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exxon valdez

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knucknutz

Posts: 35

Joined: Tue Jan 17, 2006 7:37 pm

Location: clear creek,id

Post Mon Feb 16, 2009 10:00 am

Re: exxon valdez

i replaced those bushings i mine ,shovel one,s work,with one,s with no grooves, set valves up at .0015 on int.,.0025 on ex., and put valve seals on intakes.no more problems.i have my s-s pump set at 20 lbs cold-15 lbs hot-goin down road it holds 20 all the time with no plugged and drilled fittings in head or timing cover and have put 3500 miles on bike this way this summer. those grooved bushings suck and feed to much oil to valve.with solid bushings in there they meter the oil being feed to valve.hope this helps,this was a big hassle
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fhsmith1

Posts: 200

Joined: Wed Jul 26, 2006 6:10 pm

Location: Georgia

Post Mon Apr 06, 2009 11:05 am

Re: exxon valdez

All
I have finished the work on rocker bushings. I used Shovelhead bushings without grooves. Used a Sunnin hone to get clearance. Went with about .0007" clearance. Also used Shovelhead rocker shims to tighten up side clearance. I opened up the small orfices in the rocker box fittings to .042". All seems fine for now. Have about 100 miles. Will report back after about 1000 miles.
F
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Boots99

Posts: 33

Joined: Tue May 05, 2009 3:28 pm

Post Sat May 09, 2009 11:08 am

Re: exxon valdez

When I first started running an S & S Oil PUmp on my '40 knuck, I also used the S & S drive gears. Oil pressure was way too high for a knuck engine as we all find out. Even working the pressure relief spring was not sufficient to get the pressure down to managble levles without completely losing all pressure. I found that the S & S drive gears, drive the pump at a higher rate then OEM drive gears. I think it is 4:1 vs 5:1. I was able locate a set of OEM drive gears in good condition and swaped them out for the S & S gears. That brought the pressure down to about 30 psi max cold, and from there it was easy to reduce it with the spring and then use orfices to limit top end over oiling. Now I see about 5 psi at idle hot and about 20 psi at running rpm hot. Still high for a knuck, but managable.
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Boots99

Posts: 33

Joined: Tue May 05, 2009 3:28 pm

Post Sat May 09, 2009 1:53 pm

Re: exxon valdez

One other "trick" I figured out to prevent over oiling the top end. We all know about the method of soldering up the cam cover fitting and drilling a .060 hole to restrict top end oil. Well, in my case I had it down to about .040 to make it work well. After a rebuild last year, I wanted to try it a bit bigger again so I opened that hole up to .060 again. Didn't work at all. Way too much oil. So while I'm soldering the hole back up and then trying to drill through the solder with a .o40 drill again, I break the bit off. Pisses me off and I have to start all over again. Then I look at the size of that hole in the fitting and it looks like if I thread the inside of it, a 1/4-20 set screw would thread right in there perfectly. I couldn't drill small holes in hardened set screws, so I had to buy a box of 100 brass, 1/4-20 cup point set screws. Those I can easilly drill small holes in. So I drilled a series of holes in them of different sizes, threaded the fitting, and can now change the size of the orfice in 2 minutes accurately. Its just like a carburator jet. The first thing I found out was that a .040 hole in these set screws flowed a lot more oil then the same size hole in the solder. Someone else here mentioned the shape of the hole having an influence and in solder, you don't get a neat round hole like you will in the brass set screw. I had to go down to .031 to get it to clean up using these. Even then, I found that the rear cyclinder puffed just a tad of smoke coming off idle but the front was clean. The oil line is shorter to the rear then it is to the front. With any constant flow tube, you get more fluid through the shorter tube. Thats why on injected aircraft engines it is criticle that all fuel lines to the individual cylinders are exactly the same length. So the final thing I did was to pull the oil fittings from the heads, thread them the same way, and put a .035 fitting in the rear, where I was getting a bit too much oil still, and a .0395 fitting in the front. Since I am using larger orfices at the top on front and rear then at the bottom feed point, I am not further restricting the flow overall, but it biases it toward the front slightly to make up for the shorter oil feed line to the rear. That worked perfectly. Just wanted to pass that on.
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Chris Haynes

