351M gurus

[YeahYeah01]

Need some advice.

Project truck that I've had for to long but starting tinkering with again.

1977 f150 with the 351M. I know it has an RV cam.

It's never ran right and I've almost never driven it or ran it because of that. I rebuilt the carb and put fresh fluids and sparks plugs. Got it running but it was running like shit. Sounded like a tick but thought that could be the cam. But I put a vac gauge on it and had almost no vacuum and it was bouncing everywhere. Figured a stuck valve so pulled the covers. And ended up pulling the rockers off to. Found about 6 bent push rods. 2 so bad they would not come out. Had to pull the intake off to get em out.

I'm going to order new push rods but I'm thinking of pulling the lifters to to inspect them. What the easiest way to pull the lifters? I've never done it, then do I just check them with a straight edge? Are the easy to put back in?

I have no clue what caused the bent rods. Hoping its the problem and not the symptom. I do have one stuck valve that I'm going to soak down and see if I get it unstuck.

 

[4Waters]

Pocket screwdriver, slide it under the spring retainer and lift it out, you might have to go up and down a few times to get it past the tarnish

 

[Your ad here]

Let me guess, the bent pushrods are on intake valves?

 

[YeahYeah01]

Pocket screwdriver, slide it under the spring retainer and lift it out, you might have to go up and down a few times to get it past the tarnish

View attachment 1359805

Sounds easy enough. Thanks.

 

[4Waters]

Sounds easy enough. Thanks.

Don't pry just lift

 

[monkeyswrench]

Shooting in the dark here, but thinking the clearances weren't right for the cam lift. One or two bent pushrods maybe...but that's either a lot of valve float, or coil bind.

The lifters should lift out, unless they gotten ground on or mushroomed by the cam (and whatever caused the pushrod failure.) They should appear flat on the wear surface. Any cupping is bad.

 

[YeahYeah01]

Let me guess, the bent pushrods are on intake valves?

Not 100% sure. The valves are basically the same size so I couldn't quickly identify what was intake and what was exhaust.

 

[YeahYeah01]

Shooting in the dark here, but thinking the clearances weren't right for the cam lift. One or two bent pushrods maybe...but that's either a lot of valve float, or coil bind.

The lifters should lift out, unless they gotten ground on or mushroomed by the cam (and whatever caused the pushrod failure.) They should appear flat on the wear surface. Any cupping is bad.

Is there a way to check the clearance without pulled the cam?

If I pull the lifters and get lucky and nothing is wrong would you put them back in and replace the pushrods and see if she runs right or should I be digging deeper for cause?

 

[Your ad here]

Not 100% sure. The valves are basically the same size so I couldn't quickly identify what was intake and what was exhaust.

Old ethanol fuel will cause intake valves to get stuck. When the gas gets old it gets sticky and will cause intake valves to get stuck. Enough to bend pushrods.

 

[YeahYeah01]

Old ethanol fuel will cause intake valves to get stuck. When the gas gets old it gets sticky and will cause intake valves to get stuck. Enough to bend pushrods.

What concerns me is only one is stuck the others that were bent are tinging when I tap them.

 

[monkeyswrench]

Is there a way to check the clearance without pulled the cam?

If I pull the lifters and get lucky and nothing is wrong would you put them back in and replace the pushrods and see if she runs right or should I be digging deeper for cause?

Coil bind is when the the valve is open. The lifter at it's highest point, pushing the valve down. At that point, there should be a slight gap between the loops of the coil. Basically, reassemble and use a couple known good pushrods and check. Having some bent to the point of not coming out though, not very common. In which case, like mentioned above, valves hanging...stuck really. Were the heads rebuilt? Maybe the guides were tight.

 

[YeahYeah01]

Coil bind is when the the valve is open. The lifter at it's highest point, pushing the valve down. At that point, there should be a slight gap between the loops of the coil. Basically, reassemble and use a couple known good pushrods and check. Having some bent to the point of not coming out though, not very common. In which case, like mentioned above, valves hanging...stuck really. Were the heads rebuilt? Maybe the guides were tight.

