TireSmoke.org

I've been making some slow progress since the oil pan installation was finished. The starter is installed and working, the knock sensors and heat shields are on, the oil filter adapter and oil filter are on , the engine mount nuts are torqued and it is filled with oil. Now I can take a break from crawling around on the garage floor and let all the wounds on my hands and arms heal.
Maverick came over this afternoon and we determined TDC so that the balancer hub would go in in the correct orientation. With the hub in place, it's time to turn to the reason for starting all this...the Opti-Spark distributor. I've decided not to order it until we return from our vacation in Montana. We will be back on the first of June.

There is a LOT to know about the front of the LT4 with the water pump, reluctor, distributor and pressed on hub!! A lot could go wrong without the careful research WXO has done. Improvised pullers and installers got 'er done. Well, not done, but good progress. I'm enjoying participating a little in this challenging project and looking forward to the next ride.

Our trip out West was phenomenal. Now that I have all the unpacking done, I started putzing in the garage. Before you know it, I had the new GM Opti-Spark installed and all hooked up. Then the balancer went on without much trouble. The front of the LT4 is starting to fill in.I have a few things to check before I try to start it to see if the Opti works. Probably tomorrow.

When I got up this morning, I couldn't wait. I had to know. Now I do. The new Opti-Spark works!!! She runs! Whew! I was a bit apprehensive after all I had apart. I am a bit mystified about the amount of mechanical noise coming from the engine. It isn't scary loud, just different. I have good oil pressure. I hope it's the fact that there is no coolant in the engine. I think I'll start it again later and listen more closely to see if I can learn more. Have any of you run an engine empty of coolant?

Yes, I have. From my recollection, it doesn't sound different.

-Dave

Maverick just stopped by and we listened to the engine running again. The noise is not normal. It is coming from the timing chain cover/Opti-Spark area. Rats!!

You sure it's not that big chain making more noise than the stock little chain?

-BP

I agree, pretty loud and not normal. Sounds like metal scraping on metal.

Basement Paul wrote: ↑Sat Jun 04, 2022 12:46 pm You sure it's not that big chain making more noise than the stock little chain?

-BP

I'm not sure of anything right now, but a couple of weeks ago, we turned the engine over using the starter with one spark plug out. It spun pretty fast. I remember thinking that I didn't hear any noise coming from the timing chain area. Packing that big chain and sprockets in that space resulted in some close tolerances. We called the Cloyes tech and he said .020" was all we needed. We checked and had at least that much space. I guess I'll go back to digging until I find the cause.

I went out to the garage today to regroup, study the situation and come up with well considered plan to figure out what is causing this apparent grinding/metal-to-metal rubbing noise. Looking around with a light, I saw that I had forgotten to attach the connector to the crank position sensor on the bottom of the timing cover. I'm surprised that it started and ran. There must be a fail safe system to keep it running. I'm faced with a dilemma. I hesitate to start it again to try to zero in on the location of the noise if it is metal on metal rubbing. I don't want additional metal shavings in the oil. The Opti hides the timing cover, so that it is impossible to run the engine and listen and pinpoint noises emanating from there. I'm thinking of going back and removing the new Opti-Spark. It can be done without a large amount of work. It's remotely possible that the new/rebuilt Opti might have come with a bad bearing. But if I remove the Opti, I can't run the engine to recreate the problem until I reinstall it. I thought of chucking the Opti drive shaft in a drill and spinning it. That should give me a reasonable test of the bearing. Anyway, that's the extent of my thoughts for now.

If you are grinding there will be metal in the filter so for the cost of a filter you can cut open the current filter and see what’s in there

Yes. I thought of that. The engine was run twice for about a minute each time. Do you think that enough oil would have circulated in that time to have picked up particles in the timing cover area? Certainly, that's something I will do after I check out the Opti bearing. If I open the oil filter and find metal filings, though, it could mean some serious back pedaling.

I removed the balancer and the new Opti-Spark this morning. My testing with a drill motor and also by feel tells me there is no bad bearing, just bad news. With the noise coming from the front of the engine, I see no other option but to remove the timing cover to see if I can see witness marks or evidence of metal to metal contact while running. The good news from reading the Corvette Forum appears to be that the oil pan need not be completely removed...just dropped an inch or so. This could save me a lot of additional work if it's true.

wxo wrote: ↑Sun Jun 05, 2022 4:39 pm Yes. I thought of that. The engine was run twice for about a minute each time. Do you think that enough oil would have circulated in that time to have picked up particles in the timing cover area? Certainly, that's something I will do after I check out the Opti bearing. If I open the oil filter and find metal filings, though, it could mean some serious back pedaling.

I don't know the flow rate at idle offhand but considering the metal would sink to the bottom of the pan where the pickup is I'd say its probable. Sound like you are going to find out soon.

Just an update with a few findings.
I cut open the oil filter and saw nothing alarming in the filter. Just some small black specks, but no metal. However, in the oil that drained out when I removed the filter (not the oil pan), using a flashlight, I could see a lot of sparkles in the bottom of the pan. None stuck to the magnet, so I assume they are aluminum filings.
After removing the Opti-Spark unit, with the timing cover completely exposed, Maverick and I rotated the crankshaft by hand and listened for any scraping noises coming from behind the timing cover. There was nothing! It was completely silent during rotation. No chain noise. Nothing!
I have no clear idea on what to do next.