Cam timing guides

[Jamo]

Is this pully adjustable for the belt wheel about the camshaft and also the sensor disk with the window...therefore 2 different adjustments.

1. cam timing to crank position,
2. hall sender signal relative to TDC.

Can you tell from these pics?

[Audi_CQ]

blocks have been used in Norway for some time, and they use oe belts no issues. Like I said in my previous post, timing right on head and on bottom, put on belt and no probs. One should not make it more difficult than it is

Not quite right. I'm using a tall block with 3B type tensioner, but RS2 belt with 150teeth compared with the 3B's 147 teeth. This to compansate for the extra height of the block.

What you say about "timing right on head and on bottom, put on belt and no probs" would be right if difference in distance between the low and tall block was an excact number of cambelt teeth. Problem is that it isn't. My 7A cams was 5 degrees advanced when using stock pulleys.

[urquattro-island]

well

when you change a cam belt, it is good to take a couple of turns to see it is still on tdc after turning. I dont see how timing changes, when its allready set to tdc, the belt only travels an equal lengt a time . That does not change, ok may be that some use the longer rs2 belt, but still some use the Oe also.

[Flat on my back]

Jamo.

The center wheel of the adjust. cam is fixed to the camshaft and so is the hall disc with the window cutout...so not adjustable.

Your only adjustment is the ex. cam timing relative to the crank (tdc).

Remember that the inlet is on a chain linked to the ex. cam, so moving one moves the other. The only way to return the inlet to the original timing is to change one/both inner chain wheels to adjustable types.

I dont expect timing changes you might make will move the window position completely out of TDC, reference the flywheel pin.

HTH.

[Flat on my back]

.

Did you look for a Dayco belt of a better lenght?...Its where i got my 25mm from.

[urquattro-island]

hmm

see now we are talking about a dahlbeck wheel, i was only reffering to original timing.

[mcandmar]

That wheel should work fine for what you want to do as the timing wheel is fixed to the camshaft, i.e. as long as the cam timing is set correctly the window for the hal sensor will be within spec.

Only limitation would be if you want to advance/retard the cam timing significantly from the stock timing the hal sensor window would fall out of range. But thats another issue all together.

I think pisobikers problem was nobody made an adjustable pulley with a hal sensor window when he started this project, since then DB have made the tasty little fella you have there.

[Jamo]

The center wheel of the adjust. cam is fixed to the camshaft and so is the hall disc with the window cutout...so not adjustable.

Your only adjustment is the ex. cam timing relative to the crank (tdc).

Remember that the inlet is on a chain linked to the ex. cam, so moving one moves the other. The only way to return the inlet to the original timing is to change one/both inner chain wheels to adjustable types.

I dont expect timing changes you might make will move the window position completely out of TDC, reference the flywheel pin.

HTH.

So I have two wheels, the Pisobiker one adjust the hall disc cutout and it seems the dahlback only adjusts the physical cam timing.

[Jamo]

That wheel should work fine for what you want to do as the timing wheel is fixed to the camshaft, i.e. as long as the cam timing is set correctly the window for the hal sensor will be within spec.

Only limitation would be if you want to advance/retard the cam timing significantly from the stock timing the hal sensor window would fall out of range. But thats another issue all together.

I think pisobikers problem was nobody made an adjustable pulley with a hal sensor window when he started this project, since then DB have made the tasty little fella you have there.

O.K thanks mcandmar, I think it's slowly sinking in, I wish engine building was like lego

I'm keeping it as simple as possible for now with the NM cams so it seems I have some reading to do.

anyone recommend a good degree wheel or will the printoff versions on the web do?

[S2central.net]

Just seeing this one... I believe that mcandmar is right - Pisobiker's funky pulley was to put the hall window in the correct position with that stroker setup... I think you will need two adjustable cam gear sprockets (from Dahlback for example) if you wish to adjust cam timing independently.

@Jamo - you are absolutely right to ask and check this stuff - get a timing wheel and some time on your hands to take the measurements to assure yourself that the cam timing is what it should be...

Its only when the engine is running that you'll see if the timing pulses are in spec - the crank reference pulse MUST arrive within every other hall window - ideally in the middle of it but not crucial AFAIK. Actually with the engine on a stand you should be able to visually confirm if things are aligned.

[mcandmar]

I printed a wheel off the net, plenty of them out there in google images. I used a clamp to mount a scriber to the block so the 90 degree end is pointing at the crank pulley face, find TDC, then stick the wheel on the crank pulley lining up 0 degrees

[Audi_CQ]

when you change a cam belt, it is good to take a couple of turns to see it is still on tdc after turning. I dont see how timing changes, when its allready set to tdc, the belt only travels an equal lengt a time . That does not change, ok may be that some use the longer rs2 belt, but still some use the Oe also.

Scenario: you have a cambelt that is excact the right lenght. No adjusting on tensioner. You can set cams and crank 100% right and on a 2.2 block it fits, but when you put on the cambelt on on a 2.5 the teeth doesn't line up. You must move the cams a bit to get the belt on. This of course with std nonadjustable camwheel

[urquattro-island]

ok

Scenario: you have a cambelt that is excact the right lenght. No adjusting on tensioner. You can set cams and crank 100% right and on a 2.2 block it fits, but when you put on the cambelt on on a 2.5 the teeth doesn't line up. You must move the cams a bit to get the belt on. This of course with std nonadjustable camwheel

I see where you are going, since i have not tested this on the tall block, ill have to bow down. But i do not see how the timing belt can be that short, or you would not be able to fit a tensioner on there. And if there is room for the tensioner there is room to get the belt on, without moving any teeth, there are some tight belt changes going through my hands but, as i say have not tested the tall block in real life with 2,2belt so i trust you. was only saying that some have done it without problems.

Tror du kjenner han som kjörer med original rem. Taken from zatzy.com

jonus racing
Registered User


Namn: Jon R

Registrerad: May 2002
Ort: Fredrikstad.Norge
Inlägg: 1 098
Bilder: Galleri


Skrivet: 7th February 2006, 22:29
Citat:
Ursprungligen postat av djcnp
Vad kör du med för kamrem till 2,5l blocken? för den är ju 16mm högre än ett 2,2l block




Jag kør med orginal kamrem til mitt høga blokk. Min 2,6litare i sesong o4 kørde jag på det korta orginalblokket,også med orginalkam rem

[Jamo]

Urquattro Audi CQ is right end of mate, tried it myself

[urquattro-island]

super

duper every day one learns something new.