454v8 timing-need help

[WHEELMAN]

BOUGHT THIS 86 GMC-some one five years ago.had painted and installed this 454v8.the guy i got it from.had it two year.he was not playing with a full deck.things were out of adjustment.i have been fixing little things..for awhile now.

the engine was running low power.gas just running out the exaust.no timing pointer.on the timing chain cover.i moved the distributor.towards the carb.the thing was big time.retarded.i ran the engine idle up.moved the distributor.untill the engine ran strong.

but when i go up the road.and stop some where.it cranks like the timing is off.big time.i am wondering.if the distributor.could even be out of time.with piston one.on the compression stroke..

i need to figure this out.just doing a little bit at a time.now dealing with this..tell me what you know..any one else dealt with this..on the big blocks..

 

[bucket]

Without a timing tab, you will always be guessing.

Adjust for fastest idle, set idle, then adjust for fastest idle again. If engine is hard to crank, back off timing a wee bit and try again. If it's still hard to crank, back it off a little more. Reset the idle again if it needs it, then drive it and see how you like it.

 

[HotRodPC]

Also, how many miles on this motor? Is it possible the chain is very worn? If so, even with a timing tab, and making sure you have the correct timing tab, if the chain is very worn, even with initial timing set to proper spec, your actual timing can be retarded from the light is showing, so if its high mileage, you want to add a couple degrees to compensate for chain wear.

 

[crazy4offroad]

This would help a lot...
http://www.summitracing.com/parts/PRO-66109/?rtype=10
And it would be worth the time and effort in my opinion to check the timing chain for slack, and check valve lift for worn cam lobes.

 

[89Suburban]

Also, how many miles on this motor? Is it possible the chain is very worn? If so, even with a timing tab, and making sure you have the correct timing tab, if the chain is very worn, even with initial timing set to proper spec, your actual timing can be retarded from the light is showing, so if its high mileage, you want to add a couple degrees to compensate for chain wear.

I have always went by the premonition that if you see the timing mark dancing around in the timing light that meant a loose chain. Thoughts?

 

[HotRodPC]

I have always went by the premonition that if you see the timing mark dancing around in the timing light that meant a loose chain. Thoughts?

Not always. Could be a bad inductive pick up on the tool, could be a bad wire you are hooked to, or even a worn dizzy cap and rotor causing the gun to receive bad signals. Normally a loose chain is going to hold its slack at low rpm. Where you'd notice a loose chain is if when you let off the throlle and/or stab the throttle.

 

[89Suburban]

Not always. Could be a bad inductive pick up on the tool, could be a bad wire you are hooked to, or even a worn dizzy cap and rotor causing the gun to receive bad signals. Normally a loose chain is going to hold its slack at low rpm. Where you'd notice a loose chain is if when you let off the throlle and/or stab the throttle.

 

[WHEELMAN]

I got too install a timing pointer..then go from there..

 

[HotRodPC]

You really only need the pointer for fine tuning using a timing light. Although, the pointer and KNOWING for sure you have the right one with the right balancer does give you some more ways of diagnosis.

If you think the dizzy is off with #1 compression stroke, you could always dead stick time it. Bring #1 up on Top Dead Center of the Comression Stroke. Then pull the dizzy cap. Where the rotor is pointing, in referance to what plug wire on the dizzy cap, that is where you want #1 wire plugged in. That will get it started. Then you can fine tune by ear, or timing light from there. I'd go with more advanced timing, then keep backing it down until the pinging goes away, then an additional 2 degrees to be sure you don't end up with any run on or dieseling issues.