Recent Topics
Roller Bearing Setup For Dillon Shellplate
by billt460
06/23/18 05:59 AM
Omnia - the band
by Shannow
06/23/18 02:58 AM
Guest's devices cannot connect to my WiFi
by boulderdentist
06/23/18 12:54 AM
Battery stuck in flashlight.
by Chris142
06/22/18 11:53 PM
Must read for everyone watching their diet
by JLTD
06/22/18 11:28 PM
2014 Mazda5 Valvoline Synpower 0W-20 7500 miles
by PWMDMD
06/22/18 10:54 PM
VOA Ravenol ECS 0W-20
by PWMDMD
06/22/18 10:47 PM
2020 mid-engine Corvette spy vid?!
by AZjeff
06/22/18 10:45 PM
'05 base impala. NO turn signals.FAST blinking.
by Lee4212
06/22/18 10:34 PM
Motul 15w-50, 5 Liter 4 Pack $19.42
by hatt
06/22/18 10:10 PM
High Lead Redline 5W40 thoughts? Ty
by Pajero
06/22/18 09:40 PM
Source of the Mighty Columbia River
by Snagglefoot
06/22/18 09:32 PM
Another thick/thin article to discuss
by JLTD
06/22/18 09:23 PM
Ethylene Glycol Long Life Coolant for KUBOTA
by pburchett
06/22/18 09:11 PM
Mobil 1 5W-30, 6,200 mi, 2017 2.3 EB Explorer
by Whimsey
06/22/18 08:48 PM
Chevron 10w-40, 97 Nissan Maxima, 3000 miles
by OilGeek91
06/22/18 08:36 PM
Old green antifreeze in garage storage is gelling
by JLawrence08648
06/22/18 08:32 PM
VWs at Pick n Pull
by Eric Smith
06/22/18 08:17 PM
Single Data Point: CK-4 destroys the flat tappet
by Gokhan
06/22/18 08:12 PM
Breaking in new short block
by Bub
06/22/18 07:00 PM
Newest Members
azzid0906, OilGeek91, DRancher, Newuser, Varbill
65299 Registered Users
Who's Online
55 registered (Bailes1992, 4WD, Bandito440, Alex_V, 13 invisible), 998 Guests and 68 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
65299 Members
67 Forums
285817 Topics
4769976 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Page 1 of 2 1 2 >
Topic Options
#4561247 - 11/01/17 01:18 PM What causes bent pushrods?
Nick1994 Offline


Registered: 02/19/13
Posts: 10118
Loc: Phoenix, AZ
My dad has a 1999 Fleetwood Flair 30H RV that he bought 2years ago, around 76k miles. It has the Chevy 454 engine. In August he moved up to Oregon and drove it up there towing his FJ Cruiser, 4 mpg crzy . In August before the journey he changed the oil, plugs, wires, cap, rotor, etc. On the journey it set a CEL for running lean (or rich? Can't remember) and it also has had a crack in the exhaust manifold, we thought it might be that.

It's been running fine, except last week he said it wouldn't go over 10 mph, had a rough idle, and when giving it throttle it stumbles and bangs on the passenger side.

He took it to an RV mechanic who said it had 3 bent pushrods and it runs fine now after the repair.

How do push rods get bent? I'm not that internal-engine-savvy.
_________________________
2015 Hyundai Sonata 2.4L 79k PU 5w30 & OEM
2000 Toyota Camry 2.2L 228k M1 AFE 0w30 & Wix
1996 Jeep Cherokee 4.0L 146k M1 HM 10w40 & Fram Ultra

Top
#4561251 - 11/01/17 01:24 PM Re: What causes bent pushrods? [Re: Nick1994]
JTK Offline


Registered: 08/14/03
Posts: 10587
Loc: Buffalo, NY
A hydraulic lash adjuster (lifter) that sticks all the way extended can bend a pushrod.
_________________________
2017 Ram 1500 4x4, 3.6L. 2016 Nissan Quest SV (Babe magnet IV)

Top
#4561252 - 11/01/17 01:25 PM Re: What causes bent pushrods? [Re: Nick1994]
ARCOgraphite Offline


