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Technical Checking out a used motor

Discussion in 'The Hokey Ass Message Board' started by Mopar Tony, Sep 22, 2022.

  1. Mopar Tony
    Joined: Jun 11, 2019
    Posts: 445

    Mopar Tony

    So I have never completely rebuilt an engine. I have tore one down to a short block and installed new cam bearings and camshaft but never removed pistons or crank. I bought a 1993 Buick road master with a 350 Chevy in it hooked to a 700r4 had 120,000 miles on it. The motor is a roller motor and has all the accessories intact so it should make for a decent install. The car seemed to run and drive fine but I am going to carburate it and put it in my car. I am on a very tight budget but I don't want this thing breaking down later either. With that being said I planed to to re gasket it and put a new timing chain, valve stem seals, etc in it and run it. However I am not wanting to do this a ton of times so I am curious what the best thing to do is to be sure this motor is good to go. I was thinking of running a compression check in it and while I have the heads off checking the cylinder walls etc. I did drive this car myself and it seemed strong, did burn outs, and even a donut in it before I pulled it apart LOL. I thought about a rebuild kit and putting new bearing and rings in it but I am not positive I can do it without screwing it up. I can not afford a crate engine or to send it off for a rebuild. No I'm not lazy and cheap, just plain can't afford it. Also going for a cruiser motor so most performance wise that I may do is a little bigger camshaft. (I know I'm going to be accused of half assing it and being cheap and lazy so just establishing that early.) What do you guys do when you get a used engine to check it out? What would be acceptable compression?
    Last edited: Sep 22, 2022
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  2. Tickety Boo
    Joined: Feb 2, 2015
    Posts: 1,508

    Tickety Boo
    from Wisconsin

    Is the project that your putting this engine a daily driver or a have fun Hot Rod, seeing that it runs strong I would put a mechanical oil pressure gauge on it before pulling it out of the Buick and if pressure is good continue with the re gasket & seal plan.
  3. NoelC
    Joined: Mar 21, 2018
    Posts: 384


    Do yourself and us a favor and just install it. Truly. You've said it all with:

    As far as I'm concerned nothing will kill the fun more than over thinking it. Want to know what to do, read a book. How to rebuild your SBC.
    After that, you won't think you need to remover the heads or see the cylinder walls.

    If driving it and it seemed strong wasn't enough, you had burnouts and doughnuts to convince you. However, I like taking shit apart so yea, if you got it out, take it apart and learn something. Yes, there will be times that something is you are way over your head in the deep end trying not to drown but that the way it goes as you learn.
    vtx1800, Wanderlust and firstinsteele like this.
  4. jimmy six
    Joined: Mar 21, 2006
    Posts: 11,786

    jimmy six

    Even with that many miles in that car it was never over worked at all. Changing the timing chain is a great idea. If the heads are coming off for valve seals. You can rent a valve spring “C” clamp. I’d clean all the valves with a wire wheel, the valve area with a wire brush on a drill motor, and hand lap the valves. Even if not perfect they will be better than 120k miles untouched.
    While the heads are off clean the cylinder ledge with a razor blade and a vacuum cleaner. You can also wire brush every piston top by bringing to the top and covering everything else. There will be one up on each side. Change the rear main seal it’s one piece. Clean the pan and oil pick up screen and look at the oil pump gears.
    Not much money in all of this just some time a few parts and a good gasket set. Good luck.
    MMM1693 and Mopar Tony like this.

  5. Mopar Tony
    Joined: Jun 11, 2019
    Posts: 445

    Mopar Tony

    It is going in my 50 merc that I will daily drive/cruise.
  6. Mopar Tony
    Joined: Jun 11, 2019
    Posts: 445

    Mopar Tony

    That was what I was thinking myself. My last motor build was a 360 and I did all of these things with it and added new cam bearings. I guess I am just over thinking this thing because a re-ring kit was only 180 bucks for it so should I do it or not is what crossed my mind. Being a fuel injected motor previously I'm assuming there is still cross pattern on the cylinder walls. I'll just freshen it and go from there, new seals and a oil pump and go.
  7. hemihotrod66
    Joined: May 5, 2019
    Posts: 694


    With the heads off you can see how much of a ridge is in the cylinders....To me that is what means a rebuild....You can replace all the bearings without removing the pistons....Just my two cents...
  8. I would do NOTHING. Those things run 200000+ all the time. IF I saw an oil leak, perhaps fix that. I know it is not the H.A.M.B. way, but I would not change to a carburetor. They are one of the main reasons engines wore out so soon pre '80s.

    vtx1800, bobss396, Mopar Tony and 2 others like this.
  9. I would do a cylinder leak down test on and if it passes- don't think I would do much else. If its not smoking or burning oil-why open Pandora's box?
    bchctybob, alanp561, MMM1693 and 2 others like this.
  10. choptop40
    Joined: Dec 23, 2009
    Posts: 4,421


    done this many times , remove everything down to the long block , clean it up and bolt on the conversion parts , id at least check the freeze out plugs and install new water pump at has 1 piece rear main seal ...firstinsteele makes sense on the oil pics please..good luck
    Mopar Tony likes this.
  11. Fit it.
    Leave it.
    Start it.
    Drive it.
    Don't need pics. I know what a 350 looks like...
    Wanderlust and Desoto291Hemi like this.
  12. goldmountain
    Joined: Jun 12, 2016
    Posts: 3,769


    This story hits close to home. I too ended up with a Buick Roadmaster for its drivetrain. I really didn't have a car that needed that stuff so it sat. Much easier leaving a car together than to try and find places for all its parts. Left it behind my rental property and junked it when my tenant complained that the druggies were using it to shoot up in.
  13. Rickybop
    Joined: May 23, 2008
    Posts: 8,289

    from Michigan

    It's a Chevy 350 for god sakes!