Posts: 2616

Joined: Wed Jul 05, 2000 12:01 am

Location: Los Angeles, CA

Post Sat May 09, 2009 2:50 pm

Re: exxon valdez

S&S suggests installing a rivet with the hole in it.
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fhsmith1

Posts: 200

Joined: Wed Jul 26, 2006 6:10 pm

Location: Georgia

Post Wed May 27, 2009 4:59 pm

Re: exxon valdez

All
I now have almost 700 miles since replacing the grooved rocker arm bushings. I am very proud to say that so far the problem is solved. The plugs are burning clean now and no smoke at all. I did nothing but change the bushings so that had to be the problem. Will report back after the long hot Georgia summer.
F
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s eagle

Posts: 24

Joined: Thu May 22, 2008 1:06 pm

Location: My-am-mah, Flor-a-duh

Post Fri May 29, 2009 6:43 am

Re: exxon valdez

Boots99 wrote: Since I am using larger orfices at the top on front and rear then at the bottom feed point, I am not further restricting the flow overall, but it biases it toward the front slightly to make up for the shorter oil feed line to the rear. That worked perfectly. Just wanted to pass that on.


The above statement (highlighted in blue text) is not correct; since you are reducing the the diameter of the tubing by placing a restricting orifice at the end of the tubing you are creating additional headloss through the system, since oil is an incompressible fluid this additional healoss is felt all the way back to the oil pump/relief valve creating greater head for the pump to pump against. The oil pump is a gear pump which is a varient of the rotory positive displacement pump in which flow and pressure are a function of RPM (there is also slip between the gears, but lets keep it simple for now). With a pressure relief valve as part of the system when the pressure reaches the predetermined set point, the check valve opens. Now with increased headloss through the piping to the top end and thus a greater "back presure" created at a lower flow, the relief valve opens at a lower rpm and shunts more oil off to the sump. And thus, with your new set-up you are reducing flow to the heads over your previous set-up without the additional orifices at the rocker block fittings.

The idea of balancing the flow to each head by using orifices of different diameter is good, what you did was create equal headloss through each branch of the top end oiler piping at equal flow rate.
Steven

1946 knucklehead
1976 shovelhead
2006 road king

Youth and enthusiasm is no match for age and treachery.
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Boots99

Posts: 33

Joined: Tue May 05, 2009 3:28 pm

Post Wed Jun 03, 2009 6:05 pm

Re: exxon valdez

OK, then if that is true, why is it any different to have 2 seperate orfices, one at the bottom of the oil feed line and a second larger one (in diameter) at the top of the oil feed line, then if it were simply one longer orfice in one position in the oil line? In other words, my orfices are approximately 1/16" in size (not diameter but length of the orfice hole in the brass set screws.) If that orfice length was instead 1/4 inch in length all in one position, say at the bottom, why would having 2 seperate 1/16" long orfices create further restriction then one longer orfice? When I was running solder in the bottom fitting with a hole drilled in it, as was the standard for many years on knucks running newer oil pumps, the length of that hole varied from around 1/4" to 3/8" depending on how much solder I got filling the fitting. That did seem to restrict total flow muchmore then the small brass set screw orfice.

I'm not trying to argue. I'm accepting what you say as factual, but asking for more information for my own knowledge. I am concerned that I may have too liteel oil flow to the top end now, but there isn't a good way to test for that short of pulling the heads apart to inspect the shafts.
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fhsmith1

Posts: 200

Joined: Wed Jul 26, 2006 6:10 pm

Location: Georgia

Post Sat Jun 06, 2009 9:02 am

Re: exxon valdez

Boots 99
If you read this entire thread (long winded as it may be) you will know all I have been through on it.
Now I am convinced that the rocker bushing type (non grooved) and clearance is the most important thing on Knuckle rocker oil retention.
If these are correct, they meter the amount of oil in the rocker cup. The clearance itself is the needed restriction.
The cup tin venting is also important but if there is too much oil escaping the rocker to shaft clearance, the system can not handle it and it has to come out somewhere.

