U20 top tensioner

[dscrib2]

I have 2 U20 top tensioner housings and they are different. One allows the shoe to travel all the down until it bottoms out on the back of the housing. The second housing has a step in it that allows the shoe to travel about 0.725" into the housing.
Why the difference?
Was one from an earlier version? Did they changed to or from the short travel style?
Which one would be the better to use?


Thanks,


Dana Scribner

1969 2000

[Gregs672000]

No idea regarding different housings. The most important thing to consider is to make sure it keeps the chain tight on start up. You may have seen some postings on shimming the tensioner as it fails to keep the chain tight on start up due to a lack of oil pressure. This causes a significant cam timing change that I have observed directly, and it's not good. So, bottom line, use which ever tensioner is in the best shape, mainly the pad, make sure the gasket does not cover the oil feed hole in the tensioner body to head connection, and shim the tensioner shaft so that it keeps the chain tight with just a little backward movement in the tensioner possible, like less than a 1/4" or 1/8" or so. Check the "evil L" for chain strikes and make sure it is not seriously undercut. Post pics if you're not sure of what you're seeing. Do a search in the archives for tensioner postings. Dean at Datsunparts.com sells a shim kit, or you can go to the hardware store and buy what you need. Use locktite on the bolts and be nice to them... long and thin so don't reef heavily on them. I personally don't like the metal bolt locking plates and don't use them.