Another timing question(which way to go?)

[onetallmj]

Ok, I have already asked and got some good info on my previous questions about timing but forgot to ask a couple of more.

Stats: 88 MJ with a 4.6 Renix stroker with a Comp Cams extreme cam - when I got it back from the shop that put my motor in, it started and idled fine but under acceleration hesitated and backfired.

So I put the timing mark on the harmonic balancer on the zero mark on the timing chain cover and checked the distributor rotor and it was just about on the #1 spark plug wire, sooooo I put my timing light on it and it was showing the mark up near the top of the timing chain cover marks, not sure what timing it was since my cover is worn badly but its nowhere near the zero mark.

The questions I have are: A) which way do I attemp to turn the distributor to either move a tooth clockwise or counterclockwise? I know that the timing is controled by the comp. but obviously its off a tooth or two on the cam gear.

Is the timing on a 6 cylinder with an auto tranny supposed to be at zero or what?

thanks for all the help

 

[JJacobs]

You can't turn the distributor without grinding off the locating ears. Even if you did, it would only change the fuel timing, not ignition. Read up on indexing the distributor and try again.

 

[5-90]

I've put a timing light to my RENIX's a few times, and noted that the base idle timing was way back around 30BTDC! Checked in conjunction with a borrowed MT2500 (I really need to buy one...) and found that I was NOT getting any knock signals, and everything was rock steady.

No, I haven't figured that out yet. As long as your valve timing is good, and your idle and acceleration are good, you're probalby in good shape. Try some mild throttle blips and see if they stall or stumble or not...

5-90

 

[onetallmj]

You can't turn the distributor without grinding off the locating ears. Even if you did, it would only change the fuel timing, not ignition. Read up on indexing the distributor and try again.

Yes I realize that and thought I had made that clear before.

What I am trying to do is pull the dist. up and advance/retard the shaft/rotor a few teeth.

5-90 - so your saying that 30 BTDC is ok?
I am going to try and run it down the road tonight and see how it does.

UPDATE: Fired it up and it idled fine at 900 rpm. Tried a couple pushes on the pedal and it hesitated and backfired up at the higher rpm's. Smelled like it was running rich after I shut it off but that may be from the backfire.

So now what do I do? Cut the ears off the dist. and adjust it?

 

[onetallmj]

One other thing to add to this chaos - my #1 plug is at the 11 o'clock position instead of the 5 o'clock position I keep reading about. this leads me to believe I am 180 degrees off but it starts and idles fine so it can't be that much off?

 

[JJacobs]

You need to remove the distributor, move the rotor over a tooth, put it back in. You can cut the ears off later to play around with fuel timing, but that's more fine tuning, not fixing a tooth off.

 

[onetallmj]

Ok so I need to move a tooth, but which way, clockwise or counterclockwise?
And what is the ideal timing? O degrees?

thanks

 

[JJacobs]

If I remember right, the rotor needs to be at the trailing edge of the #1 plug tower, not centered on it. So that'd be one tooth CCW. Try it and see.

A little tip to make the change easier- don't worry about having the oil pump dead on so the dizzy slides all the way in first shot. You can drop it in so the teeth engage halfway, then rotate the engine by breaker bar or a bump of the starter. It'll drop right in the rest of the way.

 

[5-90]

5-90 - so your saying that 30 BTDC is ok?
I am going to try and run it down the road tonight and see how it does.

Am I saying it's OK? I'm really not sure. But, I've got an 87, an 88, and two 89's that don't seem to mind...

As far as being 180* out - I don't think that will bother it as well. I was playing about once (OK, experimenting) after I'd found out about that 30*BTDC thing, cut the ears off the distributor, and tried to adjust the timing. I actually turned the distributor about 3/4 of the way around - with the engine running! - and didn't even get a hiccup. I've got a good 25 years of mechanical work behind me, and I've never seen anything like that.

So, if you're idling fine, see if it runs up smoothly when you blip the throttle. If that's fine, take it for a checkride and take your time. If everything runs fine, I'm willing to bet you're just ducky and don't need to worry about it. I've found the RENIX setup to be highly adaptable...

5-90

 

[old_man]

Hope this helps.

 

[onetallmj]

Well for those of you who are interested or this came up on a search - I pulled up the distributor and went CCW and CW with the teeth, took a few times to experiment I guess I got it. I had cut the ears off also and fine tuned it.

Now to break it in finally!!!
thanks everyone for your help.