Push rod question for guide plates SBC 400
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Joined: Feb 2009
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From: Brisbane, Australia
Car: 1985 Pontiac TransAM
Engine: 400SBC 24x conversion
Transmission: T700r Stage2 Shiftkitted
Axle/Gears: 2.77 9 Bolt
Push rod question for guide plates SBC 400
Hey guys,
I'm 90% sure I found the cause of the high Iron reading in my oil but just wanted to get a confirmation from someone who's seen it first hand.
I'm running a set of AFR heads with guide plates, retro fit roller lifters and 7.300" vortec stainless steel push rods.
From what I've read, I should've used hardened rods, like the Moly Chrome option as these will not rub off on the guide plates.
I've taken the valve covers off and had a look and there's a metallic paste around the pushrod holes and when I dumped the oil it had a metallic paint look to it as well. You can also see about 0.5mm wear mark into the pushrods so I'm 100% confident they're screwed, the 10% unsure bit is whether the guide plates are the right size for the rods or if they need to be replaced with guide plates with a larger clearance?
I ordered a set of 7.350" LS1 Chrome Moly push rods which arrived today and look much better in quality, and as I'm using adjustable roller rockers, the .050" should be able to be adjusted out yes?
I'm 90% sure I found the cause of the high Iron reading in my oil but just wanted to get a confirmation from someone who's seen it first hand.
I'm running a set of AFR heads with guide plates, retro fit roller lifters and 7.300" vortec stainless steel push rods.
From what I've read, I should've used hardened rods, like the Moly Chrome option as these will not rub off on the guide plates.
I've taken the valve covers off and had a look and there's a metallic paste around the pushrod holes and when I dumped the oil it had a metallic paint look to it as well. You can also see about 0.5mm wear mark into the pushrods so I'm 100% confident they're screwed, the 10% unsure bit is whether the guide plates are the right size for the rods or if they need to be replaced with guide plates with a larger clearance?
I ordered a set of 7.350" LS1 Chrome Moly push rods which arrived today and look much better in quality, and as I'm using adjustable roller rockers, the .050" should be able to be adjusted out yes?
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Re: Push rod question for guide plates SBC 400
Yes the difference in length can be "adjusted out". But there's more to it than that. The ideal length puts the rocker in the center of its arc when the valve is just a bit more than half open, and thus depends on a number of factors that are totally unique to YOUR particular engine. Even your next door neighbor's engine built from the identical same bill of materials will probably need a different length to be "ideal". The effect of the difference in length will depend on what the ideal length for your setup actually is. When you measured that, what did it turn out to be?
Yes your existing push rods are wrong for guide plates, and the excessive wear is the result. Being 3-pc doesn't make matters any better. Those are just simply inadequate for a high-stress situation. Good thing you're changing them out before one of them fails by the ball getting driven into the tube and mushrooming the end.
Not sure what the diameter of LS1 ones is. The ones for your SBC need to be 5/16" (.3125"). Might want to mic em and see what they are. Extra clearance doesn't help anything; the job of the guide plates is to guide the push rods in the right place to hold the rockers in the correct relation to the valve stem (just slightly off of "dead straight"). Expect them to fit close to and slightly rub the plates. If they didn't, the plates wouldn't be necessary in the first place.
Yes your existing push rods are wrong for guide plates, and the excessive wear is the result. Being 3-pc doesn't make matters any better. Those are just simply inadequate for a high-stress situation. Good thing you're changing them out before one of them fails by the ball getting driven into the tube and mushrooming the end.
Not sure what the diameter of LS1 ones is. The ones for your SBC need to be 5/16" (.3125"). Might want to mic em and see what they are. Extra clearance doesn't help anything; the job of the guide plates is to guide the push rods in the right place to hold the rockers in the correct relation to the valve stem (just slightly off of "dead straight"). Expect them to fit close to and slightly rub the plates. If they didn't, the plates wouldn't be necessary in the first place.