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V12 low pressure oil system


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I have a 47 Cont that broke the cam gear a couple years ago. The engine supposedly is a 47, but has a 39 cam w/solid lifters. How do I tell which year the engine is? The engine was rebuilt years ago by someone who allegedly was a v12 expert, but of all the previous owners I am the only one that has put some real miles on the car (about 5K). The rebuilder told me that he blocked off the oil to the hydralic lifters in 2 locations I guess because he was using the solid cam. I am wondering where those 2 locations are. Did the early and late engines use the same low pressure system? Looking at some other posts I see that the cam gear gets the last of the oil. I probably need that. Is there some kind of pressure valve that I am probably missing. Do I get to them by removing the intake? Thanks for the help! Kenny

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I found George Trickett's explaination of engine dating so all I really need to know is where the low pressure system might have been blocked and who has the parts I need to unblock?

Thanks,

Kenny

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I'm new here and have had trouble finding my way around, so once I found the post I figured I was going to have a bunch of guys directing me to it, but I am glad to direct you. It is on page 4 and has 4 stars. The subject line is engine & transmission identification or something like that.

Kenny

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Kenny, there are 2 valves that govern the oil supply to the lifters. They are both under the intake in the valve chamber. The feed/bypass valve is located under the large hex nut next to the fuel pump push rod bushing. I suspect that the rebuilder replaced this valve with a small pipe plug. The pressure relief valve is located under a similar hex nut at the front of the valve chamber. It consists of a spring and ball. It's function is to relieve pressure for the hydraulic lifter oil feed but if the bypass valve has been blocked off this valve serves no purpose as it sees no pressure. If your engine had hydraulic tappets at one time it could be either a '38 or '39 if the bore is 2-3/4". The '40's and '41's had a 2-7/8" bore. The '42's and early '46's had a 2-15/16" bore. From '46 to '48 the engines all had a 2-7/8" bore. Cylinder heads for all these cars interchange so the ID on these probably won't help. The '42 and newer engines all had 4 bolt carburetors while the '41 and older were 3 bolt. Intake manifolds all interchange also so this won't be too helpful.

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Oh boy, you guys are too much, you don't need George Trickett to tell you that the only V-12's that had solid lifters were the '36 and '37, '38's on up all had the hydraulic lifters, with all the attendant problems, but you know what, if the lifters do not clatter, the low oil pressure was irrelevant, and if it does not smoke excessively, nor leak out the rear main, drive it, enjoy it, and save your money for a good rebuild down the road, patch-up's on V-12's are an exercise in frustration, I have spoken, probally shouldn't have. If some mastermind did replace your hydraulic lifters with solids, then he obviously missed one of the myriad sources which feed those troublesome critters, resulting in the "low" oil pressure, how low? V-12's were designed to run with 20-30 lbs of oil pressure when new, that is why they have a 50 lb guage, so if you have any movement on the OP guage at all, be thankful, many do not, as long as it moves, the engine and the car will too.

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41Zperson, I think i cluttered up my original post with too much info. I am not trying to patch up a ragged v12. I did not say it had low oil pressure. I was asking about the low pressure oil system. The cam gear broke and I remember the rebuilder said he installed a 39 cam with solid lifters and had blocked off the oil to the lifters at 2 places. I wonder if blocking off the oil to the lifter bores has a purpose. Since the car has been a trailer queen since the 1960s and I am the first to really drive it I wonder if I am ruining the engine with no oil at the lifter bores or cam gear. So far I have only broken the cam gear. If I manage to get a new cam gear on there what will I break next? I want to keep driving it, I don't expect to rebuild it in my lifetime. It ran great, but prior to my ownership had acquired less than 1K miles in 25 years. Kenny

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Thanks for the info. Do you think there is a good reason to block the oil to the push rods? I always assumed the 39 cam (which takes a press-on gear) was a solid lifter (push rod) type, so since that is not the case maybe he called it a 39 cam since it had the press-on gear, but it was actually an aftermarket solid cam & lifters. Any idea where I could get replacements for those 2 valves or how about a metal cam gear. The only one I have found is fibre.

Kenny

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Guest imported_V12Bill

Kenny, Ford made a metal press on cam gear for use in their "big" trucks in '39. These are still available in flea markets but I 'm not sure how frequent. As stated earlier hydraulic lifters started in '38 .

Bill

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"41Z" brought up a good point about the cam and tappets. The '36 and '37 engines came with solid tappets and had cams ground with clearance ramps to work with them. They also had press-on timing gears so you could have one of those cams in your engine? Those engines didn't have a separate ( low pressure) oil line for their tappets and relied on the "splash". Excess oil pressure was relieved by a regulator valve ( ball and spring) located at the front of the valve chamber. It's purpose was to regulate the main oil line only. To my knowledge there was no dedicated oil supply to lub the timing gears even though the excess from the regulator valve was directed to the cam timing gear. Oil escaping from the front main probably supplied the lub for the timing gears. I see no reason to reactivate the oil supply line to the tappets if you keep the solid ones installed.

I believe you can get the by-pass valve and maybe the regulator ball and spring from Earle O. Brown jr. He's in the "sources" on the main page of this site. You might also contact Alan Whelihan as he also supplies these parts.

The old fiber/press-on timing gears were a source of trouble on the '38's and '39's. I remember my dad's '38 going out twice, once when the car was only 2 years old and then again 4 years later. I drove the hell out of my own '38 during the early '50's and it never missed a beat, Go figure.

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Thanks for the help. When did the press-on gear end? Did it end at the same time as solid tappets? I wonder if the rebuilder had a solid lifter performance cam that he installed and was instructed to restrict the oil. I'm trying to make some sense out of that restriction he told me about. Maybe I should pull the intake and see what is actually there and if I reverse the procedure see what happens when it has oil. I'll check those sources for the valve parts and a metal gear too. Thanks

Kenny

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