F
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Boots99

Posts: 33

Joined: Tue May 05, 2009 3:28 pm

Post Mon Jun 08, 2009 2:34 pm

Re: exxon valdez

I have read the entire thread. I know about those V-Twin shafts with the grooves causing additional and way over oiling problems as well as too much clearance in the shaft bushings. However, I do not have those grooved shafts, and I have checked the clearances myself when I lapped my valve seats a few months back. With a stock oil pump, those orfice restrictions are not needed when everything else is right, although knucks still tended toward over oiling the top end because of the poor design of the return path. However, a stock knuck oil pump, with the engine fully warmed up and running even 60 wt oil, would only put out 1 to 3 psi at idle and 8 to 10 psi at full song. With an S & S oil pump, even after reducing the over pressure spring and using the 5 to 1 original drive gears instead of the S & S 4 to 1 drive gears, (to slow the pump down) my engine pressure still runs about 10 psi hot at idle and 20 psi hot at full song. That extra pressure plus the much better flow of the S & S pump, puts wayt oo much oil to the top end which is what sees the pressure first. So we have been restricting that with a .060 hole in a soldered up bottom fitting for many years, way before those grooved shafts came into being from V-Twin. The grooved shafts just made a problem much worse then it already was.

I have a service instruction letter from the 40's that instructs how to index the shafts to control over oiling in the top end even back then with stock oil pumps. Everyone I spoke with said that never made much difference anyway, but it was an early factory attempt to fix a problem they didn't anticipate. It was their first attempt at an over head valve engine though.
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s eagle

Posts: 24

Joined: Thu May 22, 2008 1:06 pm

Location: My-am-mah, Flor-a-duh

Post Mon Jun 08, 2009 5:01 pm

Re: exxon valdez

Boots99 wrote:OK, then if that is true, why is it any different to have 2 seperate orfices, one at the bottom of the oil feed line and a second larger one (in diameter) at the top of the oil feed line, then if it were simply one longer orfice in one position in the oil line? In other words, my orfices are approximately 1/16" in size (not diameter but length of the orfice hole in the brass set screws.) If that orfice length was instead 1/4 inch in length all in one position, say at the bottom, why would having 2 seperate 1/16" long orfices create further restriction then one longer orfice? When I was running solder in the bottom fitting with a hole drilled in it, as was the standard for many years on knucks running newer oil pumps, the length of that hole varied from around 1/4" to 3/8" depending on how much solder I got filling the fitting. That did seem to restrict total flow muchmore then the small brass set screw orfice.

I'm not trying to argue. I'm accepting what you say as factual, but asking for more information for my own knowledge. I am concerned that I may have too liteel oil flow to the top end now, but there isn't a good way to test for that short of pulling the heads apart to inspect the shafts.


There really isn't. Without making your eyes glaze over by throwing hydraulic equations at you I'll try to explain. There are varying equations that describe how different types of restriction behave; the orifice or rapid contration is governed by a specific equation, as the length of the restriction increases, this portion is governed by another set of equations which are more readily applied to pipes (or tubes). So one could actually calculate the length of this elongated restriction by seting the two equations equal to each other and solving for the equivalent length of restricted tubing that would equal the same headloss created by the orifice. Therefore, we could create the same flow reduction as two orifices by splicing in a single length of smaller diamter tubing into the top end oiler tubing. In your example the difference in headloss created by the varying length of the orifice is insignificant, especially when compared to the headloss created by the restriction itself.

