Here is the oil pressure regulator from my 1930 Hupmobile H motor. The smaller spring seems to be far too stiff and is consequently allowing the oil pressure to rise too high. Where can I order a replacement spring? Does someone supply a variety so we can find the spring with the right tension? Is there anything else you know of that might affect a regulator like this? The larger spring? The slide mechanism?
Cord; If the valve functions as a relief valve, which it appears to be, then any downstream resistance will raise the setting of the valve. When it opens, oil has to go somewhere. If there is resistance, it will not want to open. The springs in these types of controls don't get stronger over time. There may be some contamination or blockage downstream of the valve. But I don't know squat about Hupmobile oil systems; just a thought.
I have not worked on a Hupmobile since the '80s when I worked for Russ Head but it seems to me like this is true ^^^ you should be able to loosen the small jam nut and back the screw off.
It's been years since I owned my 1932 Hupmobile model F, so I don't remember messing with the oil pump. But there is a business that bought out all the Hupp parts when they went out of business. I know it has been sold from the original owners but someone on the AACA board should know who to contact. If not them, try the Hupmobile club. Did it ever work correctly? Someone may have changed the spring to the wrong one in all the years since it's been built.
Salt and Pork: good points about adjustment. I assumed that would have been already tried. Maybe not, eh?
Did it come with two springs from the factory?. If not maybe someone added it due to the longer spring getting weaker as they do over time. It looks to be adjusted for max down pressure in that picture. Do you know what the factory spring rate should be?,Ford flatheads came with 50 lb. [early] and 80lb. later. Maybe you could use one of those and cut down to size if needed since it would be a know spring rate.
It looks like the adjustment screw is already backed out pretty much all the way. If there is still too much pressure, how about cutting a coil or two off that spring?
cutting a spring down reduces the stroke but inversely increases the lb's spring rate so might not actually help. When in doubt get a set of calipers and try determining what the spring rate you currently have, then start looking in Mcmaster-carr ... they have the spring.. only problem you have to figure out which one it is..
If the jam nut on the large portion of the threads is where you where running it try backing that off some looks like spring pressure on bolth springs are adjustable
Just an idea, maybe you could spec out a couple different springs from a manufacturer like this and trial and error till you get what your looking for. http://www.leespring.com/compression_spec.asp?springType=C&forWhat=Search This was the first thing that popped up. Never heard of them before. I had to do something similar years ago on a piece of equipment. Good Luck
In this case the spring is crushed and stiff, so the pressure from the pump doesn't need to overcome the tension of spring in order to allow oil to flow out of the pan and into the engine. Instead, the oil is flowing out of pan with no regulation, raising the pressure way too high in the Hupp. I hope this additional explanation helps to clarify.
Update on this. I went the McMaster-Carr spring route. We measure the immovable spring with a calipers, ordered four packs of springs we though might be right and tried them out. The smaller springs have produced the right pressure, pegged at around 40lbs I believe. I'm relying on my dad's old-school mechanic to figure these things out with me, so that number may be wrong. I believe the outside spring was there simply for keeping the piston aligned. Imagine pushing something from the center, it could start to rack and get pinched. I believe the outside spring helps to keep the piston aligned. Anyway, the pressure seems to be holding right where it ought to be now. NEW PROBLEM: Where can I have the water pump for this Hupp rebuilt? I'm going to look in my dad's contacts book, search his email, and rummage through Hemmings ads for a service that can turn this around for me right quick. We have a persistent leak we've tried to fix, but we need help. Unfortunately, after my dad's passing, our shop's resources are a little strained. I need to outsource what we use to just bring to the old man. He'd lay his hands on it, smoke a few menthols, swear and hypothesize, and soon it would be fixed. I have no such miracle workers here now, only regular human beings trying to finish the last big project of a great restorer.
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