[williamb82]

ok, i was thinking, is there a toyota engine that has a smaller diameter oil pump drive gear. that way i can over drive the oil pump a bit to help supply more oil throught the rev range till max pressure is realized.
william

 

[Dave A.]

I don't think so, at least not for the M-series engines. Maybe you could find a slightly smaller diameter oil pump drive sprocket and a shorter timing belt to go with it. 8)

 

[williamb82]

actuall, i think a s serise motor may be compatable, but if i can find a smaller pulley with the right teeth on it ill make one for myself out of the smaller pulley and a stock 7m pulley. as long as its not too small i think the tensioner may be able to pick up the slack.
william

 

[Dave A.]

I wonder if the 5M pump drive sprocket is smaller in diameter with the same belt pitch and width as the 7M? Hmmm!

 

[Dave A.]

Sorry! When you first mentioned pump drive gear, I thought you were referring to the meshed gears on the pump drive shaft and the pump itself.

 

[williamb82]

nope, the gear for the pump is the same diameter. you can even swap the cam gears between some 5m's and the 7m. the 5m's had 2 difernt style teeth. squared and round. dont remeber which the 7m has. ill have to look at the gears next time i go to my storage unit. but i just want a smaller gear that will mesh with the timing belt. i can do the rest.
william

 

[Dave A.]

Well, if you do find a smaller diameter sprocket that will fit, you will definitely need a shorter timing belt as well to match. Taking up the slack with the timing belt tensioner would retard your cams. I'll keep an eye out for a possible sprocket/belt combo that would work.

 

[Dave A.]

Then again, adjustable cam sprockets would put the cams back in line.

 

[williamb82]

actually, putting a smaller oil pump sprocket wont throw the cams off at all. ill just line them up and the crank up before i tighten the belt. the cam and crank sprokets still have the same number of teeth so the crank sproket will still spinn 2 times faster then the cam gears. the belt is pulled clockwise so that side would be tight. as long as theres isnt so much extra slack that the tensioner cant take it up there shouldnt be a problem. the sproket for the oil pump doesnt drive the cams or the crank gear so it wont have any effect on them.
william

 

[Dave A.]

As long as you re-align the timing belt to the sprockets after you install a smaller pump drive sprocket then you will be okay as long as there's sufficient travel in the tensioner to take up the slack.

 

[williamb82]

exactly what i was saying. nowm the trouble is finding one that is small, but not too small. :wink:
william