Author Topic: Timing Marks  (Read 4790 times)

Offline AdzCM

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Timing Marks
« on: June 20, 2014, 06:57:23 pm »
Just fitted my timing belt. I lined the notch on the cam sprocket up with the arrow on the timing belt cover perfectly. Then lined up the '0' mark on the aux crank pulley with the appropriate metal marker.

Problem is, when I fit the belt and rotate it a couple of times and line up the crank marking, the cam mark is slightly out. The arrow on the inner timing cover still points to the tooth gap where the notch is but the little circle notch is not exactly above the arrow.

Does this matter?

Here are pics after I have rotated it a couple of times. I have removed, realigned and refitted/rotated this several times now, and the same thing happens.



Difficult to take the picture but the '0' line is just in line with the metal marking.



Here, the notch is slightly out.

Paranoia is setting in since I've spent so much money on this build. Second opinion can't hurt.

Adrian

Offline AdzCM

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Re: Timing Marks
« Reply #1 on: June 20, 2014, 07:10:28 pm »
Just had another look. If anything, the notch on the cam sprocket is a little more out than in that picture.

Offline SamG40

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Re: Timing Marks
« Reply #2 on: June 20, 2014, 08:33:15 pm »
Are you turning it over via the crank or cam pulley?

Offline RyanC

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Re: Timing Marks
« Reply #3 on: June 20, 2014, 09:09:40 pm »
there is nothing wrong with that mate,

if you unbolt the timing cover back it will move a bit as long as it not a tooth out then its fine nothing to worry about

 

Offline AdzCM

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Re: Timing Marks
« Reply #4 on: June 21, 2014, 12:25:49 am »
Are you turning it over via the crank or cam pulley?

Crank pulley ;)

Offline AdzCM

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Re: Timing Marks
« Reply #5 on: June 21, 2014, 12:37:00 am »
there is nothing wrong with that mate,

if you unbolt the timing cover back it will move a bit as long as it not a tooth out then its fine nothing to worry about

 

That's what I was thinking. If it is lining up with the gap where the cam notch is, its not out a tooth and should be ok. Really hope so. I'm going to try what Phil advised me, and check TDC by another means incase the crank markings are out a bit due to me having to bend the metal bracket up in order for the non-g40 pulley to fit. Though I'm pretty confident I bent it down again and got it pretty straight.

Thanks man. Ill have a nosey at moving the timing cover. I did think it moved a bit when fitting it and thought [that doesn't seem to be the best setup for accuracy.

Offline PeteG40

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Re: Timing Marks
« Reply #6 on: June 21, 2014, 08:19:33 am »
thats pretty near - sometimes skimming heads and just the play in keyways etc make a difference. I bet you can move the bottom aux pulley about too undoing the 4 allen bolts

Offline AdzCM

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Re: Timing Marks
« Reply #7 on: June 21, 2014, 11:45:43 am »
thats pretty near - sometimes skimming heads and just the play in keyways etc make a difference. I bet you can move the bottom aux pulley about too undoing the 4 allen bolts

Yeah, there's definitely a slight bit of play in the bottom aux pulley if you loosen it, so all of these movements probably add up to make it seem out. I reckon it must be ok. I've tried it a few times and every time it ends up looking like those pics.

Thanks Pete

Offline randombadger69

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Re: Timing Marks
« Reply #8 on: June 21, 2014, 03:40:56 pm »
Pretty much every g40 motor I've built is like this. I end up making a Mark in front of the dot on the cam pulley.

I timed up my 1043cc g40 engine build last night, this is using square toothed pulleys for 108T belt (because I had a vernier) and it's exactly the same. Something in the manufacturing process ended up slightly off. Probably the metal pointers.

It's 180 degrees out, but you can see the mark I made in relation to the original.



First time I built a g40 motor I tried getting the marks to line up and it ended up a tooth out. Would run with the dizzy swung right round and the bolts removed.
« Last Edit: June 21, 2014, 03:54:28 pm by randombadger69 »

Offline AdzCM

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Re: Timing Marks
« Reply #9 on: June 21, 2014, 05:11:41 pm »
The dot on your vernier pulley seems to be on the tooth? Whereas the dot on the standard cam pulley is in between the teeth [where you have marked it on yours]?? Would yours still be out a bit if you used a standard cam pulley?

That's a really nice engine by the way.

Offline randombadger69

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Re: Timing Marks
« Reply #10 on: June 21, 2014, 06:34:38 pm »
The dot on your vernier pulley seems to be on the tooth? Whereas the dot on the standard cam pulley is in between the teeth [where you have marked it on yours]?? Would yours still be out a bit if you used a standard cam pulley?

That's a really nice engine by the way.

That's because I'm using a MK2 pulley and belt setup with 108 square teeth, the MK2F setup uses 128 teeth trapezoid profile.

The position between my mark and the Factory mark on my engine and your mark and the pointer looks pretty much the same regardless of teeth. The difference in degrees would probably be somewhere similar.

Thanks, it's a right mash-up of leftover parts and silly colours!

Will all look the same covered in oil and grime, assuming it doesn't melt!  ;D


Offline AdzCM

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Re: Timing Marks
« Reply #11 on: June 21, 2014, 08:08:47 pm »
Ah right, I get you now. Cheers.

Nah, it looks cool haha. Why would it melt? Get it mapped as soon as. What is it? 1341 etc?

Offline randombadger69

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Re: Timing Marks
« Reply #12 on: June 22, 2014, 01:51:38 am »
It's a PY block with 1043cc crank and pistons, PY connecting rods. Two head gaskets one G40, one generic BGA copper oil way seal job. Then a SPi head with a G40 camshaft and sodium filled exhaust valves.

A right Frankenstein!  ;D