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tusseltussel
User
Jul 21, 2007, 9:36 AM
Post #1 of 12
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ford 351 modified
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i all I have a old farm truck i picked up and it is a little rough...
it has the 351m\400 1979 f350 I would like to get this engine running
half decent it sounds ok no knockin popin or anything to bad it does
not have any of the original vacum gear the only vacum hose on it is
for the timing advance everything els is gone or plugged up wich may be
my problem I don't know but it runs really rough it starts right up and
after it warms it will idle (rough). new plugs, wires look good timing
is right on (4 degrees btdc)cap and rotor look new. smells like its
running a little rich the throttle adjustment screw is run all the way
in compressing spring all the way. when i'm driving it seems to get to a
high rpm than a sudden burst of power comes wich is nice but would be
nicer if it came a little sooner like all the time...when i picked it
up i pulled the plugs they looked good other than the fact that they
were gaped at 62 I put new plugs in gaped at 42. don't know maybe that
burned sumthing up having to create such a hotter spark to jump the gap
can anyone give me a clue as to how i can get her running better
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 22, 2007, 3:56 AM
Post #2 of 12
(8178 views)
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Re: ford 351 modified
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These are tough engines. I've owned a few. Is this a regular carb or a VV (variable venturi) type carb? If it runs at all you can get this going. Forget the exact plugs right now and work on the vacuum hoses and leaks. Need to know what carb you have -- not the exact one but the type,
T
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tusseltussel
User
Jul 22, 2007, 8:38 AM
Post #3 of 12
(8174 views)
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Re: ford 351 modified
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I belive it is a motorcraft 2150 2v the tag has d5tebma on it. It has the accel. pump on the front with 2 adjusting screws hidden below it like I said the only vacume lines are to the dist. pcv and brake booster thair is some sort of vent or vacuume lign that comes out of the carb above the accel. pump with a little plunger that is supposed to move with accel pump it looks like but doesn't. the egr valve is pluged. thair is another line comming out of the manifold looks like along the #1 cyl. port it is plugged there is a peice with 2 tubes coming out of the manifold one looks like it goes to the choke valve the other is plugged and looks like it used to go to the choke valve but somone replaced manual choke with electric and thats all i got by way of vacuum. it does not have points in the dist. it has the electronic ignition wich is what i thought was wrong because of the sudden power at higher rpm but Im no expert I thank you for any help that you can give.... do i have to go to the junk yard and salvage a vacuum setup with canister and all. well i'll stop hear i probably could babble on and on about sumthin i know nothing of.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 22, 2007, 10:26 AM
Post #4 of 12
(8170 views)
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Re: ford 351 modified
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Not sure on the carb. The VV would not have metal butterfly plates and those are hopeless and should be removed for the older type if it has that.
EGR needs to be sealed off where it mounts not just vacuum plugged as it may be working when it wasn't supposed to. Those never hurt performance but folks just forever unplugged them no knowing that.
Carb adjustment is limited to choke (confused as to if this is now manual or part automatic) air/fuel mixture - two screws that shouldn't be messed with. If they are all the way in that's wrong. If they are all messed up as to where those are take them out and spray carb cleaner in the holes and set them to bottom gently and back off about 2+1/2 turns and forget them for now. Idle speed should have been a solonoid but might be missing now. The other screw with the spring was to set it to stall but could be used for idle speed at the risk of dieseling which was a problem back when.
Cat converte(s) may be missing or never used in a 1 ton truck and doesn't matter if they are missing in that year but would matter if clogged up.
Check for erronious vacuum leaks with the engine at idle and carb spray at diaphragms, base of carb, EGR, intake gasket to heads and anything that is vacuum controlled. If a leak is there the idle will respond to the carb cleaner and use it with caution as it can flash on you if sprayed on things that get too hot.
They do make hot plugs that last longer in a worn engine. Best is Autolite - single platinum which has great resistance to fouling with its pin head electrode that doesn't hold debris well. If all plugs can fire now that can wait.
