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Open Engine Advise Please

Discussion in 'Intermediate CJ-5 and CJ-6 Tech' started by Abone327, Jun 9, 2019.

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  1. Jun 9, 2019
    Abone327

    Abone327 New Member

    Stevensville,MT
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    I purchased a 360 that had been pulled to re-gasket but then they decided to replace it with a chevy. He said it ran well and didn't have any issues other than the oil leaks. After meeting him, I tend to believe him. I received it with the oil pan, intake manifold, and valve covers removed and he had gotten as far as cleaning off the old gaskets. There are some remnants of the old gaskets still present laying around the rockers and here and there. The timing cover hasn't been removed. I have three questions. What would be the suggested procedure to clean everything out before putting it back together? And the timing chain doesn't seem to have any play, should I still remove the cover to clean and replace the timing chain? I'm not sure why he didn't remove the cover and I don't know if it leaked. He cleaned the outside of the engine pretty well so there is no evidence. Also is there anything else that should be checked before assembly. Thanks
     
  2. Jun 9, 2019
    Chilly

    Chilly Active Member 2019 Sponsor

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    Seems pretty close to fully torn down. So I'd completely tear it down, clean, inspect, put back together with minimum necessary work. If the bores and crank are OK with current pistons then kiss with a hone and re-ring. New bearings regardless. Full rebuild of AMC V8 is $2500 affair. But SBC conversion is $2k before any engine rebuild.
     
  3. Jun 9, 2019
    Lockman

    Lockman ..... He who dies with the most Tools... Wins ! Sponsor 2019 Sponsor

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    Your not gonna Know that the timing chain is ok untill You pull the cover & inspect it. Water pumps on GM's are notorious to leak at the weep casting hole. There cheap to replace & and with new gaskets and perma seal you'll have piece of mind at all of your engine gasket places.
     
  4. Jun 9, 2019
    Abone327

    Abone327 New Member

    Stevensville,MT
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    I guess my post was a little confusing. The engine that I have and am using and am inquiring about is an AMC 360. The guy I bought from is going with a Chevy. I do like the idea of going through the whole thing for peace of mind. I'd like it to last.
     
  5. Jun 9, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    No personal experience with rebuilding these engines, but they are very conventional V8s from the era. What are you replacing with the 360?

    Typically these engines have low hot idle oil pressure at high miles. This can come from either a worn timing cover or from delaminating cam bearings, if the rods and mains are not worn out. Since you have neither heard the engine run, nor measured the hot idle oil pressure, if it were me in this situation I would disassemble the engine and focus on those two areas. I would measure the cylinder taper and assume that the least I'd need to put in to it was rod bearings, rings, and a valve grind. Since the engine is apart and not running, you should measure everything you can.

    Your alternative is to put it together, run it and see what you get. If it has good hot idle oil pressure and compression, I would call it good and run it.
     
  6. Jun 9, 2019
    Abone327

    Abone327 New Member

    Stevensville,MT
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    It's replacing my original 304 which has taken a complete dump. I thought I might get away with purchasing a runner and upgrading to a 360 for a fraction of the cost of rebuilding the 304. Finding the engine wasn't as easy as I kept reading it would be. I have never been in to any engine before. I guess it's time. All advise is appreciated.
     
  7. Jun 9, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    Note that you need a 360 flywheel if you replace a 304 with a 360. Completely reasonable to make this swap - it's the best performance bang for the buck that you can make with a 304.

    JMO - put the 360 together, drop it in the Jeep, and see what you get. Not much to lose...
     
    Rich M., Twin2 and jpflat2a like this.
  8. Jun 9, 2019
    Abone327

    Abone327 New Member

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    Thank you. It is tempting to throw it together and run it. Feels like my Jeep has been down forever. I think that I would be more comfortable though to go through it and freshen it up. Hopefully I won't find any major issues. I'm sure I'll have plenty of questions along the way.
     
  9. Jun 9, 2019
    Chilly

    Chilly Active Member 2019 Sponsor

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    Give us more details on the 304 failure. Interested to know what parts are still good on it. Bulltear is a good vendor for some items. The AMC Forum is good place to learn about these engines. Guys there are kind if racey so their build recommendations might be skewed away from what a Jeep might need.
     
  10. Jun 9, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    Well, the most conservative route is to tear it down, measure everything, and bring the engine back to like-new condition. Here is abook that will help you if you want to take that route: https://www.amazon.com/Engine-Build...andbook&qid=1560128923&s=gateway&sr=8-1-fkmr2 This goes through the whole shebang, rebuilding an engine to like-new specs. The flip side to that is finding a good-running used engine, drop it in and run it. A seasoned engine (ie been running for a while) is a reliable engine. Any path between those two extremes requires careful measurement and good judgement. As I've written before, you place your bets and you take your chances.

