LEAKOIL Forum

How in the world did those keepers stay in?

Karl Kombi wrote: Tue Feb 08, 2022 5:47 pm Looks like a lot of fun. Very nice Corvair!

A friend of mine had one of those Corvair/Corvans back in the early sixties. It was a pretty cool but could not compete with VW and only lasted a few years.

New motor starting to go together, his case was already .060" over so not usable, but I had a case upstairs that wasn't cut yet. We had that line bored, heads done, new CW crank, mild Crower cam, as the CB cheater cam is on perennial backorder right now. (the 2280 I like) New cases are hard to find and about $1200 now, double what they were two years ago when I built Sean's.

Jim's is doing a tranny too, so it will have a whole new drivetrain. He did a nice job on the line bore, with my tooling it measures within a tenth (.0001") of what it should be, and that was with an inside mike (not the perfect measuring tool). Spec gives .0007" leeway. New Bugpack Chinesium crank measured dead on.

Rob's polishing the new crank with 2000 grit in the picture. We polish the cam journals, too, as I think that's what caused the premature cam bearing wear on my 2180. You can see and feel a difference after polishing with 2000. Rotating mass was balanced, too, and the pistons/rods are within a gram. (spec is 5 grams) Yes, I have a gram scale and it's for measuring parts, nothing else!

End result will be a stock 1600 with a CW and cam, and stock gears in the trans. Engine was low mileage with Brazilian heads, Mahle jugs and slugs so we'll reuse those, honed with new rings.

Dual Port wrote: Wed Apr 06, 2022 10:28 am New Bugpack Chinesium crank measured dead on.

Nothing wrong with the Chinesium cranks. A friend builds Ford FE motors and out of 300 builds has had 3 failures. one stock stroke and two stroker cranks. Most of his motors are used hard.

I think even the CB cranks are Chinese billets, but machined here.

Update:

Double bad luck on this one, the motor and trans (both new) were both junk. The tranny done by Jim's Custom jumps out of first and fourth and has a wicked gear whine.
Rob's motor (which he built but I take responsibility for) lasted 400 miles and quit in MI, the crank turns but the cam was not.

First, pull the drivetrain and split the axles for the tranny to go back to Jim's. Get the tranny back to Jim for warranty work while we figger out what's wrong with the motor.

Then tear the motor down (with Joe's help) to find the cam gear sheared half of the teeth off. Neither Jim's Custom or Bill have ever seen this before. Piece of cam gear tooth stuck in the crank gear. They were good used OEG gears from motors I have torn down over the years. Backlash was perfect through 720* (.000-.002") and everything went together smoothly. The gears looked perfect going together originally but were from different engines- not a matched set. Case was linebored and we took a lot of time to measure all tolerances. All I can say is the crank gear probably had an imperfect finish on it when it went together and ate the aluminum cam gear.

Crower cam looks great and has .0000" runout both linear and lateral. Lifters were spinning and went back in their original holes. We tore down the heads to inspect and clean them in case there was debris in the guides. All looks good and the valves were seating nicely. Going together with new bearings and etc, crank runout is under .0005". New aftermarket crank gear. We bought a new cam gear but the runout was way out of spec (.009") so we ended up using a nice original gear. Backlash was under .002" through 720* and did not walk out of the case. Endplay is about .005", I like them a bit sloppy.
Ball hone the jugs and new rings again. Check the gap. Air check on assembly, no head leaks, minimal leakage through the rings.

Long block is done, trim and run will be next. Replacing the oil cooler, of course and we cleaned the galleys with a gun barrel bore cleaner because of debris.

This reminds me of an incident I experienced nearly 14 years ago back in 2010. I was finishing the first MetroParks cruise in my '59 SO23 when I heard some awful noise coming from the engine compartment. I ran back to discover the crank pully had sheared off in two pieces.

No one had seen anything like that previously, but sure enough it happened. I went home and got another pully and Widefive removed the old nut with a pipe wrench while I cranked the motor. (Don't try that at home kids! )

Anyway, my lesson was sometimes metal failure can just occur even when everything seems right. I ran a replacement pulley on my engine for another 5 years before selling the bus, so it was obviously a flaw in the original pulley metal.

Six Volt wrote: Sun Dec 31, 2023 10:12 am This reminds me of an incident I experienced nearly 14 years ago back in 2010. I was finishing the first MetroParks cruise in my '59 SO23 when I heard some awful noise coming from the engine compartment. I ran back to discover the crank pully had sheared off in two pieces.

I remember that, I think it was in the rear parking lot at the Grindstone bar on Front St.....

Yea, sometimes shit happens without much explanation.