slack timing belt

[b3n_rix]

hey guys,

I have tried to research this problem but keep coming up with very little to no information or help. I have built a 1.5jz as most of you who have been watching my build thread know, however, my timing belt is slack.

on the tensioners side it's taught and no problems there, however, the non-tensioners side, there is roughly 10-15mm of slack in it.

I think I may have put the belt on the wrong way, because how I didnt it, was loosen the hydraulic tensioner without resetting it. could this be causing my problem?? I have double checked my bolts and everything seem tight enough so I don't really see a problem there.

any help would be awesome please as this is holding me back from starting the car.

cheers

[Hen]

I'm not 100% sure what you're explaining, but have you rotated the engine by hand after fitting the timing belt? Just enough so the cams start to turn is fine. This tensions the belt from the crank up to both cam pulleys and ensures all slack is on the tensioner side. Then the tensioner should take up all the slack.

Then check that all your timing marks still align after rotating the crank twice by hand.

[pandaah]

i know exactly what your problem is.. i just finished building my bulletproof 1.5jz so im full bottle on these engines

tell me something, the hydraulic tensioner pushes on the idler swingarm which pushes up against the belt, now, did you use the 1jz idler swingarm?.. as that will be your problem, you need to use a 2jz one.

they look identical by eye, use the same size idler bearing, but the swingarm of a 2jz actually sits the idler bearing 15mm closer to the belt, if you put them side by side youll see just the way its made, it offsets the bearing closer to the belt

but yeh, reset hydraulic tensioner slowly in the vice and put the pin thru it to lock it.. then install it with the pin still in it, put the belt on, make sure the slack is on the tensioner side of the belt and all the marks line up, (usually done but putting the crank out 1/4 of a tooth then turn it to its mark when the belt is installed) then pull the pin

if you dont reset it, when you remove it, it extends to its maximum position and it wont reset upon installation, meaning it will over tighten the timing belt AND also itll have no room to come out over time to tensioner the timing belt when it slackens



hope this helps you! any more questions just ask

[b3n_rix]

I have used the 1jz oil pump, tensioner and idler bearing. I didn't think there was any difference between them as everything I've read says you can use the 1jz one. (I'm not arguing your knowledge, just confused thats all)

I will reset the tensioner and take another look at it and see how I go. my only problem is to change the bearing most of the stuff has to come back out because of lack of room

[pandaah]

the 1jz oil pump is the same i examined them side by side, they have different part numbers in the EPC, i dont know why that is tho, maybe theres a difference i missed but i doubt it, im a mechanic and engine builder by trade..

so yeh, using the 1jz oil pump is ok, you need to use the 2jz swingarm, changing the bearing is easy just undo the bolt holding the bearing to the swingarm bracket once youve unbolted it from the oil pump..





photo copied from supra mania.. oringally posted by soapra

[pandaah]

ps what head gasket did you use and did you modify your cylinder head?

[b3n_rix]

no modifying of block or head, but used a 1.8mm 2jz head gasket, just want to see how the engine holds up while im build a built setup.

[pandaah]

Are you sure the 2jz gasket lines up with the oil gallery in the 2jz head, as i'm pritty sure it doesn't which means no oil to the head.. I had mine welded and resettled to use a 2jz gasket

[b3n_rix]

im not using the 2jz head... yes it does, it blocks the tiniest of space on it, but like I said, it's not something that really concerns me as I can see that the oil will still be able to get there no problem... I see the point behind welding the block and redrilling it, but this time is my first on putting an engine like this back together so I will learn from this and then build another one down the track (thats if this one ever breaks)

[pandaah]

Are you sure the 2jz gasket lines up with the oil gallery in the 2jz head, as i'm pritty sure it doesn't which means no oil to the head.. I had mine welded and redrilled to use a 2jz gasket

[pandaah]

Sorry double post

Ahh ok, spose there's a few different ways of porting this combo together, they run like clock work that's for sure, did you manage to tighten your belt?

[b3n_rix]

haven't had a chance to look at it, but will let you know hopefully tomorrow... any chance you would have a spare 2jz bearing floating around just in case?

[pandaah]

Nah sorry bud, only just finished 2, 2jz bottom ends so i'm out of stock on parts