    You write "freshen up;" what do you mean? New gaskets? New rings? Valve job? New bearings? It's hard to evaluate an engine that is not running without a complete tear down and thorough measurement. The measuring tools are not cheap. Your local machine shop will measure for you, but they have a vested interest in recommending that you do a lot.
     
  11. Jun 9, 2019
    Abone327

    Abone327 New Member

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    Now I don't know what I'm going to do again. I guess I've got some thinking to do. I'm don't know what all is wrong with the 304. It has low compression in all cylinders. Very low in a couple and smell heavily of burning oil just from cranking it. Won't start, oil in air cleaner.
     
  12. Jun 10, 2019
    timgr

    timgr Jeepin' Nerd Sponsor 2019 Sponsor

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    Are you put off by the effort needed to put the 360 in the Jeep? As cars go, installing an engine in a Jeep is really easy. You could build an engine stand to fire up the 360 and check it out, but it's almost certainly less work to just put it in the Jeep. Take the front clip off and you can mostly work at arm's length. You can even start the engine without putting the clip back, if you just want to start the engine. If you need advice about swapping the engine, feel free to ask that here or in a new thread. Replace the rear main seal (much easier with the engine out), finish the new gaskets, and swap the missing parts over from your 304.
     
  13. Jun 10, 2019
    Chilly

    Chilly Active Member 2019 Sponsor

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    Situations like this always lead to "while I'm here I might as well...". I think I'd probably put it together as-is and give it a try. Once you start the "might as well" path you'll end up so close to a full rebuild that you might as well.

    Check for bent pushrods. Worn out cam. Maybe hand lap the valves, replace valve seals while you are in there. Keep track of where everything goes, but back in same hole. I'd probably pull the caps and look at just the cap side bearings. If bearings and journals look OK then change the rear main seal and put it back together.

    The wild card that would scare me is how he cleaned up the deck of the block. If he used abrasives then it's game over. Scotch brite or sand paper will get between pistons and bores. Needs full teardown and clean.
     
    Tree cutter 08 likes this.
  14. Jun 10, 2019
    Abone327

    Abone327 New Member

    Stevensville,MT
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    The heads weren’t/aren’t removed. I don’t have a problem with installation or removal of the engine from the Jeep. I don’t however have any experience with engine internals. I think I would like to just pull the timing cover and check the chain, do what is necessary with the oil pump, new rear main and gaskets and put it back together. Is there a wrong way to blow out the oil passages to remove any gasket material that may have found it’s way in there? I read a while back on another forum about oil pump rehab. I think I’ll try to figure that out. I also checked out replacing the valve stem seals. Seams easy enough if it is suggested.
     
  15. Jun 11, 2019
    sterlclan

    sterlclan Member Sponsor

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    If you are comfortable doing a timing chain and oil pump you aren’t that far from pulling it apart and putting new internals if needed. I recommend getting the service manual and at least check the bearings and rings.if they all look good I would run it. Not that hard to pull bearing caps and look.
     
  16. Jun 29, 2019
    Abone327

    Abone327 New Member

    Stevensville,MT
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    So after checking some bearings I've decided to do a rebuild. Tim, I have purchased the book that you suggested. I have the engine torn down and would appreciate some input on the condition of the bearings and any other issues you all may see. Some of the piston skirts have been wearing against the bores. One especially. I have been referred to a machine shop. Here are some pics of the main and rod bearings. Thank you.
    image2.jpeg image1.jpeg image3.jpeg image4.jpeg image5.jpeg image6.jpeg image7.jpeg
     
  17. Jul 3, 2019
    Everett Reed

    Everett Reed New Member

    Southeast Missouri
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    I've seen ALOT worse than that. The connecting rod uppers are into the copper but the wear is even. I'd find someone with a bore mic and check the taper and out of round measurements before throwing in a machine shop arbitrarily.
     
  18. Jul 3, 2019
    Keys5a

    Keys5a Sponsor Sponsor

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    The crank needs polishing, but that may be all. Check the bearing sizes to see if they are standard (std). I have a 360 that got odd fitted bearings (0.001/0.003) from the factory. With fresh bearings, Plastigauge will tell what the clearances are.
    That scuffed piston and cylinder wall could be better. All the cylinders need deglazing and a light ball-hone at minimum.
    If you don't have all the tools, it might be better for a machine shop to determine what is needed.
    -Donny
     
  19. Jul 3, 2019
    Alan28

    Alan28 Well-Known Member Sponsor 2019 Sponsor

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    You need some courage, patience and money. Take your time to do what you want. This is what I did. And find good suppliers.
     
  20. Jul 3, 2019
    po35042

    po35042 New Member

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