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Technical Aluminum vs steel Pistons s

Discussion in 'The Hokey Ass Message Board' started by ERguitar, Nov 30, 2021.

  1. ERguitar
    Joined: Aug 26, 2018
    Posts: 149

    ERguitar
    Member

    Hey guys guess who has 7 steel pistons and 1 aluminum for my 81a? This guy.
    I needed 1 replacement and didn't realize there was a difference that it was possible to get (stock pistons).
    Will it make a difference? How about types of rings? It's a stock motor that I'm doing a quick rebuild on. Any advice?
     
  2. oldiron 440
    Joined: Dec 12, 2018
    Posts: 2,562

    oldiron 440
    Member

    I must be dumb, I've never heard of aluminum piston rings....
     
  3. 41rodderz
    Joined: Sep 27, 2010
    Posts: 5,718

    41rodderz
    Member
    from Oregon

    One aluminum piston .
     
  4. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 9,581

    Johnny Gee
    Member
    from Downey, Ca

    I'd be more worried about weight difference of the one piston.
     

  5. Easy ... put aluminum rings on the steel pistons and steel rings on the aluminum piston. If my math is correct, that will help with the balance issue :D

    Keep in mind, this is really just an umeducated guess ;)
     
    Deuces, 302GMC and Boneyard51 like this.
  6. Boneyard51
    Joined: Dec 10, 2017
    Posts: 5,361

    Boneyard51
    Member

    I was misled , also! But back in the day a lot of “ do what you got to do” went on! Times were hard!
    Today , as a hobby, we tend to fix things “ perfect”.




    Bones
     
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  7. squirrel
    Joined: Sep 23, 2004
    Posts: 50,301

    squirrel
    Member

    Weight them....and think about how much shaking you'd be happy with.
     
  8. lippy
    Joined: Sep 27, 2006
    Posts: 5,820

    lippy
    Member
    from Ks

    So the steel pistons your talking about are iron ones like a model T or A? Lippy
     
  9. gary macdonald
    Joined: Jan 18, 2021
    Posts: 189

    gary macdonald
    Member

    The steel pistons are actually lighter than factory ford 4 ring aluminum pistons . The ring on the steel pistons are usually very high compared to the aluminum.
     
  10. G-son
    Joined: Dec 19, 2012
    Posts: 874

    G-son
    Member
    from Sweden

    Get the right stuff. Compare the upsides of successfully using the wrong piston, with the downsides of putting it all together with the wrong piston and then being forced to tear it down, getting the right one instead, buying gaskets etc. and putting it back together one more time.
    Are you really that lucky, so you think it would work good enough with mismatched pistons? I'm not... ;)
     
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  11. Fordors
    Joined: Sep 22, 2016
    Posts: 3,971

    Fordors
    Member

    Actually for a few years flathead Ford V8’s and Lincoln V12’s did have steel pistons, but I don’t understand why Ford engineers felt that was a good idea.
    There was a guy that went to the other extreme one time. Austin Coil had John Farkonas design titanium pistons for the Chi-Town Hustler. They were machined by one of the Chi-Town’s behind the scenes players, Corvin Latus, but Coil was out of town and the pistons went into the wrong block that didn’t have the right piston to wall clearance. They never tried that again.
     
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  12. squirrel
    Joined: Sep 23, 2004
    Posts: 50,301

    squirrel
    Member

    look on ebay for nos or used pistons....you might get lucky
     
  13. Put them on a scale one at a time,and see what the individual weight is. If the two materials are close you might be able to balance to produce a set.Will the two materials react to heat different? Could be. If you try it check where the pin is located to make sure you end up with the same compression.
     
  14. finn
    Joined: Jan 25, 2006
    Posts: 932

    finn
    Member

    Lots of steel pistons used in modern Diesel engines. They can withstand higher firing pressures and cylinder temperatures.

    I wouldn’t recommend mixing them in an engine, though. Pistons shouldn’t be that hard to source unless it’s something really odball.
     
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  15. ERguitar
    Joined: Aug 26, 2018
    Posts: 149

    ERguitar
    Member

    Thanks all for the input. I suspected that it was going to be an issue but a guy can dream. Didn't even occur to me to check until I was looking online for rings and saw a vintage set in original packaging referencing "for steel pistons". Even if by some chance the weight isn't a factor and I could come up with a balanced set of pistons I am interpreting the "steel piston" reference to mean that I would need two different sets of rings (btw I haven't seen a set "for aluminum pistons"). It took me quite awhile to find this single stock bore piston so I'm not looking forward to resuming the search. Thanks again.
     
  16. squirrel
    Joined: Sep 23, 2004
    Posts: 50,301

    squirrel
    Member

    Do you have all the pistons in front of you so you can compare them?
     
  17. ERguitar
    Joined: Aug 26, 2018
    Posts: 149

    ERguitar
    Member

    6 are still in the motor. I removed one to compare it to the one I bought ( one was missing when I bought it.) I have checked the them all with a magnet though. I will probably pull them all out tonight.
     

