78 Ford LTD bent pushrods?

[dimora]

My 78 Ford LTD (The "Guzzler" as Simon refers to it) has bent BOTH pushrods on the number 7 cylinder. I'm in the process of pulling the head, but can some V-8 experts please post some possible causes?

Thanks!

Shane

[Simon]

mis-adjusted
hydro-locked (doubtful)
bound lifter or rocker

that's all i can think of off the top of my head. that sucks man. how bad are they bent?

what motor is in the barge?

[Simon]

pulled rocker studs or wiped cam lobes will do it also...

[Neggy]

timing chain jumped, you'd really notice that though because the valve would hit the piston on more than one cylinder probably.

[Wolfman]

Are they "joined" rockers ? If so, they can lock up together. Timing chain jumping a tooth or so could cause that. Compression check can tell a lot. Has the carb flooded recently ??

[dimora]

Originally posted by Midnight Rider
mis-adjusted
hydro-locked (doubtful)
bound lifter or rocker

that's all i can think of off the top of my head. that sucks man. how bad are they bent?

what motor is in the barge?

It is a Ford 400 (The block is a 351M / 400 - meaning they used the same block to make both 351's and 400's - only difference was crank and pistons) - Mine was originally a 400. It has been bored out .030 over to 408 CI.

It started making a "clanging" going down the freeway, steady cruise, and it was rather loud, then the noise quit being so obnoxious, but I could hear a clanging at certain RPM's and felt something wasn't quite right.

I limped it home.

Compression check on all cylinders was between 125 and 150, except for cylinder number 7 which only read about 25 PSI.

I started the autopsy this evening:

I pulled the valve cover to the left cylinder bank, revealing BOTH pushrods bent on the number 7 cylinder.

Should I just put two new pushrods in and "see what happens" or should I pull the head to inspect the piston top / valves for damage in case the pistons collided with the valves (or can that happen on these engines?)

Thanks, guys!

Shane

My build is the following:

Ford 351M-400 (400 original cubic inches / 6.6 liters) bored out .030 over to make 408 cubes / 6.7 liters.
Edelbrock #2171 Intake Manifold
Edelbrock Performer #1405 600 CFM Carb
Edelbrock #8844 water pump
Edelbrock Performer-Plus #2172 camshaft and lifters.
Aussie Cleveland 302C "Quench" heads
Stock compression and style pistons (these have a "dish" in the piston tops).

[Dougyver T. #746]

Piston went kaboom, IMHO. Or maybe you sucked an interesting wad o' crap in and it lodged on top of the piston.
SOMETHING had to make contact with both valves..hydro locking it won't bend pushrods (though it will do interesting things to connecting rods)..a timing chain jump would have done up all the other ones as well instead of just a single cylinder..and simultaneously locking up two adjacent rockers is pretty unlikely, particularly since Ford uses individual rocker studs rather than a shaft system. Likewise, it's purty near impossible for the lash adjusters to TIGHTEN themselves (though they can come loose!), and I'm assuming you'd already driven the car prior to this mishap.

Are ya positive about your cylinder numbering? Cyl. #7 is the second from the rear of the crankshaft. On a Pherd V8 produced in '78, that would be the second cylinder from the rear on the left (driver's side) cylinder bank.
Most American V8 engines, #7 would be the rear one on the left bank, but Ford hadda be goofy. If it's actually #8 (Which is Ford's left rear cylinder), then you may have broken the camshaft..I've seen this happen before..the rear cam bearing seizes for whatever reason, the cam snaps and you end up hammering whatever valves the broken chunk actuated..since it's only one cylinder, it would have to be the rear-most one, hence my question about your familiarity with Ford's numbering system.

Edit.
Just read your last post..yeah, you're gonna need to pull the head. My first guess would be that your con-rod is a little less than perfectly torqued at this stage of the game, and your piston made contact with the valves until the pushrods bent and gave ya a little relief from the hammering sounds..

