R&D thread for shim-under-bucket conversion!
Thread Starter
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
R&D thread for shim-under-bucket conversion!
OK I know Mazda Comp sells this but I want other options. Because. 
Ok because i'm not a member. fine.
Anyone (Brian you have my head... got calipers?) know the OD and length of the buckets?
The valve stems are 5.96mm for intake or 5.94 for exhaust. Supertech sells a 6mm lash cap which I assume will work.
I remember hearing rumors that the 4AGE buckets were the right size, but rumors aren't guaranteed to open valves.
Here's the part info:
one of those is bound to be our size. or close. or close enough 
Also: at what point do the dual springs become necessary? The Supertech duals are about 50% more seat pressure (74lb) and about 30% higher rate overall.
notes:
Mazda Motorsports "solid lifter" p/n? B6N7-12-183
From a protege site the bucket p/n is: BP2Y-12-183
http://www.maruhamotors.co.jp/miata/...camfornb8.html
thanks guys.
Ok because i'm not a member. fine.Anyone (Brian you have my head... got calipers?) know the OD and length of the buckets?
The valve stems are 5.96mm for intake or 5.94 for exhaust. Supertech sells a 6mm lash cap which I assume will work.
I remember hearing rumors that the 4AGE buckets were the right size, but rumors aren't guaranteed to open valves.
Here's the part info:
Code:
Application Part Number Diameter Length Pad Thickness / Post Weight
Toyota 4AGE 16v CF-28/3.85+ 28mm 23mm 3.85mm + Shim 1.45-3.20mm 26.3 grs
Toyota / Nissan RB26 CF-31/2.7 31mm 24.8mm 2.7mm 28.6 grs
Toyota / Nissan CF-31/3.78 31mm 25.5mm 3.78mm 30.9 grs
Toyota / Nissan / Mazda Duratec CF-31/2.5+ 31mm 25.5mm 2.5mm + Shim 1.45- 3.20mm 29.5 grs
Toyota 2JZ/3SGTE/1ZZ/Scion/ CF-31/3.28+ 31mm 25.5mm 3.28mm + Shim 1.45-3.20mm 31 grs
Tacoma 2RZ-3RZ/Nissan RB26
Opel/Peugeot oversize CF-32.5/2.5 32.50mm 23.1mm 2.54mm 26.3
BMW CF-33/ 14 33mm 26mm 14mm 33 grs
BMW CF-33/2.9 33mm 26mm 2.92mm 33 grs
BMW CF-33/3.0 33mm 26mm 3.0mm 33.2 grs
Nissan / Subaru H6 (1st Gen) CF-34/2.5+ 34mm 26mm 2.5mm + Shim 1.45- 3.20mm 32.4 grs
Nissan KA24 CF34/3.5+ 34mm 26mm 3.5mm + Shim 1.45- 3.20mm 33.5 grs
Nissan 350Z/ VQ35 CF34/6.5+ 34mm 21mm 6.5mm + Shim 1.45-3.20mm 34 grs
VW / Subaru CF-35/2.8 35mm 26mm 2.8mm 36.5 grs
VW / Subaru / Sierra Cosworth CF-35/3.3 35mm 26mm 3.3mm 36.6 grs
VW / Subaru EJ20-EJ25 CF-35/ 2.7+ 35mm 25mm 2.7mm + Shim 1.45- 3.20mm 35.2
VW / Subaru EJ20-EJ25 CF-35/ 3.7+ 35mm 25mm 3.7mm + Shim 1.45-3.20mm 38.2
BMW M12/ S14 (Long valve) / VW CF-37/3.3 37mm 26mm 3.3mm 40 grs
BMW M12/ S14 (Long valve) / VW CF-37/3.6 37mm 26mm 3.68mm 40.6 grs
BMW M12/ S14 (Long valve) / VW CF-37/3.9 37mm 26mm 3.90mm 40.9 grs
Valve Lash Caps
LC-55 / LC-60 / LC-65
5.5mm / 6mm / 6.5mm
Several thicknesses 1.2 - 1.6 grs
Also: at what point do the dual springs become necessary? The Supertech duals are about 50% more seat pressure (74lb) and about 30% higher rate overall.
notes:
Mazda Motorsports "solid lifter" p/n? B6N7-12-183
From a protege site the bucket p/n is: BP2Y-12-183
http://www.maruhamotors.co.jp/miata/...camfornb8.html
thanks guys.
