Some time last year I restricted the rocker feed by fitting a 7/64th restricter to the tank side of the return union on my 57 Dommie 99, this seems to have resulted in over oiling. I now want to revert to the standard system. Can anyone tell me the standard hole size of the return union tank end as factory fitted standard, so that I can drill the restricter to suit, perhaps if someone has a spare standard union they could measure the hole size tank end and let me know. Many thanks Steve.
Hi Steve, I did exactly th…
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Previously robert_tuck wro…
Previously robert_tuck wrote:
Hi Steve, I did exactly the same mod about a year ago and with the same result!. I solved the issue by pulling out the Union (no oil will be lost) and drilling it bigger. I just went through my metric drill set one at a time untill the overoiling stopped. Think it was two or three sizes up from 7/64 !! cant be more precise , but certainly still a smaller hole than std. The only issue I now have is a small leak of oil from the Exhaust rocker sideplate, Happy with that as its not seen much oil for the last 57 years.
Thank you for that Robert, I have now drilled out to 5mm which may be too big,can you tell me the increments your metric drills go up in or have a guess at the size you ended up with? I believe the original hole is just over 6mm but can't be sure, hence the request for that info. I think I will try it and check the result.
Thanks again, Steve.
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I think you will find 5mm…
I think you will find 5mm will work fine. You may find oil appears in places new,but thats just because it is now getting around. 7/64 just got the oil mostly circulating without bothering with the oil tank!!. I suspect that there are too many variables in a std set up to ensue consistent flow at the rockers .
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Previously robert_tuck wro…
Previously robert_tuck wrote:
I think you will find 5mm will work fine. You may find oil appears in places new,but thats just because it is now getting around. 7/64 just got the oil mostly circulating without bothering with the oil tank!!. I suspect that there are too many variables in a std set up to ensue consistent flow at the rockers
Thanks you Robert so much for taking the time and trouble to respond to my message, you've been a great help.
Best regards,
Steve.
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Hi Steve, I did exactly the same mod about a year ago and with the same result!. I solved the issue by pulling out the Union (no oil will be lost) and drilling it bigger. I just went through my metric drill set one at a time untill the overoiling stopped. Think it was two or three sizes up from 7/64 !! cant be more precise , but certainly still a smaller hole than std. The only issue I now have is a small leak of oil from the Exhaust rocker sideplate, Happy with that as its not seen much oil for the last 57 years.