Rotating cams without shims in bucket

I've found many posts that say do not rotate the cams without the shims in place.
What if I have an ultra tight valve?
The consensus is to swap in a thinner shim so you can get a reading.
How can this be done with out rotating the cam with a shim not in one bucket.
By the same thinking how can you swap shims around to get correct clearences or to send them out for trade without having open buckets?
Sorry, if this question has been beat to death but, I searched and could not find the answer.
Thanks

 

Here is the answer: loosen the bearing caps evenly so as to remove the pressure from the shims you want to swap, you can still rotate the cams without harm to the buckets. After the swap re-tighten the caps.

 

Ok this kind of makes snese.
I don't think you are saying that the cams will be loose enough that the shim will come out without the valve being held down/open?
The cams would have to be tightened down so the valve would open, on the second shim to be removed.
When rotated closed you would still have the open bucket issue.
Hhmm, unless at that point you backed off the cap bolts?

So you would have to pull the first shim, loosen caps, rotate cam so next valve is open, tighten caps so valve can be held open, loosen caps to rotate, pull shim.
Repeat
Correct?

 

It can be done very easily if you have an extra shim standing by.

DO NOT rotate the cams/turn the motor over with the cams loose.

The reason for not trying to turn the motor over with no shim in a bucket is the possibility of the edge of the bucket catching on the edge of the cam lobe and chipping the lobe or damaging the edge of the bucket or both.

If you're using "the tool" you can't turn the motor very far without crashing into it anyway.

Remove the shim on the ultra tight valve and read it. Then dig up a shim two sizes smaller and pop it in; and re-check. Hogfiddles has a shim pool; or I can mail you a pre-owned one for testing purposes (I don't re-use old shims.)

 

Thanks, yes if I had a spare shim this would be easy.
I will check my local shop to see if I could borrow/trade for one.
If not I might take you up on your offer.
Thanks again.

 

Hound, When you know what size you need, get in contact with me. Also, you're only about an hour or so east of me. June 9 I am hosting the 5th Central NY Carb Clinic. PM me and I can give you more details.

Dave Fox

 

cool!

 

If you weren't so far away I'd ask what you do with the old ones .

 

The problem would be scratching the cam lobe, not the bucket.

A solution to this dilemma would be to make some discs from Formica or Teflon sheet, as thin or thinner than a shim, but strong enough to not break under 250 LB (??) spring pressure.

 

Save them to loan out.

 

Just curious Fitz, why dont you re-use shims?

Ps. Dave I sent you a pm

 

I think the reason for not re-using old shims is that discrepancies in the wear pattern between the cam and shim may cause the shim to crack right in half.

 

I don't know of a shim EVER cracking in half, but that's just me. The main issue is that some shims have developed some wear on the top, from cam lobe action, that they may have taked on a miniscule amount of wear. I feel that this is only going to be an issue if you are putting in a used shim that will get you just barely back in spec. If you are putting one in that will put you on the good side of the middle of the range, it won't matter anyway. At worst, if you're really concerned about that, put the used shim in upside down. They're hardened both sides. The only drawback there, is that you'd better write down what the shim size is. The lob will wear the stamping off. If you don't have it written down, then you'll never know what the shim is anymore, and it will be tossed out when it gets replaced again, this time since it's worn on both sides, AND no one knows the size anymore. The numbered side is not going to be worn initially since it has always floated on the oil film, and is hence flat and true.

dave fox

 

Me either and it's not why I won't re-use them.

 

then why is it? lol

just askin'

 

I've checked new and old one with a micrometer and found no difference, I must admit. At the end of the day it's only a shim - a spacer - so even if they did wear (which would defeat the object of the design), so long as you check the clearance with the new shim, you wouldn't go wrong.

If you don't have a shim the right size, order another and don't bother trying to grind it down on a sandstone though......

 

Don't bother trying to grind down on a sandstone anyway!!! One, you won't get it right. Two, you won't get it even and flat. Three, you won't get it done anyway since the shims are hardened.. Four, if you're doing it with a machine, you're going to spend more time than it's worth to do so in the first place.

Dave

 

Thanks all.
Local shop tossed me a shim for the day.
I tell you it pays to stop by your local shop an buy some trivial crap once, twice a month.
He had no problem loaning me a shim.
Problem solved.
Swapped what I could and will place my order for some shims from the pool.
Houndy

 

there ya go!.............

dave fox