Valve Shims. Stock with 272 duration 8mm lift.

[siman]

Ok gang, I have read ONCE, and ONLY ONCE but have never seen the definant truth.

I have 272 degree, 8mm lift cams be made as we speak. A while back I read that the stock shims ( or stock thickness range) was on the "brink" if you will with an 8mm lift.

Stock being 7.4mm lift roughly.

Here on this website:

http://www.billzilla.org/4agmods.htm

low 300's and roughly 8mm lift, the 'shim over' buckets will occasionally catch the edge of the shim with the top of the lobe of the cam and spit it out the side, thus RAPIDLY destroying the bucket and most likely a fair chunk of head in the next few milliseconds.

This is judging by the way he worded it, the larger diameter shim under bucket design with a cam lift of GREATER than 8mm MAY cause this phenomenon. Though I have never personally heard of this or seen this until now, have any of you experianced it with an upgraded cam set?

This is coming from 4age tech. Roughly the exact same valve system set up as the same dated 7m series.
Though when he is talking of this phenomenon its usually dealing with HIGH REVVING motors. But since the 7m (pre-89 ecu) rev cuts at 6800 rpm, I doubt this could happen. I only see this happening on a HIGH revving motor.

I am having a hard time sourcing out a shop that could make me some shim UNDER buckets...

I know Defiant7m has them from the 1sz-fe 1 liter 4 cylinder from japan, but I cant seem to get him to answer a simple question as to HOW he aquired them.

Any help or advice is welcome. Either way I will try this set up on the stock shim over buckets with my comp cam valve springs, stock retainers, Ferrera valve locks.

Should be a good strong set up for 500 crank hp.

-Jonathan

 

[IJ.]

I bought my 1sz-fe buckets from my local Toyota dealer they just ordered them from Toyota Japan no probelms.

You need to have a size to order though which means a mock assembly on the head with a stock shim/bucket measure it then work out the new shims thickness.

It all depends on how pedantic/fussy/precise your head guy is to hom many different size 1sz-fe you end up with.

 

[siman]

How much did you pay in Australian dollars for your buckets IJ? Wait time?

I would calculate some $40 for shipping to the US etc. So just a round about price woule be great. I still have those part #'s I think.

-Jonathan

 

[IJ.]

I think they were $600 aud/$440 usd and around the 2 week mark Jon.

Can't see shipping being much more than $20 aud for the weight.

 

[chevyeater]

Get them from Jeff Watson @ Champion Toyota. No shipping charge from Japan and very prompt compared to some other sources, only a couple of weeks when I ordered over a year ago. Think they were around $10 each but don't quote me on that as it has been a while.

IIRC, Allan went with the echo buckets on his buildup. The lifter bores in the head need to be oversized to 32mm for them.

Also, I would want to raise the rev limiter to take advantage of a camshaft upgrade if I were you.

 

[siman]

Thanks guys!

This is truely an experimentle type set up. Smallish turbo ( though still much larger than the stock CT26 in comparison). Either way the car will be faster than stock and sound much better too.

Just some people got me thinking about the solid lifters LOL. I will give jeff a call. $10 a piece is a bit steep, but probably comparible to those custom made from any performance shop.

I guess I could order those when I have my head and valves all matched up ( 3 angle). I dont think it would be that much more expensive to do the 32mm bore.

Maybe I can still use the buckets. The real thing I am pondering is not of the shims cracking under the new "stress", the lift is only increasing by .5mm ( A HALF A MILLIMETER) Now if I was doing a 9mm lift, it would be another story.

Its the "phenomenon" as I would like to call it as the guy that wrote the 4age set up. But that is also being thrown out the window in lue of the rev limit.

Chevyeater, I had searched around alot and never had a straight answer. The FCON I have, the 550cc injector rom and such, never really is clear if that particular rom INCREASES the rev limiit. I am betting on a 500rpm increase. But if not, the new cams should pull harder than stock above 3800rpm.

My friend that had 272in/264ex cams in his 7m said that was about the rpm that the car really "woke up"...and that was with a quite large SP61GT on a stock exhaust manifold.

He ran his head with stock valvesprings, ss ferrera valves/locks, and 8mm lift on stock shims. All lasted until he mis-shifted going to 5th ( put her in 3rd) and send the clutch into desentigration mode. LOL
The head was fine, no chewed valves ( non interference), just the timing belt snapped ( stock ) and the clutch made a big crack in the bell housing. Bottem end was fine, it revved past the 8K rpm mark on the tachometer. probably hit 9K+ rpm.

 

[chevyeater]

The FCON equipped 7Ms I have been in did not have a raised rev limiter due to it. Anyhow, good luck with the new setup, sounds like fun.

 

[siman]

Hmm. Maybe I could find a HKS rev computer ( back in the day they made them for old distributor/cps equipped cars).

MSD has one too right?

-Jonathan