Shim Under Bucket

wrote:

Just because you haven't figure it out does not means that you need to change it it is a simple procedure that if you get it right you will only have to disassemble and assemble one time, measure the gap in each cylinder, open and measure each shim and do the math to get the right clearance.
if your current gap is to tight open put smaller shim were needed and put back together measure and do the math again. its not so complicated just not as easy as 900, but for some reason they did the design like that.
Also make sure to do not damage the threads of the cam caps screws and do not over tighten, the screws snap easy and then you have a big issue to remove that screw out.

Thank you.  To be clear, I know how to do it correctly both ways.  But here is a question for everyone to consider.  Assume you are paying a shop $100/hr for a valve clearance check.  Which method would you prefer to pay for?  Shim over bucket or shim under bucket?  Just my opinion but shim over bucket is much simpler and faster.   
 

HRM. I think you idea is solid. One more factor to add to the Pro column is shims you will have to buy or stock. I know you have build several engines and more than likely have 29mm shims. It eliminates one more item that will need to be stocked. 

My comment without knowing is, are the shim buckets the same size, OD? I ask because I bought a KHI spring compressor that had the adapter cup for a 650. Cup number 57001-242. It measures 33.01mm. It was to big to fit my 900. It stuck in the bucket bore. I ordered 57001-243. It measures 30.93mm. So does that mean the buckets are different also. Would there be an issue of putting the smaller 900 bucket in the 650? 

The 650/750 buckets are interchangeable with the 900/1000 buckets.  As long as you use the 650/750 style retainers, the 650/750 buckets drop right in the 900/1000 heads.
Very common to use the 650/750 buckets in the 900/1000 heads. I have been doing it since back in he late 70's.

So doing the reverse should not be a problem.  My question would be why???

wrote:

The 650/750 buckets are interchangeable with the 900/1000 buckets.  As long as you use the 650/750 style retainers, the 650/750 buckets drop right in the 900/1000 heads.
Very common to use the 650/750 buckets in the 900/1000 heads. I have been doing it since back in he late 70's.

So doing the reverse should not be a problem.  My question would be why???

Because it's easier and faster to set the valve lash.  And, as Mikaw points out...I have a large number of 900 shims but only a couple for a 650.  Lastly, because the less one has to do inside the engine the lower the risk of a negative consequence.
 

My question is are the valves and springs smaller thus less to compress with the caps?
Steve

I don't believe the springs are smaller since the retainers are a perfect fit with the Z1/KZ springs,  I used 650 parts to do a poor boy shim under bucket on the motor I put together last Spring. The springs may be a lighter rate since the shim under bucket is lighter and would require less pressure to close them?  As far as setting valve lash with S.U.B., it's not bad if you take good measurements and notes of shim locations, and are familiar with setting the cam timing.  However as H.R.M. has said, it does open up the chances for a " mishap" more than the traditional 900/1000 setup which requires no disassembly.  We got a lot of practice setting valve clearance in Lincoln when the 650s first came out chasing valve noise. I remember being less than impressed that the new 650 didn't have cam bearings like it's big brother. (like I knew anything at the time!)

Mike
































 

wrote:

My question is are the valves and springs smaller thus less to compress with the caps?
Steve

They are identical.  Same part number.  The spring retainers are different numbers.