Not a mechanic but I have read the other threads but everyone shakes their head with this one. Basics: 283 (1960) with Comp Cam (street performance) and matching hydraulic lifters fresh rebuild 2003 but just installed and run 1 hour. Punched pushrod thru steel rocker, two other (so far) pushrod tips broken. Valve cover inside is dry, no oil has made it up any (all 16) pushrod since it was first fired. Known tests/details: 1. Swapped one lifter to solid with orig pushrod and that rocker oils 2. There appears to be sufficient oil volume when looking in lifter pocket (lifter removed) 3. Distributor has full circle oil groove 3a. With intake off...oil is filling up the lifter tops and enough flow to spill back down the drain holes....lifters and cams are getting oil. 4. Cold oil pressure at dash (mechanical-rear block tap) and 2nd gauge from rht side front galley tap both 55psi on starter crank over. Hi volume pump is new. 5. One bank of lifters cleaned, reinstalled - still no oil on that bank (1/2 turn static preload) 6. New lifter installed on opposite bank and set static with 1/2 turn preload (same recess location and size as solid lifter). 7.Lifters pump up with drill primer, on starter, and when test fired again, no top oil 8. Pushrods swapped with others out of 265 sbc solid lifter block, none plugged, same length- no change. 9. Oil hole in pushrod lines up with hole in rocker (pushed wire thru- geometry is stock). When a pushrod is pulled, Im guessing its 3/4 full of oil From what Im told, it you conclude is a volume problem the oil pressure would drop with rpms...it doesn't. I'm about to swap lifters, pushrods and rockers but haven't found the source of the problem. Someone mentioned a "solid lifter block vs hydraulic block or the cam groove. Does this point to anything not already mentioned in the other posts??? Thanks in advance!!
As long as the hole in the pushrods is clear and the hole in the rocker looks OK there would be no reason to replace them. I would look closely at the lifters especially if they were made "offshore".
Isn't the rear of the cam bearing surface suppose to have a groove all around it to oil the top end in the early 283's?
................................................I don't know if this will help ...but I read some where that the dizzy has a grove in it near the intake to allow oil to go from 1 head to the other,..I don't know if this is true or your problem....miller
Check to see if the lifter groove is leaving the oil feed in the intake as it travels up. Could be either lifters machined wrong or wrong lifters. If the groove in the lifter becomes exposed as it travels up, it could bleed pressure and not force oil up the pushrod.
Not sure either, sounds like lifters. I found this read paragraph to the left. Same deal although this is a non oil filter block here. Also read your #1 statement. Lippy
i was always told the early 283's had to have a groove cut in the rear cam bearing journal on the cam so it could oil, but have never been told what years it is.
I never heard of a 283 needing that groove, but a 65 396 needs a rear journal groove or a grooved rear cam bearing. Lippy
I think before I replaced any parts I'd yank a lifter and run the pump up with a drill to check flow at the lifter feed hole. If it's good, it's gotta be wrong lifters or improper lifter machining.
Yeah if the replaced lifter works, that tells me that the lifters are bad. Unless I'm missing something?
Hydraulic lifters might not be pumped up. Try backing the adjustment off until the lifter rattles but still moves the valve. At that point they usually squirt oil across the room because the inner piston is acting like a pump. I liked to put the lifters in oil and use a push rod to pump the inner piston to get them to fill with oil before installing.
Two remote possibilities: I once lost a rocker to a new lifter sold with blocked upper oil hole where the pushrod seats. Autopsy showed that the hole was punched but the punched out slug remained hanging on at bottom of the hole, totally blocking it! I was able to break that plug out with my bare fingers. Maybe you got 16 made on the day they should have replaced the tip of the punch... Another, even more remote, is wrong GM lifter. In the '50's and '60's it was known that you could use a Chevy lifter in and Olds with no problem, but you could not go the other way. Olds did not have the pushrod feed hole because it lifters were oiled in a more traditional way.
Something was rattling around in my head about oddball cam bearings in early 283s and top end oiling issues. I dug around and found this: "Early 265-283 engines had a non grooved rear cam bearing housing bore. Two drilled holes were supplied in the bearing and the camshaft had a flat spot on the rear journal to transfer oil from one hole to the other.. This was abandoned early on and the only concern on early blocks. Most blocks you will encounter will have the annular groove." So if you have the early block without the grooved rear cam journal, you need the special cam bearings for the early blocks or you need to drill the extra hole. The flat spot on the cam was quickly replaced by machining a groove in the rear cam journal to allow constant flow to the lifter banks. I could not find the actual years where this changed.
I know nothing about 283s other that they are cool engines, but if it had solid lifters, and you put in hyds, and it wont oil, and you swap in an original solid and pushrod and it oils.....well.....it would seem to me that....oh well....n/m...i know nothing about 283s......
The page from the FSM above states that the manual and auto cars had different rear cam bearings, so if the rear bearing is for a solid lifter setup, it won't get enough oil to feed the top of the engine. Inadequate supply to keep the hydraulic lifters fed and still get to the valvetrain. But I too, know nothing about the 283.
Did you soak the lifters in oil before you installed them? Is it possible they have an air lock if you didn't? Not a Chev expert, just guessing here from the info provided. I would think even if the lifters were dry they would pump up pretty soon. Unless they were defective as others have suggested.
Pre 57 SBCs had annular cam grooves as did the 65-66 396. I know you said yours is a 60. Any chance you are mistaken? That's exactly what happens if you don't modify the oil passages and just run later model bearings and cam, or if you run a non-grooved later model cam with the grooved bearing surface. Sent from my iPad using The H.A.M.B. mobile app
Got ALL the oil gallery plugs installed? Including the hidden ones. Sent from my SM-G550T using The H.A.M.B. mobile app
Thanks for the input. Engine was pulled and rear galley plugs removed...standard pipe- not too deep. The oil pressure test off the front passenger side was not to the farthest lifter galley, it was to the main galley which is why it read the same as the dash. The lifter pocket appeared to have sufficient flow/pressure when the lifter was pulled and I looked down there. The lasted guru here has said it "definitely" is the cam without the groove and its an early engine (1960). If thats the case, somehow there's enough oil to pump the lifters but not enough to push oil to the top of the pushrod. I dismissed the cam as being the culprit since as many times as it came up in threads, the forum experts suggested that groove only applied to big blocks. We'll see soon. Also, everything in the top end is being replaced because of heat damage to the rockers ( and valve contact patch worn), eight pushrod tips broken off and metal in galley troughs, lifters ok but they're cheap. Due to all of the above, the engine is being torn down, checked and reassembled. My money (literally) is on the cam.
What year 283? early 283s had a flat spot on the rear cam journal and had to have the proper distributer properly clocked. So if early 283 that may be suspect.
Its a 1960 and the distributor has the oil groove all the way around. I think this only affects the right bank anyway. Flat spot cam....maybe?? Thanks!
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