Let me know on any new observations and we can take it from there,
T
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tusseltussel
User
Jul 22, 2007, 7:18 PM
Post #5 of 12
(8167 views)
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Re: ford 351 modified
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ok I took off that egr valve it looked like the diaphram cracked so i made a plate out of 1\8" stainless made a cork gasket and put a coating of ultra copper seal on it and bolted it up. thair was one lign commin out of the manifold that looked blocked off but hose was to big for fitting so it was suckin right past the plug so i re pluged it eventually i will get a threaded plug to put in thair, so i went over it all and pluged up all the leaks that i could see i havn't hit it with carb cleaner to check for other leaks yet i will do that tomarrow when i can get a new can of cleaner but it is running nice and smoth now I rechecked the timming and set it after all leaks were plugged. I drove it around a bit and I am still getting that boost of power at a high rpm, its when im about to shift, if i wind out the gears and get to that high rpm it will suddenly take off tomarrow i am going to check the weights in the dist. to be sure they arent getting stuck and make sure the diaphram where the vacuume is hooked to it is working. thank you for your help and any other help to get this tuned right would be great. thanks again and i hope to hear from you again
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 23, 2007, 2:39 AM
Post #6 of 12
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Re: ford 351 modified
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The EGR ahould be ok with just the Ultra Copper -- the cork may have a problem as that gets exhaust heat right there. It's hard to find (if you can at all now) real asbestos gasket material to cut gaskets from. Just the Ultra will do fine but always let things like that dry well as you don't want the engine to suck any in.
Plugging off vacuum lines is better than leaving them open. If one is unknown we have to dig into the basics and get the most important ones hooked up right. An easy plug for vacuum ports is just to take a peice of hose and put a screw in one end.
There were many vacuum operated things that end up at the air cleaner. For this project (unless you are restoring this for awesome good looks) they are just costly and fussy repairs. The air cleaner should be designed to pick up warm air from the exhaust manifold and use it while engine is cold and then switch to cooler air when the engine is warmed up. The vacuum trees (like a spark plug that has hose ports off of it) will be brittle and can be bypassed to needed items when and if broken and just do without that warm air pick up as it does help when cold but is a lot of effort for it to run a little better for a couple minutes cold and does nothing after that. That can fail to give you warm air all the time which is a problem.
The PCV system needs to be working as best it can. It may be clogged up with sludge and can be cleared with wire and carb cleaner (get a couple cans of that when you go out) and get the PCV free to rattle in your hand and they should be good almost forever. It is the first emission control used in vehicles and doesn't hurt a thing to work and messes things up when it doesn't.
The sudden power surge is no doubt the carb and until we can make the engine just run smoothly any adjustment to it should wait.
If you don't have one a vacuum pump (small grease gun looking thing) with gauge is a handy tool. Great for testing vacuum items or just reading vacuum.
I can't remember right now if the distributor has weights. I don't think it does but don't quote me on that. They were never a problem but that was also a long time ago when these were everywhere. Your ign is controlled by that module (away from the distrutor) and the vacuum advance.
Let us know how you are making out,
T
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tusseltussel
User
Jul 23, 2007, 5:57 AM
Post #7 of 12
(8162 views)
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Re: ford 351 modified
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got her running smooth now i sprayed around didn't hear any changes so i think i got all the leaks, it is amazing how smooth it's running im supprized and excited. i just went out and made sure pcv lign and valve were clear of build up so now it runs smooth!! oh yea and it's not being restored for good looks its a workr for haulin things to the dump work around my piece of earth and maybe an ocassional trip to the farmers market down in the little city bout 45mins. from here
(This post was edited by tusseltussel on Jul 23, 2007, 6:37 AM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 23, 2007, 6:32 AM
Post #8 of 12
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Re: ford 351 modified
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Cool Beans! That's something we say in the Boston area. Now if you still have that burst we can move on to what I think will be the carb.
Wait on spark plugs till all carb cleaning is done as it can throw junk at them and why do that to any new ones if you want to change those at all. Again when you do I suggest the Autolite single platinum or resistance to fouling. A hotter range is really not necessary if things are going well and could just cause pre-detonation if too hot.
If you can find the two idle air/fuel mixture screws with the springs on them on lower front of carb see what tool you might need. May be covered as that's about the area that they made them so you couldn't change the mixture much or at all but that foolish move made it tough to clean in there. If you see them and they probably are just a slotted head - they make a special tool that makes it easier but you can do it without it. -- Just gently screw them in till they bottom and count the turns. That is your starting point to return to at least what you have if things don't get better. After counting the turns to bottom (carefully as they are needle valves so don't get aggressive with them) take them all the way out and don't lose the springs. Set them so you put the same one back in the same hole for good measure. Spray carb cleaner in them and clean the whole area first before you take them out if dirty as you don't want dirt going in there. When cleaned put them in and bottom again. Now unscrew them 2.5 to 3 turns each and start it up and let it warm up a bit so engine is stable. It will object to having carb cleaner in there for a short while so just rev up and clear it out till stable. That number of turns should be about the factory preset. It may not be better there and tell me where they were. From there a tach helps and turn them in or out and watch tach going 1/2 turn at a time. If it gets better and smoother one way or the other go that way another half turn. If better yet go another half turn. It will get worse at some point and go back to where it was best so keep count of the turns. Should be stable and best between 1+1/2 turn out and 3 turns out. More than that up to 3+1/2 ok but much more is covering a problem. This adjustment should make exhaust smell ok and not too rich and is the idle and part throttle mixture the engine gets. At mid throttle and up it's using the float level, jets, and any metering rods to make the mixture for up to full throttle mixture and the idle mix doesn't matter there. Between stages from idle to intermediate to full throttle the carb is designed to make a smooth transition. The sudden burst of power should only be directly by your throttle request and not a surprise.
