VCCA Home Forums Thread Like Summary - 1930 Chevy Sport Roadster

I traded a bike for this roadster last month and took a couple of trips around the block. I'm still trying to decide on a plan of attack on what I want out of it but I figured I would address some issues. My two major concerns are a massive oil leak from behind the crank pulley and a leaky gas tank. I sent the gas tank to my buddy that builds chopper gas and oil tanks to have it recreated. I should have it back with a nice copy in a few weeks. The oil leak I'm fixing myself.

So today, yesterday actually, I started pulling the front end back off. I hoped to get by just pulling the radiator but my puller is too long and runs into the front pan and guide for the crank. Not much progress and it looks like I'm pulling the rest off next weekend.

If the replacement cap is machined to a different place than the original the crank may not turn, .001 will make a big difference.
Tony

Based on my experience with plastigauge the gap is on the wider side of acceptable. I have found that the plasigauge and babbitt both being somewhat flexible underestimate the gaps.

You can carefully file a little off the cap to tighten up the clearance a bit.
Use the widest file you can find.
Clamp the cap securely while filing, and try to file the same amount evenly across the flat face of the cap.
Make sure to clean the cap well and reinstall.
If you can turn the crank freely after the cap is tightened on, you are NOT too tight.
Continue until you can feel a slight drag when the cap is tightened on, then add just enough shims for the crankshaft to turn free.

I thought your front plate might be bent.
Thought that was the most likely cause of the broken cap.
Check your rear mounts.

I concur with Chipper, plastigage used with the babbitt bearings is only an indicator of the clearance, not a solid number to rely on.

When I rebuilt the '28 engine in my one ton truck (Lurch), I needed to take a little material off the middle bearing cap in order to close the gap on the crank.

I did not use a file. Instead, I flat sanded it, putting a sheet of 400 grit emery cloth on a flat steel plate and carefully sanding the bolt flanges down a little.

I think this procedure is safer than using a file where you can easily take off too much material and end up with the flanges not perpendicular to the bolt holes.

Here's the post that describes what I did, along with a few pics: Flat sanding a '28 middle main bearing cap

Cheers, Dean

When doing any "facing" like that I prefer to use a piece of window glass as a backing for the emery paper that is larger than the job so that all of the surface has contact with the emery. Unless the steel plate is machined flat the glass is generally flatter.
Tony

The "spin" test (or "drag" test) is the most accurate and was what Chevrolet recommended.

Hi again,

I made some bearing cap shims when I did my '28 engine rebuild. Here's a link to that part of the story, along with a photo or two showing the shims: Making shims and setting main bearing gaps

I should note that my initial setting of the gaps was erroneous. Towards the end of the build, when I got the engine started, it had a couple of soft engine knocks: one in the center main bearing and one in the front main bearing.

I removed shims that I had put in previously and got the knocks to go away. ;-) You'll find this part of the story towards the end of the whole thread.

Cheers, Dean

Yay bonehead mistake!

Runs now, thanks man!

To find TDC on #1, which is closest to the radiator, on the right revolution of the crank,
watch the rockers on #6 (six), which is closest to the firewall.

Turn clockwise (viewed from the front) until the exhaust valve on #6 has just closed and the intake has just barely started to open.
Watch the timing pointer at the same time for the marks on the flywheel.
You will now be at TDC on #1, on the right revolution to install the distributor with the rotor pointing to the #1 tower on the distributor cap.

Hope that gets you going! :-)

Glad I could help.
And glad it wasn't anything serious!

Getting the distributor 1/2 turn out isnt limited to beginners, some very experience mechanics have made the same mistake especially when hurrying to get the car out the door.
Tony