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No idea if this is relevant or not, but I ran across this post over an mnutter regarding potential interchange between Miata, Zetec, Duratec (MZR), and Honduh springs (and lifters).
http://forum.miata.net/vb/showpost.p...9&postcount=24
Scroll about halfway down the post for the details, including "graded" solid lifters that don't require shims.
http://forum.miata.net/vb/showpost.p...9&postcount=24
Scroll about halfway down the post for the details, including "graded" solid lifters that don't require shims.
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Any 6mm shims will work. I used a set of 16 off ebay made for a chevy. Cost $30 shipped.
You can get teh mazdaspeed lifters through MiataRoadster.com for only $200. For that price I wouldn't bother searching for other methods.
Glad to be of service.
You can get teh mazdaspeed lifters through MiataRoadster.com for only $200. For that price I wouldn't bother searching for other methods.
Glad to be of service.
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I've got an entire mazdacomp shim under bucket valve train from 99 cylinder head (springs and cams). They're stuff we ran in the motorola/grandam cup. I put them up on miatanet classifieds but got nothing but wieners.
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Rob--we were discussing your cams, but never really got to terms. If you have a price in mind for the whole set up, shoot it my way. Honestly, all my spare change is going to the block right now, but maybe...
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I'd assume that setup is too hard core for a street car?
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Randy Stocker was telling me it would be pretty bad *** for a boosted street car actually. 
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brian (neogensis "i've awaken the beast") has a good description of what it's like trying to get cams like this to idle - a lot can be tuned out, tho still lumpy compared to a stock cam. BUT with a turbo car and reduced overlap it shouldn't be as bad. I never ran these on the street, but on the track way up in the rpm they were just badass.
Without the cams, the valvetrain would be fine IMO. It's far lighter than the stock setup and will spin way easier.
Sorry about that Ben - totally forgot. I'll hang on to that stuff for your engine, just totally spaced.
Without the cams, the valvetrain would be fine IMO. It's far lighter than the stock setup and will spin way easier.
Sorry about that Ben - totally forgot. I'll hang on to that stuff for your engine, just totally spaced.
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Thread Starter
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
i already sent the money to billwilner for the buckets. just need to find brian-neo's source for the cheap lash caps.
Brian, did you get all one size or custom sizes to fit your specific application?
Brian, did you get all one size or custom sizes to fit your specific application?
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^Totally gonna show my *** here. I understand how shim under bucket works... but exactly what is the advantage over the current configuration of the valvetrain. What is this gonna buy you? What is the advantage?
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Thread Starter
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
I can deal with grinding my own caps I guess... I've got the sharpeners
Sam, the benefits are mostly reduced weight and the ability to run higher lift cams with less liklihood of destruction...
Normal shims are big quarter-sized things that are kinda heavy compared to the pea-sized lash caps used with shim-under-bucket. Plus at high rpm with big cams, if you float the valves, those standard shims are no longer captured by anything and can slip out from under the valves and do bad things.
but mostly the lower reciprocating mass means the valvetrain can handle higher speeds.
Sam, the benefits are mostly reduced weight and the ability to run higher lift cams with less liklihood of destruction...
Normal shims are big quarter-sized things that are kinda heavy compared to the pea-sized lash caps used with shim-under-bucket. Plus at high rpm with big cams, if you float the valves, those standard shims are no longer captured by anything and can slip out from under the valves and do bad things.
but mostly the lower reciprocating mass means the valvetrain can handle higher speeds.
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You dont risk spitting the tiddly-wing stock shims at high RPM, wich could damage the head. Its also lighter, which is a big deal at those RPM's.
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.
Sam, the benefits are mostly reduced weight and the ability to run higher lift cams with less liklihood of destruction...
Normal shims are big quarter-sized things that are kinda heavy compared to the pea-sized lash caps used with shim-under-bucket. Plus at high rpm with big cams, if you float the valves, those standard shims are no longer captured by anything and can slip out from under the valves and do bad things.
but mostly the lower reciprocating mass means the valvetrain can handle higher speeds.
Normal shims are big quarter-sized things that are kinda heavy compared to the pea-sized lash caps used with shim-under-bucket. Plus at high rpm with big cams, if you float the valves, those standard shims are no longer captured by anything and can slip out from under the valves and do bad things.
but mostly the lower reciprocating mass means the valvetrain can handle higher speeds.
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Thread Starter
Joined: Jun 2005
Posts: 19,338
Total Cats: 574
From: Fake Virginia
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