Report back on results of that. It may need to be taken apart and cleaned with a gasket kit and new needle valve which is called rebuilding but it's really just a good cleaning and setting other adjustments that will come with diagrams and settings in the kit. Kits are not expensive. Taking your time and not breaking things and putting all parts back where they belong is critical. I'll wait for you report on just cleaning the bottom to go to the next move. You can just spray carb cleaner down the carb with engine running and throttle held high enough to you don't stall it and that can work too for several things without taking it apart,
T
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tusseltussel
User
Jul 23, 2007, 3:32 PM
Post #9 of 12
(8151 views)
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Re: ford 351 modified
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hey, today i took out the needle valves they were at about 2 1\4 turn and 1 3\4 turn i sprayed it all out and put em in adjusted em to where they were and drove, it ran good but then i got home unplugged the vacuum hose to the advance and found no vacuum at all sprayed carb cleaner in line and it filled the line and stayed so i reved the engine and nothin it stayed ful of cleaner so i took it and plugged it into the manifold instead of carb i turned that throttle adjustment back out it was all the way in on spring i started it and it sounds great. is the timming advance supposed to get its vacuum from the carb or manifold the diagram shows the only thing hooked to the carb is the perge it looks like that is where the advance was , and the advance goes to a vpv????? whats that
(This post was edited by tusseltussel on Jul 23, 2007, 3:35 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 23, 2007, 4:39 PM
Post #10 of 12
(8147 views)
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Re: ford 351 modified
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Vacuum to the distributor may be supplied by air speed/venturi effect vacuum and not manifold vacuum. Don't know for this one and a diagram would help. The purge is just burning hydocarbons from the charcoal canister that gets caught there and would be a larger hose. Base of carb would be manifold vacuum. Mid carb would be the air speed vacuum used for EGR when engine can handle it and EGR should not get direct manifold vacuum unless it's also electronically controlled which I don't think that was in 1979.
I doubt I still have any diagrams of this on my own now. They used to put underhood diagrams but they would be near impossible to read or missing over the years. Keep digging.
The needle valves would be the same if all was new but we are not dealing with new and they can be fiddled with for best results which the car makers didn't want people to do anymore even in 1979 as it can cause more emmissions if all wrong and folks used to fiddle away at those even when they didn't know what they were,
T
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tusseltussel
User
Jul 25, 2007, 8:52 PM
Post #11 of 12
(8139 views)
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Re: ford 351 modified
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Hi tom just wanted to get back to you, I got this old truck running good now thanks to your help, you lite the way for me on this one and i thank you now i just have to go to the salvage yard for some seat belts and horn pad after that all thats left is the parking brake cables and its a fine truck expensive on gas but its not a everyday driver just when i need a truck to pick up hay or go to the dump and on and on but anyway another thing i have been trying to find is a turnsignal switch for it napa didn't have it im sure the dealership threw em all away 5 years ago so if you have anyone you know that may have one ive been searchin around and can't seem to find one which is really suprizeing anyway thanks again for your help.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 26, 2007, 1:12 AM
Post #12 of 12
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Re: ford 351 modified
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The seat belt anchors should be Torx 45 i think - the same as the door jam striker.
The turn signals could be a pest. If you know what is broken while you are out junkyarding see if you find the part used in something that is almost all apart that is still good. The lower clicking/cancel stuff can be the base nylon stuff and you will need tools to get that far and the wiring goes down the column is a pest so hope you don't have to do that.
I'll bet many full size Ford cars and trucks used the same stuff and you can get it new or used. Hit back and I'll give you a phone # of a place that will have it new or a place that will ship from a junkyard and does keep a fair amount of older vehicles around.
Thanks for the kind words and hope you can get some useful life out this old truck. For the engine try just changing oil frequently with decent oil and it can improve overall as the new oil is a slow solvent and this thing may just last a whole long time. I took a nice but abused 79 Continental Town Car with this engine to running and looking like new again with the oil change trick as I was restoring it and it was loved and owned by two others I know of and never had further engine toubles and I know it passed way over 200K.
The good ole days!
Be well,
Tom Greenleaf
Marlborough, MA
T
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