Hydraulic pushrod question
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Hydraulic pushrod question
What are the pros and cons regarding use of the old OEM hydraulic pushrods ? It seems that I've read some negative comments about them in the past, but can't seem to find the references.
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Re: Hydraulic pushrod question
doc
I don't think you will find very many "pros". The other common name for those was "anti-gravity" because the engineers assumed that the oil supply for them was going to somehow flow up the pushrod and fill the lifter unit at the top, it didn't.
don't waste your time trying to make them work, they didn't work very good when they were new and they sure won't work after they are worn out.
toss them in the junk drawer, get a set of solid push rods, steel are best, put them in and adjust them correctly and you will not have any more problems.
mike
I don't think you will find very many "pros". The other common name for those was "anti-gravity" because the engineers assumed that the oil supply for them was going to somehow flow up the pushrod and fill the lifter unit at the top, it didn't.
don't waste your time trying to make them work, they didn't work very good when they were new and they sure won't work after they are worn out.
toss them in the junk drawer, get a set of solid push rods, steel are best, put them in and adjust them correctly and you will not have any more problems.
mike
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Re: Hydraulic pushrod question
Mike is right.The main problem with the hydraulic pushrods is low oil pressure.It takes 5-6 psi to make the lifter function and when the engine is hot you likely wont have that much up at the top of the engine!I suppose if you wanted to go to the trouble of an aluminum oil pump and a 4 to 1 oil pump drive gear set you could get them to work but I cant imagine it would be worth it.
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Re: Hydraulic pushrod question
FlatheadSix /Steinauge
So when should I expect to change my 59FLH hydraulics over to solids? I have been told by a couple of mechanics to leave them in. Before I go to do this, what are the benefits and downside? Cost?
Thanks
So when should I expect to change my 59FLH hydraulics over to solids? I have been told by a couple of mechanics to leave them in. Before I go to do this, what are the benefits and downside? Cost?
Thanks
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Re: Hydraulic pushrod question
ozwick, the discussion here is about the hydraulic pushrods used form 1948-52. During these years, the hydraulic unit is actually a part of the pushrod itself, and --oddly enough-- is on the upper end of it. Your '59 has 'modern' hydraulic tappet units, same similar design as used to this day, and will function just fine.
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Re: Hydraulic pushrod question
I guess I missed the word "old" in the sentence.
Thanks
What are the pros and cons regarding use of the old OEM hydraulic pushrods ? It seems that I've read some negative comments about them in the past, but can't seem to find the references.
Thanks
What are the pros and cons regarding use of the old OEM hydraulic pushrods ? It seems that I've read some negative comments about them in the past, but can't seem to find the references.
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Re: Hydraulic pushrod question
You can pick up good used OEM hydraulic pushrods cheap--- and there's a reason for that. As has been explained, they tend to starve for oil when hot, and consequently partially collapse, causing a lot of rattling and incomplete valve opening, resulting in a rough running motor. One of the old-time fixes was to gut the hydraulic unit and braze it shut, effectively creating a solid pushrod; this was back in the days when possibly only Tom Sifton was offering solid pushrods in the aftermarket world. I recall when that was hot stuff, putting in a set of Sifton aluminum pushrods. I still have a set of those early brazed pushrods, which I replaced with a set of Sifton's pushrods in my old Pan.
The 'pros' of running the hydraulic pushrods? I can't think of any, unless you'd just like to be able to stand beside the motorcycle and know that you're running OEM pushrods.
The 'pros' of running the hydraulic pushrods? I can't think of any, unless you'd just like to be able to stand beside the motorcycle and know that you're running OEM pushrods.
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Re: Hydraulic pushrod question
I have been told that hydraulics are easier on the valve train? Is this true?
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Re: Hydraulic pushrod question
ozwick 86,
Sure, as long as they are not leaking , pounding, or otherwise screwed up. I tend to modify my motors so hydraulics have never really been an option.
Robbie
Sure, as long as they are not leaking , pounding, or otherwise screwed up. I tend to modify my motors so hydraulics have never really been an option.
Robbie
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Re: Hydraulic pushrod question
I know of a "Ole School" mechanic that told me to run hydraulic lifters in my Pan Head because its easier on the valves and cam and push rods and make even the meat around the valve seats and valve seats too......plus he told me to always run "steel Push Rods" and Not aluminum because they expand to much hot and you loose tappet clearance that way, and he told me that a Pan Head thats temperature (((HOT))) the heads will gain 35 thousands height.....and If You Run "Hydraulic Lifters" then....they will compensate for that gain by pulling is some extra oil and that will keep the tappets adjusted just the same Or Very close to when that motor was cooler....I hope this all makes the decision to run solids or hydraulics a easy answer.....and i always add 4 oz of Marvel Mystery oil to oil tank when i change oil..he told me that stuff is great to keep them lifters units clean...and the engine will benefit from it also.
