Hey all, hopefully someone can give me advice on what to do next. I just finished a fresh rebuild on a 72 302 motor for my 67 coupe and am getting a lot of valve noise. With my wood stick stethoscope a couple valves are hammering pretty good. I was getting vac readings about 12-13 so I thought maybe I had the valves adjusted a little too loose. I readjusted the valves, and carburetor mixture screws and now vac is about 15 and steady but still valve tics and hammering issue. I'm running a comp High Energy 268 cam, mild .457 lift 218 dur, scorpion roller rockers, guide plates and screw in studs. I adjusted valves zero lash + 3/4 turn but had a dial indicator on top of valve and noticed at about 3 full turns the valve would start to open, well actually it would open at earlier intervals but would bleed down and close again but at 3 full turns was when the valve would stay open. Just cant understand the valve tic and hammering issue. The cam is super mild. Any thoughts? Engine seems to start and run well just the hammering issue I'm afraid of doing damage.
help with lifter issue
Gary's 67
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Hey all, hopefully someone can give me advice on what to do next. I just finished a fresh rebuild on a 72 302 motor for my 67 coupe and am getting a lot of valve noise. With my wood stick stethoscope a couple valves are hammering pretty good. I was getting vac readings about 12-13 so I thought maybe I had the valves adjusted a little too loose. I readjusted the valves, and carburetor mixture screws and now vac is about 15 and steady but still valve tics and hammering issue. I'm running a comp High Energy 268 cam, mild .457 lift 218 dur, scorpion roller rockers, guide plates and screw in studs. I adjusted valves zero lash + 3/4 turn but had a dial indicator on top of valve and noticed at about 3 full turns the valve would start to open, well actually it would open at earlier intervals but would bleed down and close again but at 3 full turns was when the valve would stay open. Just cant understand the valve tic and hammering issue. The cam is super mild. Any thoughts? Engine seems to start and run well just the hammering issue I'm afraid of doing damage.
G
Guest
·If you have lifters that are not pumping up correctly, you may be able to spot that by pushing on them. Another thought is about the cam break in . . . other than the noise, does it run smooth ?
Yea, runs like a champ, feels strong and responsive, idles great about 800.I'm leaning towards a bad lifter or maybe a couple of bad lifters. Break in went smooth, coated everything with proper cam lube, Brad Penn break-in oil which I changed oil and filter after break-in with Brad Penn 10w-40. Inspected springs, rockers, everything looks good. Just cant believe lifters are bad out of the box
Rebuild went by the book, everything new, even had rotating assembly balanced, not from a performance state of mind just longevity. Engine runs smooth, throttle response is good, just this valvetrain noise issue. Might have to pull intake which just really irks me to have to do this. If I end up replacing the lifters, which by the won't be comp cam lifters, can anyone recommend a good set and what happens with break-in again????
G
Guest
·As long as there is no damage o the camshaft, yes. So you should check closely, the lobes after the lifters are removed. You are looking for "any" roughness on the loge, galling, anything you can feel with your finger nail etc. That would show abnormal wear during break in.
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602 Posts
This is my Comp 268 after 4 months. The thing was knocking bad and the cam had shredded. I believe the lifters were initially installed with way too much pressure. I installed a new cam and set the lash at 0 plus 3/4 turn and the new cam is working like a charm
Attachments
G
Guest
·Great pictures, that is exactly what I was describing.
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602 Posts
Drop the oil pan. There will be metal in the pan if this has happened. You can also shine a light up and see the issues with the cam, if there is damage. You may have to rotate the motor to see the entire cam
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12,382 Posts
Any chance could be a leaking exhaust gasket.? This is well known for sounding like a lifter issue. Either check and re-torque the exhaust manifolds or loosen and double the gaskets. I would consider this operation first, in light of your vac reading and general running condition being good. BTW, you stated you performed a vac check. What was the action of the needle?
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6,834 Posts
Is the vacuum steady, or is the needle erratic?
Vac is steady as a rock, really confident its not an exhaust leak. I am running the ford racing aluminum tall valve covers and am aware that these probably do amplify the sound somewhat but I understand there will be a little valve train noise, but I can hear a definite hammer on about cyl 6 or 7. Haven't run without valve cover on, so might try that to identify exactly which one. I went by the book rebuilding this thing , double and triple checked everything, fastener torques, clearances, end play, etc. If its a lifter or cam, I'll be livid that you pay good money for items and this crap happens. Guess that's the way things are nowadays, not many people take pride in what they do its all about the dollar.
G
Guest
·It isn't uncommon at all these days to have a cam wipe during break in. Blame lack of zinc and cheap metal/treating. Even engine builders have problems.
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6,834 Posts
If the vacuum is steady, I doubt it's a wiped load or a lifter not pumping up, but anything is possible I guess. I'd lean towards the rockers.
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1,049 Posts
It's easier to cut open the oil filter to look for metal.
I've always had luck with the plain old Sealed Power lifters. Like I said, I had a brand new Edelbrock one that was bad. It was stuck and wouldn't bleed down at all, I'm lucky it didn't wipe out the lobe, but I found it right away. Me engine ran smooth too, just that damn lifter noise.
Matt
Matt
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