If following the service manual this only talks about the exact same parts as what was in the engine before so this is where im stuck now...

So these are the specs for my new cam:

Lift: In = 267"
Ex = 260"
Duration: In = 316 deg
Ex = 309 deg

What the problem is is that now i am putting on my cam & crank sprockets and the timing chain and getting these inline and working together is the problem.
The manual says the camshaft dowel hole must be inline with the key groove on the crank sprocket when first installing the timing chain - and in theory if all correct when setting No.1 piston at TDC the match mark for the crank will align with the key groove & the match mark for the cam will align in the center of the other........(tell me if i explained that sh|t )

BUT! the problem is that with my new cam these markings do sweet bugger all as their quite different (i.e not working as one!!)

SO, the question i have is, is there a way i can easily calculate where my timing marks should be without getting someone else to do it or taking it to the dyno or something??? If more specs on the cam are needed i have the whole sheet right here....

Advice greatley appreciated!
Cheers
Dave (this is all a bit too much for me! )

My book also says sumthin about there being 10 links on the slack side of the chain between the dots on the two sprockets. (10 links is a guess by the way, I don't know exactly off hand)

However, if you have ad a lumpy grind put on your cam, you will have to check the timing using a degree wheel and a DTI.

Well i do not own a degree wheel or DTI (whats that stand for?) or a timing light etc...

Well surley if set at TDC on no.1 and then putting the cam sprocket and adjusting that to the match mark on the crank sprocket would work the same no?
Wat im trying to get across is that the two dots on the two different sprockets WOULD line up if set at TDC on no.1 and then just adjust the cam to suit the other dot...But i have had no experience with this so please, someone show me some guidence!!! I know that the cam size does not change, like the lobe is the same (turns the same) but the timing is much different...

Should i just ask the shoip who did all my bits or what?

Dave

I hope you have an A series engine if so ...

That is kinda what I was on about.
However, when a cam is ground, material is removed from the base circle. When you have increased duration, the ramp is changed. This means that the valve opening (or the "event") may occour sooner.
What is done in i this instance, is true tdc is found (there is about a 10 degree dwell period at tdc) by turning the cranshaft one way untill the piston reaches the top of it's stroke. A marknis placed on the pulley . (or degrree wheel)) tThen the crank is rotated the other way untill the piston reaches the top as well. Another mark is put on the pulley. The point halfway between theese two marks is exactly tdc. Then you set up a DTI in a magnetis base on the block deck, with the pointer of the DTI iin the cup of a pushrod. turn the cam srocket untill the lifter is on the back of the base circle. (No lift) Then zero the DTI. There are a few ways of doing it from here.one way is to wind the cam around till the DTI shows peak lift, and the rotate the crank till the degree wheel show the number of degrees at which peak lift occours on the cam specs.

If aftere doing this, the dowel hole lines up, then your cam is said to be "Straight up" . Depending on how much meat has been ground off, you may get away with this.

A buddy of mine, had a full race A12, with a mega lumpy cam. It used to pull to 9500. But when he dialed it in, he had to advance it buy about 13 degrees.

Datrat_dave,
If everything so far has confused you or you don't have all the fancy equipment, give this a go!

It seems your cam has similar lift & duration on inlet and exhaust. Have a look at the actual timing figures. If your inlet valve open (IVO) and exhaust valve close (EVC) figures are the same (symmetrical) or close, then this means at top dead centre (between exhaust and intake strokes) the two valves are both open and pretty well level.

ie, If your head isn't yet bolted to your block, slip both cyl.1 pushrods in and they should achieve equal lift at TDC. This ONLY works if the IVO and EVC figures and lift figures are equal.

I've used this method before and it was obvious as to what chain link the cam should be on, even though the lift was slightly different.

Yo dude.
It's worth spending the time to get it right, as the cam is the 'brain' of your engine, and it'll all just end in frustration and dissappointment if it doesnt perform as you expect.

The total duration is pretty meaningless, it's just impossible to accurately state where the valve starts opening,. you really need to either ask the cam grinder where to set the thing up at (inlet fully open at XXX degrees atdc) or get the specs at a fixed lift (usually 050 thou) and derive where full lift should be.

You really need a dial guage (the afforementioned DTI) and a degree wheel (like a big protractor). You can then set about finding out exactly where top dead centre is, and where the cam's happening at!
You then need some way of adjusting the cam timing (I suspect that Erol will be able to source you an adjustable sprocket)

A little time spent now will be worth it, and hey, you'll learn a heap which is never a bad thing!

Thanks for all the info guys i finally got it right.........The usage of the 10 links between both match marks worked fine and both came inline when turned to TDC. My cam specs are usful in this application aswell in setting the right tappet clearance for my rockers, i think the manual said no more than 15mm clearance otherwise adjust but mine were all intact and gewwwwd!!!
The guy from the shop also told me another method of finding the timing mark...You set it at TDC, put no.1 pushrod in and measure the clearance between the rod and rocker and tappet clearence, i cant remember what distance is required but this is also another way i found out!!!
My motor is now fully assembled with rocker cover and everything, BUT i ran into a problem...My new extractors hit my intake manifold when i fit them and i have about a 3cm gap, so now i have to adjust or make my own set!! But it dont matter much atm as i just lost my licence for 3 months which sux so i have time...

Cheers
Dave