Firing order & TDC

[oldguy668]

I'm getting ready to install pushrods and rockers and I just want to confirm one thing. When #1 is at TDC and both lifters on the base circle, is #6 at the same condition? 90 degrees after, should #3 and #5 also be at TDC? In other words, one complete revolution of the crank, stopping every 90 degrees gives me an opportunity to adjust all 16 pushrods? Or is it 2 revolutions, stopping every 180 degrees?

[rich grsc]

I'm getting ready to install pushrods and rockers and I just want to confirm one thing. When #1 is at TDC and both lifters on the base circle, is #6 at the same condition? 90 degrees after, should #3 and #5 also be at TDC? In other words, one complete revolution of the crank, stopping every 90 degrees gives me an opportunity to adjust all 16 pushrods? Or is it 2 revolutions, stopping every 180 degrees?
With #1 at TDC, #6 will not be on the base circle, exhaust will just be closing, intake will just be opening. It will take 2 revolutions to adjust all the valves.

[edwardb]

It's definitely easier to follow the firing order when installing and adjusting your pushrods and rockers. As you rotate the crank, you can see the lifters move onto the base circle, and with your thumb over the spark plug hole you can fell the piston come up to TDC. But you don't mention the firing order of your build. Small Block Ford 260, 289, 302 order is 1-5-4-2-6-3-7-8. 302 HO/351W order it is 1-3-7-2-6-5-4-8. Most aftermarket cams use the HO/351 firing order. Make sure you're using the right one.

[Jeff Kleiner]

What edwardb said RE: firing order. Check your cam card to verify which order you need to use.

Jeff

[oldguy668]

It's an old block using an E303 cam, so late firing order. So how are the cylinders paired and how many degrees until the next pair ?

[edwardb]

E303 cam will be the 1-3-7-2-6-5-4-8 firing order. Once you have #1 on TDC, a 90 degree turn on the crank will take you to #3 TDC, then 90 degrees to #7, etc.

[oldguy668]

Okay. I'll go with that. One cylinder at a time 90 degrees apart. Two revolutions gets me all 16 valves.