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Re: Early Big Block Cam/ Top End Oiling
the big problem with the oiling is that the exhaust rocker arms get hotter then the intakes because of the heat transfer from the exhaust valves. if you put in new rockers on the exhaust they have a chance to get to hot in the pivot point and blue up the rocker balls. when i had to replace a exhaust rocker arm and ball i always took a used one from a intake and installed the new one on the intake. the drippers in the covers are very important because without them the oil overshoots the rocker pivot point.if you use roller rockers you can even use edge orifice lifters to cut down on the amount of oil that gets to the heads and prevent having the pan run low at continuous high RPMs -
Re: Early Big Block Cam/ Top End Oiling
Joe - I am getting ready to rebuild my 66 427/425...and have been searching for a 3143 without luck, maybe I will find one in Carlisle this week. I plan to make sure it is grooved, and I will use grooved bearing shells too. FYI, I do have a 1989 vintage crate LS6 engine that came with a 4362 GM cam, and it is grooved.....but the block is the new style with annular groove behind the cam bearing, and, I used the modification mentioned in the How to hot rod your BB chevy book of soldering the hole shut that oils the rear cam journal and drilling it to 0.060 vs the large .250 hole, since it pumps into the annular groove in the cam, and splays the oil in all directions. Seems to be fine...som far the engine has 3 hours of break in so ha ha hard to tell. My point is the 3143 and 4362 as sold by GM had the groove as far as I know. If I get stuck buying a current blueprint grind through GM...made my Crane, my guess is it will NOT be grooved, and I will have to perform that operation in my metal lathe to put the proper 3/16 wide and deep groove in place for my 66 block. Now, I also spoke to a guy in Bloomington this year, and he swears that the early blocks also need 0.060 holes in the front two plugs to spray on the timing chain, which is a good idea anyway, but he claims these early blocks get air pockets in the front lifter area and cause problems. Personally, I don't see how this is any different than the newer blocks in this respect. Seems there are zillions of opinions in this area...but I plan to drill the small holes to oil the cam chain anyway, as I did on the LS6 crate...CraigComment
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Re: Early Big Block Cam/ Top End Oiling
one .030 dia hole is all you need to oil the chain. i also drill a .030 hole in the face of the front cam bearing boss into the oil passage to get extra oil to prevent the wear of the cam gear thrust surface of the block. if you use a needle bearing thrust between the gear and block you do not need to do this. those .060 holes in both galley plugs were for use with hyd lifters to bleed out the air to prevent lifter noise on startupComment
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Re: Early Big Block Cam/ Top End Oiling
I got the #3904362/ 3863143 cam from the local GM dealer about five years ago and it was not grooved. From what you are saying, it must be a current blueprint grind made my Crane. In any case, the engine has nearly 2500 miles on it- almost 800 to the regional in Woodbridge last year cruising at 4000 rpm with the 411 rear and N11 exhaust, and so far it seems happy!
Once again, I wouldn't recommend going this route. I just wanted to close the loop on my original post and report for anyone who may end up in my boat, that an ungrooved cam with a grooved bearing seems to supply sufficient oil to the top end.Comment
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Re: Early Big Block Cam/ Top End Oiling
Thx Joe and Clem....I have had zero luck Thurs/Fri/Sat at Carlisle finding a 3143, but did get some GM NOS BB sidepipes for my 66, and some grooved GM balls for the rockers, #3899622, for $20 for 19. Also got a set of 7/16" bolt BB dimple rods with pressed pins NOS for $250. Spent 4 hours today watching a guy from Al Knock install 66 leather seat covers...very interesting. I guess I will end up with the crane repro cam also, and will plan to groove it for my installation. Talked to Doc Rebuild at the show too...always nice to see him!...CraigComment
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