Timing Mark Line Up

[Don Dada]

Correct me if i'm wrong but when u line up the two dots on the cam gears to the corresponding lines on the backing plate by turning the engine,isnt the first line on the balancer 0* suppose to correspond with the line on that cover?

[The Dan]

Correct me if i'm wrong but when u line up the two dots on the cam gears to the corresponding lines on the backing plate by turning the engine,isnt the first line on the balancer 0* suppose to correspond with the line on that cover?

No.

There is a dot on the lower timing belt gear and it lines up with a notch on the oil pump.

Lining it up via the balancer is dodgey to say the least.

What balancer do you have? What engine and what model car?

[Don Dada]

Yeh i know about lining up the the dot on the crank gear with the corresponding mark on the oil pump, but i just wanted to know if it was possible to make sure my timing was ok without taking out the balancer to see. Just thought the first line on the balancer was suppose to line up with the mark also.

R33 Rb26

[The Dan]

Yeah, on those, the first mark = 0 and it lines up with the notch on the cover.

You have to look at it with your head above the power steering pump though. Don't look at it straight down from the centre.

[Don Dada]

So i guess my timing is off 5* then because when the cam gaears line up with their marks, the balancer is on its second mark ?!?

[The Dan]

So i guess my timing is off 5* then because when the cam gaears line up with their marks, the balancer is on its second mark ?!?

Don't go off the balancer mark. Line it up first, then see where the cam gears are. Once again, dodgey way to do it, but if you can't pull the balancer off then that's all you got.

If it's out, then you have to pull it off anyway

[Don Dada]

This seems strange because when i changed the belt on my rb25 i lined up all three marks ie. the 2 cams and the balancer before doing anything else.

When i took off the balancer and the backing plate the dot on the crank gear was already lined up with its mark on the oil pump, so i just fitted the new belt and bolted back up everything and all three lines were spot on.... no need to turn anything.

So going from this i thought it should be possible to line up all thee marks again, and as they don't line up, i assume my timing is off.

[Sydneykid]

You have to look at it with your head above the power steering pump though. Don't look at it straight down from the centre.

This is important, if you are looking straight down, lining up the cover timing mark and the balancer mark it will look like it's 5 degrees out. You have to have your head over near the airfilter box. the timing mark on the cam belt cover is not a simple dot, it's a straight line and you have to look along that line, not across it.

Cheers

Gary

[Don Dada]

Yup i'm doing exactly that.

[blind_elk]

Just to be sure, as you rotate the crank pulley in the normal direction (L->R, when looking from in front of the engine bay), the first line to line up with the timing mark on the crankcase cover will be 30BTDC, then 25, then 20, etc.

[Don Dada]

It's definitely on the second mark from the left ie. 5* when the cam gears line up.

I even turned the engine a couple of times and it always come back to the same position when the cam gears line up.

So is the timing off 5* ?????

[Sydneykid]

It's definitely on the second mark from the left ie. 5* when the cam gears line up.

I even turned the engine a couple of times and it always come back to the same position when the cam gears line up.

So is the timing off 5* ?????

Looks like it. From memory there are 48 teeth on the camshaft pulleys, so 3.75 cranksahft degrees = 1 camshaft pulley tooth. Correcting 5 degrees will be tricky without adj camshaft pulleys. You could step one camshaft pulley tooth, then it will only be 1.25 degrees out.

Cheers

Gary

[blind_elk]

Looks like it. From memory there are 48 teeth on the camshaft pulleys, so 3.75 cranksahft degrees = 1 camshaft pulley tooth. Correcting 5 degrees will be tricky without adj camshaft pulleys. You could step one camshaft pulley tooth, then it will only be 1.25 degrees out.

Cheers

Gary

Isn't it 1 tooth = 15 crankshaft degrees?

The crank does 2 revolutions for each revolution of the camwheel. So 48 camwheel teeth per 720 crankshaft degrees -> 15 crankshaft degrees per camwheel tooth.

If I'm correct (I've been wrong before), I wouldn't be worrying about it. If you bring the engine to TDC (as per the crank indicator), then the cams would be out (advanced) by 1/3 tooth (2.5 cam degrees, 5 crankshaft degrees), which is close to the adjustment applied on adjustable camwheels.

[Don Dada]

So what is the procedure to correct it?

I'm not too skilled in this area

Isn't it a matter of lining up the cam gears with their marks on the backing plate, take the balancer off and turn the crank until the crank gear lines up with its mark on the oil pump an put the belt back on???

Thanks

[The Dan]

Isn't it 1 tooth = 15 crankshaft degrees?

The crank does 2 revolutions for each revolution of the camwheel. So 48 camwheel teeth per 720 crankshaft degrees -> 15 crankshaft degrees per camwheel tooth.

If I'm correct (I've been wrong before), I wouldn't be worrying about it. If you bring the engine to TDC (as per the crank indicator), then the cams would be out (advanced) by 1/3 tooth (2.5 cam degrees, 5 crankshaft degrees), which is close to the adjustment applied on adjustable camwheels.

yeah 1 tooth on the cam is approx 15 degrees crank timing.

[The Dan]

So what is the procedure to correct it?

I'm not too skilled in this area

Isn't it a matter of lining up the cam gears with their marks on the backing plate, take the balancer off and turn the crank until the crank gear lines up with its mark on the oil pump an put the belt back on???

Thanks

Yeah, remove the balancer, line all the marks up and get someone who knows what they are doing to come and set it all for you. That way you won't start a 'My engine doesn't crank over anymore' thread.

[Sydneykid]

Isn't it 1 tooth = 15 crankshaft degrees?

The crank does 2 revolutions for each revolution of the camwheel. So 48 camwheel teeth per 720 crankshaft degrees -> 15 crankshaft degrees per camwheel tooth.

If I'm correct (I've been wrong before), I wouldn't be worrying about it. If you bring the engine to TDC (as per the crank indicator), then the cams would be out (advanced) by 1/3 tooth (2.5 cam degrees, 5 crankshaft degrees), which is close to the adjustment applied on adjustable camwheels.

Your right, I'm wrong, I should stop doing things from memory.

Cheers

Gary

[femno]

Like its been said, remove the balancer and check with the timing gear on the oil pump. You do know it is possible for the rubber in balancers to come adrift and rotate slightly dont you?

Why are you checking the cam timing? Are you looking for a problem or just trying to create one?

P.S theres no way one tooth is 5deg on the balancer, think about it.

[r33_racer]

isnt the second line zero? first line -5 deg?

Even so, just pull number one spark plug out and use a dial indicator to set no.1 to TDC and if your timing marks for the cams line up it should be good.

Just make sure you follow that dotted tooth back along the gear and line it up from the rear of the gear rather then eyeing it off from the front.

[Don Dada]

"Why are you checking the cam timing? Are you looking for a problem or just trying to create one?"

Yes i actually do have a problem!

This is an engine i got from an importer and installed in a C35 laurel chassis.

The engine at idle is a little lumpy even though i cleaned aac / throttle bodies etc, plus when given a quick rev it gives a "noisy tappets kinda sound as it falls back to idle and then is normal again at idle.

The other noise that had me concerned and made me start investigating is an "over tightened timing belt" kinda groan coming from the exhaust rocker cover in line with the no. 2 piston.

This noise is very audible and can be pinpointed to this one spot using the ole screw driver method, and only happens when the car is up to temp.

So i guess this may be the reason my idle is lumpy?!?

And can some one pls tell me what this groaning noise might be ???? it really has me bummy!