Wanted Valve Shims 2.50 and 2.45

Hello All. I am in need of (3) 2.50 and (1) 2.45 valve shims for my 1981 xj550 Maxim.

Thank you all in advance.

 

Did you try hogfiddles? He has a shim pool going where you can swap your old ones.

 

Yes he did--- I don't have any in those sizes right now---

Order some new ones from Len.

Dave

 

Stupid question of the day, what is a valve shim and why might we need them?

 

They sit Ina depression on top of the valve bucket, and are what the cams press against to open the valves. They are removeable and we put progressively thinner shims in to maintain proper valve clearance as the vves only recede into the head. If it is not done, eventually the shims will ride on the cam too long and cause valves to stay open too long and cause compression loss, performance loss, burned valves, backfires, etc..

 

Ahh that makes sense your the man hogfiddles. So what changes the factory "shimming"?when I do pods/exhaust etc. Is that something I'll have to learn? I read someone taking about Haynes manual specs. Is that the guide on this I should be reading?

 

As the engine racks up the miles, the valves slowly pound themselves deeper into the head. At specified intervals, we need to check the clearance (space between the shim and the cam lobe) and when it is finally closer than the minimum clearance, we need to pull the old shim out, check its size (stamped on the reverse side of the shim), and step down a size or two ( or more, in rare circumstances) to regain the proper clearance...... Til the next time it's finally out of spec again. That gets done for each one of the valves. Be careful with manuals --- some of them are incorrect. For the airheads your clearance ranges are as follows:
Intake -- .11-.15mm clearance
Exhaust--.16-.20mm clearance

General rule :

in spec is in spec, ok to leave til next check
Out of spec is out of spec, swap the shim

 

Id imagine there's a thread on how to check. Appreciate brotha. You made that make so much sense for me lol

 

Yep, there's threads...... It's a lot easier than it sounds-----