Ride safe.....and Keep that HIGH BEAM On During the day time .
MotorCycleMike In Kansas
I see that the "main question" refers to the ole OEM push rods that had the lifter units in the tins and i added my 2 cents for what it's worth !
My Late Dad had a Pan with the lifters in the tins 1948 and it sure rattled and it was a REAL HARLEY BOO BOO !
Oil will NOT Run UP HILL that only lasted a few years LOL !
Ride safe.....and Keep that HIGH BEAM On During the day time .
MotorCycleMike In Kansas
I see that the "main question" refers to the ole OEM push rods that had the lifter units in the tins and i added my 2 cents for what it's worth !
My Late Dad had a Pan with the lifters in the tins 1948 and it sure rattled and it was a REAL HARLEY BOO BOO !
Oil will NOT Run UP HILL that only lasted a few years LOL !
Last edited by Motorcyclemike on Fri Sep 04, 2009 4:41 am, edited 1 time in total.
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Re: Hydraulic pushrod question
just what year are you talking about..early Pans had them in the tins and the later one had them above the cams ! i see that your getting all kinds of answers So ?doc308 wrote:What are the pros and cons regarding use of the old OEM hydraulic pushrods ? It seems that I've read some negative comments about them in the past, but can't seem to find the references.
MotorCycle Mike
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Re: Hydraulic pushrod question
Mark
The entire valvle train is engineered to work as a system. A cam shaft is usually ground to operate properly with either hydraulic or solid lifters, but not both. Some cams which are designed to run hydraulic lifters will show premature wear and higher component failure when converted to solid lifters, this leads to the belief that solid lifters are hard on cams. A cam which has been engineered to run solid lifters is just as durable and reliable as a hydraulic lifter system.
The real advantage to hydraulic lifters is that they approach zero-lash at operating temperature, run quiet, and require little or no routine maintenance. Hydraulics are easier on the operator, not on the engine.
Solids which are not adjusted correctly can cause other problems, if set too tight the valve will not close completely and result in burnt valves, if set too loose they will not open as far or stay open as long as they were intended to and the result will be loss of performance.
So, OK, I guess the hydraulics are easier on both the mechanic and the engine.
But the fact remains that you have limited choices for a '48-'52 pan engine. Unless you want to start drilling oil passages to feed hydraulic lifters or replace the oil pump and drive ratio to provide higher pressure and flow to the top end enough to feed the original oil-can hydraulic push rods your best bet is tossing the OEM push rods and replacing them with a set of solid rods.
The conversion on a '48-'52 engine is so easy that even a cave man can do it, and it works! You don't have to replace any parts other than the push rods and you don't have to disassemble anything to do it other than opening up the cover tubes and cranking the adjustment on the tappet down far enough to remove the old push rod and insert the new one.
mike
The entire valvle train is engineered to work as a system. A cam shaft is usually ground to operate properly with either hydraulic or solid lifters, but not both. Some cams which are designed to run hydraulic lifters will show premature wear and higher component failure when converted to solid lifters, this leads to the belief that solid lifters are hard on cams. A cam which has been engineered to run solid lifters is just as durable and reliable as a hydraulic lifter system.
The real advantage to hydraulic lifters is that they approach zero-lash at operating temperature, run quiet, and require little or no routine maintenance. Hydraulics are easier on the operator, not on the engine.
Solids which are not adjusted correctly can cause other problems, if set too tight the valve will not close completely and result in burnt valves, if set too loose they will not open as far or stay open as long as they were intended to and the result will be loss of performance.
So, OK, I guess the hydraulics are easier on both the mechanic and the engine.
But the fact remains that you have limited choices for a '48-'52 pan engine. Unless you want to start drilling oil passages to feed hydraulic lifters or replace the oil pump and drive ratio to provide higher pressure and flow to the top end enough to feed the original oil-can hydraulic push rods your best bet is tossing the OEM push rods and replacing them with a set of solid rods.
The conversion on a '48-'52 engine is so easy that even a cave man can do it, and it works! You don't have to replace any parts other than the push rods and you don't have to disassemble anything to do it other than opening up the cover tubes and cranking the adjustment on the tappet down far enough to remove the old push rod and insert the new one.
mike
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Re: Hydraulic pushrod question
Anybody know where I can get steel push rods for a 56 FLH? All I can find are aluminum ones....
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Re: Hydraulic pushrod question
Well,you could run the little drop in solid lifters that take a stock pushrod.
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Re: Hydraulic pushrod question
Thats the same year That i have a 1956 FLH and i got my "Steel Push Rods" from Jireh cycle.steve_wood wrote:Anybody know where I can get steel push rods for a 56 FLH? All I can find are aluminum ones....
The Steel push rods were made in the USA Too.
Good Luck
Motor Cycle Mike*