    Short story.
    Maybe some assurance for you.
    Demolition derby. Guy lost his drive shaft on his Chevy. Pissed off, he floored it. Kept it floored while everybody else duked it out. 350 engine finally got so hot it caught on fire. They had to pause the derby to put out the fire. Engine was still running.

    Your results may vary.
    Dustin 257 likes this.
  14. Budget36
    Joined: Nov 29, 2014
    Posts: 9,449


    Does it need valve seals, does it need to have new gaskets?
    I’m with @NoelC first comment, use it as is.
    I do know about “while it’s out and in front of me, may as well…”. But is it necessary?
  15. I had a '95 350 (originally fuel injected) that accepted all the factory roller stuff but left the factory with a flat tappet cam. I went to the wreckers and grabbed all the roller stuff off a Roadmaster and tossed it in. Engine ran great. That being said, the '95 block I had was not drilled for a mechanical fuel pump. Apparently the blocks can be drilled if a person wants to but I didn't bother and here's why ... the GM factory roller cam does not have the lobe to drive a mechanical fuel pump and I wasn't spending money on an aftermarket roller cam (which apparently generally do come with the fuel pump lobe). I had a Carter electric fuel pump left over from a previous car so that is how I got around not having a mechanical pump. Just something to keep in mind. I never bothered with rings, bearings etc, the only thing I changed was the timing chain because I had the engine opened up to put the cam in.

    As stated above, the engine was originally fuel injected (I bought just the engine) and I wanted carburetion so I installed a factory GM intake from a 1987 Monte SS. This was a bolt-on/fit perfectly and allowed me to use a quadrajet carb. Supposedly you can re-drill older intakes and use angle spacers/shims to work with the different angles of the four center intake bolts but I had the Monte intake and was fine using a quadrajet.

    Oh yeah, one more thing ... I ran an older style HEI (none computer type which worked perfectly with the carb) but I had read that the drive gear on the dist must be changed to a melonized gear in order to be compatible with the roller cam so I went to the dealer and bought a melonized gear (found the part# on line).
    Last edited: Sep 22, 2022
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  16. indyjps
    Joined: Feb 21, 2007
    Posts: 5,090


    Compression and oil pressure check, if it's goodish - run it.

    Next step up, re-gasket it, timing chain if ya want.

    Next step up, swap cams while you re-gasket

    Ah Ha, now we can talk about cams, ultimately where every SBC thread ends up.
    Mopar Tony likes this.
  17. Budget36
    Joined: Nov 29, 2014
    Posts: 9,449


    And there ensues creep for a simple job. ;)
    bchctybob, '28phonebooth and indyjps like this.
  18. NoelC
    Joined: Mar 21, 2018
    Posts: 384


    I'm driving a 91 Roadmaster with 170k on the clock. It's my spare 5.7 and transmission. It's OT so no pictures, but I'm waiting for someone to hit it for the payday, and then it's being parted out. As far as it goes however, if you read the book, there are some very simple tests to gauge the fitness of an engine.
    You might also have to think, that maybe...just maybe, it had been well maintained all its life? Maybe it was replaced at some point? Or maybe, the general just build a great engine for those Buicks.
    firstinsteele likes this.
  19. BamaMav
    Joined: Jun 19, 2011
    Posts: 5,772

    from Berry, AL

    I’d check the compression, it that was ok I’d check the slack in the timing chain by turning the crank back and forth a bit while watching the rotor movement. If the rotor seems to move just as soon as you move the crank the timing chain should be ok. If those two things check out, I’d replace both the front and rear seals, and any other gaskets that show signs of leakage. That is what I did with the 302 that had sat 10 years before I put it in my car. I ended up having to pull it back out and change the head gaskets because they had rusted out and were leaking, but I was dealing with an unknown engine, you have ran yours so you should know more about it than I did mine. In other words, if it ain’t broke, don’t fix it. The crank seals are a lot easier to fix before you put it in the car, just good preventative maintenance there.
    Mopar Tony and alanp561 like this.
  20. If its out of a 93 , its possibly an LT1 with the distributor under the water pump and if I remember correctly, reverse rotation cooling. Replace the distributor "cap" before you install the engine, you'll be glad later. Mitch. *NOTE*-- I AM WRONG.... it seems the LT1 was introduced in the '94 Caprice and Road master. Sorry :(
    Last edited: Sep 23, 2022
    Mopar Tony and alanp561 like this.
  21. gimpyshotrods
    Joined: May 20, 2009
    Posts: 20,869


    Pan gasket, rear main seal.

    Run it until it explodes.
    bchctybob and olscrounger like this.

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