'79 351w Issues - From great, to bad in 2 hrs ??

If you are looking to buy a new distributor, you may want to consider H.E.I. style unit and forget all about points and condenser problems. Davis Unified Ignition (www.performancedistribitors.com) make a great unit. No external coil needed. The part number for a revers-rotation unit is M35820RRRD (and, yes, it's RED).

LINK to distributor

Or

LINK 2

JQ

JDQF has spoken

You absolutely must get the red one

If the stretched out spring is the heavier gauge one, and has oval shaped ends, that's how it was made.

The light one affects the advance curve all by itself up to about 3500 rpm or so and then the big one comes into play.

Without seeing what you have it's hard to say if things are in decent shape but they didn't just suddenly get all screwed up on you to give the problem you have.

I'd say like you said go new since everything else is new and make Jonny happy.

You forgot JDQF, I like that one the best especially in red   

Just curious because clueless. When installing a HEI, do you still have to time it afterwards ?

How about this Mark,he would just have to reuse the RR gear and it would be brand new
Link

Something else to rule out if the timing really is jumping around.
Didnt these early Ford 351W come factory with a Nylon Timing Sprocket on the camshaft?
I know the 460 engines did and I suspect the 351W did also.
The Nylon Sprockets eventually just fracture and leave you stranded with an engine that will not run right.
The manufacturers used these for about 10 years and the reason was less cost but also they ran quieter than the steel sprockets.   They went out of favor quickly as owners were fed up with expensive timing repair bills just to change out a failed sprocket.
The Marine Engines may have speced out a Steel Sprocket for the Camshaft you will need to verify.

Ford used the nylon coated teeth on the upper gear well into the 80's on their marine 351W's

I'd guess that his great running engine didn't just suddenly lose the coating on a bunch of teeth while sitting for 2 months and that the issue is elsewhere without a better description of the timing fluctuations

I installed an HEI in my 1987 Malibu the first year we owned it. It worked perfect for the next 20+ years, only 750 hours use. They are a reliable and simple system and offer much better cold start up.   You just have to jump that price tag to enjoy it. I still think one hours work would have had your old distributor working so you could evaluate the rest of the engine.

In the above link that Gary S posted about e bay distributor - wonder why the standard rotation would be $30 more than the LH rotation ? Is the RR gear hard to change ? Do you need a press or any special tools ?

I see now. There were two e bay ads for distributors.(the one that Gary S posted above with the long shaft that said LH ) and another one that said standard rotation.. Now I see that the gears are the same direction. So will the distributor that Gary S posted above with the long shaft work on my 1988 351 W as long as I reverse the gear ?

Guys - Well...I...finally got the HEI (DUI) distributor installed with a ton of help - over the phone - from jonnyquest. Thanks again for the recommendation and help JQ!

Some hiccups and challenges but all in all took me about 3 hours to get in and wired.

The motor is running and idling very well. Holds a 6-700rpm idle, revs fast, starts clean. But thats all on the trailer. I'm thrilled to have it running again, and that the ignition was in fact the issue. But, there are still a few oddities that I want to shake out:
-The motor runs better when I create a 'vacuum leak' - If I pull the rubber cap off of the port under the primary bowl on my QuickFuel M600, the revs increase noticeably. Forgot to look at the tach, but I'd say it is going up from the 700RPM I'm idling at, to 1,000rpm and smooths out.
-When I get the vacuum gauge hooked up to the port the RPMs drop back down to 700 and I get a reading of 15-16 of vacuum. I have played a bit with the idle screws and this is peak - 15 to 16. My recollection from last year when I got it running after the rebuild was that 12-13 was my max vacuum I could get, even when I had it running great. -Regardless of the carb setting I do NOT get a steady reading. It is always bouncing between 15 and 16. And the engine and boat (sitting on the trailer) have a pretty good shake - kind of like it has a performance cam. If you get out and listen to the exhaust, it is steady with no lope etc., but sitting in the boat with the engine cover up it feels like a lope or stutter.
-Timing is still a bit of a mystery. When I set the new electronic Dizzy I shot for 10-15* of advance. When I fired it up with the timing light it read over 30* BTC, but ran fine. I spun the dizzy back to 12* and that actually dropped the RPMs and it seemed to run a little rougher (see above). Does that make sense?

Am I being OCD? The engine seems to be running well - I'll know more tomorrow when I get it in the lake. But the above characteristics just don't seem 'right to me.

Thoughts??

Off Trail wrote: Guys - Well...I...finally got the HEI (DUI) distributor installed with a ton of help - over the phone - from jonnyquest. Thanks again for the recommendation and help JQ!

All normal. Yes too much initial advance will increase rpms. but thats inconsequential. One doesn;t don't ski at idle.
So is adding air at idle. Ripems will go up. Doesn't mean its right. It will fall on its face in gear and stumble off-idle
Yes, i also suspect some overthinking.

zwoobah wrote: If you've got a shake at idle you may have a misfire. Could be a fouled spark plug from your previous ignition issues, or you may have put a wire back into the wrong place on the new distributor. If it still shakes/skips after you verify firing order and correct wire installation, unplug your plug wires one at a time. If you unplug one and notice zero difference, that plug is fouled. Pull the plug - if it's wet, it is fouled and will not fire.

I'm not sure the stutter is that bad, and it runs 49.5mph at 5200-5300RPM (going to try my 'taller prop') so I can't imagine it is running on 7 cylinders. But, simple test and good recommendation, so I'll pull wires and check.

By the way - The plug wires that Summit Racing recommended with this dizzy DO NOT fit well. I have two running over a valve cover, through exhaust manifold, just to make connection. Going to have to replace those.

If pulling wires doesn't change anything, i will do some carb tuning and call it a day. This new ignition is starting first crank, no hiccup on idle to hard full throttle. Happy I spent the money on the DUI.....though I'm sure someone will say I could have gotten the same result with 2 hours of work on the old dizzy. Ill post a picture at some point - it was rough.

Appreciate all the help and advice and hope I don't need to be on here for help for a while!

Wires just don't go bad specially with the hours you guys put on your boats. My Avalanche had over 2500 hours before the plugs and wires were replaced on it's 100k service. I have a 73 year old Ford tractor with it's original wires on it, several 50 year old Honda motorcycles with their originals on. If you guys are replacing your old oem red GT40 wires send them my way I'll pay shipping