'69 427 Bent Push Rod
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I started working on vettes about 1980. Since I had a big garage friends would bring over side jobs. Originally wasn't a big deal back then and the 390 hp 427s were really low on the performance scale. It was very common to replace 427s with the more common and powerful 454s
Because of your casting numbers it is very possible that you have a lower budget rebuild 454
Because of your casting numbers it is very possible that you have a lower budget rebuild 454
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Those valve springs might be 40 year old truck springs. Low lift low rpm soft when new. 85 to 100 lbs seat pressure. And worn down from there. They might be brand new and too high a spring rate for the valvetrain. You have the top end pretty much apart. Pull couple of springs and get them ID'd any cyl head shop can tell you what spring pressure at seat and fully open and how far from seat to coil bind. I forgot this was a roller lifter setup. Now we don't know if they are solids or hydraulics. Shine flashlight down pushrod hole and get a look at the top of a couple lifters. Pic is a solid roller lifter. A hyd lifter will have a snap ring showing on top.
Last edited by derekderek; Mar 10, 2019 at 10:29 AM.
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
Those valve springs might be 40 year old truck springs. Low lift low rpm soft when new. 85 to 100 lbs seat pressure. And worn down from there. They might be brand new and too high a spring rate for the valvetrain. You have the top end pretty much apart. Pull couple of springs and get them ID'd any cyl head shop can tell you what spring pressure at seat and fully open and how far from seat to coil bind. I forgot this was a roller lifter setup. Now we don't know if they are solids or hydraulics. Shine flashlight down pushrod hole and get a look at the top of a couple lifters. Pic is a solid roller lifter. A hyd lifter will have a snap ring showing on top.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
In my estimation and given the harsh conditions, seems those "crap" sealed power PRs comported themselves admirably.
And while they're correct OE replacements, their lengths may or may not be correct for a modified build-combo; perhaps length/geometry wasn't even considered during the "freshening."
So far anything's possible, but I doubt PR length was a significant factor here.
Once the valvetrain problems are diagnosed, and as they're sorted, suggest pushrod length/geometry should be checked before ordering new PRs.
Seems, I've seen where another poster suggests OP's Cam is a roller.
? Does it have roller lifters ? ... I doubt it, as those replacement PRs are far too long for any typical aftermarket BBC roller setup.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Ok hyd lifters. Valve springs. Are there big steel umbrellas on outside of springs that cover the top half of the springs? If so orig truck springs. Got a pic of the valve springs as they sit?
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Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Two things did gm in
haha
Pushrods are kind of a fusible link, op you are probably fine put some good ones in and motor on.
I bent a few on a brand new motor somehow got ahold of some knockoff Manley pieces it screwed teh valvetrain up (ALL of it) in 60 mi
Guy overat Manley sent me the real deal no issues since.
Gearheads sometimes convince themselves pushrods and old springs "are fine"
Pushrods are kind of a fusible link, op you are probably fine put some good ones in and motor on.
I bent a few on a brand new motor somehow got ahold of some knockoff Manley pieces it screwed teh valvetrain up (ALL of it) in 60 mi
Guy overat Manley sent me the real deal no issues since.
Gearheads sometimes convince themselves pushrods and old springs "are fine"
Le Mans Master
Joined: Mar 2004
Posts: 7,499
Likes: 1,507
From: Little Rock AR
Solid lifters have snap rings too.
All bent push rods are intake push rods so issue should be found there. Pull an intake valve spring off and inspect bottom of retainer and top of valve guide. Look for any witness marks showing contact between those points. If the seals are aftermarket, they can get hammered and that will confirm the interference. Could be coil bind. This push rod bending happened very recently after some kind of change in the valve train or over revving the engine. Too much lift for the intake valve train happened somewhere. If compression is good the valve head is not bent.
Maybe rotate engine with a checking spring on an intake valve to see if you can see (or feel) the binding.
All bent push rods are intake push rods so issue should be found there. Pull an intake valve spring off and inspect bottom of retainer and top of valve guide. Look for any witness marks showing contact between those points. If the seals are aftermarket, they can get hammered and that will confirm the interference. Could be coil bind. This push rod bending happened very recently after some kind of change in the valve train or over revving the engine. Too much lift for the intake valve train happened somewhere. If compression is good the valve head is not bent.
Maybe rotate engine with a checking spring on an intake valve to see if you can see (or feel) the binding.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Just once or twice
To the OP all it takes with a hydraulic is a couple of times well over reved and lifters pumped up from it and the valve springs are no good. While you have it apart toss the valve springs in the trash and start over. Any good chrome molly .080 thick 3/8 pushrod what you need, check tour cam and lifters. Any stick shift hydraulic lifter car should have a rev limiter put on it.
Thread Starter
Racer
Joined: Apr 2013
Posts: 302
Likes: 16
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
wire retainer v snap ring
http://toplineauto.com/wp-content/up...ch-165x300.jpg
reference pic above
typical Hydraulic lifter on Left has wire retainer < L >-----------< R > typical Solid lifter on Right has an internal snap ring
nothing is absolute ... of a mix scattered on a bench, you can usually pick out hydraulic or solid ... nothing is absolute
reference pic above
typical Hydraulic lifter on Left has wire retainer < L >-----------< R > typical Solid lifter on Right has an internal snap ring
nothing is absolute ... of a mix scattered on a bench, you can usually pick out hydraulic or solid ... nothing is absolute
Le Mans Master
Joined: Mar 2004
Posts: 7,499
Likes: 1,507
From: Little Rock AR
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
WAG
cam may be hyd flat tappet sealed power pn CS1015R
-edit-
an even closer WAG may be hyd flat tappet Melling pn 22296
cam may be hyd flat tappet sealed power pn CS1015R
-edit-
an even closer WAG may be hyd flat tappet Melling pn 22296
Last edited by jackson; Mar 10, 2019 at 06:27 PM.