[Simon]

modifieds are known for wiping cams. actually, the whole oem valvetrain is notoriously problematic. if it were me, i'd do a full top-end tear-down and make sure it is right. it's not your daily so you're really not out anything but some time and some gaskets. inspect the rockers and stud height thoroughly and work your way down.

[Neggy]

slap 2 new rockers and push rods in it, pull the coil wire, crank it over see what happens with the valve cover off.

If they don't bend hook the coil up and light it up. Adjust the hot lash, pull the plugs and run compression again to verify the valves are good. If it is popping out the carb the intake valve is shot, popping noise out the exhaust
leans towards a bad exhaust valve.


if you have a spare cover cut the top off to keep oil from running all over the place, find an old mechanic that has a set of oil deflectors that clip over the rocker arm to keep the oil from pissing out all over the engine bay. Watch for oil fires on the exhaust manifold and Y pipe

Check the timing, watch for the mark jumping all over the place as you give it little gas. If you see the mark jumping, pull the plugs and the distributor cap, rotate the engine over by hand backwards till you hit TDC, then rotate it the other way, watching to see when the rotor starts to turn, read the number of degrees when the rotor starts to move off the balancers timing marks, it shouldn't be more than a couple of degrees tops. If the chain jumped chances are the car will be down on power and when you check the timing it will be way off, requiring a lot of movement of the distributor to get base timing.

I'm a bit rusty these days but I think most of the above is basic V8 diagnosis 101

[dimora]

It is definitely number seven - I already have the valve cover off and the bent rods in my hand. Pics to follow soon.

This happened while cruising down the freeway - so it can't be hydrolock, I don't think, but what do I know - unless the bend happened on startup?

So the consensus is pull the head?

[Simon]

it's not hydroed.


waiting for pics...

[Dougyver T. #746]

Yeah, pull the head..likely to be followed by pulling the oil pan to figger out WTH stretched..

Before ya yank the head, you might wanna do a leakdown test if you've got the equipment..at least you can find out if your valves are still seating (pretty unlikely, IMHO) before tearing down.

[EA6BMECH]

What Neggy said, but I'd pull the plugs, fan and shroud if you have to and try to motor it by ratchet or BF 3/4 breaker bar and socket so if you feel it bind up you can stop right there instead of munching it all over again.

Pulling heads.... I feel a broken manifold bolt coming on......

[dimora]

The engine runs (even with the bent pushrods).

I ran it yesterday and listened to it...so there is no binding going on. I should have told you all that.

I also heard what sounded like a possible leaky head gasket when it was running yesterday.

The coolant was down yesterday as well.

I have a theory here...I think perhaps it blew a head gasket (possible overheat with my wife driving it) and coolant leaked into the #7 - just enough coolant to hydro it and bend the pushrods while it sat - and then it "relieved" itself by blowing the gasket fully to the external atmosphere.

That is my theory...I'll pull the head tomorrow morning. MNMYKE is here to help me, so we'll get to the bottom of it all. Right now my $$ is on finding a blown head gasket when that head comes off.


I REALLY hope the bottom end is good.




As always, you guys are the best. whether it is motorcycles or pushrod V-8's, you guys have it going on.

Even though I don't know much about these engines, I read manuals well and am fearless with a ratchet, so I'll get it done - and do it myself with MNMYKES help.

[Simon]

i'd say you're analysis is right on the money with the new details.


i'll give you $500 for it. that's 50cents a ton.

[Simon]

even if you find that it was a leaky gasket i bet you pulled rocker studs. check em out.

[dimora]

Originally posted by Midnight Rider
even if you find that it was a leaky gasket i bet you pulled rocker studs. check em out.

Will do, Simon! I don't know how, but I have two really good books and I'll figure it out. Are those roller-rockers all the shiznit and worth doing while I have it apart? This build only has 12,000 miles on it.

[dimora]

Originally posted by Midnight Rider
i'd say you're analysis is right on the money with the new details.


i'll give you $500 for it. that's 50cents a ton.

I don't know if you could handle is pimp-a-lisciousness, Simon. We roll deep in tha' ATL, you know what I'm sayin'? Just keepin' it real. Representin. This thing might be too much for Ohio to handle.












