10 replies to this topic

[Avtovaz]

standard 998 engine, and cam. single chain, alowing for stretch of the chain etc, where should i set the cam in at? 

 

thanks

 

[Dusky]

108 degrees.

[ACDodd]

That’s 2 degrees retarded I would install that at 104.

Ac

[Cooperman]

108 degrees.

 

That is what I normally set a BMC/BLMC cam to as the nominal is 110 degs.

For a Kent which is nominal at 106 degs I set 104.

I once did a check on a new duplex set-up with a 286 cam and after about 1000 miles and some high revs on rally stages, I took the cover off and checked. The chain had by then stretched initially by 2 degrees and after the initial stretch the chain settled down and the stretch is then much slower. After 7 or 8 rallies I change the chain, but leave the timing at 2 degs advance from nominal.

It is always surprising how far out the cam timing can be when set 'dot-to-dot' on the sprockets, although many people never check the actual installed figure.

[ACDodd]

If it’s an a+ engine the timing is 9/41.

To work out the lobe centre angle of the inlet lobe the equation is, 9+41+180=230 of duration. Divide this by 2 equals 115, then take away 9 = 106. Therefore install at 104 inc 2 degrees of advance.

Ac

[Avtovaz]

ok thanks! i was expecting like with my volvo engine t5 cam lift at tdc. 

 

Opening Duration 300 degrees
cam lift 12.9mm
Lobe center line angle 108 degrees
TDC lifting about 4.5mm.
Valve clearance 0.35 mm
Lash cap required: Yes; 4mm thick is recommended

 

 

but i can work this out!

 

 

thanks

[Avtovaz]

checked the timing today and from the factory it was 108. 

 

i thought maybe it could be out but its ok.

[Kevybmini]

Daft question, can I check the cam timing on a complete engine 

[Spider]

Daft question, can I check the cam timing on a complete engine 

 

Yes,

The way I have done it, you'll need to pull the Radiator out, find TDC and fit a Degree Wheel. I have used a Piston Stop (search it) to find TDC and zero in the degree wheel. Then fit a DTI to measure cam or valve lift, I used the latter.

[Kevybmini]

Cheers, i might check it 

[Shooter63]

To expand on Spiders post, buy yourself a 14mm chainsaw type piston stop ( The metal type around £4.50 ) looking down the no1 plug hole, bring the engine up to best guess TDC, make up a pointer and fit your degree wheel to zero. Now back the crankshaft off say 45 degrees and fit the stop, slowly and carefully rotate the engine clockwise, you will feel the piston hit the stop, note down the reading on the degree wheel, now rotate the engine anti clockwise until you touch the stop again and note down the reading, then divide by 2 and adjust the wheel accordingly. If you haven't got a degree wheel you will need the pointer on the bottom pulley with masking tape on the pulley, make the two marks as above, use a flexible rule, measure and divide by 2 to find your TDC. Then its just a case of getting the circumference of the pulley dividing it up into degrees and bingo, a dti on no1 inlet valve and off you go.

Shooter