Newbie Question on Rebuilding a 74 motor

jjsto · 10-17-06, 10:04 AM

I have been restoring a 1974 3 spd. fj40 for about a year now. I have basically finished everything, and only have the motor left to work on (which i know next to nothing about.) The motor is original with about 95k miles. My mechanic says the motor is basically clean and in good shape, but that it is slowly burning oil. He has suggested replacing the piston rings, the valve seals, and the head gasket. For this he will charge $550. For the same amount of money he will also replace the bearings, and put in new pistons if I buy them. Is this worth doing? Do you know of a cheap place to get the parts? Thanks a lot for any comments..........

DanL · 10-17-06, 10:57 AM

Sounds fair to me. I would consider doing a complete valve job on the heads. If he is going to put new rings and bearing in you would be at a fresh motor stage. As long as your not looking to make it a hot rod you should get many years of service doing as described.

igotta40 · 10-17-06, 11:37 AM

Something doesn't sound quite right with his quote. For $550 he will repair the oil burning. You buy pistons and bearings and he installs for free, basically. It sounds reasonable but also raises questions. Sounds like he means rod bearings only, and intends to leave the crankshaft in place during the repair. Not wise. But if he means all the bearings, you need a complete gasket set and seals, may as well do a valve job, and the list will go on. I'd wonder why I needed new pistons at 95K. Of course, then you've rebuilt the motor to fix a minor problem. I can't imagine a Toyota motor needing a rebuild at 95K miles...

Start with a compression test, replace the valve seals, and go from there.

jjsto · 10-17-06, 12:01 PM

Thanks for the reply, igotta. For $550 he would replace the valve seal, gaskets, and piston rings. He is basically saying that 95% of the work is taking the motor apart to get at the pieces and that if i want to change the bearings/pistons he would do that for free since he was already in there. But, yeah it does seem pretty ridiculous to rebuild the whole motor (which runs great) just to prevent a small amount of oil from getting in there. He also mentioned trying a type of thicker oil that is not sold in retail stores, and that doesnt smoke when burned. The added thickness would also make less oil leak in, but that sounded kind of shady to me......I will definitely start with the compression test and valve seals......thanks. any other advice??

REZARF · 10-17-06, 12:52 PM

Also, do a leak down test. You can start to get a good idea if you are leaking oil and where from both a compression test and and cylinder head leak down test.

What is "burning a little oil?" If is hardly noticeable, I wouldn't mess with it. However, if it is a quart of oil everytime you fill the gas tank up I would go for it.

I am in agreement, that I can't see why the pistons would need replacing.

A head gasket is not a hard job on these old motors, you could pull it and reinstall it yourself, and have your mech. do the valve job.

I would deck the head while it is out to bump up the compression just a tad.

Good luck

Rezarf <><

jjsto · 10-17-06, 01:14 PM

Thanks, i will definitely start with both a compression test and a leak down test. A little oil means that there are traces of smoke while the motor is running sometimes, and that you can see residue that has built up over time on the spark plugs. I just changed the spark plugs, and put in a different oil, so I will have to see what kind of difference, if any, that makes...thanks....

igotta40 · 10-17-06, 02:22 PM

This is difficult to post without sounding sarcastic. Honestly, if 95% of the work is disassembly, and thicker oil not available in stores will fix your motor, he's not really your mechanic. The guys responding to you are right.