Bent push rods?
Thread Starter
|
Senior User
Joined: Sep 2008
Posts: 318
Likes: 1
From: Portage Des Sioux, Mo
Bent push rods?
A friend has an 80 F350 with 400M engine. Just replaced timing chain (2 month ago) due to rattle. Now truck is bending push rods. He has replaced a couple twice and it runs good for awhile and then bends them again. Any idea what could cause this? He needs truck bad. It is his living.
Elder User
Joined: Aug 2010
Posts: 567
Likes: 1
From: Vancouver, WA
The only way that I can think of any way that he may be bending push rods is if he didn't get the timing marks correctly lined up when he replaced the timing chain. Unless he's racing that motor, or someone did a questionable engine rebuild, it's darn near inpossible to bend a push rod during normal operation. Is he sure he replaced the correct length of push rods? Did he torque everything to the correct specs?
Thread Starter
|
Senior User
Joined: Sep 2008
Posts: 318
Likes: 1
From: Portage Des Sioux, Mo
He says all he did was replace chain. Engine has not been rebuilt. It is an old guy. Uses the truck just for hauling scrap/junk. Doesn't abuse it. I was wondering about push rod length. It did bust 1 of the lifters this time. I am going over in the morning to look at it.
Elder User
Joined: Aug 2010
Posts: 567
Likes: 1
From: Vancouver, WA
If he damaged a lifter, then the cam is also done. This would indicated he didn't get the timing marks correct. New cam and lifters, new push rods at a minimum. Depending on miles on the engine, maybe time for a rebuild or replacement.
Thread Starter
|
Senior User
Joined: Sep 2008
Posts: 318
Likes: 1
From: Portage Des Sioux, Mo
Yeah I think he needs a new engine just because I know what kind of mileage he has on it. I found a replacement on craigslist for $500 but don't know its condition, says it runs good but you know how that goes. Doin a complete rebuild on the last runs good I bought.
Fleet Mechanic
Joined: Aug 2005
Posts: 1,462
Likes: 74
From: Hartford, AL
Ditto. Incorrectly installed timing chain. You may even have bent valves now. I would guess entire valvetrain may need replacing...and as planehunter said...depending on miles, either a full rebuild or replacement.
Thread Starter
|
Senior User
Joined: Sep 2008
Posts: 318
Likes: 1
From: Portage Des Sioux, Mo
Found out the first time this happened was 2008. This is 4th time. more valves each time. Only intake valves. He says he has had valve covers off while running and could see valve stick. I am wondering if this could cause push rod to fall out of socket and stick against bottom of rocker, or cause lifter to pump up. Engine has 150,000. 3rd engine, normally gets 300,000 out of an engine. Did notice back of intake valves had excessive carbon build up. Thinking excessive EGR causing carbon that causes valve to stick. EGR is disconnected but that doesn't mean it is not stuck open.
Trending Topics
Fleet Mechanic
Joined: Aug 2005
Posts: 1,462
Likes: 74
From: Hartford, AL
Bent valve causing sticking and bent pushrod is my bet, due to incorrectly installed timing chain. 80% sure.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
DutchmanAZ
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
24
Jul 28, 2017 08:43 PM
joslawn33
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
24
Dec 4, 2016 09:09 PM
sonny1965
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
7
Jun 3, 2016 07:42 AM
