Engine Advice Please

Buhner Dec 18, 2014

  1. Buhner

    Buhner New Member

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    I am painfully new here and need some advice. I have a '78 FJ40 that I used to drive in college 20 years ago. Now I am trying to rebuild it for my son to drive. It had been sitting in a garage for the last 10 years when I took it to a mechanic to get started. The number 3 cylinder is seized and will the estimate to rebuild the original straight 6 engine is $2500. Am I better off doing an engine swap or rebuilding the existing straight 6? What are the pros and cons of each? What is cheapest? What will take the least amount of time? Thanks in advance for the advice.

    D
     
  2. Cruiser Innovations

    Cruiser Innovations New Member I am in united_states

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    This is my cup of tea :)
    My suggestion is to swap out the stock 6 which I would imagine is a 2F (Not a bad engine) and install a GM small block 350. Hands down you cannot find a better parts selection than for a 350 SB.

    Pros:
    Better fuel economy over a stock 2F. Ball park is about 3-5 MPG better over the 2F. Fuel system setups make a big difference as to how good of fuel economy you can expect from your sb.
    Lighter in weight than a 2F
    More horse power and torque
    cheaper parts = cheaper rebuilds

    Cons:
    Additional cost for conversion in parts and labor (If you are having someone else do it)
    Your stock FJ40 (If it is in fact completely stock) is no longer completely stock.

    better yet go with a 4BT cummins:
    Pros
    -25 MPG
    -Crazy long life engine life span
    -Crazy torque and can produce a lot of horse power with just injector and turbo mods should you choose (Probably not with a teen driver). I saw a Camaro with a pumped up 600 Plus HP 4BT cummins!
    -Slow if left stock (Great for teen)
    -Higher re-sale value

    Cons:
    -More adapter parts needed than a 350 conversion
    -Cost of the engine and rebuild is a little high. A good donor is around $2000 while the rebuild will cost you another $3000 - $3500
    -Would be better to run a stronger trans like a NV4500 5 speed. The stock FJ40 4 speed is a little on the light side when setup with a torque monster cummins
    -More fabrication work needed for engine / transmission setup
     
  3. watrob

    watrob Active Member I am in australia

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    Cheapest and quickest is get another 2F, not sure of your location and availability of a second hand 2F in your area but that's what I would do if its your first time rebuilding a 40.

    Its a good introduction into the inner workings of a 40 and you can always rebuild the old 2F over a period of time?
     
  4. pcd

    pcd New Member I am in united_states

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    Hi - I am new to the forum, but have been slowly restoring a '73 FJ-40 4-speed for about 10 years and love the vehicle. Then a year ago the original straight-6 threw a rod. The rebuild of the original engine was an option, then an F2 was presented as an option. The second option seemed great at first but the delivery was not as anticipated so I requested a return of my deposit and am now exploring new solutions. Is the advice above your advice for me as well?
     
    Last edited: Jul 15, 2016
  5. Beau

    Beau Well-Known Member I am in guyana

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    A trick someone told me before trying to turn over a old motor, is to poor ATF (Automatic trans fluid) used, or new into the cylinders and let them soak for a few days. Apparently it helps lube up the rings and un-seize them at the same time. ATF wont pit or do any harm to the actual motor. Obviously a oil flush is a good idea as well.

    Maybe a silly question, but how does a mechanic exactly tell if one cylinder is seized in comparison to the others? Other than if hes actually stripped it down?
     
  6. pcd

    pcd New Member I am in united_states

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    I do not know. The engine did turn, even to back it off the trailer, so it wasn't a "complete freeze". But a mechanic told me it was ready for a rebuild at $4K. Not a mechanic so that is the best I can tell you. I had no reason to disbelieve him. He was an old timer on the coast and I think he knew what he was talking about.
     
  7. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    A seized engine doesn't turn. Anybody telling you an engine that turns over is seized doesn't know what they are talking about.
    So it actually runs? You backed it off the trailer with it?
    Something doesn't add up here.

    Welcome all the newbies on this thread BTW. :)
     
  8. pcd

    pcd New Member I am in united_states

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    It ran then. At times it runs. But I dindn't say the engine froze. I said the diagnosis, good or incompetent, was that a "rod was thrown". Same thing? Does a rebuild become an option? A great answer would be an estimate of repairs - a mathematical solution. Math is something that is universally understood among engineers. Mechanics isn't my trade.
     
  9. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Ok, I'm not trying to catch anybody out here it's just there are some very mixed messages on this and with a bit of assumption thrown in that can lead to all sorts of misdiagnosis and wasted time and money.

    In your op

    A rod thrown is not necessarily a seized engine unless it was seized before it was payed up. You cannot break a con rod sitting in a garage not started.

    A seized engine on any piston does not turn. A thrown con rod would likely end up rattling like a machine gun if the engine were started and usually ends up with a hole in the side of the block. Have a look at videos on YouTube and you will gain some valuable knowledge. Not being funny here, at all, you say you're not a mechanic, neither are a good proportion of the members on here myself included, so you're in good company and there is a mountain of knowledge on here that you can absorb. It's just whenever we hear of somebody having been told by a garage something that doesn't sound right we will say so. There are a lot of great mechanics out there but there are bad ones too. The thing is, on here, without being in front of the engine (or whatever we are being asked about) it is difficult to judge what is best or to troubleshoot. That's why we need clear correct information without any guesswork or assumption to throw us off the scent.

    Posting on here and asking questions is probably the best move you've made with your 40. Now, can we have some photos please. :)

    Back to the engine, how many miles on it?
    Is it noisy when it runs?
    What tests did your 'mechanic' do to decide it needed a rebuild? Chances are he did a compression test and found no compression on no3 cylinder. After standing for 10 years there's a good chance piston rings are stuck and possibly a valve, don't know this engine so don't know whether it would mangle a stuck valve.

    I think this thread needs to start afresh from here on as you've had some great replies on seized engines and replacement that are potentially barking up the wrong tree.

    So, tell us what it does and what it doesn't do. What smoke if any out the exhaust, does it smell of unburned fuel? We need evidence my dear Watson!
     
    clivehorridge likes this.
  10. clivehorridge

    clivehorridge Well-Known Member Supporter Guru I am in romania

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    Bravo Rich :clap:

    Buhner may save his 2F yet!!

    I agree, a thrown rod is catastrophic, even if it doesn't venture through the block. It can do all sorts of damage to the bore and even the crank. The engine simply wouldn't run at all, or it would sound like a brick in an empty concrete mixer.

    I've had seized pistons in bores on long standing engines, but as Beau said, you would only know which one with the head off and see which piston doesn't move a fraction when you tension the crank back and forth.

    Often, they do free up with oil left standing on the piston and once you get them running, they bed in just fine.

    If the engine turns, I'd just get it going and then see what the symptoms are, smoke etc., I recon the garage quoting $2,500 was toting for business.
     
  11. pcd

    pcd New Member I am in united_states

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    Wow, there must be a disconnect that I was looking for semi-coherent mechanical opinions and diversions from my actual question. Truly amazing. Answer: you are all wrong, engine has thrown a rod. There is a brick in the cement mixer. I will call the person above for actual data that will get me to a new engine because the global mansplaining network will just regurgitate more nonsense until I do. Best of luck in your future endeavors.
     
  12. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    With an attitude like that best of luck with yours too.

    End of topic for me.
     
    Firewout, hopeless wanderer and Chas like this.
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