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Technical Bead blasting an engine block

Discussion in 'The Hokey Ass Message Board' started by ekimneirbo, Feb 24, 2021.

  1. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,216

    ekimneirbo

    Making some preparations for getting a block machined and I inquired about baking the block and then having it bead blasted. The shop told me if I had it blasted it would need align honing and decking after the blasting. I had not heard of this before and in this particular case I really don't want to align bore the mains because it creates some slack in the timing chain and there are no smaller chains available for it. What have your experiences been?:)
     
  2. Moriarity
    Joined: Apr 11, 2001
    Posts: 30,773

    Moriarity
    SUPER MODERATOR
    Staff Member

    Bead blasting peens the material and effectively changes the size of things much like knurling. Why do you want to bead blast a block? I would think it would be tough to get all the beads out of all the passages...
     
  3. Baumi
    Joined: Jan 28, 2003
    Posts: 3,043

    Baumi
    ALLIANCE MEMBER

    I would not do it, just because of what Mark stated. Imagine there could be some oil or grease residue in an oil passage and the beads will stick there. Imagine also you won´t be able to clean out 100% of it. And sooner or later, when the engine is running again, the stuff will break loose and take a trip through your new bearings... Not sure about the surfaces, but if your shop guys say better not, I´d follow what they say.
     
  4. Baumi
    Joined: Jan 28, 2003
    Posts: 3,043

    Baumi
    ALLIANCE MEMBER

    And, with alignboring, they usually keep the crank- camshaft-centerline distances as they are , grinding off material from the main caps, bolting them back to the block and boring the caps back into a round shape. Never did that myself, but it´s how I understood it is done. You shouldn´t have any slack in your timing chain after an align bore.
     

  5. RichFox
    Joined: Dec 3, 2006
    Posts: 10,020

    RichFox
    Member Emeritus

    The shop I worked with always did just what you are asking about. Ended up with the cleanest block I ever saw. No residue and no line boring, This is with steel shot. Bead blasting usually means glass beading. Which I have done on plenty of aircraft parts and my own turbocharger compressor housing and wheel. Never hurt anything and set several SCTA Bonneville and El Mirage records. Reading Randy's post made me change this one to Steel Shot. That is correct
     
    Last edited: Feb 24, 2021
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  6. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,138

    57JoeFoMoPar
    Member

    The only way I'd consider any sort of blasting on an engine is if the engine were basically all together and sealed off. Valve covers on, valley pan in, gasketed up...the whole 9, to prevent any of the media from getting inside.

    I'm going to assume that you want to do this in anticipation of paint on the engine. None of the people I know who have painted engines for full show cars have blasted the block, and instead have used some combination of wire brushes, roloc discs, carbide burrs, etc., sanding wheels, an so on, on a die grinder. From there they've primed with a 2K epoxy and auto paint no different than the car's body.
     
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  7. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,672

    Jmountainjr
    ALLIANCE MEMBER

    Talk to the shop. Baking and shot blasting as been used for some time, but today there about a dozen things you can do to clean the block after baking, or not: soda blasting; wet blasting; air less blasting; ultrasonic; solvent blast; etc. Ask how they prefer to get your block clean to meet your needs and minimize after cleaning machining.
     
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  8. BigDogSS
    Joined: Jan 8, 2009
    Posts: 979

    BigDogSS
    Member
    from SoCal

    2015-07-02 16.03.15.jpg IMO, a good machine shop has the ability to get your block 100% clean without having to ask. Here is my 327 block.
     
    Last edited: Feb 24, 2021
  9. Unique Rustorations
    Joined: Nov 15, 2018
    Posts: 623

    Unique Rustorations
    Member

    I had this very rusty looking block tumble-cleaned.
    This machine shop uses it often and recommends it in rusty applications. It uses steel shot. No other machining was required. I did stud the mains and had it line bored but that was my choice.

    Randy

    IMG_8870.JPG


    Sent from my iPhone using H.A.M.B.
     
  10. Joe H
    Joined: Feb 10, 2008
    Posts: 1,525

    Joe H
    Member

    Degrease it, then sand blast, then power wash, all before sending to the shop. It was cast in sand, so cleaning it shouldn't be any different now then when it was made. Any shop worth using should be able to clean a block of all oils and sludge. And you should always clean it before assembly using brushes and soaps.
     
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  11. 73RR
    Joined: Jan 29, 2007
    Posts: 7,174

    73RR
    Member

    It sounds to me like an extra step that likely isn't needed. As richfox notes, bead blasting usually indicated glass beads and given the very small size unlikely to peen any metal or change anything on/in a block. 'Media' blasting usually refers to any other particulate such as walnut shells, again, hard to imagine doing any structural damage...
    If all you are try to do is insure a clean block then a good 'ol hot tank with a fresh charge should do the job.
    As with any cleaning process, you will want to follow with a steam or hot water flush and possibly a second dip/flush.
     
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  12. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,138

    57JoeFoMoPar
    Member

    I'm not ashamed to admit I've (recently) eaten off of things dirtier than those last 2 engines.
     
  13. SEAAIRE354
    Joined: Sep 7, 2015
    Posts: 537

    SEAAIRE354
    Member

    You mentioned the ship said align honing which will shorten up the chain some. That may be the only method the shop has. As said if it is align bored then yes you indicate of the block and take the majority of material of the caps and minimal from the block. SHOT blasting after baking is common but the shop should have a shaker that the block goes into and removes all shot. I don’t believe you mentioned your reasoning behind wanting this done. If the inside is clean and not a ball of rust then the outside can be done with the usual methods. If the inside is a problem I’ve had great luck with doing the best by hand and painting it with glyptol. And naturally all the oil passages need to be spotless.


