1/2 Tooth off?

[Anthony]

In December of 2021 I had to replace my crankshaft. I did it with the engine in the car and used a degree wheel to set everything up. Replaced the sprockets and chain. The engine starts and idles ok, Can cruise at 50mph at 2500 rpm. Engine also seems to run a little hotter. Car has very little power under acceleration in any gear, bogs down and occasional detonation. The car then sat for over a year while other things took precedence. Before this work the car had very good power and was vacuum tuned to 17 Hg. The car now runs best at just under 13 Hg. When setting up the new crank I left the hood on and suspect that I may not have had a proper view when aligning the sprockets. Would the 1/2 tooth difference result in symptoms like this?

Thanks for any insight or information.

[poolboy]

Do you mean camshaft not crankshaft, Anthony ?
If so you can check that with a fully assembled engine if you have a stock cam shaft or even a non-stock if the lash is the same for intake and exhaust
Just see if the valves 11 and 12 are 'on the rock' (equal lash) when piston # 1 is at TDC on the firing stroke with both valves completely close

[Anthony]

Cam shaft, I will try that method. Thanks

[Anthony]

Poolboy,
Today I put the engine at TDC on number 1 and 11 and 12 are partially open, no lash to measure.

[poolboy]

Keeping an eye on the marks damper or your degree wheel card oscillate the crankshaft clockwise and counter clock until you can measure equal lash on 11 and 12.
If that occurs within either 5* before or 5* after the TDC mark, you have the cam timed close enough not to be the cause of the problem you described.

[Anthony]

Great, next up. Thank you

[Anthony]

Way off, 180 degrees? that's just of get one of them closed. When the gaskets come I will get the cover off and put the old cam sprocket on. When I set up the new sprocket I mated it up to the old one, not realizing that the 2 pairs of holes are not symmetrical.

[poolboy]

180 ? Before you do anything make sure that # 1 piston is TDC on the firing (compression) stroke with both valves 1 and 2 are closed.....
Piston 6 will also be at TDC but at the end of Exhaust and the beginning of Intake (aka overlap) with valves 11 and 12 having equal lash.....Don't expect that to be .10" like the fully closed valves...11 and 12 will have less when they are 'on the rock'

[Anthony]

I was probably about 60 degrees that 11 had closed and had some lash, I did not keep turning it at that point. Motor was definitely at TDC both closed. I turned it clock wise and anti, similar result just different valve .

[poolboy]

If you have a Bentley, you could follow the foolproof steps for new unmarked sprockets.
ENGINE chapter. Section 12.41.05 Steps 73 thru 87.

[Anthony]

I only have Haynes, but I am thinking to just put the old one back on. I only changed it because when I replaced the crank I thought the chain was stretched too much. Thanks I will probably get a copy now.