I haven't fixed my engine noise issue, however I am now able to start the engine and it runs well. My assessment of the fuel pump being good was dead wrong! Even after I took it off and opened it up, I thought it was good, however last month I was doing some more troubleshooting and realized no fuel was getting to the carb. Put on a new fuel pump and it fired right up and runs well. Now to figure out the original noise issue and fix that. As luck would have it, I live about an hour or so south of Lars and as soon as he has a short opening in his schedule, I'll trailer it up to him and I have no doubt he can at least identify the problem if not fix it the same day.

 

I had a similar issue....its likely the transmission inspection cover hitting the crank flange. If its loose, it will flex and make a banging sound as you describe.

You didn't take the oil pan off or Id suggest the windage tray...

Front engine things to check: idler pulley or another pulley or brace hitting the water pump pulley or radiator shroud.
Loose fan bolts.
If you determine it is behind the timing cover, its relatively easy to pull the cover and check the cam bolts.

 

 

Check the crank pulley. I had the same problem...and it took weeks to track down the fact that the pulley had a crack in it between two bolts and was flexing when the engine was running. Replaced the pulley.... fixed it.

 

If you need to pull the timing cover it can and has been done thousands of times without pulling the oil pan. Today with the product "The Right Stuff" you can do this job without introducing a leak path. "The Right Stuff" I think is made by Permatex and is like a Super Silicone product enhanced with rubber. It has allowed several repairs for me that would have been much more involved prior to it coming along. It is fast and PERMANANT from what I have seen. A tube of it is around $17.00 but worth every penny for certain repairs.
You get about 10-15 minutes work time on install so be prepared to assemble quickly once you apply this stuff and do not over apply or you may end up with chunks of this stuff in your oil filter.
I fixed my son's late model LT-1, we had to pull the timing cover and replace the gear set. The 1997 model LT-1 had a rubberized pan gasket that was torn on removal of the timing cover. This model also has Two seals on the front cover. Crankshaft and Water Pump both protrude through the cover making this a difficult install while in the car. I sliced off the factory rubber pan gasket where the block meets the timing cover. Replaced this section with "The Right Stuff" We owned that car for 3 years after the fix and it never leaked. It saved a lot of time under the hood. I don't work for Permatex or make money from them, it has just surprised me how good it works.
It is too expensive to replace Silicone for those jobs Silicone can easily do but for tough jobs you do not wish to ever tear down again this is good stuff.
In searching for really odd noises I have found some odd *****, one timing set had a mounting bolt back out, made a lot of noise once it started hitting the timing cover. Wore a hole right through.
Mark

 

Is your harmonic balancer rubbing up against the timing cover?

 

Go get a mechanics stethoscope at HF, it will help you zero in on where it might be, you say its running well since you replaced the fuel pump but you still have the noise, the timing chain is not going to jump a tooth and still run well.

 

I have not checked that but I will. I had to replace my harmonic balancer about 5 years ago when it cracked and started wobbling.

 

Those stethoscopes should be part of every tool box. Most are less than 10 bucks and possibly the simplest tool to use. Short length of heater hose can work and can even be modified to listen while driving the car - yes a knock sensor for tuning used by the pro's.

 

What oil filter do you use?

 

I use AC Delco.

 

Mark is dropping the car off with me in the morning, so we'll see what the problem is shortly - I'll post up some pictures and inspection results...

Lars

 

 

Go to the new post for follow up and problem diagnosis of this issue:

https://www.corvetteforum.com/forums...post1598684962

Lars

 

looks like there should be some sort of prize for cuisinartvette, shouldn't there? He scored a bullseye.