I Think I've Messed Up My Timing Belt Change

[mistermeena]

So I changed my timing belt, tensioners and water pump but I was apparently not paying enough attention to the instructions and now I'm worried.

Before I removed the belt, I only lined up the timing marks on the two cam pulleys up top and didn't pay attention to the mark on the crank. I was careful not to move anything, but the belt was hard to get on so now I'm worried that something might have moved.

I haven't fired the motor yet and I don't want to until I know this is right. So any advice on what I should do? Is there anyway I can safely check that it's lined up correctly?

[scotty nm35]

A screwdriver down the first bore can give you close to top dead centre, then make sure the marks are correct on the cams.

Make sure you turn it over by hand first a few revolutions. That way you can be sure the valves aren't hitting the pistons.

[mistermeena]

Ok so I need to get cyl 1 to tdc on the compression stroke, and at that point the two marks on the cam pulleys should line up? What about the mark on the crank - should that line up with the notch cut out on the bottom side, or should it be at the 0deg timing mark on the belt cover?

and if it turns easilly by hand (besides the resistance of compression) then the pistons arent hitting?

Edited June 5, 2014 by mistermeena

[89CAL]

The crank gear mark should line up with the mark on the oil pump. Timing marks on the cam gears lined up on the back plate and then yes everything should be at top dead centre cyl 1

[mistermeena]

Ok thanks. The car is in a mates driveway so I cant try this until monday. Just another quick question, what do I do if they don't line up?

[scotty nm35]

Make them line up?

[mistermeena]

...by turning the crank gear in whichever direction is closest to making it line up?

[scotty nm35]

By turning the cams. It should be on the crank gear and lined up at the bottom first.

You won't know if it's right until you put it on the tensioner rollers.

[mistermeena]

ah yep so when cyl 1 is at tdc, the crank gear mark will be lined up with the notch on the oil pump? And if it's wrong on the cam gears I need to take the belt off and adjust them in the direction closest to making them line up?

Seriously hope it all lines up lol

[533 RYC]

Belts are a bit hard to get on, abit harder when they are new. You have to get them started on each sprocket, idler & then tensioner, then evenly push the belt on all the way around, it's the easiest way.

If you have doubts, before turning the engine over, get a mirror & visually sight that crank & cam marks are lined up. Then, slip the lower cover on & sit the balancer on the crank nose by hand & see if your marks line up. Then if all good, release your tensioner, bar the engine over 2 revolutions, re-check all 3 marks. If it's good, then hold the eccentric in that position with an allen key (please, do not add more tension, your only causing premature stretch in the belt & loading the idler & tensioner bearings unnecessarily!) & torque up the bolt.

If your in Sydney I could come & have a look.

[533 RYC]

ah yep so when cyl 1 is at tdc, the crank gear mark will be lined up with the notch on the oil pump? And if it's wrong on the cam gears I need to take the belt off and adjust them in the direction closest to making them line up?

Seriously hope it all lines up lol

Correct.

[mistermeena]

nah not in sydney but thanks for the offer.

regarding the tensioner...doesnt the spring on the back of it set the tension automatically?

[89CAL]

Not exactly. The procedure is once you get the timing belt on, you rotate the engine backwards to put tension on the belt (Think it reccomends turning it over 3 times backwards by hand) then get an allen key to fit in the tensioner just to hold it in that position while you do it up.

I think thats right anyway. something along those lines anyway

[533 RYC]

Never ever turn an engine backwards (anti - clockwise)!

When fitting the tensioner, you need to wind up the spring so that after you have fitted the belt & release the tensioner BEFORE winding the engine over (clockwise) by hand, you actually already have spring tension applying force on the belt.

The whole purpose of winding the engine over (clockwise) is remove any slack from the installation process before torquing the bolt.

[89CAL]

Sorry yes, it was clockwise you had to turn the engine, I had backwards in my head for some reason.

What is your reason for never turning an engine backwards?

[scotty nm35]

It just makes it hard to align the marks, as the slack is on the wrong side. Cam timing is important to get right.

I saw an RB26 actually running backwards the other day, both cams were 90 degrees out, set up like Toyota cam wheels accidentally. Exhaust was coming out the airbox and fresh air sucking in the exhaust. Once the marks were realigned properly it ran fine, didn't even bend a valve.

[jiffo]

ah yep so when cyl 1 is at tdc, the crank gear mark will be lined up with the notch on the oil pump? And if it's wrong on the cam gears I need to take the belt off and adjust them in the direction closest to making them line up?

Seriously hope it all lines up lol

Not to put too fine a point on it but with No1 at TDC you can still be 180 out on the cams.

So don't panic if the cam marks don't appear with No1 at TDC.

Turn the crank another revolution and then see if the cam marks are looking better when referenced against the back cover.

Don't take any notice of markings on the belt at this stage.

Not cranking an engine backwards harks from timing chain engines with hydraulic tensioners. With the engine cranked backwards, the spring pre-tensioner may be insufficient to keep the chain on the sprockets.

[GTRPSI]

I saw an RB26 actually running backwards the other day, both cams were 90 degrees out, set up like Toyota cam wheels accidentally. Exhaust was coming out the airbox and fresh air sucking in the exhaust. Once the marks were realigned properly it ran fine, didn't even bend a valve.

Yep saw the same one as you Scotty, the issue was they were black tomie cam gears and the dot was not highlighted in white, silly bugger set them up like 2Jz gears not seeing the dot.

When i got home i looked at my gears and the dots had a dab of white paint on them, go figure, maybe not genuine tomie cam gears?

I had a backup set of valves on my bench if he needed them, didnt in the end, it surprised me.

That car ended up back on the hoist a few days later, they had setup antilag on it and a new clutch, owner spent the next day doing launches showing his mates and destroyed the clutch, never gave it a chance to bed in properly.....

[533 RYC]

It just makes it hard to align the marks, as the slack is on the wrong side. Cam timing is important to get right.

I saw an RB26 actually running backwards the other day, both cams were 90 degrees out, set up like Toyota cam wheels accidentally. Exhaust was coming out the airbox and fresh air sucking in the exhaust. Once the marks were realigned properly it ran fine, didn't even bend a valve.

Yep saw the same one as you Scotty, the issue was they were black tomie cam gears and the dot was not highlighted in white, silly bugger set them up like 2Jz gears not seeing the dot.

When i got home i looked at my gears and the dots had a dab of white paint on them, go figure, maybe not genuine tomie cam gears?

I had a backup set of valves on my bench if he needed them, didnt in the end, it surprised me.

That car ended up back on the hoist a few days later, they had setup antilag on it and a new clutch, owner spent the next day doing launches showing his mates and destroyed the clutch, never gave it a chance to bed in properly.....

Hahahahaha RB26 Honda engine!

[jiffo]

So how was the oil pressure on this backwards-running Rb?