In regard to adjusting flow by rotating the rocker arm shafts, I believe this feature was for '39 and earlier models only, and I think you would need the early rocker arms. On page 30 of the original '40-47 shop manual it says that "Oil to rocker arms and valve stems is metered through a fixed orifice in each rocker arm shaft and no adjustment for more or less oil is provided".
Steven

1946 knucklehead
1976 shovelhead
2006 road king

Youth and enthusiasm is no match for age and treachery.
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Boots99

Posts: 33

Joined: Tue May 05, 2009 3:28 pm

Post Fri Jun 12, 2009 1:44 pm

Re: exxon valdez

Thanks for the explanation Eagle. I think that I now understand why I was getting so much more oil with a drilled set screw orfice rather then the hole in the solder I had previously used. The drilled solder would have been a much longer hole and with rougher walls since you can't drill a clean hole in soft solder. The brass set screws are as cleanly drilled as a carburator jet. All that explanation convinces me that putting those additional jets at the top to bias the oil flow will do the proper job and not hurt anything although they will cause less total flow as well. I'm pretty good with equations, but I hadn't considered the length of the orfice as a factor the way I would water through a long pipe.

Take care.
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s eagle

Posts: 24

Joined: Thu May 22, 2008 1:06 pm

Location: My-am-mah, Flor-a-duh

Post Mon Jun 15, 2009 9:25 am

Re: exxon valdez

Boots99 wrote:Thanks for the explanation Eagle. I think that I now understand why I was getting so much more oil with a drilled set screw orfice rather then the hole in the solder I had previously used. The drilled solder would have been a much longer hole and with rougher walls since you can't drill a clean hole in soft solder. The brass set screws are as cleanly drilled as a carburator jet. All that explanation convinces me that putting those additional jets at the top to bias the oil flow will do the proper job and not hurt anything although they will cause less total flow as well. I'm pretty good with equations, but I hadn't considered the length of the orfice as a factor the way I would water through a long pipe.

Take care.


In terms of hydraulic analysis this is an extremely important point; a smooth uniform orifice will have a lower friction factor than the rough drilled hole, and thus a rough orifice of the same size will create more headloss, resulting in greater flow restriction. But keep in mind we're discussing theory, in actually practice is this significant? Probably not unless you are right on the tipping point between too much and the right amount of oil delivery. So nevertheless, I believe that no matter how we slice it, creating a restriction in the top end oiler is a trial and error process, with a starting point restricting orifice of .06 as suggested by S&S and the other aftermarket pump manufacturers.

Edit: I was thinking about the trial and error process; it maybe more efficient to use a smooth orifice (like Boots mentions above) because of the repeatability of the orifice physical properties. For example, when you drill a hole in each of two pieces of soft solder, the roughness and shape may not be identical and therefore each orifice may flow differently. This may also occur when altering the size of the drilled in soft material orifice. If you can control the roughness and shape factors you really have comparable varience in resizing the orifice. I believe I read on this forum (or maybe some other) of this cat who was using S&S jets to adjust the top end flow rate. By doing this he removed the uncertainty related to the variations in the drilled soft material.
Steven

1946 knucklehead
1976 shovelhead
2006 road king

Youth and enthusiasm is no match for age and treachery.
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Nick55KH

Posts: 121

Joined: Thu Mar 27, 2008 9:51 pm

Post Mon Jun 15, 2009 7:41 pm

Re: exxon valdez

My head hurts!!!
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s eagle

Posts: 24

Joined: Thu May 22, 2008 1:06 pm

Location: My-am-mah, Flor-a-duh

Post Tue Jun 16, 2009 11:05 am

Re: exxon valdez

Nick55KH wrote:My head hurts!!!



Yea, that's the usual reaction when I get into hydraulic geek mode (see what I meant by "eyes glazing over" and I didn't even get to the equations). Take two aspirin, and a long ride, and all will be better. That's Doctor's orders!! :)
Steven

1946 knucklehead
1976 shovelhead
2006 road king

Youth and enthusiasm is no match for age and treachery.
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Boots99

Posts: 33

Joined: Tue May 05, 2009 3:28 pm

Post Tue Jun 16, 2009 4:14 pm

Re: exxon valdez

Thanks eagle.

It was the S&S carb jets that gave me the idea to drill the oil filltings 1/4-20 and then use 1/4-20 brass set screws drilled with numbered bits to create small jets very similiar to carb jets. It seems to be working pretty nicely now.
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