Author Topic: Pushrod adjustment for hydraulic lifters  (Read 5156 times)

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Online hotrodshovel

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Pushrod adjustment for hydraulic lifters
« on: Saturday, October 03, 2009. 07:57:40 PM. »
76, I just found Samuel's instructions you posted a while back in response to someones question.

I have a question or two regarding those instructions. I'm switching over to hydraulics, by the way so this is new to me. I've had solids forever.

Sam mentions finding TDC by watching the points as they begin to open after the front intake pushrod begins to come down. How do I measure this with an electronic ignition?

Next, both pushrods of each cylinder are done at the same time without turning the engine over again, correct?

Thanks for any opinions.
John

Offline shovelryder

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Re: Pushrod adjustment for hydraulic lifters
« Reply #1 on: Saturday, October 03, 2009. 09:24:35 PM. »
I have a76 FLH...heres how I do mine.

Rotate engine until the the lifter moves as far DOWN into the lifter block as it will go before it starts to come back up. Now run the pushrod for that lifter out until it doesn't have any play (and isn't compressing the spring in the lifter hydraulic units cup) then turn it out 4 1/2 more complete turns (this compresses the spring) Tighten and move to the next one..it doesnt matter what order you do them in.

Important:  make sure the lifter is at the bottom of its travel and make sure the hydraulic unit in the lifter is seated all the way in the lifter and not sticking up some (by hydraulic pressure) or this will give you a false adjustment

Online hotrodshovel

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Re: Pushrod adjustment for hydraulic lifters
« Reply #2 on: Saturday, October 03, 2009. 09:29:10 PM. »
Very cool, how about bleed time to allow the oil in the lifters to run out?
John

Offline CraigArizona85248

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Re: Pushrod adjustment for hydraulic lifters
« Reply #3 on: Saturday, October 03, 2009. 09:47:04 PM. »
You need to make sure that 4 1/2 turns on the push rod is correct for your brand of pushrods.  The number of turns on the pushrod after removing the slack is based on the TPI (theads per inch) of the pushrod.  My method is slightly different.  What I do is I check the lifter specs to find out how much piston movement is allowed by the lifter.  Typically this is around 0.200" but it varies from manufacturer to manufacturer.  Lets say for the sake of this example that the lifter piston has 0.200" of travel.  My goal when adjusting the pushrod is to put the piston in the middle.  So that would mean I want to compress the piston 0.100" after taking up the slack.  Now for this example lets say the threads on the pushrod are 32TPI.  You would want to open the pushrod 3.2 turns (19 flats) to compress the lifter piston 0.100".  But if your pushrod is 24TPI you would only open the pushrod 2.4 turns (15 flats) to get the same 0.100" of piston compression.

I let the lifter sit for about 10 minutes after preloading to allow it to bleed down.

-Craig

Offline shovelryder

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Re: Pushrod adjustment for hydraulic lifters
« Reply #4 on: Saturday, October 03, 2009. 10:03:56 PM. »
Craig,
The whole TPI thing is something I've heard for years but here's my take on that.  I've wondered what difference does it make? As long as you haven't tighten the pushrod to the point of bottoming out the hydraulic unit (cup and spring) thus in turn opening the valve I wouldn't think it mattered if you go 3 -4 or how ever many number of turns..The unit is hydraulic and any slack (give or take) is going to be taken up as soon as it pumps up. Just like the old days of adjusting chevy V8 units..crank the car and tighten them one by one until they don't clatter...kinda hard to do tho on a Harley pushrod!!

Just my ramblin..

Online hotrodshovel

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Re: Pushrod adjustment for hydraulic lifters
« Reply #5 on: Saturday, October 03, 2009. 10:17:16 PM. »
Craig, Shov...I always did my solids exactly the way Shovelryder said except I don't have to worry about bleeding down. I do understand what Shovel says regarding the turns as long as I don't bottom out I should be OK, or am I missing something big here. Wouldn't be the first time!
I'm using a Sifton hydro set up, so I would guess that all this info you are talking about will be included with the kit, such as the travel of the lifter piston and TPI.
John

Online 76shuvlinoff

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Re: Pushrod adjustment for hydraulic lifters
« Reply #6 on: Sunday, October 04, 2009. 01:49:04 AM. »

 I do mine the way shovelryder lists  for the stock rods. I have been running some aluminum rods (S&S maybe) in my current S&S shovel type mill and Jims lifters.  I think the adjustment there is 7 flats. It's a set it and forget it proposition so I look it up every time.

 Mark
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Online hotrodshovel

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Re: Pushrod adjustment for hydraulic lifters
« Reply #7 on: Sunday, October 04, 2009. 02:32:31 AM. »
Set it and forget it.....thats what I heard about hydraulics, thanks very much, again!
John

Offline flhswingarm

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Re: Pushrod adjustment for hydraulic lifters
« Reply #8 on: Sunday, October 04, 2009. 09:17:40 AM. »
Rudy
I just yesterday converted from solids (which I used for years) to hydros (Sifton,like yours) When I adjust I take them out.....open them up and remove all oil from inside with a clean rag or q-tip, .......put the lifter back together and squeeze to see if it has full travel..........now pop em back in and snug push rods down with your fingers so the spring is compressed....then back off 7 flats (like 76 sez).........and lock em in ..........oh yeah, with the rear wheel off the ground ,and the spark plugs out ,and the bike in 4th gear you can find bdc on each lifter  one at a time

good luck with it

Online 76shuvlinoff

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Re: Pushrod adjustment for hydraulic lifters
« Reply #9 on: Sunday, October 04, 2009. 02:50:51 PM. »
I should speak up, my current (aftermarket) adjustment is 7 flats down from zero slop at the top, not 7 flats from bottomed out. But if it works, it works.  :up:
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Re: Pushrod adjustment for hydraulic lifters
« Reply #10 on: Sunday, October 04, 2009. 03:46:20 PM. »
Flhswingarm, 76, Shovelryder, Craig....Once again I thank you for making my life easier as a Shovel Head.
John