will get pulled and rebuilt, along with a complete restoration of the truck. For now, I just want to get the truck running and on the road so that I can enjoy it. I've had it for almost 5 years and have never driven it....

Revving the engine with no load isn't as good idea. If you do that, keep it under 2500 RPM, but even then, it serves no purpose other than entertaining you. It won't tell you a thing about the performance under load since the carburetor mixture will be different, manifold vacuum lower, different vacuum advance position, etc.

No-load revving WILL put unneeded strain on the rod bearings at the top of the exhaust stroke when the pistons have nothing opposing their inertia. I'd suggest dropping the oil pan and inspecting the rod bearings, and keeping your greasy grub grabbers off the throttle in the future!
Jerry

Ouch! Got it, though. No more revving.