Do I need to rebuild?

Fri Aug 08, 2014 9:04 am

I'm facing some tough decisions on my A. I still haven't cleaned the mud dauber nests out of the engine, and to do that I will have to:

Remove the head

Remove the crank pulley and front cover

Remove the oil pan (did this, just haven't cleaned it out yet, replaced pan temporarily)

I have already removed the front end, gas tank, carburetor, and the manifold. Every gasket I've come to needs replacing, and the manifold has some serious pitting on the sealing surface around one hole, so it will need sealer when it goes back on.

I want to go ahead and prep, prime and paint each part I have off of the tractor, as I get them off and clean them.

I'm just wondering this: It's always a possibility that the engine needs to be rebuilt. Because of the mud-dauber mess, I can't crank the tractor until I clean the engine out with the aforementioned steps, and get it put back together. I don't know what I'm talking about here, so help me out: I can't check compression on the engine without being able to crank the engine, right? Are there any other things I can check to know definitively whether or not I need to rebuild? What about when I remove the head?
I'm really enjoying working on this A, it's just that I'm worried that It's going to be a lot of wasted effort if I get it torn down, put back together, and THEN find out I have to rebuild the engine. I would have to tear it down twice... :cry: I also bout a complete gasket and seal set, and I will have to put in all new gaskets for the parts I take off and put back on. If I have to tear the engine down a second time, won't it ruin some if not all of the new gaskets? How does that work? Is there a way to avoid this?

If any of y'all can answer any of my questions, I'd sure appreciate it. Also, please give me your general opinion on which direction to take this project. Thanks a lot!

-Jordan

Re: Do I need to rebuild?

Fri Aug 08, 2014 10:10 am

Measuring compression is an indirect way of determining engine wear without tearing the engine apart. It helps determine the need for a tear-down and what to expect when it is opened up. Once you have pulled the head off, you can directly measure the major wear items. Results of a compression test are of minimal value at that point. The major thing to check is wear of the cylinder bores. If they show no wear, you can leave the cylinders/pistons alone and put it back together. Moderate wear may call for a new set of piston rings while major wear indicates need for a sleeve/piston set.

Definitions of no/minor/major wear are in terms of bore size and out of round. I can't give you those limits off the top of my head but they are published in shop manuals. You may need to go to an local engine rebuilder to get the measurements done. If you know someone that does such work part time, you may get him to come to you and do the measurements. Most regular shops will be willing to check it out but you will need to take the engine block to them. In any case, I would take the head in for a valve job. If it is in pretty good shape, a redressing of the valves and seats is of minimal cost. They will typically check valve stems/guides for wear and you will get into additional cost only if they find excessive wear.