improve oiling to rocker arm rail

[cudabob340]

I have a 1971 340 'Cuda that is being re-built. A couple questions have developed by my builders. Did the 1971 340 have any problems with the oiling system in the "J' heads? Knowing how the "J' heads oiled, we currently have the ability to change any older issues. But that does not mean that the fix is proper.

By opening the oil galley on post 2 may change the flow but could impact on the pressure to down line rocker arms. I am looking for builder with knowledge on this question.

Please advise with tech knowledge from past history. We are looking to improve if their was a problem. Plymouth was real smart about fixing problems but smaller fixes did escape then sometimes.

 

[Rob C]

There is no oiling issues with the stock engines.
If you are upgrading to a high performance engine that will see more than 6400 rpm's, the. What you want to do is open up the oiling galley passage ways in the block to the head to 9/32.

Oiling modifications can be found in the MoPar "Engines" book which is now divided up into separate books for there engine family.
B - RB - Magnum - small block, etc....

 

[cudabob340]

Outstanding young man. Thanks for the info.

 

[Rob C]

Thank you but I have to decline. See this thread for truly outstanding work;

http://www.forabodiesonly.com/mopar/showthread.php?t=103623

 

[moper]

Actually, if you want to improve oil delivery to the heads you have to address that issue by the camshaft and cam bearings. The system works by oil coming up to the cam bearings, and them pasages in the cam aligning the oil from the lower end and the passage to the head. It only feeds presurized into the upper gallies when the holes line up and only fr the number of rotational degrees it takes to get past the holes. So the oil volume to the top end is managed that way. If you want significantly more oil, you have to either fully or partially groove the cam, or convert to pushrod oiling which means new lifters and pushrods at minimum. The trade of is more oil up top means less to the bearings in the bottom end. The passages in the block to the heads and holes in the bearings are usually slightly off. Enough to partially block those feed holes up to the heads. So on all the engines I do the cam bearing and cam itself are modified to guarantee at least the intended oil volume. It's not drastically increased, but makes sure what was supposed to get up there get's there, plus a little. The oil gallies that are enlarged to 9/32 are not upper end feeders, but rather the passages that feed the main bearings which come off the right side lifter galley.

 

[Adam]

One other area to check are the 19/32 holes behind the cam thrust plate. Some engines have plugs, some don't. Some engines have a fourth bolt with a hole in it, in the top left corner (looking at it) Shouldn't matter as the holes are blocked by the plate, but if you want to ensure better oiling of the timing chain a small hole can be drilled in the plate or bolt so oil drips down onto the timing chain oiling tab.. (cant remember the correct name).