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351M with frozen distributor, among other things

Craigwell

Improvising Adventurer
I'm sure my friends in the rust belt might identify with this one:

I recently bought a 78 F150 with a 351M. My investigations to this point have determined that I have a fully intact emissions system, non-catalyst, and what appears to be the original carburetor and distributor.

I've been tuning the engine with a vacuum gauge, and have found it reading low.

I started with the carburetor, and found I had to turn out the idle screws 4+ full turns to get up to about 18" of vacuum.

Then I cleaned up the dampener and found that I had about 30* advance at idle with the vac advance running off the manifold through a ported vacuum switch on the tstat housing.

When I disconnected the vac advance, I found I had about 4* of initial timing.

The emissions sticker says I need 14*.

I cannot get the distributor to move, regardless of what I do. I have sprayed fluid film on it for a few days, and have tried tapping at the base of the distributor with a hammer and drift. Obviously I don't want to break the aluminum housing, so I'm not giving it very strong with the hammer.

I'm thinking I might need a stronger penetrant, like Zep 45 or Wurth product, but I'm wondering what level this might reach, without destroying the otherwise functional unit. (Vac and mechanical advance seems fine).

Could I get away with some heat on the cast iron around the area???

Thanks for reading
 

havi

third member
Marvels Mystery Oil. Let it soak, and then tap it with a rubber mallet, or hammer and drift like ya did before. If nothing else, remove the oil pan, and hit it from below.
 

smokey

Hitech hillbilly
Staff member
I would spay it with PB Blaster and tap it while applying a rotational force. The pb blaster or Knocker oil seem to be the best for loosing things up. Never used the fluid film so I'm not sure how well it works.
 

Craigwell

Improvising Adventurer
I will try the PB Blaster.. It is available to me locally, while I don't think MMO is, even though it sounds like an excellent product!

I like the oil pan removal idea, hope I don't have to go that route!!

Thanks for the suggestions!
 

1985 Ford F-150

Country Boys Can Survive
7,816
307
Tooele, Utah
You could heat up the manifold with a propane torch or ive also heard of guys packin dry ice around the distributor and insulating the manifold.
 

Craigwell

Improvising Adventurer
on the list for this:

1) PB Blaster overnight soaking and more tapping, fluid film still soaking now
2) Propane torch. Might help. This isn't in the intake manifold, it's the front of the block on this sucker

Beyond this, another issue has reared it's head - the rear main seal is leaking. Just now getting my head wrapped around and making a plan off stuff like: Pull tranny back or lift out the mill? Drop pan and unbolt an engine mount, lift a bit to clear? assuming same style as windsor block, remove rear main cap and fish old one piece out and replace with a two piece??

I'm a big six fan and wont hesitate to pull / swap the entire drivetrain - BUT this does work well otherwise, so i'm leaning toward fixing it.
 

Craigwell

Improvising Adventurer
thanks smokey, i'll dive into my shop manual and make sure of the seal type. It's the 1977 set, but I just remembered the 351M was first year '77 in these, so i should have the info.
 

Craigwell

Improvising Adventurer
Got the PB Blaster an hour ago, dizzy soaking now. Gonna grab my shop manuals here in a bit.
 
Last edited:

UNRULEE

^LARGE carbon footprint^
I had the same problem a few years back. Penetrateing oil, a LARGE channel locks, and a prybar got mine out of the block.

Just be sure to put some anti-sieze on it before you put it back in. And change the o-ring on it.
 

Craigwell

Improvising Adventurer
i've been working it with the pb blaster and a pair of channel locks. So far nothing, but I'm patient.

Looking at the corr block, thanks dennis
 

Craigwell

Improvising Adventurer
Ok, the other day I got the dizzy freed up. PB Blaster and 10" channel locks got'r done.

So far it doesn't seem to be leaking oil up around the seal, which I half expect it to eventually.

I have put the timing much closer to the 14* advance this thing wanted out of the factory with it's emissions schedule, and obviously it works much better.

It still doesn't want to take it's fuel under mid-throttle, but will handle modest take-off and WOT ok if rpm's are high enough.

I need to check my curve and get my vacuum advance off the ported vacuum switch, and just go ported vacuum for both my dizzy and the egr. I'll throw away the rest.
 

UNRULEE

^LARGE carbon footprint^
Good job. Persistance pays off.
 

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