Pulley Timing Mark?

[whitenviro]

Hello: I'm not on here often, but have been trying to get the timing chain set on a Sprint engine I am building up from a TR7 2L block. I still have access to the flywheel, so I can line that mark up with the line on the engine back plate. When I install the timing cover and pulley, the timing marks are off completely; by about 38 degrees!

I think the pulley may have slipped on the rubber section. Shouldn't the timing mark be close to the slot for the woodruff key? That would line up with the gauge. If it has slipped, I don't know if I should use it, but over here in the U.S. Sprint parts are hard to come by. I could just cut some new marks on the inside and outside of the rubber and keep an eye on it in case it slips again. I don't think it can do any engine damage, but it could make setting the timing more difficult in the future.

Here's my pulley: Is that mark in the right place?

Thanks

[Mad Mart]

Your pulley is fine, it can't slip otherwise it would be broken. The flywheel has probably been put on in a different position. I've not come across many where the flywheel lines up with the mark with piston no.1 at TDC.

Make sure no.1 piston is at TDC then see where the mark lines up on the pulley. The mark on the pulley should line up with the zero on the pointer. If it doesn't then you will have to remove the timing chain cover and redo the valve timing.

[whitenviro]

Thanks for the quick answer. The rubber part slipping was a topic on the Wedge List a while ago, so that put the idea in my head that it might have happened. My other thought was that it was a modified TR7 pulley, since that timing mark on one of those is about 30 degrees different than the Sprint. It wouldn't surprise me if the flywheel were out of position; I'll check that.

[Jon Tilson]

TR7 and Sprint timing covers are totally different and the timing marks have to be done as a set. The flywheel marks are only ever approximate.
The timing mark should be within a degree.

I suspect you have a 7 pulley and a Sprint case. They will fail to align as you see there.

Is this going in a 7 or a Sprint? Flywheels and end plates are also different, as is the sum and engine mounting setup and alternator fitting.

Jonners

[whitenviro]

Good points all. This is a TR7 block with lightened TR7 flywheel and TR7 backplate, so those marks will be the same and should be TDC (but aren't). The pulley and cover are Sprint and once lined up at REAL TDC, actually are correct. It is going into a 7, so I'm pulling the other interchangable parts (alternator, sump, etc.) from the TR7 block. Distributor, head, intake, carbs and many other parts collected mostly from the helpful people on this forum over the last couple of years.

The issue turned out to be the balancing that was done on the engine; they did not have the backplate with them at the machine shop, so they balanced everything with the flywheel in a different position not aligned to that mark. Now I need to keep it in their position to stay in balance, so those marks will never line up again. To do the chain, I was lining up those TDC marks, when I didn't realize they were actually almost 40 degrees out of whack. Lucky I didn't damage a valve; I had turned the engine some by hand after installing the chain. Unfortunately I had to pull the head back off to confirm no damage. So one step forward, three steps back.

Thanks for the help and comments!
Dan

[Jon Tilson]

Valve timing is critical and may well be out a little on the cam timing marks too if the head has been skimmed.
Now you have confirmed your crank pulley and timing cover marks are right its well worth checking the valve timing.

Jonners

[whitenviro]

Yes. With the head back off, it will be starting over completely on the timing. I wrecked the head gasket taking it back apart, so I'm waiting for the new one to arrive, which could be a few days. I had a light skim done on the head so had used a thicker head gasket, but was having some chain issues; it seemed off by part of a tooth. I don't think I needed the thicker gasket, it was a very light skim. This time I bought a Payen standard thickness gasket from Rimmer. Hopefully it will all line up and I can move on to the next challenge.

Dan

[80Sprint]

A light skim will not make much difference. Assuming this was the first ever skim. There is a measurement I have, and on where somewhere, that shows the minimum head height from the face to the cam journal on the Sprint head.

[whitenviro]

Another good point; I looked it up on here as 120.5 mm. I'll see where mine falls, but I'm pretty sure this was the first skim on it.