So basically when the springs are fully compressed there should not be so that tight, that makes sense on causing it to bend.

I honestly don't know if the heads were rebuilt or not. It wouldn't be that hard to pull the heads at this point though but maybe first all get the new rods in, I just order a full see in case any others where slightly bent. I could reset it and hand crank the motor to look at the values. Of course I need to get that one stuck one free . If I can't get in stuck I'll pull the heads.

 

[monkeyswrench]

@YeahYeah01 , I've had pretty good luck unsticking things with Seafoam spray. Seems to get carbon junk off. If it is the weird residue from ethanol, "Startron"...it's a fuel additive in a blue bottle. I use it to clean that gunk out of old carbs that have been sitting. The good old standby, WD40, may work as well. Just spray it down, and gentle tap the valve with a mallet. Sometimes it doesn't take much and it pops back up. At that point, take a look and see if the valve stems look comparable. If the heads are bent, they can't return all the way. You could also then use a compression test fitting, and air check the cylinders.

 

[coolchange]

400 push rods in a 351.

 

[YeahYeah01]

400 push rods in a 351.

What do you mean? That I should put 400 rods or that it may have the wrong rods?

Its running 9.5" rods now. Not sure if its the right length or not, I was trying to find a Rod length checker that size but its seems like more a special order and takes a while to come in. I also have never used one but does not seem that hard.

 

[jetboatperformance]

Years ago I had an Older Ford truck (56") come in that had a small block Chevrolet The customer opted for Me to build and install a fresh 350 , The nite I finished Iit it up for 30 seconds (job well done) Next day decided to break the cam in But it wouldnt start cranked but had zero compression .................. found all the intake valves and push rods stuck/bent ............. What happened ? In my haste I started it on its own fuel (instead of a run tank) The varnishy fuel coated the intake valves in the brief run time lesson learned

 

[YeahYeah01]

Years ago I had an Older Ford truck (56") come in that had a small block Chevrolet The customer opted for Me to build and install a fresh 350 , The nite I finished Iit it up for 30 seconds (job well done) Next day decided to break the cam in But it wouldnt start cranked but had zero compression .................. found all the intake valves stuck/bent ............. What happened ? In my haste I started it on its own fuel (instead of a run tank) The varnishy fuel coated the intake valves in the brief run time lesson learned.

I am wondering if that was the main problem. I did drain tank down and replace with fresh fuel but this could have happened a long time ago.

 

[YeahYeah01]

I found a Push rod length checker shipping from close to me, I tried will call but has to ship. Ill wait for it before I get real deep into it. At least verify that.

 

[jetboatperformance]

Having Thousands of forensic inspections The stories I could tell ........................ At Ford in Arroyo Grande once I have a 5.0 Mustang with bent intakes similar to what I described on mine Turns out the owner was a "for hire" exotic dancer She stripped at a party and apparently wasnt great , one of the guests dumped a liter of Coca Cola in her fuel tank ...........................

 

[YeahYeah01]

Having Thousands of forensic inspections The stories I could tell ........................ At Ford in Arroyo Grande once I have a 5.0 Mustang with bent intakes similar to what I described on mine Turns out the owner was a "for hire" exotic dancer She stripped at a party and apparently wasnt great , one of the guests dumped a liter of Coca Cola in her fuel tank ...........................

With all the bent rods there is only one stuck valve all others are tinging nice. I did not mess with the valve much to get it free. In your option if it does not unfreeze, would you think bent valve? And just pull the head to check?

 

[coolchange]

What do you mean? That I should put 400 rods or that it may have the wrong rods?

Its running 9.5" rods now. Not sure if its the right length or not, I was trying to find a Rod length checker that size but its seems like more a special order and takes a while to come in. I also have never used one but does not seem that hard.

