Technical push rods

hi again,
once again i need some help and i know someone on this forum has the answers.
i'm working on a 1951 chevy styleline deluxe, 216, 3spd. in the process of getting the engine running correctly, i found a couple of push rods that are a bit bent. it does not seem to be a problem with first start and running it in the driveway but, as long as i'm in there i thought i would change out the bent rods.
now getting the replacement rods is not a problem. everyone seems to have the "correct" one but the trouble is the correct ones, according to the various vendors i have went to, are different sizes than what i have. so....what is the correct length? can it run with the wrong size?
i also have a problem getting oil to the rockers. i have cleaned everything from oil pan to the rockers including the feed tube but i still get very little oil up top. granted the engine has only ram at low RPMs in the driveway but could the pushrods be wrong and be a factor?

thanks again.

 

sorry, here is a pic of what i found in the motor

 

How much difference is there in the length?





Bones

 

i just got 2 more that are very close. i'd say the stock is about 1/8 inch max shorter. the pic shows new on the right

 

I’m not familiar with your engine. Do you have adjustable rocker arms?






Bones

 

I sent Smith Bros. a sample from my 235 and they made me a set a lot stronger, with the correct ends and the correct length and pretty well priced.
Warren

 

adjustable rockers, i'm not sure, ( still a new guy to this) but i do have to adjust the valve/pushrods. i've read .006 and .018 if that helps.

 

In high performance engines push rod/ rocker arm/ valve alignment/ geometry is critical. Stock engines, not so much. It is always the best to get exact replacement items, but lots of times the replacement item is a little different. As in your case. Push rods are available for most engines in various lengths to change the push rod/rocker/ valve geometry. Install your new push rod, adjust, check your geometry. If ok , use it. That statement is true on any engine, not just your six, as I am not familiar with your engine.

Also you measure push rods at the contact point. The outer shell can be misleading. To actually accurately measure your push rods you would need to put a ball bearing ball , the same size or a little smaller, as your rocker adjusting bolt pivot point, into the push rod cup and measure from there.




Bones

 

Sorry, I couldn't help it, push rods. HRP

 

A 216/235 push rod.
Warren

 

If I remember right 11-1/4” for a 235
And 10-1/4” for a 216

there are variants of these as well for solid and hydraulic lifters like @boneyard said there is a correct way to measure these , I don’t know what that is I usually just match them up.

 

If your top end isn't oiling well, do you know what your oil pressure gauge reads? If it's reading good pressure, then I'd be concerned about lash adjustment. If it's too tight the top end wont get oil.

 

216 Chevies do not oil through the pushrods. If you have oil dripping from the rocker shaft that is about all you are going to get, don’t expect oil all over the place like a SBC.

 

216, 235 and 261 all oil from the rocker shaft. The oil is fed either through a npt fitting in the head about 1/2 way back on the distributor side or from a 1/8" line running from the rear of the engine to mid point behind the lifter cover. These lines and holes get plugged up over the years. A special head bolt with a drilled center carries the oil from the feed line to the tin oiler oiling the rocker shaft. I do suggest you send a sample to Smith Bros in Oregon. Quick service and cost friendly.
Warren

 

hey thanks for the replies. so 1971bb427, the gauge face has 0 dot 30. at idle its just below the dot. when i when i rev the motor it goes almost to 30. could this be normal?
so wuga, i don't have the exposed line in your pic. the top end seems to be fed from a copper line. if i remove the side panel, i can see it comes up from the motor/pan and feeds the top rockers connecting on the top of the head in the center of the rocker shaft. i have tried to remove this line but so has someone before me and it is in bad shape and on very tight. i have blown compressed air down the line and have also squirted carb cleaner down it.
so should i just force the line off? is the pressure i'm seeing enough and just try and drive it with some sea foam or the like in it and see if it starts pumping? or how about the oil distributor? is that something that could cause this? i have not pulled that apart, should i?

thanks again for the info.