under bucket shim conversion 1uz

The 1UZFE EGR Delete Kit is available for sale here.
Buckets from NZ engine.. Yaris etc..
If getting custom cam from Teigh / Kelford ??
You may consider a bigger base circle to take up the clearance ??
From memory it's 0.020 .. Saves shiming the valve stem...
Check clearances FIRST ...
 
I've done it with two engines now.

As XR8TT points out, the Yaris shimless buckets work OK, and if you need more thickness than they can provide, you'll need to go to a retainer that is setup for SUB (shim under bucket), or specify cams that have a bigger base circle.

For the first engine I used the Yaris shimless buckets, and OEM 2UZ retainers, which are machined for 5.5mm valve stems. My engine builder remachined the retainers for 6.0mm stems and that solution worked fine, however he said the retainers really took a toll on his tooling. Going this way, we were able to use stock 2UZ shims.

The second engine was built with Yaris shimless buckets, but with aftermarket titanium RB26 retainers, and custom shims from Precision Shims there in Oz. The spring seats of these RB26 retainers are just a bit too big for the UZ valve springs, so they need to be turned down just a bit, or different springs sourced.
 
I use XR6T valve springs in my engine.

The springs supplied by Kelford became coil bound before full lift.

The XR springs fit without any modifications and are pretty reasonably priced.

I have around 110lb seat pressure. Stock UZ is around 60-70lb.
 
thanks for the replies. are you saying that the xr6t springs fit the titanium rb26 retainers without modification. and all fits under the yarris buckets. whwre would i get the retainers from. im running std cams.
 
In the US, both Manley and Supertech sell the RB26 Ti retainers. Manley's are setup for single springs, the Supertech for dual.

I've not seen or tried the XR6T springs on either of these retainers so I wouldn't know if they fit.

And probably neither Zuffen nor XR8TT have tried these retainers with their springs.

I can, however provide the dimensions of the retainer's spring seat, and Zuffen or XR8TT can probably measure the ID of their springs, and we can see if they'll work OK, together.
 
Here are the pertinent dimensions for the retainers. First 2 pics are for the Supertech which takes double springs, 3rd pic is of the Manley.

Note, you can't simply use these dimensions in isolation, because while you can find beaucoup springs whose ID's will be fine, and these retainers will sit down on them just fine, the springs' OD's will be too large for the spring seats in the heads. That's when things get expensive.

So the trick is to find springs with good ID's and good OD's, plus a good seat pressure, and won't go into coil bind with higher lift cams. That narrows the selection down quickly.

The approach for my 2nd engine was to use a spring that met all the above criteria, except their ID's were a bit too small for the Manley retainers, so we milled that 0.761" dimension for the Manley down to 0.755", and we were golden.
 
John,

Don't you realise the rest of the works works in mm?

Inches went out of fashion 30 years ago!

At one stage it was illegal to sell Imperial rulers or tape measures in Asutralia!
 
Zuffen said:
John,

Don't you realise the rest of the works works in mm?

Inches went out of fashion 30 years ago!

At one stage it was illegal to sell Imperial rulers or tape measures in Asutralia!
Click to expand...

Not in aviation or race cars, and metric standards are well below imperial standards.
Seeing as the majority of the worlds hi tech items are manufactured in the USA and we buy most of our military hardware from the USA, it is surprising that our government has outlawed imperial dimensions.

To make matters worse, we have not really gone to metric sized items, we have just changed to a metric conversion, 1" tube is not 1" any more - it is 25.4mm ---- crazy!

I suppose I must be a bit crazy, as I mainly work with open wheel race cars.
 
I was surprised to find that the manufacturers of the springs and retainers used a mix of imperial and metric for their specifications, so I just stayed with imperial measurements (and the spring tester that I used was calibrated in inches and lb's.)

The springs that I found (readily available) were Honda springs for their high revving S2000 motor. Better seat pressure than stock, no binding problems with higher lift cams, and they fit the UZ head's spring seats. Lextreme's springs also fit and had good, but not excessive, seat pressure. Both these springs required the retainers to be milled slightly.

I have no idea what the XR6T springs' dimensions or specifications are, but they would be very good to know. Rod? XR8TT?
 
I'll have to get back to you on demensions as they are being set up now...
With shimless buckets.. Cannot rush these things ... Sheesh !!
 
Paul, they're the same size. The Toyota dealers that most of us deal with here in the US prefer to sell the Yaris version of the buckets for availability reasons (actually I think they're the same P/N's as the MRS buckets)

Still only a range of 5.06mm to 5.95mm.
 
I tell you what... I'm all messed up now after reading this post... could someone clean all this up and just list what is needed for big cams for N/A hp gains...
:) my head is spinning... lol

I would rather build an N/A motor then a turbo one. I know its more money... but for class rules, and I want the sound of a good reving V8!!!
 
d962r said:
I tell you what... I'm all messed up now after reading this post... could someone clean all this up and just list what is needed for big cams for N/A hp gains...
:) my head is spinning... lol

I would rather build an N/A motor then a turbo one. I know its more money... but for class rules, and I want the sound of a good reving V8!!!
Click to expand...
The motor I'm building is turbo yes..
But the valve gear would be the same for N.A engine..
Maybe bigger valves ?? For N.A application.. But with high rpm a switch to
shimless is better.. There is a big chance at high rpm of a shim popping out.. Possibly from valve float...
The o.p asked about shimless / under bucket conversion...
 
Last edited:
You must log in or register to reply here.

Similar threads

D
Most Aggresive cam without shim under bucket?
Replies
8
Views
6K
XR8tt
XR8tt
cribbj
Shim over, or under bucket...or shimless?
2
Replies
22
Views
10K
XR8tt
XR8tt
K
99 vvti swap, e30 bmw, no power under load
Replies
3
Views
741
George_R
George_R
D
No power and bad backfire under throttle
Replies
5
Views
1K
dweinhart
D
EIL_V8
Dashboard installation (covers under steering wheel) help needed please.
Replies
1
Views
1K
stine1990
S
B
Rough under load
Replies
4
Views
712
ivan129
ivan129
J
3uz-fe weird idle and throttle lag under 3k rev
Replies
16
Views
9K
Jgrov2
J
H
Under the timing belt two metal pieces coming off the block
Replies
4
Views
1K
gloverman
G


Top