timing belt wont tension - 7rib -

[NH-hillbilly]

Greetings gentlemen

I'm currently putting a motor together for a friend and am running into issues getting the timing belt to tension properly. Its a 7 rib grey market block, with a 16 valve big port US head. I was provided a 113 tooth gates timing belt, new tensioner, new idler, new drive gear etc. When I pull the pin on the tensioner and it tensions, it doesn't have enough reach to tension the belt properly. I tried a different tensioner with the same results. A 111 tooth belt is too small, is a 112 tooth belt available for this motor? I saw pictures on google where someone drilled and tapped the back of a hydraulic tensioner and used a nut and bolt to manually adjust tension of the belt, and am hoping that isn't the route I am forced to take.

[matt dunn]

I thought hydraulic tensioners were only used on the Blacktop 20V engines ?
The Blacktop uses a different belt to the Silvertop as the tensioner wheel is in a different location.
That may be why you are a tooth out in the belt,
as the Silvertop 20V has the same tensioner setup as all the 16v's.

[yoshimitsuspeed]

Yep sounds to me like you are using a Blacktop tensioner on a 16v.
If so the easiest solution would be to get a 16v oil pump and tensioner. If you are rebuilding the motor it's a good idea to replace the oil pump and tensioner anyway.

[MisterJerk]

16v timing belt with 20v oil pump is a huge pita to get to work. you can extend the 20v tensioner, which i did(drilled out an m6 allen bolt and tacked it onto the end of the tensioner. eventually, i switched out to a 16v oil pump with new tensioner, etc. if you are still running the 20v lower pulley, you should go to the 16v one. unless you like tearing up the alternator/wp/fan belt.

also you will notice the alternator mount and the 20v tensioner utilize some of the same space.

[oldeskewltoy]

if indeed you do have a 20V blacktop pump, once you switch it out.... DON'T rely on the STUPID timing belt tensioning spring!! Here is the FSM specifics for tightening the timing belt