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Old 03-07-2003, 12:12 PM   #1 (permalink)
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Evo Cam Swap and Pushrod Problems

I have been riding and working on Evo Harley’s for years. I have put many cams in without a hitch. The reason I am writing I have one that has stumped me!

Here is what I have:

98 FLSTC, 11,000 Miles. I put in a Sifton 143 cam, new Harley Tappets, S&S Steel Breather, and Screamin Eagle Pushrods. The valve train, pistons flywheels are all stock.

Here is my issue:

I installed the cam with the stock cam gear and checked all clearances for proper lash etc. I installed the tappets and the adjustable pushrods. I adjusted the pushrods via the technical paper that came with them. (2.5 flats) When restarting the engine and giving it time to pump up lifters the engine sounded like it needed a pushrod adjustment. Valve train noise like I have not heard. (I always check compression and listen to engines prior to installing cams etc.) Okay, I thought that I might have not adjusted the pushrods correctly so I went through that process again (loosen the pushrods down, always adjusting the pushrods while the lifters are sitting on the low part of the cam lobe, I even walk away for a few hours to make sure that the pushrod spins freely before going to the next) Start the engine and let it get to operating temp (good oil pressure by the way) and again very noisy.

I put a screwdriver to the valve train and to my ear and I cannot hear any slapping or out of the ordinary sounds! So, again I adjust the pushrods and again it is noisy!

My Question:

Am I adjusting the pushrods to mush (2.5 flats) even though the technical sheet says to adjust them that much? Should I go less? How about that Steal Breather? Is that making all the noise? As you know the stock one is plastic! I have even tried different lifters with the same result so I cannot say the lifters are bad.

The Sifton Cam has .510 lift and I was wondering if that is too much for the valve springs even though Sifton says you could use stock valve springs.

Any Help or advice I would much appreciate!
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Old 03-07-2003, 01:11 PM   #2 (permalink)
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I'm not an expert by no means and someone else may be able to answer this, but I was under the assumption that the stock springs were good up to .500 lift. Being that the bike has 11,000 miles on it and your putting in a .510 lift, I would have certainly installed fresher and stiffer springs to compensate for the additional lift. Like I said, this may not be the problem, but I think I share the same concern as you do.

Good luck and let us know what you find.

God Bless Our Troops.
"So you have a sixty thousand dollar car, eh? Well, I'm real impressed. I have a quarter of a million dollar combine that I only use two weeks a year."

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Old 03-07-2003, 01:25 PM   #3 (permalink)
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I hear ya. I have always done the same. But Sifton swears that you can run stock springs with 143 Interstate cam!

I did talk with my Mechanic bud at the local HD dealership and he suggested that I turn the adjustable (SE) pushrods 3 full flats instead of the 2.5 that the tech page suggests. He said that on all the 143 Interstate cams and SE pushrods that they install they adjust the pushrods 3 flats.

I will let you know! I am going to try this tonight. If this doesn't fly then I have a extra set of topend gaskets and the heads are coming off and then I will check spring tensions.

More work than I wanted to get into and I never had one like this before..

I guess we can all benefit from what I find.. I'm just the one with the busted knuckles

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Old 03-07-2003, 06:15 PM   #4 (permalink)
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The preload on the pushrods should be .100 inch. What I do is put the lock nut up to the barrel of the pushrod when all the slack is taken out. Then I measure the distance when im adjusting the rods. 2.5 flats doesnt sound like enough, probably should be 2.5 turns.
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Old 03-08-2003, 07:33 AM   #5 (permalink)
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2.5 flats doesnt sound like enough, probably should be 2.5 turns.

You are absolutely right! I wrote it incorrectly in my message above. On the SE pushrods there is a number stamped on one of the flats. I use that as a reference and there are 6 flats per lock nut. The tech sheet says that you adjust 18 total flats or 2.5 “Full Turns”.

Just to let everyone know I adjusted the pushrods to 3 full turns (24 flats) and it worked! I am getting a little noise from the S&S steel breather (not excessive wine like an incorrect pinion gear) but that is normal (Harley uses plastic breather for that very reason.. So, I am told by Harley Mech’s).

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Old 03-09-2003, 10:18 PM   #6 (permalink)
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Steel breather valves are not noisier than plastic. HD uses plastic because it is cheaper. Carbon and debris from the crankcase imbeds itself into the plastic and tears up the breather valve hole in the case. That is why you go steel. With everything else going on in that motor you are never going to hear a breather valve spinning. The difference you hear is the difference in gear lash from one cam to another. Even the slightest amount of lash will sound like lifter problems and a hair to tight will create whine. If you have a nice quiet motor when you replace the cam use the gear off the stock cam. It will save you alot of grief.

Last edited by D.Ed; 03-10-2003 at 08:32 AM.
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Old 04-06-2003, 02:23 PM   #7 (permalink)
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D. Ed is correct in all he told you....very good and it's the truth. I will however add to that....A plastic breather gear also lags from friction in the bore which alters your breathing at higher rpms, this altered breathing can and will give you ring sealing problems due to crank case pressures.
Any time you alter your cam with more aggressive ramps, longer duration, lift, ect, ect you are going to pick up more valve train noise.....especily if you run a wind shield......tightining up the push rods past the correct setting for those push rods will only make the valve train louder because the lifter can be bottoming out. The answer you got up above is a good rule of thumb.....set them to .100 preload. Your engine only expands .060 to .100 under operating conditions.....you don't need to go any futher, if you did back them off and listen to them again....I think you will hear a little differance.
God Bless you....hope this was inlighting for you.
P.S. it's always best to install you stosk gear on the cam you got.....it will have the correct gear fitment you had......also this way you have to degree the cam for better performance
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