400 has taller deck and longer push rods. Just measure one. Push rod checker not needed for stock valve train.

 

[lbhsbz]

Shooting in the dark here, but thinking the clearances weren't right for the cam lift. One or two bent pushrods maybe...but that's either a lot of valve float, or coil bind.

The lifters should lift out, unless they gotten ground on or mushroomed by the cam (and whatever caused the pushrod failure.) They should appear flat on the wear surface. Any cupping is bad.

Maybe some was trying to beat a Chevy with it? That would explain the carnage

 

[YeahYeah01]

Maybe some was trying to beat a Chevy with it? That would explain the carnage

After the work was done it went to my Dad, who never drove it hard and then I got it and have not either so its pretty strange.

 

[Your ad here]

With all the bent rods there is only one stuck valve all others are tinging nice. I did not mess with the valve much to get it free. In your option if it does not unfreeze, would you think bent valve? And just pull the head to check?

I noticed that after you pointed it out about only 1 valve stuck. I'm curious as to what caused the push rods to bend. More curious to know how 2 got really bent. Seems the only way to really bend pushrods is to have stuck valves but you only have 1 that is stuck.

 

[YeahYeah01]

400 has taller deck and longer push rods. Just measure one. Push rod checker not needed for stock valve train.

Ya I figured Id measure the intake and the exhaust rods just to be sure

I noticed that after you pointed it out about only 1 valve stuck. I'm curious as to what caused the push rods to bend. More curious to know how 2 got really bent. Seems the only way to really bend pushrods is to have stuck valves but you only have 1 that is stuck.

Timing maybe? Or wrong length push rods? I'm a bit lost on it too.

 

[wzuber]

After the work was done it went to my Dad, who never drove it hard and then I got it and have not either so its pretty strange.

It might help to back up some here and clarify this statement? Are you saying it ran for a while (days, weeks, months, years etc.) For your dad correctly, without issue and then again for you before this issue occurred? And they after sitting for a period of time (length?)
Then this issue occurred when you attempted to restart after the extended duration of not running?

 

[YeahYeah01]

It might help to back up some here and clarify this statement? Are you saying it ran for a while (days, weeks, months, years etc.) For your dad correctly, without issue and then again for you before this issue occurred? And they after sitting for a period of time (length?)
Then this issue occurred when you attempted to restart after the extended duration of not running?

He drove it from Paso Robles and it seemed to run well. This was years ago. Then he maybe drove a few hundred miles before I ended up with it and I've driven less than 10 miles probably. It didn't sound right to me at all once I got it and planned tearing into it and finally got around to it.

Before starting it I drained the fuel. Replaced the fuel pump and filter, fresh fluids. But did not attempt to manually crank the motor over to inspect the valves.

It did sit outside at my dad's got years and I doubt he started it much but that could have been where things started going wrong. I also vaguely remember him messing with the distributor for some reason that neither one of us can recall why lol. But if he did pull the distributor and maybe the motor really wasn't at top dead center, the timing could have been thrown and maybe that's why it never sounded right to me at all.

It's been stored the last few years of my garage.

 

[monkeyswrench]

Maybe some was trying to beat a Chevy with it? That would explain the carnage

My personal experience has always lead to the liberation of pistons and the highlighting with stripper glitter...sometimes pushrods were the only survivors

 

[monkeyswrench]

He drove it from Paso Robles and it seemed to run well. This was years ago. Then he maybe drove a few hundred miles before I ended up with it and I've driven less than 10 miles probably. It didn't sound right to me at all once I got it and planned tearing into it and finally got around to it.

Before starting it I drained the fuel. Replaced the fuel pump and filter, fresh fluids. But did not attempt to manually crank the motor over to inspect the valves.

It did sit outside at my dad's got years and I doubt he started it much but that could have been where things started going wrong. I also vaguely remember him messing with the distributor for some reason that neither one of us can recall why lol. But if he did pull the distributor and maybe the motor really wasn't at top dead center, the timing could have been thrown and maybe that's why it never sounded right to me at all.