    Sent from my iPhone using H.A.M.B.
     
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  14. squirrel
    Joined: Sep 23, 2004
    Posts: 55,934

    squirrel
    Member

    My experience bead blasting iron parts that bolt to the block, such as heads and main bearing caps, is that it does not change the dimensions or surface finish in a way that would require it to be re machined.

    I have no idea what the guys at that shop are smoking.
     
  15. Do not bead blast, if you do anything at all soda blast it. Before hot tanking.

    The block should not need align boring if you keep away from the main bearing saddles or protect them. As for the decks a minimal whack would clean them up, maybe even a little time with a DA would clean them enough to for a gasket to seal.

    More often then not hot tanking will remove the paint or most of it then a cup brush and an angle grinder will clean it the rest of the way off.
     
  16. Is it possible that "baking" the block could tweak the alignments to some degree?
     
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  17. Not likely. Of course anything is possible.
     
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  18. lake_harley
    Joined: Jun 4, 2017
    Posts: 2,159

    lake_harley
    Member

    I wonder if we're all talking about the same process. Isn't there a process that uses larger steel shot to clean? I've always thought if it as being more like shot peening. Perhaps that's what the shop is thinking? If it is, I could see that dinging some stuff up if they use very high pressure.

    I'd share the same opinion as a couple others though on actual "glass beading" not being a problem. I think the beads would break before they'd do any serious damage. I just did a pair of heads, so I hope I'm thinking right!

    Lynn
     
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  19. egads
    Joined: Aug 23, 2011
    Posts: 1,419

    egads
    Member

    Interesting. Done correctly it doesnt sound like it's any problem.
     
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  20. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,910

    dirty old man
    Member Emeritus

    The You tube video above stole my thunder, LOL!! Exactly what was done on the last engine I built (for my Hiboy), except I also had a align honing job done on the mains and decked it for optimum quench clearance of .035" from head to piston top.
    The align honing process doesn't require as deep[ of a cut as align boring, so a shorter timing chain isn't needed.
    IMO, if it's going in a hot rod that's going to be driven like a hot rod, then you need to make sure all is OK before you put it together.
    With the price of parts nowadays plus the worth of the time to redo the job if it fails, it's cheaper in the long run.
     
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  21. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,299

    oldiron 440
    Member

    I have my 440 block and heads Magnafluxed every refresh, the last time it had been years so this dictated removal of all rust and paint, in the tumbler they went. I'm not sure what all the concerns are, you clean all oil galleries, blow out water jackets run taps on threads etc. and wash after whatever else you need to do, you would do this anyway.
     
  22. doyoulikesleds
    Joined: Jul 12, 2014
    Posts: 306

    doyoulikesleds

    we had an ampro cleaning system back at 500 blast in its airless blaster for 10 min with stainless shot then tumble to remove any shot. worked great only extra work was you had to run a broch or ball hone through the lifter bores because it would some times cause a very small lip on the tops. you could clean the main bores to shinney with a few seconds with a schotbrite pad and the decks where just blocked with some 80 grit
     
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  23. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,216

    ekimneirbo

    You are correct. I should have said "shot" instead of "bead". Thanks for pointing that out.:)
     
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  24. Fiftyplus
    Joined: Jan 8, 2010
    Posts: 10

    Fiftyplus
    Member

    Shot blasting will do a great job cleaning a engine block. It will also remove the factory broach marks on the engine pad that are a judged item in some of the chevy and corvette organization. You would need to protect this area if its important to you or a future buyer.
     
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  25. Budget36
    Joined: Nov 29, 2014
    Posts: 13,173

    Budget36
    Member

    Did I miss the intent of blasting the block? I’m curious for what @ekimneirbo wants to do.
     
  26. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    56sedandelivery
    Member Emeritus

    @With modern EPA requirements. a lot of shops have had to go with the shake and bake method; I had not heard of blasting a block with anything unless it was corroded. I'd rethink what you want to do. I am Butch/56sedandelivery.
     
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  27. doyoulikesleds
    Joined: Jul 12, 2014
    Posts: 306

    doyoulikesleds

    did this to lots of blocks heads and even some cranks but they where getting ground
     
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  28. Every time you align hone a block, you will remove some material from the block. If the block has been done several times, you will have a problem. Depending on how much damage was done to the mains such as spun bearings, you may have to cut the caps more than 10 thousandths. You're going to cut into the block several thou to make the bores round. It doesn't take much in center to center dimension changes to make a chain looser.
     
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  29. Joe H
    Joined: Feb 10, 2008
    Posts: 1,525

    Joe H
    Member

    Hot tanks are on the way out, around here ( Kansas City ), it's getting hard to find someone to hot tank. They all are going to the jet wash which only removes loose paint, grease, and oils. To get a bare metal block, heat and blasting, or elbow grease with wire wheel is the only way to get down to bare metal. Watch any of the Redline rebuilds from Hagerty on youtube and you will see the heat and blast cleaning method being used. They don't do any special machining because of the cleaning method.
     
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  30. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    Shop around here uses a barrel with I guess water or something they lower the block in then use an electrolosis (sp) process. He said the old harsh chemicals are no longer. Lippy
     
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