timing belt/camshafts

[eLuSiv3egT]

here's the situation...my timing belt is jumping around when i rev the engine past 1500rpm but at idle it is fine. the belt is pretty firm as far as having slack (or not having any slack) goes so im a little confused :thinking:as to why it would still jump around. it's an LS motor with stage 2 turbo cams and aftermarket gears... so my question is is it possible for aftermarket cams to affect the tension of the timing belt in any way???

[Tech5]

answer your question No ...What do you mean jumping around , could you get a VID of this and post it please.

Is it moving around between the first cam gear down to the crank pulley if so this is normal ...But if its at the top between the two then something isn't right either cam is moving around or gear is bad or bad belt ....but get a VID please

[eLuSiv3egT]

I'll post a vid when I get a chance but yes it's jumpin ( bouncing back and forth) from the ex cam to the crank pulley. I thought it was supposed to vibrate a little but it just seems like it's just vibrating more than it should even though the belt is tight....thanks for the info

[RBS]

your belt is just loose, when you feel the belt you just so happened to feel the tight side of the belt. put crank at TDC and tighten the belt.

[Theycall_Metue]

prob off a tooth, the side returning to the crank is lose correct?

[Tech5]

Its normal to see it bouncing around from ex cam to crank ... But It might might need to be tighten or replaced, also can be a bad tensioner also.

[gsrteg]

Is you motor setup a stock LS motor or LS-Vtec? The stock LS timing belt has less teething, while the GSR or B16 timing belts have more teething. Make sure you have the correct timing belt and water pump. Oh yea, I believe the SI (b16) timing belt is shorter in length than the GSR (b18C) timing belt. So take all this info into consideration. And make sure when you redo the timing, all TDC (top dead center) markings are correct and precise. Once the belt is on with the tensioner good and you are sure all is at TDC, tighten the crankbolt. Then manually crank the crankpulley bolt with a rachet 2-4 revolutions counterclockwise to ensure the timing belt is still tight.

[gsrteg]

If you are using aftermarket adjustable cam gears, it can throw off the timing sequence (thats if you don't know how to set it). Don't over advance or retard the timing gears if you don't know what you are doing, so look at the timing cam gears to see if its at zero (goto the camgear manufacture's website for documents/instructions). Find someone with a timing light gun, to check if your timing is within the correct spec and/or desired degrees.

[Black4DrEK]

Its normal to see it bouncing around from ex cam to crank ... But It might might need to be tighten or replaced, also can be a bad tensioner also.

THIS

[Tech5]

Is you motor setup a stock LS motor or LS-Vtec? The stock LS timing belt has less teething, while the GSR or B16 timing belts have more teething. Make sure you have the correct timing belt and water pump. Oh yea, I believe the SI (b16) timing belt is shorter in length than the GSR (b18C) timing belt. So take all this info into consideration. And make sure when you redo the timing, all TDC (top dead center) markings are correct and precise. Once the belt is on with the tensioner good and you are sure all is at TDC, tighten the crankbolt. Then manually crank the crankpulley bolt with a rachet 2-4 revolutions counterclockwise to ensure the timing belt is still tight.

Wrong , Rotate the crank 3 teeth counter clockwise not 2-4 revolutions as you put it ....BTW B16 belt is short

[Tech5]

If you are using aftermarket adjustable cam gears, it can throw off the timing sequence (thats if you don't know how to set it). Don't over advance or retard the timing gears if you don't know what you are doing, so look at the timing cam gears to see if its at zero (goto the camgear manufacture's website for documents/instructions). Find someone with a timing light gun, to check if your timing is within the correct spec and/or desired degrees.
They only allow 10 degree adjustments and will not cause a bouncing timing belt .

[gsrteg]

Wrong , Rotate the crank 3 teeth counter clockwise not 2-4 revolutions as you put it ....BTW B16 belt is short

My bad. Yea what he said. You can always use this as a guide too:
http://www.c-speedracing.com/howto/timingbelt/tbelt.php
http://www.c-speedracing.com/howto/timingbelt/tbelt2.php

[Black4DrEK]

For a LS V . What timing belt needs to be used? B18C correct?

[Tech5]

Either GSR or Type R which are the same

ONLY use B16 timing Belt with B16 Block