Cam and crank timing

[blitzkraig]

I'm currently in the process of reassembling my engine. I purchased a timing chain kit and started to put everything together on the front of the engine, but the cam sprocket timing mark won't line up when the crank is at TDC. When the notch is lined up the crank is two marks from TDC on the harmonic balancer according to the timing pointer. I realize there's three different orientations on the cam sprocket to advance and retard the cam but should everything line up on 1 when I replace all the front end pieces? Any help greatly appreciated

[Zedrally]

Without looking at the manual. I have no idea. This shows the importance of having the FSM at your fingertips when undertaking operations such as this.

From memory [and I wouldn't trust it], I thought the cam sprocket lined up on #3.

Now I'll sit back and wait for the corrections!

[blitzkraig]

Well I tore out all the timing stuff and reset the crank at TDC and put it all back together at the 1 mark on the sprocket. The marks are closer now for some reason (I hate it when that happens:tapemouth ). However they don't quite line up. The sprocket mark is just at the right edge of the thrust plate mark. Is this acceptable or should it be dead center matched?

Thanks for any replies

[Bambikiller240]

Originally posted by blitzkraig

Well I tore out all the timing stuff and reset the crank at TDC and put it all back together at the 1 mark on the sprocket. The marks are closer now for some reason (I hate it when that happens:tapemouth ). However they don't quite line up. The sprocket mark is just at the right edge of the thrust plate mark. Is this acceptable or should it be dead center matched?

I'd suggest checking this in a shop manual (preferably a Factory Shop Manual), since I don't have my manual here and I'm going by memory but I believe that what you are showing in the .jpg is correct (or within spec).

[JEFF]

I went through my whole engine 2 months ago. This was the easy part. If you 'reset' your crank to TDC - do not move it. You need to rotate the cam untill the #1 dowel hole lines up,Both valves on the #1 cylinder must be closed. This will put the top 'Bright Link' at about 3 o'clock. Your bottom 'Bright Link' will also be at 3 o'clock on the crank gear.

- Jeff

[sjcurtis]

looks like you got some good information. Can I just add, set up on position 3 if it is not to late,The L series Six loves it there for some reason the four cylinder l series engines like position1 and position 2. The v notch is good up high on the slot like that if the rest of the alignment is good.

cheers

Steve:classic:

[blitzkraig]

I put the sprocket in the other positions as well to see if it lined up any better and the first position is the closest. Aren't the other two positions for if your timing chain is wearing out?

[Bambikiller240]

Originally posted by blitzkraig

I put the sprocket in the other positions as well to see if it lined up any better and the first position is the closest. Aren't the other two positions for if your timing chain is wearing out?

They can be used if the chain is stretched. Also, back in the day, the C Production Z cars routinely set up their cars with the #3 position to get more power out of the engine. AIR, the differnce in cam timing between each of the positions is something like 4 degrees advancing the cam timeing in relation to the crankshaft timing marks. Of couse back then, there was higher octane gasoline available so this may not be something you could get away with (in the US) now.

Maybe someone with more knowledge can pipe up here and advise us both, as I'm about to start assembling the top-end of my newly rebuilt short block L24 and I'd like to optimize the engine for the best power I can get out of the crappy gas we have here in California.

[sjcurtis]

Agree C production thats where it got started, a lot of other diffrences in those engines to run the high octane fuel. I dissagree with the rational that repositioning the cam within the three dowel hole range will affect operation adversly when utilizing poor fuel grades as legislated in by the State legislators, a lot of other engine build considerations come into play. I do not know what restriction or fuel you are running so I can not advise there.

To my own situation my cam is a standard profile "smog" Z cam set up to position three, all gear was as new at engine build.

My last smog test on this engine was CO 2.11% and HC270 PPM with unleaded about 87 Octane fuel and that was carried out under full test conditions by the Pollution Control Commission of NSW. I was well within optimum range and the engine was passed as acceptable.

I hope that someone can advise you guys for the California Requirements.

Good Luck

steve

:classic:

[blitzkraig]

There will be nothing but premium gas for my baby when she's back on the road, so I would like to squeeze more power out of the little motor. However I just finished up sealing the timing cover this evening so it's a little late now. Check out my gallery to see how the motor turned out