Bbc timming

[Frankenblazer]

Went to time my engine 77 454 to my surprise it was at 33 degrees, after I finished doing head gaskets, set valves 0 lash then half turn, set timming to 9 degrees, ran very poorly cranked up ign,timming up to 33 where it was before runs good there.kind of puzzled why so high?

 

[centexk5]

Did you have the vac advance on the distributor hooked up? I just did timing on mine this weekend and with the vacuum hooked up it's around 30-33* and unhooked it's at 10*.

 

[Frankenblazer]

It was unplugged

 

[Frankenblazer]

I thought bbc timming should be 4 to 8 degrees

 

[skunked]

Are you sure your timing marks are correct?

 

[Frankenblazer]

Yes I actually used dial indicator to find true tdc. And mark it ,it was off about 4 degrees

 

[Wes Harden]

Timing chain sloppy

 

[Frankenblazer]

Could be, thanks for the direction

 

[diesel4me]

Harmonic balancer slipped ?...or is that why you checked with a dial indicator ?...
Timing chain slop is a possibility,but I kinda doubt it could be that far off and not have jumped time yet..or maybe it did already ?..
Only other thing I can think of is maybe someone used a crank gear with multiple keyways and set it up on the retarded position ..

 

[Frankenblazer]

I also marked pulleys, the tab was unreadable, so while I was doing head gaskets I found true tdc and marked the tab,when I bought vehicle last year everything has been so missmatched,it's been one thing after another

 

[Wes Harden]

B4 you go after the chain, double check distributor clocking and wire position.

 

[Frankenblazer]

I hear you brother,been there done that,but definitely good advice

 

[1-ton]

Sounds like the timing is not advancing. If the vacuum advance canister diaphragm is bad the distributor will not advance. Advancing the distributor to 33-degrees initial timing is putting in all the timing the engine needs at higher RPM's.

 

[Frankenblazer]

Good call I will definitely check that,I honestly didn't even think about that,thanks

 

[76zimmer]

My general rule of thumb ( and each engine/vehicle needs vary) is start at 10* static mechanical only, and run the rpm up to 3500 and have all the mechanical advance in by then, I shoot for 34 on a BBC, then plug in the vacuum advance and shoot for 48-50 without it surging at cruise.
Its a good starting point, then you can fine tune it from there, depending on what the vehicle and engine are comfortable with.
Your results may vary!

 

[Frankenblazer]

Workingon it right now removed rotor .missing springs and plate broke, WTF, always the little stupid things