Here is my favorite. Grandpa White on the day he bought it in 1978. Grandpa is on the right. Check out the plaid pants on the other guy!

[Dougyver T. #746]

Neat theory, except ya don't bend pushrods in a gasoline engine by hydro locking a cylinder.
It just plain don't work that way in my experience.
If'n ya pull the head & there are no valve marks on the piston, I'll eat my words..but I betcha I don't have to!

[youngzrxer]

Sounds like an opportunity to rip that 400 anchor out and put in a 460...

[Mad Irish]

I had one of those , when I was in the great white north. Well not quite , it was a regular 1976 4 door with a 302. Bought it in Saskatchewan, drove it across the Trans Can to New Brunswick in the middle of winter. Now that was cool old boat Before I moved down here , the motor froze , cracked the block. So left it there.
Ah simpler times

[Simon]

that is just too damn cool! Shane, you are the man in my book. family matters and keep it documented.


as far as the LTD goes... fo sheezy my neezy! we rollz like dat in da O H O.



alright... $650

[Simon]

Originally posted by Dougyver T. #746
Neat theory, except ya don't bend pushrods in a gasoline engine by hydro locking a cylinder.
It just plain don't work that way in my experience.
If'n ya pull the head & there are no valve marks on the piston, I'll eat my words..but I betcha I don't have to!

ummm... cylinder fills with fluid, valves have nowhere to go... what's your theory?

[dimora]

Originally posted by Midnight Rider
yes, roller rockers rock! get the stamped rollers though on a budget build. i'm pretty sure you can use 1.7's on the M's too. that will obviously increase your cam lift. lemme make a call tomorrow and i can give you some decent pointers. i've built a few windsors and one cleveland but never a modified. my details are rusty to say the least.

is an M 1-3-7-2-6-5-4-8?

Yes - 1-3-7-2-6-5-4-8.

It is actually quite a powerful build I have - the Aussie heads I have on it are Ford's version of Hemi - but they couldn't call it that - so they called it "quench". I haven't had it on a dyno, so I don't know its exact output - but I need to do that. I'll get this sorted and do a run with it just to see. OEM these things only had 155-160 HP. Geez, my ZRX has that. But they had a ton of torque - around 298 foot-pounds.

My cam is somewhat mild, as I wanted a bias toward torque and not HP due to the car's size, and it is automatic transmission boulevard sled.

Desktop dyno back when I had it built says I should expect to have the following approximate numbers:

HP: 345@5000 RPM
Torque: 424 ft-lbs@3500 RPM

I have a C6 tranny (freshly rebuilt).

I had someone else build it for me, so I have no way of knowing if it was done right, but he used to build dragster engines back in the day, so I trust he did it all correctly. I really do think an overheat led to the failure.

We will see tomorrow!

[Todd 55]

Oh my GOD!!! How many Chicken Littles can run out from under the tree at once?

Shane, I did the same thing on a 73 LTD with the 400M.... I just hammered it coming into the subdivision, and rattle rattle rattle. I only bent one pushrod, but I had it fixed in no time. I was only 16 at the time..... if I remember, it was the second from the rear on the passenger side though.

Never had another problem with it, and we had it a few years after that happened. I'll put money that nothing else is tweaked...

[dimora]

Originally posted by youngzrxer
Sounds like an opportunity to rip that 400 anchor out and put in a 460...

This engine will demolish all but a seriously built 460. It will walk all over a stock 460.

The 400 is nothing more than a "stroker" 351 - 4 inch bore and 4 inch stroke. With the Aussie heads I have on it, it is high compression. It is a formidable motor the way I have it set up for being such a boat anchor. It spins the tires on that big sled.

[Simon]

alright... $789

[wario]

Originally posted by Midnight Rider
pulled rocker studs or wiped cam lobes will do it also...

I'm guessing the latter - these motors were starved for oil. You can get a boneyard motor for under $500 that'll keep it purring into the next gas crisis!

[KWICK]

It's because of the fender skirts.

[zrxrob]

i'll give $651.27