The Stovebolt Site Forums The Shop Area Engine Shop 1949 Straight Six Engine ?s

Hello

So, my husband, Phil, was tearing down the engine this afternoon and realized that it appears to have already been rebuilt. The cam gear has already been upgraded from the fiber wheel, the pistons look great, and he suspects it maybe already converted to full pressure. He has a few questions for those that have worked on these engines:

1. When should he stop tearing it down? Should he break it completely down and clean it all? Or is there a point where if he continues, he will start doing more harm than good?

2. How does he know, for sure, whether it is full pressure oiling or not?

3. Is there a good way to tell if things do not require to be rebuilt? (ex: cam shaft bearing, crank bearings, etc.)


Thank you so much for any help you can send our way

Welcome from another new guy !
Tearing an engine down before you know what it really is a "cart before the horse" operation.

1) Stop now. Find the engine serial number near the distributor (near dipstick). Know what that motor is before you have to purchase parts.
2) Full pressure conversion or not? Simplest way is to look in the oil pan for the troughs and nozzles, or on piston rods for the "little dippers".
3) Micrometers & plastigage are the only true measure of whether there is a need to rebuild. A leak-down test, or compression test before tearing into the motor would have helped. Get a Shop Manual for the specifications and tolerances. LQQK here 1948-51 truck Shop Manual Don't guess at the numbers.
Best of Luck to you all.

I agree with what Jackass_Jack says. Confirm what you have first. There's a few numbers that will help ID what the engine really is. One is the number beside the distributor, which will tell what vehicle the engine originally came in, what trans it was equipped with, and engine size. Depeding on year, it could also give either the model year or Month/Day the engine was assembled. There is also a casting date on the passenger side of the bloace, near where the starter mounts to the bellhousing.
One thing I would like to note, having the aluminum camshaft gear is not necessarily anindicator of a rebuild. for the most part, Truck engines used the aluminum gear as factory equipment instead of the qieter fiber gear found in Passenger engines. Thsi is not an absolute, as I have heard of Truck engines with the fiber gear, due perhaps to a parts shortage.

if it is a 1946, it could have been rebult 2 or 3 times by now.

Welcome to the Stovebolt! Here is a link to the dtfferent features of these old Chevy Chevy Sixes Picture 10 shows the device that only exists on low pressure versions.

I like to run an engine to see it and hear it, before I tear it down. That way I have an idea what I am working with.