VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1928 Chevrolet Engine Rebuild Experiment

Hi All,
As some of you know, I recently went through the drivetrain of my 28 Coupe and rebuilt the transmission and rear end replacing all bearings, bushings, and seals. At the same time, I installed a rebuilt (experimental) motor and a Johnson overdrive unit. I have been promising to post a more detailed article and although I only have a couple of miles on the car so far, I thought I would share my results.

It all started last May when I took my spare engine down to H&H Antique Engine in Southern California. I told Max the shop owner I wanted to be able to drive this engine 55 mph all day long. He gave a funny look and said he would work on it. Basically, I had new insert main and rod bearings installed, counterweights added to the crankshaft, a new performance cam grind, and new rings and pistons. Plus, the entire assembly was completely balanced. The mains required some welding to bring them to the proper size for align boring. Here is a picture of the engine sitting upside down in my garage.



I specifically asked Max if I need to modify the oiling system because of the new insert bearings and he assured me it would not be necessary. All the bearings were drilled with the proper oiling holes and that should be sufficient for this application. I took his word for it when reassembling the engine.

After reassembly and evaluating the condition of my oil pump, I decided to opt for a new gear-type oil pump from Egge. This pump is roughly the same size as the original and requires the use of a modified 1937-1939 Chevrolet pickup screen. I had to be careful with the clearance between the pump and the new counterweights on the flywheel. The fit was very close and required some abrasive adjustment on the oil pump to reach a comfortable clearance. The pickup screen also required some modification to fit properly in the stock 28 pan. Here is a picture of the oil pump and modified pickup screen.



After getting the pan to fit correctly, I measured how far the dippers on the rod caps dipped into the oil pan troughs with the new cork pan gasket in place. It's a good thing too because rod one was rather questionable as to whether it was dipping at all. In order to remove all doubt, I raised the oil level in all the troughs by raising the walls of the troughs at their lowest level. This was accomplished by silver-soldering some carefully shaped pieces of tin to the outer walls of the troughs. Further testing concluded that all dippers were now submerging themselves into the troughs by a comfortable margin.

Priming the pump prior to starting the engine required the use of an electric drill with a screwdriver tip inserted down the distributor shaft hole. I ran the pump for a couple of minutes to make sure the oil troughs had plenty of oil in them. I also primed all the main bearing and cam bearing channels prior to installing the pan for the last time.

Starting the engine was a breeze. The first time I hit the starter, the engine kicked back a couple of times so I got out and retarded the distributor timing just a touch. The second time I hit the starter, the engine fired right up and began to idle although a little rough. Some minor adjustment to the distributor and I had it running quite smooth.

Careful observation of the oil pressure gauge revealed that the idle pressure was between 20 and 25 PSI. This concerned me a little as the gauge only goes up to 30 PSI. After the engine had time to warm up, the oil pressure dropped to a comfortable 10 PSI at idle and 20 PSI at higher RPMs. I am currently using SAE 30 oil but I think if I try a multi-grade 10W30, the oil pressure should be more manageable when the engine is cold.

My first trip around the neighborhood was uneventful except for some minor chatter from the clutch. After installing a new crank pilot bushing, throw-out carbon and clutch ring, there might be some break-in time required for everything to settle in. If not, I may pull the transmission again and try to evaluate the problem. I sure have more clutch travel than before. Prior to rebuild, the clutch went almost to the floor before disengaging. Now, the clutch begins to disengage more toward the top of its travel. This in combination with the rebuilt transmission, shift lever, and overdrive made me learn how to drive the car all over again. A task I am still working on.

The engine certainly outperforms its predecessor. I believe the more aggressive cam grind is partly responsible for that. There is also a lot less engine vibration at high RPM. I believe the combination of the new engine and overdrive unit will make the old gal a lot more drivable than she was before. I am also considering the use of high compression pistons but I want to get some miles in before I make that decision. It might just be overkill.

The testing is still in progress but the prognosis looks good. If there are any specific questions I can answer about my experience, fire away. I found this to be a rewarding experience and hopefully I learned something along the way.

Regards,
-R

Your pictures are pretty "cool." Did you do any modifications to the head? How does the cooling system deal with the new motor? Thanks for sharing that. Ricardo

Hi Ricardo,
I had the cylinder head rebuilt a couple of years ago. The engine was idling rough and I noticed the valves guides were so loose I could wiggle the stems. I ordered new stainless valves and springs from Egge. The guides were drilled and new hardened guides were pressed in. That cured the trouble. As for engine temp, so far it runs cold. After about 30 minutes idle, I was able to hold my finger in the water and it was just warm. I haven't been on any hill climbs as of yet so I can't say how it will react under load.

Regards,
-R

Is that housing surrounding the oil screen pick-up something from a 1932 chevy? Is your copper tubing that goes to the oil pressure readout same diameter as original pipe or tubing? How is the standard chevy oil filter handling the added pressure? Ricardo :)

Hi Ricardo, Actually the oil screen and pickup are from a 1937 to 1939 Chevy. It took some adjustment to fit inside the 28 chevy pan. I had to grind some off the bottom and flatten one side a little with a hammer. The copper tubing is standard 5/16" variety that I was using with the original pump. The oil filter is a beefy reproduction of the original filter and it seems to handle the pressure just fine. Actually I removed the test plug to check oil flow and it squirted me, the engine compartment, and the right front fender with oil before I could get it plugged. What a mess :eek:

In yuor chat, you mentioned you had rebuilt the transmission! What is used for oil seals, say the ones for the lower shaft? I have one leaking and would kind of like to find some pics before I start on it. ANy information or where I could find a schematic or breakdown of tranny would be nice.
Thank you

Remove all the "innards" from the transmission. Clean the inside of the transmission. Start the assembly and brush a liberal coat of gas tank sealer on the bottom shaft and the inside of the hole through the case. Do the same for the top shaft. Let it set without movement for at least 24 hours to allow the sealer to set up.