  18. Back to the clinic for you!!!
     
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  19. squirrel
    Joined: Sep 23, 2004
    Posts: 50,301

    squirrel
    Member

    Might want to check the ring widths, pin location, etc. And see if you can find a scale of some sort, to compare weight.
     
  20. gary macdonald
    Joined: Jan 18, 2021
    Posts: 189

    gary macdonald
    Member

    Were you the one that needed std pistons flat top steel ? If so I found a set . Yes by the way they are set up to different clearances . And ring depth ( if I remember correctly) is different as are pin clearances . The steel pistons with liners were a great easy rebuild forever idea , it would still be viable IF ford still made the sleeves and pistons . No machine work would be needed to resleeve your block with new pistons . It could all be done at home . If only
     
  21. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,204

    ekimneirbo
    Member
    from Brooks Ky

    How much can 1 piston cost ? Might be time to revive the "worst mechanic" thread.:(
     
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  22. ERguitar
    Joined: Aug 26, 2018
    Posts: 149

    ERguitar
    Member

    Not sure I appreciate your implication. To me it's a valid question, I haven't done it and I haven't said I was going to do it. BUT aside from the absolutely valid points regarding weight/balance and wrist pin location what is the worst thing that can happen all things being equal? I admit it would drive me a bit crazy knowing 1 of these 8 things is not like the others (aluminum vs steel). The motor has 1 ford patent crack, virtually no wear on the bores and the bearings look like new. As I stated it was only missing 1 piston (?) In my mind not everything needs to be immediately bored and brought up to Lexus specs if it's still reasonably good, hence my attempt to buy a single piston and move on. I'll keep looking for a steel piston or maybe buy a matching set I suppose.
     
    Last edited: Nov 30, 2021
  23. buick bill
    Joined: Dec 18, 2008
    Posts: 787

    buick bill
    Member
    from yreka;ca

    doesnt hurt to ask others their opinion . dont mean any one of us will agree on anything . i dont think it would be wise to mix/match . sit back and think on it . do overs really suck ! dont ask how i know . ...i try to do shit right and it still goes bad most the time . the odds are against you if your sure its NOT right .............aint faster , cheaper or easier when ya go back in !
     
  24. squirrel
    Joined: Sep 23, 2004
    Posts: 50,301

    squirrel
    Member

    heh...I wound up putting a .040 piston in the Hudson a couple years ago, it had three different sizes!

    So leave him alone, and give me the worst mechanic award.
     
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  25. lostone
    Joined: Oct 13, 2013
    Posts: 1,866

    lostone
    Member
    from kansas

    I wouldn't mix and match either BUT if you do and it works out perfectly run out quickly and buy several lottery tickets!!
     
    WB69 likes this.
  26. Sometimes these things aren’t as difficult/important as we like to make them eh?
     
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  27. ERguitar
    Joined: Aug 26, 2018
    Posts: 149

    ERguitar
    Member

    Ok. let's sum this up, I " probably" won't do it but I have to admit that at this point no one has told me what could actually go wrong (aside from balance and wrist pin location) . Is it "correct"? , no but even in my very limited flathead experience I have yet to see something that doesn't make you scratch your head a bit on almost every motor , yet was functioning perfectly well. Bottom line I don't put 25000 miles a year on my cars and don't pretend that I ever will. In fact, at this point they will most likely be obsolete (no gas etc) long before they wear out. I don't even have a project for this motor. Again, I understand that everyone wants to portray that they are the perfect mechanic, cost is no option etc. I weighed the aluminum vs steel piston/rod and it is 23 grams difference, sounds like a lot to me but I have no actual factory baseline to compare that to, but I have to admit that at this point it's tempting to pull every piston, match the aluminum one up with a steel one that is close and see what happens. AND if we are giving worst mechanic awards to @squirrel Then I retract my earlier reservations, in fact I demand that I get one too.
     
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  28. lostone
    Joined: Oct 13, 2013
    Posts: 1,866

    lostone
    Member
    from kansas

    Several things would worry me, first off is any weight differences, second is the way the 2 metal dissipate heat differently, and last the different rates the metals expand while absorbing heat.

    While this might not matter in this situation, when dealing with the cost involved and the rarity of the parts involved I would take any precautions I could to protect both the cost and the parts.

    Not only that but the time and energy involved.
     
  29. squirrel
    Joined: Sep 23, 2004
    Posts: 50,301

    squirrel
    Member

    The balance is the only thing that's really a problem.....it doesn't really matter if the pistons operate at different temperatures or clearances, does it?
     
  30. lippy
    Joined: Sep 27, 2006
    Posts: 5,820

    lippy
    Member
    from Ks

    It's very hard to help someone that feels he already has the answer. And this is not meant to be a smart ass answer either. :D Lippy
     
    warhorseracing likes this.

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