Good-Lord, now this

[Already a Rover]

Hi - The saga continues.  While waiting for parts to arrive from the Twilight Zone, I started looking into setting the timing between the cam and crank.  It turns-out that with the new ACR cam they want me to use the six-key cam chain-wheel and not one but TWO dial-gauges.  Three is even better, four would probably be even better yet, then I could measure the deflection of the timing chain. 

Okay, I'm exaggerating.  Does anyone have or know where I can get a 6-key chain-wheel?  Yes, I could call Ivor, but his wife is not too well these days.  Malcolm is still in NZ I think. 

Since the email from ACR is open, I'll paste what the fellow there said when I asked about just putting the camshaft back into the same (relative) position is was before: 

Good to hear from you! The Power plus camshaft, in order to get
the best from it does require careful timing in to establish
the relationship between the crank and cam. Unfortunately, its
unlikely to be right if fitted onto the original Land Rover
marks.

With the number 1 piston at TDC, the inlet and exhaust have to
be open by the same ( small ) amount. This correctly positions
the overlap stage. If one finds that out of the 6 offset key
ways on fitting the chain one is slightly tight, and another
slightly slack, then use the tight setting.

You don't have to fit the chain when finding the right key,
simply drape the chain over the chain wheels and you can
quickly run through the various keys in quick order.

Hope this helps! It is worth the effort getting it right.

[Red90]

If they require this with their million dollar camshaft, why do they not include it in the kit?

[roverwanabe]

Malcolm is back.  Spoke to him last week.

[Already a Rover]

Hi - yes, why not.  I got an email back from Bill Neilson in NS and he says the position they want you to find is called the "crossover" position, and this is exactly what the 2.25 wants with the old camshaft.  Does this sound right?  If-so, he said he can send me a cam gear with a mark on it.

Oh good, Malcolm is back, thanks.

Jim

[Red90]

You are setting the cam at the top of the exhaust and start of the intake stroke.  At that point the exhaust valve is closing and the intake opening.  What they are asking is to set the crossover point at TDC.  It is a strange way to set valve timing, but there you go.....  On a stock 2.25, the crossover is past TDC but this cam probably has more duration.

Normally...  with adjustable valve sprockets, you bolt on a degree wheel and set the timing based on the peak point but whatever they ask for.  If you are keen, you could grab a wheel and check out the whole came profile.  Stock settings are in the manual.

[Already a Rover]

Hi John,

In the diagram you sent, the crossover point occurs after TDC.  Is that a generic diagram, or??

I like the idea of the degree wheel - their method required two dial gauges. 

[Red90]

Yes that is just a generic chart to understand how the cams work and overlap. You should be able to get a degree wheel at an auto parts store or print one yourself.

[Already a Rover]

Hi - thanks.  I just sent this letter to ACR - hopeful of receiving a decent reply:

Hi Roland,

Nice to hear from you too.  I am caught in the middle, all the while desperate to get my engine together, but not wanting to rush on something as crucial as valve timing.  Getting parts has been a major hassle.  Anyway, back to the getting caught in the middle part: 

I have someone who can send me a single-key cam gear with a mark on it from a stock 2.25 engine, along with some other parts I need.  He and others INSIST the position you require for the cam - the crossover or overlap stage with the piston at TDC  - is the same for a stock cam.  This may be true, the goal may be at the overlap stage, but is it found at the same place/angle on the new cam?  That is, at the SAME ANGLE WITH THE KEY??  For a stock 2.25 engine, the Rover manual says the cam should be set mid-way between the fully-open intake and fully-open exhaust with #1 piston at TDC (you probably know this already).  I can use the gear he is sending and test to see if this is the overlap position on your cam with two dial gauges (which I will have to borrow from someone far-away), but if you can confirm whether or not the midway position on a stock cam is equivalent to the overlap stage on YOUR cam, then I will relax (a little).  If-not, then I know to get-going and pick-up the dial gauges and I can tell him to keep his cam gear.  Or, I am told I can use a degree wheel if the specs are available for your cam.

Can you send me the relevant specs for the PP cam?  Or may I ask you the same question as before, but in more detail, because, as I said, I am caught in the middle, and don't know what to do:  For your cam, is the keyway at the same position as a stock cam, and is the overlap stage mid-way between the  fully-open intake and fully-open exhaust with the piston at TDC?  Or perhaps the fully-open positions are different as well??

I am sorry to be so pedantic.  It is a major achievement for me to even ask this question coherently, and I hope it makes sense.  I am absolutely willing to be told I just have to do it your way, but this issue has caused some discussion between members here, and so some closure would be nice.  When you say "unlikely to be right" I am not sure if you really know, or are just trying to be safe, but someone there must know.  I would appreciate it if you can confirm (or deny) the above, forward the specs, or just say (again) "Do it our way" if necessary.

I look forward to receiving your reply AND to the improvements your PP head and cam will undoubtedly provide (along with a 60-over bore, 2" exhaust and TBI).