 |
|
I was shopping for a new timing belt yesterday at RockAuto’s website. To my surprise they had two different size timing belts listed for my 1987. They had a number of 127 tooth belts and…two 128 tooth belts. How can there be two different lengths?
That would mean that the crank and cam would get out of synch one tooth every revolution, right?
So I bought one from BavAuto
The timing would not be affected. The pitch of the belt teeth is the same for both belts, only the length of the belt is different. Because the pitch has to be the same the distance between the sprockets on the load side remains constant.
The 128 tooth belt was used up to 10/85 and that belt and tensioner were superceded by the 127 tooth variety starting with 11/85 production.
Ranger, the 128 tooth belt was used on the early m20 engines and later superceded by the 127 tooth and the proper tensioner for that shorter length. Since you have no supervision over the tensioner, you should always replace it with the new belt to be on the safe side. Regardless of the new belt, a tensioner going bad will cause enough stress at a given point, enough to damage the new belt and , of course, your cyl. head. Sorry to butt in as I am usually a spectator and know JLevie always saves you at some point. Correct belt part # 11 31 1 713 361 has been superceded to 11 31 1 469 240. Tensioner part # 11 31 1 711 153 has been superceded to 11 31 1 468 743. Some places like Bav Auto still use the old #s but still the correct part. Good luck with your engine build… 
You forced me to reconsider the geometry of the situation and I can see now how you’re right.
This is a pretty darn obscure factoid. How he hell did you know this?
IAP wrote:
No apology necessary. Smart guys are always welcome.
And chicks. Hot chicks are welcome. And beer. Well, and there’s pizza. BBQ. And more beer. But only good beer. Weasel piss is right out.