406 Rebuild

Discussion in 'High Performance Modifications' started by 1980RS, Sep 19, 2018.

  1. 1980RS

    1980RS Veteran Member

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    This week I had time to teat my old 406 short block apart. Now this engine has over 400 passes on it so before I blow it up I decided to tear it apart and re-ring and bearing it.
    I bought this from a builder which I do not normally do. It was .030 and balanced but the crank was not .010 like he said and the bearings show that. It is a cast crank (no biggie for me) with 5.7 rods with .200 TRW forged pistons. Everything looks good but the bearings. Surprisingly the crank is in mint shape for being STD. Discus the rod bearing pictures.
    View attachment 65002
     

    Attached Files:

  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    If you blow it up and look close... It looks like road kill. :roadkill:
     
  3. tom3

    tom3 Veteran Member

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    I'd say you caught that just in time. I'd take the crank to a good shop for a polish, or regrind, as needed. And take a look at the type oil used and/or pumping. Experts say too much oil flow is not a good thing?
     
  4. 1980RS

    1980RS Veteran Member

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    I was thinking the same thing as I use 20W50 racing oil but have now switched to 10-30 or 10-40. I was told to also use aluminum bearings and not to use tri-metal bearings on a cast crank so I am not sure. I do know one thing no more HV oil pumps for me stock is fine after talking with my NHRA stocker friends.
     
  5. cadillac_al

    cadillac_al Veteran Member

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    I have seen some pretty funky bearings come out of perfectly good running high mileage engines. They don't always wear smooth and pretty. I still think you caught it just in time though. I would be curious enough to plastigage the old bearings (at least a couple). If the crank still looks mint, since I'm cheap, I would buy some new bearings and plastigage them. If they are in spec I would run it.
     
  6. NYH1

    NYH1 Veteran Member

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    I run a Mellings 10552 oil pump, it's stock pressure with 10% extra volume. I get 15-20 psi. at idle and about 10/12 psi. per 1000 RPM's after that with 10w-30 synthetic oil.

    NYH1.
     
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  7. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    I never recommend a hi-volume oil pump on a small-block. High volume won't help anything but will do a nice job of emptying the oil pan into the valve covers.

    I'd have to wonder if you just got a bearing that was off a little out of the box before.

    If you ask me, dry-film coating on bearings is cheap insurance
    http://www.polydyn.com/bearings
     
  8. 1980RS

    1980RS Veteran Member

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    Ya, I will not use HV pumps anymore as you are right they are not needed. I did not build this one, bought it from a builder and it was the first time but I was in a pinch for a new short block and the price was right. I know when I tore my 358 apart a few years ago that has almost as many runs on it the bearings looked a ton better than these ones did. Waiting for my new bore gauge to show up then I will check some specs, as I hate using plasti-gauge.
     
  9. Mullerice

    Mullerice Member

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    If you chaps are up for it, I’d like some educating here. If HV Pumps offer no advantage, why are they available? Clearly it would be folly to pump oil out of the pan faster than it can return via gravity (wet sump setup); but would a larger capacity oil pan married to a higher volume pump offer any advantage?
     
    Last edited: Sep 26, 2018
  10. jeff swisher

    jeff swisher Veteran Member

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    Some of my friends like the HV pumps and have never had any issues with them.
    I like the old M55 and now the 10552 is what I have used many times now.
    1980RS that looks like what is on page 5.
    http://www.speedperf6rmanc3.com/content/Engine Bearings.pdf

    Many times additives can kill the oils ability to perform well.
    Shear is a big issue with oil when you get into high output stuff.
    I was always worried about shear strength and if I beat on my car or bike hard it may only have the oil in it for 2 days and it got changed.

    I have ran FM and clevite 77 bearings on cast cranks for many years and never had any issues.
    I built my own stuff though and ran quality high zinc oils always. You need it for more than just flat tappet lifters you know.

    I will also add I have ran my personal 350's with 12+ compression and 7500 plus RPM on daily basis and never had a Clevite or FM bearing look worn Cast cranks were used.
    Tune was on the money. and my stuff never got hot.

    Many variables.
    I did have a fluid damper eat the front bearing 2 times in a row before I replaced it with an elastomer one.
    I think the cold weather may have froze the stuff inside or made it not work well. No idea but I scratched my head wondering what was up with bearing wear as I had built many the same way and the only thing different was my buddy wanted that damper.
    Everything was spot on including line hone and balanced and resized rods ARP everything and crank was index ground.. nothing spared in the machine work.
    The bearings lasted a month and then slight knocking.
    After the damper switch and 3rd set of bearings it lasted many years and a couple head and cam swaps.
    I purchased it from him when he went LS and I have beat on it for a few thousand miles and 7000 rpm shifts.
    His shifts were 7500.
    He had an M55 HV pump in it. Bearings were fine. cast crank in it also.
    Has an old M55 in it now.
     

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