1800 project update - cam timing

[Nut124]

I finally got the engine out of my -78. It has been on block for at least a year. Bad trans and too much blow by.

With engine on a stand, I decided to degree the cams to see what my baseline is. These are the Bayless(?) 40/80 - 80/40 cams installed back in 2000 or so.

See blow for the results and pics. I built an extension to my 1" dial indicator to measure tappet travel. Note that the dial indicator plunger is not perfectly parallel to the valve, so total lift numbers are a bit off.

Anyway, results show the intake cam is 5 deg retarded. The ex is 3 deg or so. Im thinking about putting a 42/82 intake and using adjustable pulleys to to lobe centers at 110.

Do you think the 42/82 cam is too much?

Anyone use/like TotalSeal gapless rings?

[Nut124]

I had to check the cam theory and how specs are defined again.

So it does look like the intake cam is 5deg retarded, based on max lift (115ATDC), or 10deg based on intake closing at 90deg vs. 80deg ABDC.

The EX, however is advanced by 3 deg, not retarded. This is because the EX cam spec numbers for max lift are BTDC, not ABDC, so a bigger number is advance not retard.

Below is the cam chart with corrections, clarifications.



I wonder if the 10deg late closing of the intake was the reason this engine only developed about 135psig cranking pressure?

I took the block, crank and the head to a machine shop. They look good. Bores need inspection and a hone. Crank is good. All bearings looked normal. Head has a few nicks, not sure if it needs a resurface. Valve seats and guides are good.

Valves need a very light 45 grind. Does anyone grind valves to 46 for 45 seats anymore like the Croft book suggests?

Need to order HC pistons, clutch, adjustable cam sprockets. Gasket set. Seals.

Want to improve the oil pan but do not know what to do. On the track in the past oil was blowing out of the breather tube in RH corners.

Ideas?