Dot on cam sprocket

[btetley]

998 with 266 cam regrind.

I'm trying to set up my distributor shaft and can't get the correct angle to the dizzy housing as per manual. (I'm checking I'm not one tooth out on chain)

Anyway I pulled the timing cover housing off to find that the dot on the cam sprocket seems to be 180 degrees away. I expect it to be adjacent the dot on Crank pulley when no 1 piston is TDC and no 4 valves are rocking (this should be when no1 is on compression stroke)

Any come across this scenario? . I'm really confused. Do cam sprockets ever get "dotted" 180 degrees out?

[GraemeC]

Turn the engine over one full revolution - you’re not on TDC on cylinder one firing stroke.

I used to misunderstand the term ‘rocking’ and preferred to look for cyl 1 valves being ‘loose’.

[btetley]

When I do this no 1 intake valve is opening and exhaust closing. So this means I Was already on compression stroke at TDC previously.

[GraemeC]

Just to check - you are taking number 1 as being at the water pump end?

[johnv]

You're not confusing the cam timing dots with piston tdc are you?
(sorry if that's too obvious, but I did it after a long day!)

[Andrew1967]

How far out is the distributor drive compared to the pictures shown in the manual ?

I've found that they never line up exactly as the pictures show.

[agricola]

I have an engine on a stand I will try and post pictures.

[ricardo]

Rocking means both inlet and exhaust of the same cylinder are a little open (in the overlap period).

Being n.1 the closest to the timing end, if you put piston 1 and 4 at TDC, 1 on firing stroke (both rockers 'loose') and 4 rocking, you should be able to get your dizzy spindle like this (the slots on the spindle more or less align with the dizzy bracket bolts).

[johnv]

Rocking means both inlet and exhaust of the same cylinder are a little open (in the overlap period).

Being n.1 the closest to the timing end, if you put piston 1 and 4 at TDC, 1 on firing stroke (both rockers 'loose') and 4 rocking, you should be able to get your dizzy spindle like this (the slots on the spindle more or less align with the dizzy bracket bolts).

Right.. But the sprocket dots won't be lined up

[btetley]

You're not confusing the cam timing dots with piston tdc are you?
(sorry if that's too obvious, but I did it after a long day!)

Not sure what you mean?

[btetley]

Rocking means both inlet and exhaust of the same cylinder are a little open (in the overlap period).

Being n.1 the closest to the timing end, if you put piston 1 and 4 at TDC, 1 on firing stroke (both rockers 'loose') and 4 rocking, you should be able to get your dizzy spindle like this (the slots on the spindle more or less align with the dizzy bracket bolts).

Right.. But the sprocket dots won't be lined up

Are you using a minispares duplex sprocket by any chance?

According to the Haynes manual the dots should be adjacent to each other (lined up) when the distributor is just like your picture and no1 is on compression stroke.

I have done more hunting on the internet. On the MiniSpares forum I came across someone else who has the same issue. What they found is that the MiniSpares duplex cam sprocket has the dot 180 degrees out compared to the simplex sprocket.

I verified this with a spare camshaft and sprocket I have. On compression stroke with no4valves rocking and the dots line up.

[btetley]

Just to check - you are taking number 1 as being at the water pump end?

Yes