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Discussion Starter · #1 · (Edited)
okay so here is the deal. i had my cams ground to the hks 264 specs. they took off .035" (.889mm). when i checked the clearance on the shims they were .035" off all around. so i checked to see if they make shims large enough to make up for the metal that was ground off the cams- they don't.

so, this is where i stand: i have a almost stock head that was rebuilt (new valve guide seals, etc.), stock valves, stock springs, and a set of reground 264 cams.

i am looking at 2 ways to make this work (maybe 3). i took the head to my machinist and we looked into a few options....they are as follows:

(1)- on the GENII head the stock intake valve is around 99mm and the exhaust is around 98mm. on the GENI head the intake valve is 100mm and the exhaust is 99mm. meaning if i replace all my GENII valves with GENI valves it will make up for the amount of metal taken off by the grind on the cams, that way i can issue the proper sized shims to get my valve clearance in spec.

(2)- cut the valve seat so it sits higher and will make up for the gap. meaning the keepers on the valve will be closer to the top (i think) of the valve than to the bottom and will make the valve stick up taller and (in terms) make up for the gap.

(3)- go with the shimless buckets. the stock shims for the GENII are made in sizes ranging from 2-3.3mm in thickness. i believe the shimless buckets are made in thicknesses ranging from 5.06-5.95 (quoted from http://www.rossmachineracing.com/3sbucket.html). so the problem is, i am not sure of the thickness of the stock GENII bucket minus the shims. if i go with the shimless buckets i am not sure if they will have the thickness i need to make up for the grind. (ex. bucket-3mm + shim-3mm= 6mm total thickness ~ meaning that there is not a shimless bucket that will work)


so, these are my options. i'm hoping i can get away with option (2) cause it'll be the cheapest, however, i'm not sure of how reliable or how good it'll be. if i do option (1) they are going to be GENI OEM valves and i've never heard about any differences between GENI and II valves, and i don't know if they are going to be as strong or perform as well. option (3) would be the best bang for the buck cause its lighter and can withstand higher rpms, however, i don't even know if these will work cause i have no clue if they even have the size i need!!

so any and all advice is welcome. i'm really looking for some good expert advice and i figured you guys would know a thing or two! ;)
 

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Discussion Starter · #2 ·
oh by the way, if everything checks out here and its okay to use the GENI valves, i might get those and the shimless buckets. so i'm also considering options 1 & 3.....supposing any of this crap will work! hopefully i can make this work (fingers crossed)!!
 

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My expert advice is option #4 - the option you forgot to mention, or tried to avoid...

The problem is the cams. Not the shims, not the valves, and not any of the other parts; the problem is your improperly modified cams.

Get rid of the problem (the bad cams), and don't build solutions around the problem (masking the effect rather than dealing with the cause); buy a proper set of 264 cams. The reason they are expensive is because they have to be made from scratch to have taller lobes than can give higher lift, not because they want to rip you off (although I have my suspicions about that too...). If you look at the cost of properly welding lobes and modifying cams, the HKS cams are a pretty good deal when it's all said and done - they are by no means inexpensive, but the alternatives are more costly, so...

You can't peel off the base circle of a direct-acting cam lobe to achieve increased lift and duration. That cheap-trick can be applied to motors with a rocker assembly (SR20, American V8's, some euro-trash), but not to high tech little sewing machine motors from Japan that were actually designed within the last two decades (i.e. our 3S-GTE obsucrity)

cause : effect


cam base circle too small : can't set proper valve lash clearance

* "valves not long enough" is NOT the problem
* "no shims thick enough" is NOT the problem

The base circle for a Gen2 & Gen3 is 32.5mm
The base circle for a Gen1 is 28.0mm

if the base circle of your cams is not 32.5mm, then it's just plain wrong, and should be rectified
 

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Not to mention that options 1 and 2 won't work because your springs won't extend that high... at least not and still have the right pressure to pull the valve closed at high rpm. Bad juju when valves start kissing. Also even if you could get the springs and valves a little higher you risk having the taller lobes of those cams remove your shims for you while the engine is running because they contact closer to the edge of the shim. If you want to keep those cams you only have two reasonable options... Underbucket shims or shimless buckets. You won't know if there are shimless buckets tall enough until you measure them like it says on that rossmachine website. :)
 

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Discussion Starter · #5 ·
510rob said:
My expert advice is option #4 - the option you forgot to mention, or tried to avoid...
yeah #4 is something i didn't mension cause i was trying to avoid it. thanks for the advice, i'll definately take that into serious consideration before i give my machinist the go ahead with any option.

i was thinking in my head that it would just be cheaper to to buy the hks 264's than to do all this other crap, and i might be right. thanks for the advice guys....more is welcome!!
 

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Discussion Starter · #6 ·
another thing i was considering was getting some aftermarket springs, like the ones that ATS racing sells. that would help if i chose to get the taller valves, right?
 

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Discussion Starter · #8 ·
dude, i've thought about using those, but i can't find them anywhere! those go UNDER the bucket, right?? if so, where can i find them???
 
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