Registered: 05/17/09
Posts: 11970
Loc: N.H, U.S.A.
overrevving usually.
_________________________
2014 Nissan Rogue S CVT, OC#9 41392mi-QSUD10W30 + M110A CHAMP Filter; 2017 Subaru Crosstrek CVT OC#2 ?? mi-SOA/Idemitsu 0w20 + SOA Filter

Top
#4561256 - 11/01/17 01:27 PM Re: What causes bent pushrods? [Re: Nick1994]
ARCOgraphite Offline


Registered: 05/17/09
Posts: 11970
Loc: N.H, U.S.A.
He need to get a old Suzuki Samurai or a Smart for a tow behind. That FJ is a fat piglet.
_________________________
2014 Nissan Rogue S CVT, OC#9 41392mi-QSUD10W30 + M110A CHAMP Filter; 2017 Subaru Crosstrek CVT OC#2 ?? mi-SOA/Idemitsu 0w20 + SOA Filter

Top
#4561257 - 11/01/17 01:29 PM Re: What causes bent pushrods? [Re: Nick1994]
Chris142 Offline


Registered: 06/05/03
Posts: 16825
Loc: Deplorable in apple valley, ca
Overrevving. All that weight pushing it down a hill usually.
_________________________
02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40

Top
#4561258 - 11/01/17 01:30 PM Re: What causes bent pushrods? [Re: Nick1994]
BrocLuno Offline


Registered: 09/06/15
Posts: 5519
Loc: Kalifornia Kollective
Bad lifter as stated above ..

Or, it is the rocker arm not having enough slot clearance so that the arm stops moving and the cam/lifter does not. So if this engine ever had a cam change (?) and they did not install "long slot rockers", it might be close to the limits ... An over rev and lifters pumped up will put it over the limit.

Or, it could be piston/valve interference due to a worn timing chain (long shot), timing jumped one tooth (also long shot, but still needs worn chain), or piston/valves set too close and carbon build-up has closed the gap (best probability) ...

I would not drive it until I found out why?

Find a tune-up shop with a bore scope and have them look in the cylinders. If it's carbon-ed up, get it cleaned (various ways). If it not carboned up, then it's mechanical ...



Edited by BrocLuno (11/01/17 01:33 PM)
_________________________
Formerly in marine engineering. In an earlier life I owned my own petroleum tank truck, and hauled for the majors and independent's.

Top
#4561259 - 11/01/17 01:32 PM Re: What causes bent pushrods? [Re: Chris142]
SatinSilver Offline


Registered: 01/24/08
Posts: 10172
Loc: OH
That's like towing a 4Runner behind it as far as weight goes. Yikes!

Top
#4561260 - 11/01/17 01:32 PM Re: What causes bent pushrods? [Re: ARCOgraphite]
Nick1994 Offline


Registered: 02/19/13
Posts: 10118
Loc: Phoenix, AZ
Originally Posted By: Chris142
Overrevving. All that weight pushing it down a hill usually.
It took a lot of throttle to get it up the mountains to Oregon from Arizona, not sure what else he could have done. Also, it ran fine when he'd drive it around town occasionally the past couple months, he said it was all of a sudden. He doesn't drive like a race car driver so I don't think he was redlining it around town.

Originally Posted By: ARCOgraphite
He need to get a old Suzuki Samurai or a Smart for a tow behind. That FJ is a fat piglet.
He was moving, wasn't for a vacation. It was a flat tow too with a tow bar so no trailer weight.
_________________________
2015 Hyundai Sonata 2.4L 79k PU 5w30 & OEM
2000 Toyota Camry 2.2L 228k M1 AFE 0w30 & Wix
1996 Jeep Cherokee 4.0L 146k M1 HM 10w40 & Fram Ultra

Top
#4561261 - 11/01/17 01:32 PM Re: What causes bent pushrods? [Re: Nick1994]
DoubleWasp Offline


Registered: 05/21/12
Posts: 5236
Loc: Fort Lauderdale, FL
As I said in the other thread, BBC engines are not exactly happy with high sustained rpms. Most of the time when we see BBCS with bent pushrods, it's either broken or soft valve springs that allowed pushrods to escape their position and be rammed into a new position after escaping the rocker, or collapsed lifters allowing the same.

