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Thread: 4AGE main bearing cap failure - billet option

  1. #1
    Junior Member Grease Monkey
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    Default 4AGE main bearing cap failure - billet option

    I recently had a stock main bearing cap fail on my 4AGE powered AE86 race car. It has cracked accross the cap right down to the bearing shell. In my cas it is probably ecessive revs I think that have caused the failure. My shift point is RPM 8800 but I may have exceeded this by one or two hundred on a few occassions last street sprint at Lakeside.

    I have been toying with the idea for a while that I should look into some billet main caps. Up until now I have not been able to find a supplier and I thought I would have to get them custom made at a huge expence.

    I have come accross a shop in the States that have organised to get a manufacturing run done from ProGram who specialize in this area. They don't normally do the 4AGE but will do a run.

    If you want to get some get in touch with Jeff Burdick from Orion Engineered Motor Werks

    [email protected]

    The cost is $575US. He seems like a good honest guy who is keen to help out. I am not trying to sell his poduct but only trying to help out fellow 4AGE owners. Hopefully the modirators will see it this way also. Feel free to contact me if you need any more info.

    Cheers
    ToddW

  2. #2
    Senior ****** Carport Converter Sam_Q's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    there was a big thread on this a little while ago. One of the options was a pair of hardened steel strips that fit above the main caps

  3. #3
    Junior Member Backyard Mechanic
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    Default Re: 4AGE main bearing cap failure - billet option

    I think a CNC billet 1 piece girdle is the way to go if your spending decent money on end caps. Worked 2J's on standard caps take 1000hp, 1500hp on billet caps, 2000hp on a CNC girdle. I'd agree with Sam that bars to hold the 2 bearing cap bolts firmly together at the same distance made of chrome moly will distribute the load and also reinforce the weak spot that is the thin spot in the dead center and stop these kind of failures as good as a billet caps.

  4. #4
    Senior ****** Carport Converter Sam_Q's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    I do wonder why they would fail at 880 though as that's pretty piss-weak.

    what C.R and rods are you using Todd?

  5. #5
    Junior Member Backyard Mechanic
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    Default Re: 4AGE main bearing cap failure - billet option

    What oil pump are you running? Later ST or BT non cavitating type I hope?

    Dead bearings normally = poor oil pressure.

  6. #6
    AVGAS DRINKING Carport Converter 30psi 4agte's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    What sort of main cap fasteners were you using i wonder ?

  7. #7
    Olde mechanic Carport Converter oldeskewltoy's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    Quote Originally Posted by 30psi 4agte View Post
    What sort of main cap fasteners were you using i wonder ?
    good question


    also... which cap failed #2, or #4?


    here is a photo of strapping in #2 and #4 main caps

    Information is POWER... learn the facts!!

  8. #8
    Gary Motorsport Inc. Too Much Toyota takai's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    I wasnt having any issues with my 4AGE at 8800rpm and higher with the mains caps.... flywheel softness on the other hand.
    -Chris | Garage takai - Breaking cars since 1998
    Sparky - AE86 IPRA Racer | RZN149 Hilux - Parts and Car Hauler
    I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself. - D.H.Lawrence

  9. #9
    Junior Member Grease Monkey
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    Default Re: 4AGE main bearing cap failure - billet option

    I am running ARP stud kit, stock oil pump with shimmed up relief valve, Pauter rods and CR of 11.8:1. Probably saw 9000rpm or so. Cap failure was #4. Let me know your thoughts. I would have thought for a little more money than the Tomei cap strengthing staps the billet caps are the way to go.

  10. #10
    Gary Motorsport Inc. Too Much Toyota takai's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    Problem with the custom caps is that they will need to be undersized, and then the block/cap assembly linebored, hence most people wont be interested as it will significantly add to the cost.
    -Chris | Garage takai - Breaking cars since 1998
    Sparky - AE86 IPRA Racer | RZN149 Hilux - Parts and Car Hauler
    I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself. - D.H.Lawrence

  11. #11
    Junior Member Grease Monkey
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    Default Re: 4AGE main bearing cap failure - billet option

    Quote Originally Posted by takai View Post
    Problem with the custom caps is that they will need to be undersized, and then the block/cap assembly linebored, hence most people wont be interested as it will significantly add to the cost.
    Yes you are correct - for me it isnt an issues as I am doing a full rebuild which will include line bore on the main cap tunnel.

  12. #12
    DIY Bloodline Domestic Engineer Talasas's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    What was your bearing clearance?

    I'm not sure what would happen if the clearance was too tight for those revs.
    "In the beginning, the universe was created. This has made a lot of people angry and has widely been regarded as a bad move." -HHGG

  13. #13
    Im a hopeless Domestic Engineer
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    Default Re: 4AGE main bearing cap failure - billet option

    if it was too tight wouldnt it just heat up and score the bearing?
    -JZX83 in the build
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  14. #14
    Gary Motorsport Inc. Too Much Toyota takai's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    Quote Originally Posted by toddw View Post
    Yes you are correct - for me it isnt an issues as I am doing a full rebuild which will include line bore on the main cap tunnel.
    Yeah, for those of us who build serious NA 4AGs its no issue at all, infact if it was a few months earlier i would be interested. The problem is that to get enough people together for a run will take people who arnt building serious NAs to be interested, and in their case the Tomei caps are probably enough, and they wont want to go to the expense of lineboring a crank.
    -Chris | Garage takai - Breaking cars since 1998
    Sparky - AE86 IPRA Racer | RZN149 Hilux - Parts and Car Hauler
    I never saw a wild thing sorry for itself. A small bird will drop frozen dead from a bough without ever having felt sorry for itself. - D.H.Lawrence

  15. #15
    Junior Member Backyard Mechanic dangdang's Avatar
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    Default Re: 4AGE main bearing cap failure - billet option

    Quote Originally Posted by toddw View Post
    I recently had a stock main bearing cap fail on my 4AGE powered AE86 race car. It has cracked accross the cap right down to the bearing shell. In my cas it is probably ecessive revs I think that have caused the failure. My shift point is RPM 8800 but I may have exceeded this by one or two hundred on a few occassions last street sprint at Lakeside.

    I have been toying with the idea for a while that I should look into some billet main caps. Up until now I have not been able to find a supplier and I thought I would have to get them custom made at a huge expence.

    I have come accross a shop in the States that have organised to get a manufacturing run done from ProGram who specialize in this area. They don't normally do the 4AGE but will do a run.

    If you want to get some get in touch with Jeff Burdick from Orion Engineered Motor Werks

    [email protected]

    The cost is $575US. He seems like a good honest guy who is keen to help out. I am not trying to sell his poduct but only trying to help out fellow 4AGE owners. Hopefully the modirators will see it this way also. Feel free to contact me if you need any more info.

    Cheers
    ToddW
    I might not be doing an N/A build at the moment that would require something as serious as this but I do appreciate the heads up of letting us know of someone that can supply them, and they are a hell of a lot cheaper than a girdle, even with the line boring added in I'm sure.

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