401 nailhead distributor moved.....

The timing is off because the the u clamp loosened an the distributor moved. Can this mess my whole motor up? I have driven it an didn't know at first. Is the motor trashed?

 

What does my timing need to be set too? 401 bored .80 over,stock cam. Went with electric cooling fan, probably didn't need too cause I'm thinking now my timing was the cause of the overheating at idle the whole time.

 

start at 6*. total timing 30*-32* is it bored out 80 thousand or 8 thousand.

 

All your questions can be answered in this thread;

http://www.v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/

 

Ok the 0* 5* 12* on the timing chain cover an then the factory groove or line on the harmonic balancer. I used the timing light an turned the distributor till that line was between 0*5* This is what I read in the 1966 chassis model book. I'm not sure that I did it right though. Still hesitates on acceleration. But when I first drove it felt fine then started hesitating. It's making a noise between 45 an 60 I'm hoping it's just spark knock. I don't know what that sounds like though. Anyhow I'm learning about this timing thing all together. I do know it did do this until I swapped from clutch fan to electric fan. This electric fan only has a 30amp fuse,I would not think this would cause this motor hesitation. The timing is off I hope is what is going on. Dang!

 

make sure you pull the vacuum advance line off first.if you bored it out 80 thousands no wonder its running hot.

 

I set the timing again today at the 12* mark on the timing chain cover. I shot the timing light at the line on the harmonic balancer. Turned the distributor to the 12* Before I did that though I used a compound meter. Air gauge that i connected to the intake. That gauge took the car to know more hesitating but alot more spark knock. So when I put the timing light on it of course it was wrong, way retarded so I turned to 12* on the dot an the car is running really good no more spark knock!!! So good an so much faster it's scary. I really don't think the timing was advanced that much but like I said No More hesitating an No spark knock so I think the car is good. My question is with timing set to that 12* perimeter is the motor safe for the long haul? I just want everyday cruising speed. I am not racing this car but now, it really feels like I could, will this be alright. Thank you

 

^^^^ You have to read this, understand it, and follow the procedures.
We don't know what distributor you have. Some Nailhead distributors are set up for 12* initial advance, some are set up for 2.5* advance. Either one should limit total mechanical advance to about 32*.
An advance curve kit should help your low end performance.
It's all described in Larry's thread mentioned above.

What do you mean by 'compound meter', 'air gauge'? A vacuum gauge? An engine will idle better with lots of advance, but you don't want to do it that way.
You can damage an engine with too much timing advance as that will cause spark knock/detonation. That usually happens during medium to high load..... gong up hills, or when it's floored. Detonation can damage piston rings and even break or melt your piston in extreme cases! Be careful!

 

I have a regular timing light not a dial back so I am trying to understand where to make my 30* mark. Larry's post says to measure 1 3/4" exactly. Measure from what starting point? Measure by wrapping tape measure around the outside of the balancer? My balancer is a 401 nailhead damper is that diameter different from the buick 350 an 455 balancer?

 

The car is running good at the 12* mark? No spark knock that I can hear. Can I keep running the car like this safely? Or does this timing have to be perfect? An also if the timing is not exact does make the air/fuel ratio run too lean? Try to find a dial back timing light now, these part stores don't seem to know what I'm talkin about, who would've figured.

 

I got a dial back timing light follow the directions an got spark knock. Set it to 12* an tightened the distributor in place, drove with no spark knock but now between 10-15mph the transmission seems to hit a little hard but not noticeable at higher rpms. Also when I got back from driving shot the timing light again an the mark had move away from the 12* How does this happen when I have the distributor tightened in place? At 12* idle it should equal to 32* WOT correct? Cars drives good just not as loud when revved up an the trans hits a little hard from a dead stop going slowly faster. Thank you all for your help!

 

It depends on which distributor is in the car.
Only the 2x4 and Dynaflow engines had distributors which required timing set at 12*. Total was near 32* (+20*)
The other distributors, including the GS 401, had timing set at 2.5*. Total was also near 32* (+30*)
If you set the 2.5* distributor at 12*, you may end up with over 40* of advance!

Like Joe said, timing should be set up with the vacuum line at the distributor disconnected and plugged.

Does this mean you set it for 32* with the engine revved to 3000-3500 rpm?
That is how it's normally done.... adjust the timing for 32* at full mechanical advance at 2500-3500 rpm, (wherever the timing advance stops), and your initial advance should end up somewhere between 2 and 12*.
The maximum advance is what is important to prevent engine damage.

If your timing seems to be changing, there's likely another problem. Maybe the vacuum advance is bad or the advance weights are sticking.

 

Maybe this is relevant or maybe not, but I know the base of my distributor has a little wear "notch" where the the hold down clamp hits it. I discovered after I recurved it, the distributor wants to return there which now puts my total timing at like 38 degrees. I have to check it and bring it back about 4 degrees every couple months. Weird, but my 71 Stage 1 is that way too....

 

Rhett,

That's because the 455's have an aluminum distributor the "Nails" are cast iron.
Put the dizzy's on a lathe & turn them down flat again. I'm sure Tech8 can perform this service for you.

Tom T.

 

always have to check the timing after you tighten the distributor down, when you reach in sometimes your wrench or hand will move it. just a slight movement changes the timing many degrees. try to keep the the bolt as tight as possibly while your adjusting your timing, just barely being able to move the distributor. had to believe 12* at idle only gives you 32* total timing, with out having the distributor re-curved to limit the advance.

 

on most of my cars, just tightening the distributor down will advance it two degrees as the clamp takes up any play in the housing...

 

I have a question but it may make a difference. Are you sure that you're light is connected to the #1 plug? It's underneath the a/c and/or alternator. #1 is always closest to the radiator. If you're on the power steering side, you're hooked to #2.