quote:Originally posted by PanteraDoug:
Small block Fords, i.e., 260, 289, 302, 351w that use the rail type rocker arm system and the cast rocker arms show more wear on the valve train than do the Clevelands but they have their issues also.
Wear like this IS oiling related. Is it wear and tear? Yes, but wear and tear caused by insufficient oiling properties.
On those SB Fords, I have had to replace entire valve trains on engines with as little as about 75,000 miles.
I always advise that in addition to the accessable top end parts I am changing, that the cam should be changed and the valve guides are probably elongated too and should be redone.
I advise putting in roller rocker arms probably more than most, and when the price is mentioned, probably install the least.
There's more to it than just not enough ZDDT.
Just to be clear for everyone the worn cam in the original photo is from a 302 Cleveland NOT a 302 Windsor, so we are talking about Cleveland engines not the Ford smallblocks.
I must say i had always been disinterested in roller rockers, i had felt that the standard Ford rockers were perfectly ok.
Until i took some off a engine that had only 6,000 miles on it. The valve tip and pushrod cup were fine, perfect in fact but the sled fulcrum and surface inside the rocker arm were shocking.
This corresponded to the wear i had seen on all stock Cleveland rocker arms of all mileages, but the thing that surprised me was that this level of wear had taken place so soon after a rebuild. The load and fiction on the fulcrum must be immense and replacing the "sled" with a roller bearing would have to be advantageous.
So i fitted a set of roller rockers to the engine and was pleased to find the engine ran more quietly and revved more freely which i hadn't really expected to be able to notice.
So this leads me to think are we all at some stage going to have to upgrade to roller camshafts to avoid the type of cam wear as shown in my original photo ?
That cam had done 130,000 miles but i have pulled down a 351C that had done 230,000 miles and the cam was in much better shape than the 130,000 mile cam. Both engines had been well looked after.
I recently read a article by Crane Cams where they blamed premature camshaft wear on the more common fitting of windage trays and modified sumps, their thought being that the reduced amount of oil "splash" on the camshaft from better oil control was reducing cam lobe lubrication.
Comp cams now lifters available with a oil hole in the centre of the face to provide "positive cam lubrication".
Comp cams provide a tool (believe it or not) to cut grooves in the lifter bores to feed oil from the lifter gallery to the cam lobes.
Cutting grooves in the lifter bores to feed oil from the lifter gallery to the cam lobes in a Cleveland seems a ridiculous concept to me. We talk of fitting lifter bore bushes to prevent the leaks from the oil gallery now Comp Cams is suggesting to increase the leaks. Clevelands leak enough there as is.
I think Crane's suggestion of windage trays causing cam wear is also faulty. Even with a windage tray and better oil control in the bottom end there is still a tremendous amount of oil exiting the crank bearings and being thrown on to the camshaft by the crank.
There is clearly a automotive parts manufacturer's blame game going on.