Different Valve Covers??

I can't find any info on the different valve covers for the 22r/re series motors. My toyota dealer says the 83-85 valve cover was a slight bit lower than others. But if they made a low profile valve cover, wouldn't the valve train and cam gear need to be lower as well? I thought the cam gear was the same size for the entire 22r/re (25 years?)run.

If the cam gear and chain has always been the same size, how could the valve cover ever have been lower?
(if they lowered the gear, then the chain would have to be smaller, right)

Heres the situation:
-I bought the truck on Monday.
-Sounds like it needs a timing chain.
-I took the timing cover off today.
-There is wear on the inside of the timing cover from loose chain slapping.
-The timing components are all near brand new, minimal wear.
-The plastic chain guides are perfect.
-The timing componens are an unknown (not toyota) brand.
-**There is (fresh, hard to tell) chain wear on the underside of the PCV routing in the top of the valve cover.
-There is only a 16th-8th of an inch clearance between the chain and the valve cover while sitting.
-Toyota Dealer says the 83-85 valve cover was available with a lower deck.
-The diameter of my CarQuest timing chain kit cam sprocket and the currently installed cam sprocket is either the same or within a 16th of an inch difference.


Possible issues:
1:My favorite: The valve cover is too low, or the pcv components in the ceiling are for the wrong year.
PROS-Explains the valve cover scarring, and why the guides are still perfect. Nothing needs replacing except the valve cover (JUNK YARD!!!).
CONS-I can't get it to grind the way it is. There is an 8th of an inch clearence, so the only way it is grinding is if the centrifugal force is pulling the cain off the cam gear just enough to cover that clearence. Depends on the existence of a low profile valve cover for a series of motor that has the same valve train and timing component dimentions for 25 years. If they made a low profile valve cover, then there ould have to be a low profile timing chain to match.

-The Cam (and crank) sprocket is too big.
PROS- Explains the valve cover scarring and the good guide condition.
CONS-It seems unlikely as my (aftermarket) CarQuest timing components are the same dimentions, doubtful that they are both wrong. It means spending BIG MONEY on Toyota Brand timing gears.
-The tensioner is not getting oil pressure, and the chain is loosely riding the cam gear.
PROS-The most traditional issue. Perhaps the loose chain just hasn't started eating the new plastic guides yet.
CONS-Very unlikely that the loose chain hasn't eaten the guides...

I don't know. Any body know anything about different size valve covers?

If the valve cover gasket has been reused, it might be compressed allowing the valve cover to sit too low.

Don't know about the different heights for valve covers, but the head has changed height and that may affect the difference in the height of the valve cover.

There is a difference in valve covers, the round front vs square front, but I don't know if there's a height difference.

But there is a difference in head and block height between the 84- 22R's and the 85+ 22R/RE's, there is no interchangeabilty between heads/blocks/TC's/etc.

You can probably get a lot more experienced assistance at www.yotatech.com (http://www.yotatech.com) or www.toyotanation.com (http://www.toyotanation.com)

Good Luck!