It's been stored the last few years of my garage.

Not too common, but the valve stems could have gotten a little rusty if it sat for a long time outside. That could make them "stuck" enough to bend the push rods on initial refire, but then be freed up now.

 

[jetboatperformance]

With all the bent rods there is only one stuck valve all others are tinging nice. I did not mess with the valve much to get it free. In your option if it does not unfreeze, would you think bent valve? And just pull the head to check?

Hard to tell assuming its not a valve to piston contact issue (due to lack of clearance) then you probably should disassemble to check possible sticking valves for other reasons

 

[YeahYeah01]

Hard to tell assuming its not a valve to piston contact issue (due to lack of clearance) then you probably should disassemble to check possible sticking valves for other reasons

I never saw any indication of metal to metal but who knows. I'll start with trying to free the one valve this afternoon and see what I can figure out.

 

[jetboatperformance]

Heard along time ago "when you hear hoofbeats, think Horses not Zebras" If the engine ran succesfully for a period of time and then didint Got a hunch Its not due to some mechanical issue overlooked but rather sticky guides etc like I advance to you earlier

 

[wzuber]

He drove it from Paso Robles and it seemed to run well. This was years ago. Then he maybe drove a few hundred miles before I ended up with it and I've driven less than 10 miles probably. It didn't sound right to me at all once I got it and planned tearing into it and finally got around to it.

Before starting it I drained the fuel. Replaced the fuel pump and filter, fresh fluids. But did not attempt to manually crank the motor over to inspect the valves.

It did sit outside at my dad's got years and I doubt he started it much but that could have been where things started going wrong. I also vaguely remember him messing with the distributor for some reason that neither one of us can recall why lol. But if he did pull the distributor and maybe the motor really wasn't at top dead center, the timing could have been thrown and maybe that's why it never sounded right to me at all.

It's been stored the last few years of my garage.

Good reply, now we have more clear direction to work. Good luck getting the one valve unstuck. Less stuck valves were the likely culprit of the bent pushrods. Sounds like you should manually verify all the valves are free and travel their full distance before attempting a restart w/your new P.R.'s
Eliminate 1 potential issue at a time.
It would be a real good idea to pull the distributor and prime the oiling system for 5 minutes before attempting a restart since it has set for a long time. Or, at the very least, crank it over until you see oil coming out of all the rocker arms.

 

[Neverbowdown]

Maybe some was trying to beat a Chevy with it? That would explain the carnage

SEE POST #16

 

[YeahYeah01]

Good reply, now we have more clear direction to work. Good luck getting the one valve unstuck. Less stuck valves were the likely culprit of the bent pushrods. Sounds like you should manually verify all the valves are free and travel their full distance before attempting a restart w/your new P.R.'s
Eliminate 1 potential issue at a time.
It would be a real good idea to pull the distributor and prime the oiling system for 5 minutes before attempting a restart since it has set for a long time. Or, at the very least, crank it over until you see oil coming out of all the rocker arms.

The one valve is fighting for sure. I'm worried it's bent. To verify rocker travel, just hand crank the motor correct?

 

[YeahYeah01]

Heard along time ago "when you hear hoofbeats, think Horses not Zebras" If the engine ran succesfully for a period of time and then didint Got a hunch Its not due to some mechanical issue overlooked but rather sticky guides etc like I advance to you earlier

That would be good news. I did verify that the lifters look great. So I'm thinking the cams in good shape

 

[YeahYeah01]

I'm going go pick up a spring compressor, the ones you can use with the head attached and pull the spring on the stuck valve so I can try and spin it at least.

 

[timstoy]

Do a leak down test on the engine. If the valves hit the pistons you are going to pull the heads off regardless.