When we do the marine versions, we almost always replace the valve springs with something aftermarket that will take the beating, unless preserving a crate engine warranty.

Collapsed lifters are nowhere near as common as broken or soft valve springs.
_________________________
07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio

Top
#4561277 - 11/01/17 01:57 PM Re: What causes bent pushrods? [Re: Nick1994]
BrocLuno Offline


Registered: 09/06/15
Posts: 5519
Loc: Kalifornia Kollective
Well, I assumed that broken valve springs were not the issue because the OP did not relay that info from the mechanic?? But maybe we don't have the whole story ...
_________________________
Formerly in marine engineering. In an earlier life I owned my own petroleum tank truck, and hauled for the majors and independent's.

Top
#4561279 - 11/01/17 01:58 PM Re: What causes bent pushrods? [Re: Nick1994]
Kuato Offline


Registered: 10/23/05
Posts: 7094
Loc: Colorado
Credit to Chevy's 454 for operating that long with several bent pushrods! Yeah at high rpm you get valve float (valves stay open) and when they're in the way of the piston or other parts....well something's got to give.
_________________________
Thick vs Thin test: 15k / 43k miles complete

Top
#4561357 - 11/01/17 04:00 PM Re: What causes bent pushrods? [Re: Nick1994]
dishdude Offline


Registered: 11/14/08
Posts: 8754
Loc: Phoenix
.


Edited by dishdude (11/01/17 04:02 PM)
_________________________
2018 Challenger SRT

Top
#4561386 - 11/01/17 04:51 PM Re: What causes bent pushrods? [Re: Nick1994]
ShotGun429 Offline


Registered: 12/09/04
Posts: 426
Loc: Dayton,Ohio
heavy towing up a mountain (heat) can take out the oil film on the valve guides,Cast iron guides, steel valves, hangs them (valves) open off the valve seat, and Piston hits said valves and you end up with Bent pushrods, Just replacing pushrods may not fix your issue long term.

Top
#4561406 - 11/01/17 05:16 PM Re: What causes bent pushrods? [Re: BrocLuno]
DoubleWasp Offline


Registered: 05/21/12
Posts: 5236
Loc: Fort Lauderdale, FL
Originally Posted By: BrocLuno
Well, I assumed that broken valve springs were not the issue because the OP did not relay that info from the mechanic?? But maybe we don't have the whole story ...


I didn't get that impression either, just passing along info.

Multiple bent pushrods definitely makes me think of valve float due to collapsed or semi-collapsed lifters.

Part of me even wonders if low oil pressure allowed the lifters to leak down enough to set a few pushrods free.

Not an easy one to hit dead on unless you're the mechanic who was on that engine.
_________________________
07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio

Top
#4561503 - 11/01/17 07:00 PM Re: What causes bent pushrods? [Re: DoubleWasp]
Nick1994 Offline


Registered: 02/19/13
Posts: 10118
Loc: Phoenix, AZ
Originally Posted By: DoubleWasp
Originally Posted By: BrocLuno
Well, I assumed that broken valve springs were not the issue because the OP did not relay that info from the mechanic?? But maybe we don't have the whole story ...


I didn't get that impression either, just passing along info.

Multiple bent pushrods definitely makes me think of valve float due to collapsed or semi-collapsed lifters.

Part of me even wonders if low oil pressure allowed the lifters to leak down enough to set a few pushrods free.

Not an easy one to hit dead on unless you're the mechanic who was on that engine.
I posted all the info I got from my dad, sorry if it wasn't enough.

I believe the gauge reads good oil pressure too, he filled with 10w40 MaxLife before the journey.
_________________________
2015 Hyundai Sonata 2.4L 79k PU 5w30 & OEM
2000 Toyota Camry 2.2L 228k M1 AFE 0w30 & Wix
1996 Jeep Cherokee 4.0L 146k M1 HM 10w40 & Fram Ultra

Top
Page 1 of 2 1 2 >