23 is very good. Not to beat a dead horse but have you tried to back the timing of initial with the advance as it is now?

 

I haven't tried 10 degrees for awhile so I will again because the setup is now so different. I have been trying manifold vacuum for advance for some time because of an earlier posting, but I think I will try ported vacuum again because of the changes. I still am wondering about springs in the distributor though. Does anyone have experience? I looked at MUSCLEFORD which was good but I would like to know if some springs I have would do the job.

 

If you already have spark knock or detonation then I'd think going with lighter springs would only make it worse. You already have too much timing for the set-up since it is still spark knocking.
I'v played around with manifold vacuum lately myself and went back to ported as I could'nt get it to run like I wanted but each engine is different.
You need to map out your mech.advance. Get a buddy to help and plug the vacuum advance. Start at idle at your base timing. write down your timing at each 500 rpm increase until about 3k. This will tell you how much mech. advance you have.
I'd think you would'nt want anymore than about 32 degrees of timing all in by 2500 rpms'.
If it is too much you can check the reluctor arms in the dist. and see if you can rotate the arms to the other side. They usually have 2 different settings. It'll be like 13l on one side and 18l on the other. Alot of the cars had alot of mech. advance but with stiff springs you will see full mech. advance only at high rpm's like over 45oo. If you still get too much you can modify the stops to decress it. Then you can change the srings to bring it in earlier.
Hope this helps instead of confusses as I'm confussed now. lol
Clint

 

My detonation seems to be at low rpm-low advance- while at high rpm -high advance - it seems to go away. I think my problem comes from late burning fuel in the exhaust. thats why I'd like to advance earlier?

 

If you where runing the engine with the distributor connected to manifold vacuum as in vaccum at idle then I think that is your problem too much initial with full vacuum at idle, that explains a lot of the pinging. Hook it to the carb where there is zero vacuum at idle, probably explains the good/high manifold vacuum at idle as well on a junkyard motor. Then drop the initial to 10 and you should be good. Getting close, hopefully won't be too long and you'll be running good

 

I argree JWTaylor, low rpm, high vacuum and spark knock too me means too much vacuum advance. Back out on it some more and try it
Clint

 

I did try changing the vacuum advance to ported last night and had more noise, poorer throttle responce. The more I work on this it seems my problem is late ignition rather than early ignition. Maybe I haven't used the proper terms though to explain it. The sound might be easily discerned by an old time mechanic but they are becoming rare.

 

Well no offense but that makes no sense to me. I have to ask, have you confirmed the timing marks on the distributor are correct? And in reference to where the tdc falls or is in relation to the pointer your timing number flashes right at that same point. Not to start throwing out new ideas but sounds like it is something other than your ignition or fuel delivery if you have the above done. I guess we should have specified does it sound like you have a rock rattling around in a glass bottle, detenation sounds almost identical to this? Or does it sound like a deeper knock persistant and consistant in the rhythm such as if you hit your knuckle against a hard piece of wood, a thrown bearing will sound a lot like this? If it is a constant tick tick kinda like an amped up clock sound it is the lifters more likely than not or maybe a rocker out of adjustment. Reason I meniton this is you said you got the engine from the junkyard, maybe this is why it was there in the first place. If it was rebuilt it could possibly be the bearings or something they installed as I had some trouble with a rebuilder who couldn't install main bearings. Let us know, here I thought we were getting close.

 

If you ar running the factory small valve heads S-can them... get you a good set of pre 72 non emmission 1.94I/1.54E or aftermarket heads World products windsor jr. or the Roush 200 heads with heads 2.02/1.60 valves for now 18 deg. is to high you should be around 8 btdc

 

I've been watching this from the sidelines and I have to side with jw. I think he's been reading my mind. I have a 69 351-4v. It has 10.5/1 compression. Initial timing is about 6 using ported for advance and I get no ping. If I go as high as 10 it starts to ping but usualy at higher rpms.
I thought you had this figured out but your last episode made no sense to me either. I'm starting to think that maybe this isn't a timing issue. Maybe it's something else that is causing you to set the timing up enough to make it run properly, causing the ping.
Not wanting to start something but, are you sure you don't have a couple wires crossed. I think I would have to go back and check compression and make sure there isn't a cylinder that has a problem.

 

stepman, im convinced that ford screwed the pooch on the emmission heads they work ok on the stock 302 ,but they are too small for the 351...
my dad's 74 van has a 351 with a 1/2'' cam and 71 big valve heads 9:1 compression NO PING on reg gas..

 

Taht's where you lose me. They used the same heads on both motors? I don't understand how that would create a ping though. Maybe less power but....

 

termyt00
your post was intended to say stock heads are crap. What you actually said was if my dad can run 9.5:1 compression and get no ping then 351 Power should be able to run 8.8:1 and not ping. See what I mean?

Your right though, the heads on the 80's 351 were 302 heads. Later

 

also, his carb could be too lean for the application...
it took me awhile too get my 81 bronco right and its using the heads off a 85 town car. but it still pings , just not as bad.i have the timing at 2* anything more it will ping at cruise
>step , from 69 to 72 the 351 w heads had larger valves 1.94I-1.54E
the "emmission" heads used from the mid 70's till the end of the windsor production had small valves 1.84I-1.46E
all the 351w i own with the exception of dad's 74 van and the 75 sportcraft (boat) have the emmission heads and a pinging problem ...
my 400m with boss cleveland heads runs on 87 octane with less ping than the windsors

 

termyt00
Did the distributor happen to be a replacment?