Mid- Engine Modified Sports

[jacksoni]

Sometimes things like a rod kissing an oil baffle/scraper etc can sound bad but usually not cause lot of damage unless it shreds stuff into the oil. Not counting the emotional stress though....

[manta22]

I cranked it over for a longer period of time and there is some muffled noise as it rotates. Pan coming off...

Regards, Neil  Tucson, AZ

[manta22]

I finished pulling the engine and transaxle out of the chassis this afternoon. Now to unbolt the transaxle and set the engine on an engine stand, drain the oil, rotate it upside down (after removing the lifters), pull off the pan and look inside. Any bets as to what I'll find?

Regards, Neil  Tucson, AZ

[manta22]

One more.

[RaceEngineer]

Neil,

My bet is pinched ring land due to detonation (lean running condition due to filter on the suction side of an undersized fuel pump) or rod bearing damage.  Hope it's minor and cheap to fix

Regards,

[manta22]

I'll find out for sure in the next day or so. The piston tops don't show visible signs of detonation but  teardown will reveal all.

Regards, Neil  Tucson, AZ

[Lemming Motors]

In picture 1 of this series - someone has been writing on a piston crown - my guess is there is a marker pen in there somewhere.

John

[tauruck]

Holding thumbs down here Neil.🙏

[floydjer]

Is THAT what that is ??  I thought it was a blue bikini with a huge pair of...……………..

[manta22]

In picture 1 of this series - someone has been writing on a piston crown - my guess is there is a marker pen in there somewhere.

John

Those are my notes from when I assembled this engine. I'll look for a pen in there, too. 

Regards, Neil  Tucson, AZ

[manta22]

Today I drained the engine oil through a paint strainer to see if there were any bits of metal in the oil. Fortunately there were none, only a small amount of very soft fuzz on the magnetic drain plug. I'm not surprised to see some of that, being a new build so everything is wearing in a little and the rings were seating.

The strange thing I noticed about the oil is its color- sort of an old army summer uniform tan/khaki. Here is a photo of it in the sunlight. In the shade it looks darker. Any guesses as to why Mobil-1 has turned this odd color? Water in the oil? or....

Regards, Neil  Tucson, AZ

[Peter Jack]

That sounds like a really good guess Neil. That's what it looks like to me.

Pete

[manta22]

It looks like you were right, Pete.

I found evidence of water getting into the cylinders after pulling the pan and rotating the block on an engine stand. There is some rust/corrosion on the low sides of the cylinders due to water that drained through the carb and intake manifold into the cylinders. After returning from WOS, we had a heavy rain before I could unload the car off my open trailer and pushed it into the shop. I'm sure that was when the water was ingested. My air cleaner has a big spun aluminum top that is indented where the hold-down stud goes through so that acted like a funnel and the water ran down the opening around the stud. Arrrggghhh.

I hope a honing to 40 over (now it is 30 over) will clean up the cylinder walls. Otherwise it is bore it 60 over; I am not near the displacement limit of B class since I'm only at 383 CID right now. In either case, I'll need to replace the pistons and rings.

So far the rods and cam look OK but I need to pull some rod & main bearing caps and have a look. I did find two broken teeth in my starter ring gear, undoubtedly caused by hydraulicing the engine after letting it sit overnight with a loose power valve draining gas into the cylinders. The gear bolts on to the flywheel so it is not a big problem. I think the noise I heard when cranking the engine over on the starter was the bad ring gear. Turning the crank with a wrench on the harmonic balancer seems normal.

Regards, Neil  Tucson, AZ

[SPARKY]

ooooo  I have similar  car still on the trailer with a  storm---I didn't have to pull the eng though..

[manta22]

I’ll set up a depth mic and check the height of each piston at TDC, that should me tell if any rods are bent. The dust/corrosion may be too deep for the rings to seal even if the cylinder is touched- up with a hone. Since I did not know that water had leaked into the intake, it set with water in the cylinders for a couple of weeks. I suspect that I’ll need to hone or bore it to the next oversize. I do have a bore mic so I’ll check it. I might be able to get by if it was a mild street engine but not a race engine. The KEP pressure plate uses a bolt-on ring gear so I’ll just order a new one and install it. The starter pinion gear looked OK by eye but I’ll check it more carefully under a magnifying glass. Tomorrow I’ll pull off a few bearing caps and wipe as much oil as I can off of everything to get a better look.

It is beginning to look like the reason the engine went down on power and then quit may have been due to two things- the carburetor power valve was too high so that even at modest throttle, it was opening and dumping way too much fuel into the engine. And, listening to the video of my run, it is clear that the RPM drop from the shift from first gear to second was way too much. I now think I accidentally shifted from first to fourth, so the large throttle opening at low RPM just flooded it with too much fuel. The driver of a chase truck commented that black smoke was coming from the exhaust. This supports the too much fuel rather that my fuel starvation theory after I found that my fuel suction filter was 10u instead of 100u.

My shift pattern is reversed (1st is to the left and back, second is to the left and forward, etc) so I’ll change the shift lever pivot point to make it a standard pattern. It’s hard to unlearn a shift pattern. Smile

Regards, Neil  Tucson, AZ