My Willys 3A and 3B Community

3A, 3B, DJ Technical Knowledge Base => "Original"-- Technical Questions, Answers, Observations => Topic started by: dluyk on July 11, 2019, 01:37:57 PM

Title: Rebuild or Let It Be?
Post by: dluyk on July 11, 2019, 01:37:57 PM: Hello all, we are in the beginning stages of a 1953 CJ3A restoration, still planning..

We have toyed with the idea of having the engine rebuilt. We just did a compression test on the ol' girl and here are the results:

Dry: #1: 110, #2: 115, #3: 115, #4: 110
Wet: #1: 115, #2: 120, #3: 120, #4: 120

The engine seems to run fine but we have an air/fuel mixture issue we havn't figured out. It seems to run rich.

The question we have for you is this: do those compression numbers seem healthy to you? We recognize that we will never have a better opportunity to rebuild the engine, but we're not interested in spending extra time and money on an engine rebuild especially if it's not really necessary. Original odometer read just over 62k miles.
Title: Re: Rebuild or Let It Be?
Post by: mtnman37879 on July 11, 2019, 02:11:24 PM: Your compression is fine. Rebuild your carb.
Title: Re: Rebuild or Let It Be?
Post by: oldtime on July 11, 2019, 04:35:19 PM: Those are pretty good compression readings for an L-head.

There is great benefit in knowing exactly what you have.
I suggest you pull the head off and take a close look at the valves etc.
With good lighting and magnifying glass look for hairline cracks between the #2-3 exhaust valves.
If all looks well; do a precision valve adjustment with each valve fully seated then buy a Copper head gasket and call it good.

That should help ensure you have a dependable engine with little time /expense.

Do not clean deck area or pistons with a wire wheel nor any abrasives!
A single piece of wire can easily ruin a bore.
Title: Re: Rebuild or Let It Be?
Post by: stony on July 16, 2019, 09:05:13 PM: I an in the ï¿½if it ainï¿½t broke donï¿½t fix it schoolï¿½. You have decent compression, so that looks OK. I think rebuilding the carb and adjusting the valves is a good idea. Make sure your ignition is in tip top shape and the timing is correct. Look for any hint of oil or bubbles in the coolant. Once the carb is rebuilt, put in some new plugs and take her out for a nice long ride, then when you get back pull the plugs and take a Good look at them. They should be a nice light brown. If the look good save the rebuild for later.