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Thread: 4AG headwork, now block too

  1. #46
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork

    I've been "playing" with these heads for about 8 to 10 years now....... I'm no expert... but I'm not a layman either.........

    I practiced on 2 junk heads first..... and this was what I used.....

    Dremel - A tungston carbide round for cutting down the shrouds. Then a Pink, or white stone, arrow shaped, for the first stage of smoothing after the carbide cutter. 320 wet/dry sandpaper to blend where the stones wouldn't. Then new Dremel tip "finishing abrasive buffs" Then I went to the polishing cone with the compund given... then I finished with a 1" felt wheel using Mothers wheel polish as the last bit....
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  2. #47
    Junior Member Grease Monkey
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    Default Re: 4AG headwork

    Would deshrouding a 4AGE head with forced induction yield little gain except to prevent pre-ignition/hot-spots ?

  3. #48
    ......... Carport Converter jeffro ra28's Avatar
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    Default Re: 4AG headwork

    Quote Originally Posted by oldeskewltoy
    Hmmmm, a photo of OEM 9.4 to 1 piston(on the left), and OEM 10 to 1 piston....



    more surface area??? better heat dissipation?
    Yes a cast surface has more surface area. As for better heat dissipation that was just a wild guess. I never said it actually did anything.

    Still i hardly doubt that polishing a cast surface is going to decrease compression ratio by any more then .01 of a unit of compression.

  4. #49
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork

    The engine has been @ Loyning Engines. There is a reason why I chose Loyning.....




    here is a shot down the exhaust port


    The only change on the horizontal part of the intake port is a flair at the outer gasket surface.... this flair is less than 10mm deep into the head... from that point to the transition it was left stock...

    Intake multi angle


    exhaust multi angle


    Comparison of chamber edge before and after..... was 37cc, now 33cc


    The head is done!
    Last edited by oldeskewltoy; 19-07-2008 at 06:02 AM.
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  5. #50
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork, now block too

    Well, there is usually a block that goes along with a head,




    You may have spied the high compression TVIS pistons...




    or the more recent thread "Wrist Pins".


    I've been putting together another frankenmotor(mixing/matching) This time I'm using the matching block for the smallport head. The smallport block WAS equipped with squirters,.... Yes, WAS, because the internals are not smallport, but large port, and largeport high compression CAST pistons are not made for squiters.

    Why use largeport - actually more correctly 3 RIB(40mm rod jounal crank) internals... (for some largeport engines did come with 42mm rod jounal cranks) There are a few reasons I chose 40mm internals...
    1) early 4AGEs are reputed to rev easier... the small journal is one of the reasons... less total surface area... less drag. Yes, I am giving up some strength, but there were many 150+hp early engines with little of no issues...



    2) besides a savings do to less drag, the 40mm crank is a KILO LESS than the 42mm crank, Not only do you save a kilo on the crank... but you save 66 grams per rod...



    I finally did have custom pins made... stock ones have a mass of 89 grams, these will be 64 grams, that is a savings of another 25 grams



    Since I'm waiting on the pins, the block is not yet finished.... but heres a trick being done... overbore and hone will occur while the block is at operating temp.

    Here's a shot of the crank awaiting final assembly...

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  6. #51
    Your mum is a Conversion King TERRA Operative's Avatar
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    Default Re: 4AG headwork, now block too

    You going to knife edge that crank?
    Sorry guys, I'm living in Japan so I can't do ECU repairs for the time being.
    Tereno Empireo Rapidmova Reakcii Armeo
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  7. #52
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork, now block too

    Quote Originally Posted by TERRA Operative
    You going to knife edge that crank?
    No need to since the crank doesn't spin in the oil....
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  8. #53
    ......... Carport Converter jeffro ra28's Avatar
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    Default Re: 4AG headwork, now block too

    agreed, knife enging is totally overatted on particular engines with a high crank.

  9. #54
    Your mum is a Conversion King TERRA Operative's Avatar
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    Default Re: 4AG headwork, now block too

    I didn't think any cranks spun in the oil, due to problems with foaming the oil.

    I was led to believe that knife edging reduced the resistance to spinning the crank by making the crank more aerodynamic as it passed through the oil-laden air in the crank case, also reducing windage, but I guess a high crank will do the same.
    Sorry guys, I'm living in Japan so I can't do ECU repairs for the time being.
    Tereno Empireo Rapidmova Reakcii Armeo
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  10. #55
    Balloon Slayer Backyard Mechanic jimmmayyy's Avatar
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    Default Re: 4AG headwork, now block too

    More to do with reducing rotational mass than reducing resistance.

  11. #56
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork, now block too

    While waiting for the 64 gram pins..... AND after reading Bill's opinion on ceramic coating...

    I asked Loyning's if we could add a ceramic coating to the piston head. He told me that as of now the piston to head clearance is too tight to add a ceramic coating! He explained that a proper depth to a ceramic coating would be .003" (~.1mm), and as of right now there isn't enough clearance for the addition of a .003" coating to the piston top.

    Because I am running full skirted pistons he did recommend a skirt coating to further reduce drag.....


    sorry about the poor pic quality
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  12. #57
    SC14 7AGZE Grease Monkey
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    Default Re: 4AG headwork, now block too

    Im running GZE pistons which are already ceramic coated, but I really wanted to coat the skirts on my pistons, but am still unsure how much impact it will really have.

    Any more info or advice from Loynings?
    SC14 7AGZE build: http://beasted86.webs.com/

  13. #58
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork, now block too

    Quote Originally Posted by turbo4agte

    Any more info or advice from Loynings?
    concerning??????
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  14. #59
    ......... Carport Converter jeffro ra28's Avatar
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    Default Re: 4AG headwork, now block too

    Geez oldskewl you must have tight squish not to allow an extra .003"!!!!

  15. #60
    Olde mechanic Automotive Encyclopaedia oldeskewltoy's Avatar
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    Default Re: 4AG headwork, now block too

    Quote Originally Posted by jeffro ra28
    Geez oldskewl you must have tight squish not to allow an extra .003"!!!!
    I DO expect the squish to be snug... but I'm guessing that they have a tolerance/minimum they want to keep and the .003" would intrude into that tolerance.

    I know they are sticklers for tolerance... it took me 6 weeks to find a press fit wrist pin that was .001" inch...larger than the rod bore. They didn't want, nor feel comfortable with a .0008", or .0009"....
    In my opinion, that is having a tolerance and sticking to it........
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