Ouch, sorry my optimism didn't hold for you. Did you measure lift with dial indicator? ☹️

Related question - what are you using for oil?

 

Having now slept after the findings, this may make more sense!

Ernie reminded me that I had suggested months ago that it seemed down on power so we think this has been a gradual wearing on the lobe so hopefully no 'pieces' of metal just fine particles?

This is a NCRS top flight car so I'd be very reluctant to replace the numbers matching motor.

We didn't Ed but when we ran it with the valve cover removed and the coil disconnected the rocker movement was clearly reduced.

I'm going to speak with Ernie again later but for now the car is out of action. I've also reached out to a previous owner, the owner that had the car judged in Canada who tracked me down in 2017 to fill in a lot of the cars history. In doing so he revealed that the motor had extensive work during the restoration in 2005. Below is a small excerpt from his very informative email:

Ok, now for the engine. It was quite tired when I purchased it and was leaking oil badly. After speaking to a mechanic, we agreed it needed to be rebuilt. This was in 2005 IIRC and it was pulled and set to the machine shop. We decided on the choice of solid lifter cam and was recommended to increase the compression ratio to approximately 10.25:1 from its original 9.0:1 for increased horsepower. The original pink rods were in good shape and reused. Pistons replaced as mention above and one more thing was done. Are you sitting down? We replaced the standard crankshaft with an Eagle 383 crank!! The machinist estimated the horsepower with the 383 crank and 10.25:1 pistons anywhere from 375 to over 400HP. How could I say no considering none of the upgrades could be detected by looking.

I've asked if he recalls if the original LT-1 cam was reused.

Ed, oil is below and changed once or twice per year:

 

That is a stunning looking car...well done!

Thanks for added details....a few questions?

I am assuming that Eagle 383 crank was forged like the OEM LT-1 crankshaft for added durability and strength and not cast iron? Also, you mentioned the prior owner reused/reconditioned the OEM forged LT-1 connecting rods with the 383 crankshaft which would have required machining the 5.7 rods to fit properly with the 383 crank. I believe (others can chime that know more) that the 5.7 rod with the 383 crankshaft is not the ideal setup due to the inherent geometry mismatch and greater cylinder scuffing with the 5.7 versus 6 inch rod? There was a another forum member who recently had an engine issue with a 383 conversion in either an early 70's LT-1 or L-82 using the 5.7 rods as well, if the machining is not spot on?

The other thought is the 10.25 compression with stock heads causing some detonation that you could not hear? I run 10.2 compression in my L-82 with AFR aluminum heads with 89 octane fuel with zero detonation but would be cautious with OEM stock iron heads with that compression and depending on the cam specs.

The Oil used looks good with the solid lifter cam..........I would personally have used Mobil 1 15W-50 made for flat tappet cams in older engines..1,200 ZDDP PPM as an alternative to racing oil.

Just a couple of thoughts..

 

Cut your oil filter open. I bet you find the cam lobe there.

 

There isn't really much I can add but I have emailed the previous, previous owner who had all the work done and has probably told me everything he can already. He did have the work done a professional machine shop and the motor has done close on 15k that I know of since it was rebuilt in 2004 so I'm guessing that it was done correctly. I have a huge pile of pics of the body on restoration and motor build:



But nothing that would shed light on what you pointed out. I'm sure I recall discussing with Ernie about the comp ratio so that is likely closer to original specs. I'll look for the oil you suggest thanks

That's the hope and hopefully just minute particles. Looking on the bright side, the original copper radiator had been changed to a modern aluminium type and I do have it so I'm going to pressure test it, straighten some fins out and fit that while we can.

 

some of it's in filter ... some of it's throughout motor.

 

Damn... The red one, yes? What a kick in the can... I'd be down in my cups for certain.

 

Agree. When my fuel pump lobe went away, I replaced the cam and flushed the oil. Motor ran fine for years afterward.

It will be of interest to hear what your mechanic recommends but I didn't tear mine down.

 

Agree^^^^^.

I often read of folks talking of tearing the engine down after a cam wiping and I am just as often perplexed about this concept that the engine will be destroyed by all the lobe metal fragments. Maybe in some cases, the exception, the engine will need a rebuild but as we often did during the 70/80's when cams went bad, which they did OFTEN, the engine required just a flush, new cam install, and the engine was good to go for MANY miles. Cam failures back in the 70/80's were very common and it was not the oils but bad cam metal materials. My buddy's 82 CFI wiped a cam back about 15 years ago and he put a new cam and has been driving the car ever since with zero issues. No engine tear down needed...

Generally speaking, a wiped cam does not necessarily warrant an engine rebuild/tear down......

 

Don''t tell the wife that. Makes for a nice LSx crate engine swap..........

 

Red one yes. A kick in the can! A saying that is new to me but if it means what I think it does then my duck is knocked off for sure

That's pretty much his / our thinking depending on what we see in the filter

I have said that Ernie is old school so he's seen it all before and that was his initial thought

I like your thinking

 

If you do not remove the engine.....pull the pan and inspect everything......check a couple of rod and main bearings and the oil pump thrust plate.......
If it is a real LT-1.....it will have trap door in the pan.....make sure you clean this thoroughly....it is hard to get behind it.....
There is nothing wrong with a 5.700 rod 383......stock 400 Chevys had an even shorter 5.650 rod......the 6.00 is ideal but not necessary.......
Check out the rod ration of a 347 Ford stroker sometime......now that rod leans over!!!

Jebby

 

I wouldnt put an LS in an LT1 car
Pull the cam if the cam bearings got copper everywhere maybe its rebuild time. Otherwise put a cam in it and keep going

383? A 282 s cam would rock in there...do some head work
have you seen trick flows aluminum tfs 175 heads? Options

 

Very muggy here today so not ideal for car work but it needed to be done. Drained all the oil and ran it all, every drop through a 1200 micron paint filter with my strongest magnet in there and got a sum total of next to nothing metallic material. Filled with new oil & filter and ran it round the block and it sounds normal. The main clackety noise will have been from the loose rocker on E3 but it definitely has minimal movement so it'll be taken out, checked and replaced if necessary. I need to improve on my oil changes as the oil was black as sin.



Thanks for all the help, suggestions & advice offered

Stuart

 

Cut the old oil filter open and run your magnet thru it. Just to make sure. Piece of mind.

 

Well that certainly doesn’t seem too bad. So much for your LS7 conversion

 

I was going to ask about current developments. It would be interesting to take a dial gauge to each rocker and measure the lift.

Major bummer in any case. :-(