 

[4Waters]

If you have a valve that won't move it's time to just pull the heads

 

[YeahYeah01]

If you have a valve that won't move it's time to just pull the heads

I got it free. It was varnish, bad.

Pulled the spring off and soaked it with intake valve cleaner. Then used a piece of gasket and vise grips and slowly worked it to where it would spend and then it started moving up and down really smooth once I cleaned it again.

No vent Valve.

I'm a little worried about the other ones even though they seem free may not be because this one was real nasty. But that little valve's been compressor isn't the easiest thing to work with trying to put the keepers back in so I'm not sure I want to pull everyone.

 

[jetboatperformance]

I got it free. It was varnish, bad.

Pulled the spring off and soaked it with intake valve cleaner. Then used a piece of gasket and vise grips and slowly worked it to where it would spend and then it started moving up and down really smooth once I cleaned it again.

No vent Valve.

I'm a little worried about the other ones even though they seem free may not be because this one was real nasty. But that little valve's been compressor isn't the easiest thing to work with trying to put the keepers back in so I'm not sure I want to pull everyone.

This means I win the internet today right ?

 

[JUSTWANNARACE]

Rockers may have been loose or lifters may have stuck from sitting, if hydraulic, may have allowed the push rod to come out of the pocket/cup of the rocker which would cause the push rods to bend

 

[Bigbore500r]

I got it free. It was varnish, bad.

Pulled the spring off and soaked it with intake valve cleaner. Then used a piece of gasket and vise grips and slowly worked it to where it would spend and then it started moving up and down really smooth once I cleaned it again.

No vent Valve.

I'm a little worried about the other ones even though they seem free may not be because this one was real nasty. But that little valve's been compressor isn't the easiest thing to work with trying to put the keepers back in so I'm not sure I want to pull everyone.

If you want to verify if any of the valves are noticably bent or damaged, a quick way to do it is to remove all of the rockers, and lay a straight edge across the tips of all the valves. Unless it has had a horrible valve job, they should all be exactly the same height. If one (or more) of them are lower than the rest, that can signify a bent valve, dropped valve seat, or something has chewed up (or is obnstructing) the sealing surface.
If they're all the same height, they *probably* did not hit the pistons, of if they did, they survived.....

If the valves seem to be freed up (and not bent) - toss a new set of pushrods in there and re-install the rockers. Roll the motor over with a breaker bar by hand, and watch all the rockers fully open and close. Do this with all the plugs out. Make sure all the rockers return to the fully closed position after a complete cycle. if there are any noticable tight spots, see if you can pinpoint which valve is causing the hangup. If no binding - next step....

Take an intake, and an exhaust valve at their peak lift, and insert a feeler gauge between the coils - confirm there are no coils on the spring with less than .080" clearance between them (some say as little as .050" is acceptable, but you should be nowhere near that limit with a stock-ish motor)

If that all pans out - put the plugs back in, valve covers on, and crank it over without the coil connected - does it crank even, or does is have a "skip" to it? It may have a gallop at first, then even out - that's the lifters getting oil pressure and pumping up. Sometimes a motor will take a bit to even out when it's been sitting. If it cranks over evenly without signs of a dropped cylinder, that's a good sign.

If all that pans out, make sure your on fresh fuel and see if you can get it fired up. If it runs decent, you probably are out of the woods. Seafoam the shit out of it and dump a few oil changes thru it after the seafoam. Buy a lotto ticket and vote for Trump in November . . .

 

[wzuber]

This means I win the internet today right ?

Well, at least the rdp internet for now. State compitions begin @ 8pm tonight and national comps @ 12am....
Good luck.

 

[YeahYeah01]

This means I win the internet today right ?

Lol well see when I get it started.

 

[YeahYeah01]

If you want to verify if any of the valves are noticably bent or damaged, a quick way to do it is to remove all of the rockers, and lay the straight edge across the tips of all the valves. Unless it has had a horrible valve job, they should all be exactly the same height. If one (or more) of them are lower than the rest, that can signify a bent valve, dropped valve seat, or something has chewed up (or is obnstructing) the sealing surface.
If they're all the same height, they *probably* did not hit the pistons, of if they did, they survived.....

