I have bought a 235 chevy short block motor with a hyd. cam, and my old motor was a 58-62 sold cam type motor. does anyone know if the rocker arms have to be change if you switch over the lifters and push rods to Hyd., I was told you didnt have to but is this true and why???
Ditto what Heathen said. The rocker arms on the 235 have the provision for adjustment, regardless of cam type. You could install a solid cam in the engine if you want to, but you do have to use lifters for the '58-'62 block, due to the oiling p***eges.
It's the lifters that are different, and the grind profile may be different for each type of lifter. A solid lifter is just that - a solid hunk of metal that rides the cam and pushes the pushrod up to roacker arm. These are noisier than hydraulic lifters and need to be adjusted more often but they give excellent response to the cam. A Hydraulic lifter will have a hollow space in it with a cup on top for the pushrod. This cup will ride on a cushion of pressurized engine oil. They're quieter than a solid lifter and a little more forgiving to misadjustments in the rocker arm but still need to be adjusted correctly.
so when i change over to a HYD. lifter can i use the stock rocker arms??The arm that i Have don't have a hole in them to let oil through so how would the oil escape out of the push rod?? would it just stay filled and not come out???
You may have to change pushrods, but your rockers can stay the same. If the height of the old lifters is different than the new ones you'll need new pushrods to maintain proper valve geometry. The manufacturer of the lifters should be able to supply you with the measurement for the correct length pushrod. If your engine has adequate oil pressure the oil will escape from the pushrod. It'll lubricate the rocker arm at the pushrod then run out, just like holding your thumb over the end of a garden hose. The pressure will force the oil out. Ask your supplier of the new lifters if you'll need new pushrods. Ask them about the lack of a hole in the rocker and if the new lifter will limit the oil flow to the rocker arm. Whatever company you're getting lifters from can help you make sure everything is the way it should be.
The 235 doesn't oil the rockers through the pushrods, there's an oil line that connects to a p***age in the head that gets an oil supply from the block.
Since I'm not too familiar with 235's, is this a shaft mounted rocker set up? Sounds like it from what you described.
Yeah, the rockers are shaft mounted. There's an oil tube that is in the center of the shaft that curls around it and is partially pinched off at the end. This is press fit into the head. The partially pinched end allows for exess oil to escape. Pretty much all early ('37-'62) Chevy 6's use the same rocker arm/shaft setup. There are some diffs in how the oil line is run, but that's mainly in the block, not the head.
it seems to me that it would cause valve opening and closing problems if the is no hole in the rocker arm to let the oil out of the push rod??is anyone familar with changing the stock 55-57 chevy 235 motor over to a HYD. cam, and HYD lifters and Push rods, what would you have to do about the rocker arm. the Org. rocker arm ***emby is on an oil bar like explained above. the only Adj. on the rocker arm is on the push rod side..they are much like these
The '55-'57 can only be set up wiht a hydraulic cam if it was hydraulic originally. There are 2 different blocks in thise years. Actually, this is the same back to '50 when the hydraulic cam 235 w/PowerGlide was introduced. The oiling p***eges are drilled differently from solid to hydraulic. If you go with hydraulic in a solid block, they won't work as they'll be starved for oil. Now, some mid '56/'57 manual car and truck blocks did go out with a hydro block and solid lifters, and you will occaisionally see a stick/truck with hydro lifters, but generally speaking, if it's solid lifter, you cannot put a hydro cam in it. This changes in '58, when all blocks were drilled the same , regardless of cam. There are other diffences in the oil system, too. Namely, the oil p***age for the rockers is drilled into the block in an extra cast section, rather than the tube used on the earlier engine. Also, the later 261 (2 ton and larger) truck engine after '59 used full flow oil filtration, as opposed to the bypss system on the 235.
So i bought this short block off ebay and the guy said it is a HYd. cam in it. So what exactly were you saying? Since the cam is HYd. does it mean i need to run Hyd. lifters and Push Rods with the hole down the center for the oiling. Or should i run the soild lifters with the old push rods. if this was the case i would be useing the old rocker arm ***embly. but what do you do when you go to HYD? THe old block that i had took out came up to be a 58-62 engine when i ran the numbers, and i am going to use the head from that on this new short block. will that work??
I don't know which lifters and such you cn run in which motor,but I am reasonably certain that the cam profile for hydraulic and solid lifters are different. I tried putting hydraulics on a solid cam once and the result was that with the lifters nailed down to quiet mode the engine wouldn't idle it acted like it had a gargantuan vac*** leak. Backed the liters off till they rattled and the motor ran fine. I put 11000 mi's on the damn thing.LOL Got pretty decent fuel milage too.
krazyk, With 58-62 235 blocks, it's only the cam and lifters that make them solid or hydraulic. They are drilled the same. Pushrods and rockers are the same, regardless what type of cam/lifter set. The pushrods don't have oil running through them from the bottom up, which Longbox55 already stated. They get lubed from the rockers and oil just runs over them down to the lifters. Takes only very little oil from the rocker shafts. If your old pushrods are straight, you can use them. With hydraulic lifters you just tighten them so the clicking goes away and maybe another 1/8-1/4 turn - as long as they are spinning, your are good. If a pushrod/lifter doesn't spin, your adjustment is too tight, or the cam lobe is worn, or the pushrod is not straight. Solid cams are ground different and have 'ramps' so the rockers don't slam on the valve. Hydraulics don't have these ramps, because the rocker is always in contact with the valve. You could use hydraulic lifters on a solid cam, but the other way around is not recommended. So yes, you can use your old head, rockers and pushrods on the new hydraulic cam/lifter block. Just make sure the rocker ***embly is also from a 58-62 with the pinched tube in the center, feeding the rocker shafts. I got hydraulics on my daily driver for about 12 years now and like that I never have to adjust anything and the engine runs a little quieter.
The Jalopy Journal
