TOP DEAD CYLINDERS???'s

[dickeymoore]

When a sbc engine is at tdc at cylinder compression stroke on number 1 is it also at tdc at cylinder number 8 and so on like tdc at cylinder 4 and 3 etc?Thanks

 

[Built6spdMCSS]

TDC at 1, and TDC at 6. Google it.

 

[dickeymoore]

couldn't find do you have link you can send me

 

[79 USA 1]

I believe this is what you are looking for.
1 8 4 3
6 5 7 2
(1 and 6), (8 and 5), (4 and 7), (3 and 2) are companion cylinders, therefore they are at TDC (one on compression, one on exhaust) at the same time.

 

[Built6spdMCSS]

couldn't find do you have link you can send me

www.google.com

 

[79 USA 1]

I recall being told by a high school shop teacher MANY years ago on Chevy small & big block engines and most V-8's to take the firing order, place the first 4 in sequence above the second 4 and that would give the companion cylinders. Could be verified by the 180 degrees apart on the distributor cap. Sounds hokey but has seemed to work. Below is a illustration on a small block Chevy.
Hope this helps!

 

[Built6spdMCSS]

Nothing hokey about it, it literally is the mechanical motion of the Pistons on the Crank. Any V Block 4 Stoke engine with 4 or more Cylinders that have 2 Cylinders per Rod journal on the Crank in even multiples will be this way. First half of firing order will be paired with the last half of the firing order. Thats how you get your Cylinder events.

Inline Engines even multiple of Cylinders (4, 6, 8..) on a Flat Plane Crank will be the same way.