If the valves seem to be freed up (and not bent) - toss a new set of pushrods in there and re-install the rockers. Roll the motor over with a breaker bar by hand, and watch all the rockers fully open and close. Do this with all the plugs out. Make sure all the rockers return to the fully closed position after a complete cycle. if there are any noticable tight spots, see if you can pinpoint which valve is causing the hangup. If no binding - next step....

Take an intake, and an exhaust valve at their peak lift, and insert a feeler gauge between the coils - confirm there are no coils on the spring with less than .080" clearance between them (some say as little as .050" is acceptable, but you should be nowhere near that limit with a stock-ish motor)

If that all pans out - put the plugs back in, valve covers on, and crank it over without the coil connected - does it crank even, or does is have a "skip" to it? It may have a gallop at first, then even out - that's the lifters getting oil pressure and pumping up. Sometimes a motor will take a bit to even out when it's been sitting. If it cranks over evenly without signs of a dropped cylinder, that's a good sign.

If all that pans out, make sure your on fresh fuel and see if you can get it fired up. If it runs decent, you probably are out of the woods. Seafoam the shit out of it and dump a few oil changes thru it after the seafoam. Buy a lotto ticket and vote for Trump in November . . .

This is awesome. Thanks!

 

[YeahYeah01]

Okay... I'm at the restart finish line. Everything I seem to check out fine. So far. I reinstalled the intake manifold. Now I'm working on the distributor. I don't trust how it was set up before.

I set the engine to top Dead center on the compression stroke. The distributor is a Mallory HEI. And I believe I have the rotor pointing at the number one cylinder. Now once that is done is the first spark plug wire to fire the one right after the rotor? I'm connecting that to the number one cylinder. And then after that doesn't matter what order the rest of the plugs wires go?

 

[bonesfab]

Set the balancer to 15-20 degrees and point the rotor to the terminal closest to it. Should be good enough to get it to fire.

 

[YeahYeah01]

Set the balancer to 15-20 degrees and point the rotor to the terminal closest to it. Should be good enough to get it to fire.

Can you dumb it down a little more for me? So if the distributor's out instead of setting it at top dead center set it at 15 to 20°? Then I put the distributor back in with the rotor pointing at the number one cylinder? Then the firing sequence for the first cylinder is the one directly after the rotor? And then after that the wire sequence doesn't matter? It'll fire in order?

Because I set it at top dead center dropped in the distributor with the rotor pointing at the number one. Set the first cylinder spark plug wire on the connector directly after the rotor and then I just connected the rest of the plugs in no specific order, just the cleanest route I could take with the wires. Attempted a fire and I got a insane exhaust backfire.

 

[lbhsbz]

Okay... I'm at the restart finish line. Everything I seem to check out fine. So far. I reinstalled the intake manifold. Now I'm working on the distributor. I don't trust how it was set up before.

I set the engine to top Dead center on the compression stroke. The distributor is a Mallory HEI. And I believe I have the rotor pointing at the number one cylinder. Now once that is done is the first spark plug wire to fire the one right after the rotor? I'm connecting that to the number one cylinder. And then after that doesn't matter what order the rest of the plugs wires go?

It absolutely matters what order the wires go in. I don’t speak ford, so I don’t know what the firing order is on that thing…I know ford had a few different firing orders over the years. When in doubt, roll the engine over and what the order in which the intake valves open…that’s your firing order:

Whenever I stab a distributor, set crank to TDC on compression for #1, I mark where #1 is and line it up exactly, the turn the body against rotor rotation so my mark is about 1/4” behind the rotor tip…that usually lands me somewhere around 10 degrees BTDC. Then draw an arrow on the cap so you don’t forget which way is spins, and get all the wires in the correct spot