Cam gone flat? Here's a interesting video.

-
pishta said:
My 82 Mazda has a spray bar over the cam and it's an OHC so I'm sure it's needed as there is no crank sling on an OHC. I've never wiped a lobe ( knock on wood) but I don't deal with battleship springs or wild lifts either. Spray bar would be easy to fab up. Just a small closed end brass pipe with some strategically drilled .010 holes on the underside plumbed to an oil feed. Mount on bottom of a Moroso lifter valley pan, bottom of intake or rigid directly across the valley above the camshafts. R blocks need not apply as they have a restricted camshaft exposure valley. 340 shown with all it's camshafts oiling access.
View attachment 1716017409
Click to expand...
How about those lifters with the oil hole in the face? I wonder how good they work. I would think pretty well. Direct Lube is what Howards calls theirs.
 
pishta said:
Could also go with EDM lifters...direct oil pressurized onto cam lobes at lifter base. Maybe grooving the lifter bores so lifter galley oil bleeds out onto camshaft. More than one way to skin the cat.
Click to expand...
I had those with the '528. I still lost 10 lobes.
 
1MeanA said:
So lack of oil isn't the problem then.
Click to expand...
It seems more lack of crown on the lifters and lack of taper on the cam lobe. Of the few failures I have seen the lifter wasn't turning yet you could spin it in the bore with your finger.
 
toolmanmike said:
It seems more lack of crown on the lifters and lack of taper on the cam lobe. Of the few failures I have seen the lifter wasn't turning yet you could spin it in the bore with your finger.
Click to expand...
Maybe we will find out one day that some bean counter decided they could make more $$$ if they skipped the crowning operation :) (no disrespect to accountants in general) Back in the 80’s I worked for a company where this actually happened.
 
1MeanA said:
Maybe we will find out one day that some bean counter decided they could make more $$$ if they skipped the crowning operation :) (no disrespect to accountants in general) Back in the 80’s I worked for a company where this actually happened.
Click to expand...
I married my accountant. Good and bad there! :lol: :lol:
 
I check the crown on every lifter I install Just put them feet together and note the (non)fit. I've never seen a new one not crowned. If the wear pattern on a pulled lifter is not circular, they are not rotating. I got a set of slants that are concave! Paint a strip on the top edge and when you start the motor without a valve cover you should see all of them rotate. If not stop and find out why.
 
This one is out of by buddy's 440. It didn't turn.

joe's lifter.jpg
 
This situation is where REfacing of the original lifters is a viable procedure.
 
Offenhauser race motors that ran at Indy in the 50’s and 60’s were overhead camshaft, with the cams having a hole gun drilled through the length of the cam. Engine oil was pressure fed into that passage. There were a pair of connecting holes drilled in the lob just ahead of the point of max valve lift to deliver oil to the lifter - lob interface.
 
Buy American made parts and verify your machine shop work with the best micrometer and gauges you can afford. It's part of the assembly process that is more often neglected by the assembler/owner. Results without verification of clearances are 50/50 at best, but hey its your engine and your success or failure.
 
The old Mopars that were used as Police Duty didn't have this problem. If they did they would have worked out the problem, especially since warranty work would be involved. Cop cars and taxis did a lot of idling, although most cabs were sixes. Cop cars idling waiting for you to go speeding by with their Radar gun pointed at you. So it would seem that the biggest difference today is the removal of the zddp from the oil. And like anything else an occasional bad cam or lifter could be the reason for some of the problems. So at this point we still don't have a definite reason for the problems some people have encountered. I'll go with the oil with the added zddp and keep my fingers crossed.
 
You must log in or register to reply here.
-

Back
Top