Bent push rods
Cargo Master
Joined: Jul 2005
Posts: 2,313
Likes: 367
From: Kansas
when the push rod bends and falls out the cam pushes the lifter out of the bore and you lose oil pressure.
Cargo Master
Joined: Jul 2010
Posts: 2,099
Likes: 8
From: York, Pa
This is correct. It may have had a little oil pressure but it probably wasn't much.
Junior User
Joined: Oct 2016
Posts: 72
Likes: 0
This is exactly what happened to my 351M. Suddenly lost ALL oil pressure, significant loss of power and started to knock and rattle. Unfortunately I had to drive it 8 or 9 miles home. Was knocking bad under load. Took the valve covers out and could see one broken push rod, one bent push rod and a lifter in the lifter valley. Replaced only the push rods and the lifters due to luck of $$$ (even though some of the lifters looked like a soup bowl). Put it back together and it has been running great fros several months (after fixing sam carb issues I had), no knocking of noise of any kind, good power , really good oil pressure. Don't know how long it will last, I would think the cam would be in bad shape. In any case, I was surprised at the resiliency of this engine, for all the bad press it gets.
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New User
Joined: Jul 2015
Posts: 21
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This is exactly what happened to my 351M. Suddenly lost ALL oil pressure, significant loss of power and started to knock and rattle. Unfortunately I had to drive it 8 or 9 miles home. Was knocking bad under load. Took the valve covers out and could see one broken push rod, one bent push rod and a lifter in the lifter valley. Replaced only the push rods and the lifters due to luck of $$$ (even though some of the lifters looked like a soup bowl). Put it back together and it has been running great fros several months (after fixing sam carb issues I had), no knocking of noise of any kind, good power , really good oil pressure. Don't know how long it will last, I would think the cam would be in bad shape. In any case, I was surprised at the resiliency of this engine, for all the bad press it gets.
Junior User
Joined: Oct 2016
Posts: 72
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Long story short, never quite found out what caused the bent rods, I have wondered if the rods were already bent when I got it (thus all the smoking) and then, after my driving it a couple of times, the lifter popped out causing the loss of oil pressure.
You might want to check the vacuum to see if it gives you an indication of stuck valves.
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New User
Joined: Jul 2015
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Your absolutely correct. Found 3 very tight valves that I cannot move with a deadblow hammer. I feel much better about the repairs knowing what caused the problem. Thank you for your helpful insight!!
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New User
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Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Stale gasoline I bet. Bad stuff. It will burn, it will run, but upon shutdown and things cool off, it turns to glue/varnish coating valves &c. Then, the next time someone goes to start - it breaks things.
Good to use a fuel stabilizer, and keep the tank topped off if it won't be used very often. Try to keep it out of the sun or wide temperature swings. I use marvel mystery oil in the fuel in the old solid lifter engined truck, it sure seems to help with sticky valves and rings and help prevent this.
Good to use a fuel stabilizer, and keep the tank topped off if it won't be used very often. Try to keep it out of the sun or wide temperature swings. I use marvel mystery oil in the fuel in the old solid lifter engined truck, it sure seems to help with sticky valves and rings and help prevent this.
Cargo Master
Joined: Nov 2011
Posts: 3,354
Likes: 49
From: Great American SouthWest
Nice thing about pushrods is that when they bend/break they are cheap and easy to replace. The reason for the damaged pushrod is the real problem-usually a stuck or bent valve
fortunately, it's a warning that other things need to be addressed
When my 351m was bending pushrods, it was due to gummed-up valves. I always run Chevron fuel, but I have no idea what previous owners ran. When I replaced the cam and lifters, the bottom of the lifters were so heavily varnished that I had to use vise-grips to twist them out. Destroyed the lifters-they came out in pieces.
On a plus note, the cam didn't push them out of the bores at an inopportune time!
fortunately, it's a warning that other things need to be addressed
When my 351m was bending pushrods, it was due to gummed-up valves. I always run Chevron fuel, but I have no idea what previous owners ran. When I replaced the cam and lifters, the bottom of the lifters were so heavily varnished that I had to use vise-grips to twist them out. Destroyed the lifters-they came out in pieces.
On a plus note, the cam didn't push them out of the bores at an inopportune time!
Junior User
Joined: Oct 2016
Posts: 72
Likes: 0
Nice thing about pushrods is that when they bend/break they are cheap and easy to replace. The reason for the damaged pushrod is the real problem-usually a stuck or bent valve
fortunately, it's a warning that other things need to be addressed
When my 351m was bending pushrods, it was due to gummed-up valves. I always run Chevron fuel, but I have no idea what previous owners ran. When I replaced the cam and lifters, the bottom of the lifters were so heavily varnished that I had to use vise-grips to twist them out. Destroyed the lifters-they came out in pieces.
On a plus note, the cam didn't push them out of the bores at an inopportune time!
fortunately, it's a warning that other things need to be addressed
When my 351m was bending pushrods, it was due to gummed-up valves. I always run Chevron fuel, but I have no idea what previous owners ran. When I replaced the cam and lifters, the bottom of the lifters were so heavily varnished that I had to use vise-grips to twist them out. Destroyed the lifters-they came out in pieces.
On a plus note, the cam didn't push them out of the bores at an inopportune time!
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New User
Joined: Jul 2015
Posts: 21
Likes: 0
M.E.K. works great if you can find it. It's the main ingredient in carb cleaner but hard to get these days because the meth cooks use it... Try an industrial paint store.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Man, is there anything those tweakers DON'T use to make meth? Jeeze Louise.. "Yessir, I gots some battery acid, some Draino, 20,000 matcheads, some MEK, and alkaline batteries, we're gonna party tonite. What time you comin' over anyway?
Fleet Mechanic
Joined: Aug 2004
Posts: 1,311
Likes: 31
From: Nevada
yup
Personally, I wouldn't spend the time scrubbing with a chemical on the old valves.... remov'em and gently massage them with a copper grind wheel brush (I know its a sin for some of u pro mechanics)... If you have a steady hand it only takes about a minute per valve, inspect the valves, if there in good shape, put'em back in and hand lap them............take a good look at your springs and keepers.... If your on a budget, put'em back in Now if you can spare the change and don't want to roll the dice u could drop the $120 and get a set of springs, valves and keepers off EBAY...... 
Now if you can spare the change and don't want to roll the dice u could drop the $120 and get a set of springs, valves and keepers off EBAY......
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New User
Joined: Jul 2015
Posts: 21
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no scrubbing was involved I soaked the entire head in hot MEK and blew them off with air. leak tested them and good to go. if I were going to dismantle them Id put new ones in. I do like the way you think however.
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