Guys I need some help! We had a 351 Clevor built and it ran fine for a few races. Then while we where else where, our driver raced it at a local circle track and then told us he “ blew it up”.... Holey shit! When we got it in the shop, we pulled the valve covers and found #5 exhaust rocker sideways and the push rod wedged in the guide!! We put the rocker back on, look at the rest of the valve train....looks ok. We come back the next night and run the engine enough to get warm, pull the valve covers.... #5 intake is sideways! We reset all lifters, hydraulic, and notice that all the rockers on the drivers side appear to have been hot at the fulcrum.... all therockers on the passenger side show no signs of heat! Any ideas???? Bones
This may help https://www.cartechbooks.com/techtips/351-cleveland-lubrication/ Looks like it may be tear down time to see what shut down oil flow.
If you are on a Windsor Block, those 3” mains take a lot of oil and I would guess you have either spun, or about to spin some bearings. I would be looking in the bottom end. What pan do you run and do you use an accumulator? SPark
Usually when the Rockers come off the valve to tip of the valve is not flat anymore Sent from my SM-J737T using The H.A.M.B. mobile app
If you are running the stock cleveland rockers and aluminum rocker stands, I would get the steel stands. if the #5 rocker was completly out of place(sideways), the hyd lifter took a hell of a beating too.and may have ruined the lifter, causing the repeated problem on #5. who ever was driving it over reved the valve train, floated the valve at least on #5 rocker. If allowed, run the full roller rockers.I also use the HV oil pump, 100# releif spring, and clean up the oil passages in the block. Those sled type rockers produce a lot of friction and heat, causing blueing.
We do not have an accumulator, our pan is a Ford Motorsports circle track racing pan designed for left turns. Can’t remember the part number. We are running Crane roller tipped rockers( not roller fulcrum). We have steel screw in rocker studs. Bones
Can you run full rollers? With the same rocker failing twice, I would be looking for a bad lifter, bent stud or a bind with the push rod. Might have a piston to valve clearance issue too. Especially by now. SPark
Cannot run full rollers, actually the same rocker didn’t come off, first the exhaust, then the intake..on the same cylinder. Sorry if I wasn’t clear on that. When we checked it for the second time, the adjusting nut had backed off a long ways. We checked the push rods for straightness and any bind, all looked good. It appeared that the adjusting nuts for the front drivers side just back off. Not sure why? Bones
The engine was built by another guy not sure about “ poly locks”. I’ve been out of racing fir close to forty years. Not real familiar with all the terms. The adjusting nut is tall and has a set screw in the center to positively lock the nut. I went back and included some pics. Sorry for the upside down pic....... but they are Australian heads! That pic is the passenger side, the other a close up of the rocker on the drivers side, all eight look like that. Bones
Those are poly locks. It somewhat bothers me that you have that much of the lock screw sticking out the top of the nut. Should be closer to the top or even inside it. Where is the tip of the rocker running on the valve stem? Is it centered on the stem? ;eft to right and fore/aft? Color the top of the stem with a sharpie, put the rocker back on and adjust it. Then turn the engine thru 2 revolutions and pull the rocker off and see where it wore the marker off the top of the stem. Make sure you have the correct push rods. It's hard to look for correct geometry in a splayed valve engine like a Cleveland or BBC. I had a head once that the shop was a hair off on the angle they cut the hole for the screw in stud on a Cleveland head and we fought problems on the same 2 cylinders half a season before we found it. Another thing that will allow a poly lock to back off is the top of the stud is not true and square. Most aftermarket studs are surfaced on top, some cheapos or stockers are not. Check to see that the top of the stud is flat, should have a nice ring where the set screw was against it. SPark
Some manufacturers will sell their big-block Chevy rockers for Cleveland and 429/460 Ford engines. The ratio is close, but the geometry isn't right. They don't contact the center of the valve stem. Try checking the rocker geometry.
The amount of set screw sticking out is about the same on all studs. The surface of the stud where the screw goes is flat and has a nice ring pattern. I beginning to think may the two problems are unrelated. Since both rockers backed off on the same cylinder, may be the builder forgot the final torque on that cylinder. We can find no other reason for them to back off. But I still think we have a problem with the rockers heating on the drivers side. To me heat equals lack of lubercation. We have 60 lbs of oil pressure while running. Bones
Get a oil priming tool and give it a spin and see what you have for top end oiling. Did the engine builder install restrictors for the top oiling? How much valve spring pressure are you running? What kind of oil are you using?
With polylocks the top of the stud top needs the be surfaced flat some studs don't come that way. As to saltflats question about restrictors with hydraulic lifters I doubt it has them.
Our builder stated he used no restricters , any where. I’m not sure of spring pressure, but assume he used the same springs for both sides? The owner of the engine bought the oil.... I put it in, 20-50 , but I forgot the brand. We added eight ounces of “ Power up” for tomorrow’s race. The owner of the engine didn’t want to start it with out the valve covers on, to see about oiling, because of the mess it would make....... so I guess we’ll see if it holds together tomorrow! Bones
A tip for you on preventing the poly lock from coming loose....adjust the outer nut to the correct adjustment, then back it up looser by 1/16 to 1/8 of a turn....THEN lock down the set screw, and using a box end wrench and the allen wrench, turn the whole assembly together that final 1/16 to 1/8 turn. This will really wedge that set screw to the top of the stud a lot tighter than you can tighten just the little allen screw.
SBFs will force the casting plugs out of the oil galleys in front behind the timing chain , with a super tight engine . It is a must to drill and tap these on any High Pressure / High Volume oiling system or you will notice low , low oil pressure at idle on your newly rebuild race prepped engine . Ask me how I know this will happen .
That’s how we reset all lifters. Keeping my fingers crossed, won’t be in the pits tomorrow....Mom duty! Bones
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