Engine cam run-in

[Rainer S.]

I just ran my engine for the first time. (63 F.I.)
The engine was rebuild by a local,(Michigan),reputable engine builder and the F.I. unit was restored by a well respected F.I. restorer.
I installed the engine on my frame, hooked-up the coolant system, fuel supply etc.
Started the engine, and after a few delays to get it started, thanks to the Forum's help earlier in the week.
Ran the engine for an initial 20 min. at 1800 to 2000 RPM. Made minor adjustments to the timing and point gap and ran for an addn. 20 min. During both the first and second run, the engine ran smooth, coolant temp. , measured with laser temp gage, never exceeded 165 degrees.
Refilled gas tank, after it ran out of gas and re-started engine . Engine started to run rough, first blue and then dark gray smoke was coming out of both exhaust pipes. Could not keep engine running. Removed all spark plugs, all (8) were covered with soot.
Checked compression, 180 PSI on all but #5, 170 PSI.
Drained oil, it was black thru-out, but no particals in bottom.
Refilled with fresh oil and changed filter.
Plugs were fouled, so I installed new plugs.
Inspected valve train, looked OK, no bend rods.
Started engine up, ran, but still gray smoke out of both pipes, more on side.
Ran for (5) min and stopped.
Drained oil again, and it is black again.(lsimilar to oil you would see on a Diesel engine).
Here is my question:
What happened ? Did I spinn a bearing or wipe out the cam ? Why is the oil so discolored ? Could it be due to the grease/oil the engine builder used for building ? It should have been flushed out with the first oil drain. (I will not be able to ask the engine builder till Mon)
Does any body have any clue of what might have happened ?
I am planning to drop the oil pan tomorrow to inspect the cam lobes and bearings as best as I can.
The fouling of the sparkplugs could be caused by running too rich, but I am puzzled by the black oil after running for such a short time. (I must have used 4 to 5 gal of gas for a total of (1) hour run).
Sorry the such along post, but I am really puzzled.

Rainer

[Tracy C.]

Re: Engine cam run-in

I do not think cam or rod bearing are at issue here Rainer. If so you would hear lots of knocking....

Fouling plugs indicate a rich fuel mixture or oil burning. If all are fouled about the same, sounds like a fuel problem. I find it hard to believe that oil would be getting past the valves on all 8 cylinders.

You have good compression, so I don't think it's a ring problem. It does take awhile for the rings to seat in the pistons though.

I wouldn't drop the pan. Blackened oil is normal after a rebuild run in.

tc

[Jon #40768]

Re: Engine cam run-in

What did the plugs look like the second time? Was the discoloration different top to bottom or all the same. I would not pull the pan until I talked to the engine man as he could be upset if he thinks that you did something and use that for an excuse.
Jon

[Joe R.]

Re: STOP Engine cam run-in

Rainer,

Sounds like the spill plunger in the FI unit is stuck. Not a problem to service the spill plunger. Your engine is running so rich that raw gas is going past the rings into the oil pan.

You need to fix the problem before running the engine any longer. Drain the oil again along with changing the filter before starting it up.

Your engine is not hurt but the problem (stuck spill plunger) must be fixed before running again.

If you need help on the spill plunger just ask.

Regards,

JR

[Frank H.]

Re: Engine cam run-in

It's sure to be running too rich if you burned 5 gallon in an hour,but I know nothing about F.I. units,but a enrichment circuit sounds to be stuck open,their's no reason to tear into the engine,the cam should be fine as it was run at proper break-in,but since the rings aren't seated yet and with excessive unburned fuel present,it likely is washing down the cylinders,smell the dipstick ,smell like gas, check ignition,a weak spark will load-up the cylinders and cause abnormal vacuum ,use excessive fuel,
check spark ,needs to be bright blue spark.
Review manual on possible setting on fuelie unit if you have one.

[Joe L.]

Re: Engine cam run-in

Rainer-----

The oil coloration which you described is completely normal as a result of the moly-based assembly lube which many engine builders use. It is totally unrelated to the other problems you are having and it will cause no harm, whatsoever. Even if you had a core engine problem I would not expect any coloration such as this to be caused.

I strongly suspect that your problems are related to some problem which has developed with the FI unit or the ignition and is NOT a core engine problem, at all.

[Mike McKown]

Since it is a '63 unit, another likely cause is

a ruptured cranking signal valve. Sorry, it's been too long. I can't tell you how to bypass it but I think you can apply vacuum from the source side to check and see if it is holding.

I wouldn't even think of looking inside the engine unless you were hearing some type of noise. As JR stated, this needs to be fixed before you run the engine any further or you could damage engine internals.

[William C.]

Re: Since it is a '63 unit, another likely cause i

A quick check for the cranking signal valve is to start the engine and close the rubber connecting tibe between the cranking signal valve and the line fron the "T" on the fuel meter diaphram cover. A pair of needle nose pliers will work nicely. Squeeze the rubber line closed when running and if the S/S valve is the problem, the engine will clean up in a minute or so. I'd do this before I got into the unit for stuck metering parts.

[Rainer S.]

Re: Since it is a '63 unit, another likely cause i

Thanks everybody for such detailed and expert advise. I did a quick check on the fuel meter unit this morning, and noticed, that the ratio lever is stuck. Apears to be stuck, between the power stop and the economy stop. Will look into it further tomorrow, do not have time today...
But, like you guys suggested, my problem is definately in the fuel metering unit.
I will study the corvette shop manual, which has a very detailed description on the F.I. system. But thanks to everybody's detailed and expert advise, I now now what to look for.

Rainer

[G B.]

Calibration and hot testing

Did the fuel injection rebuilder test run and calibrate the unit before returning it? Have you called him to express your concerns about improper fuel meter operation? If you dive into the fuel meter yourself, will he still honor his warranty?

Most importantly, what kind of rework guarantee did you get on operation of the FI unit?