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[Hoist!]

Don't thing you're missing anything.  It's just that the dealership isn't thinking through the question any further than the written words in front of them.  They read something (and passed it on) that said "with this cam if such and such a head is used you need such and such a pushrod."  They just didn't bother to (or weren't able to) think the problem through from any other angle.

OK, so which pushrod am I using for the SE 251 Cams? Can that be answered straight up, without measuring anything? Hoist!

[Twolanerider]

OK, so which pushrod am I using for the SE 251 Cams? Can that be answered straight up, without measuring anything? Hoist!

You're going to have to know what some difference is.  In your case the heads are staying the same.  The cams are changing.  So while the cam sheet is giving you a specification relative to differences from the cam (i.e., the heads) you can also figure what you need to with the differences of the cam itself.  But you'll still need a comparative measure.  The comparison being the stock cam's diameter versus the new cam's diameter.  That is all that's changing in your motor after all.

[grc]

Howie,

It's not the cam lobe that needs to be measured, but the base circle.  This is the surface the lifter rides on with the valves closed, and is where the pushrod needs to be the correct length to allow the piston in the lifter to be centered. 

BTW - I'm with you on using one piece rather than adjustable pushrods.  One less potential failure somewhere down the road.

Jerry

[Twolanerider]

Howie,

It's not the cam lobe that needs to be measured, but the base circle.  This is the surface the lifter rides on with the valves closed, and is where the pushrod needs to be the correct length to allow the piston in the lifter to be centered. 

BTW - I'm with you on using one piece rather than adjustable pushrods.  One less potential failure somewhere down the road.

Jerry

Too true.  Got lazy last night and wasn't careful with what was said.  Importantly he can still use the cam measurement to determine which pushrods to use.  As importantly, I'm an idiot when I've been up too long.

[grc]

OK, so which pushrod am I using for the SE 251 Cams? Can that be answered straight up, without measuring anything? Hoist!

Howie,

Based on the attached chart from the SE catalog, it looks like your assumption of 18401-03 is correct.  I just mentioned the cam measurement as an easy way to verify this before you bolt it all back together.  Since the 18401-03 is 0.030" longer than a stock pushrod, the base circle diameter of the SE251 cam should be 0.060" smaller than the stock cam (radius 0.030" smaller).  As 2lane pointed out, since the heads/rockers/cylinders aren't being changed the only variable involved is the cam base circle dimension.  It's an easy check which will add to the "peace of mind" factor once she's bolted back together.

Jerry

[Hoist!]

Thank you very much Don and Jerry. I'm just surprised that when using SE parts for mods, that they make it so difficult to determine this. You should be able to match the 110" cam/head/pushrod data from the catalog, like you can for other SE engines. He should have all 3 sizes handy and then measure base circle dia. for both cams. There is no surefire way, based on the Tables, unless you know exactly what heads you have. Hoist!

[djkak]

Hey dj, how are you these days? Thanks for the info. This means you'd need the +.030" Perfect Fit Pushrods (18401-03) for the SE 251's used with stock heads, according to the Parts Book. Any reason to assume that might not be right for 110 Heads? I assume stock pushrods don't work with the SE Performance Heads, and the 110 Heads would be like stock measurements then. Can that parts book be counted on for this? It's a completely stock engine, just cam and pushrod change is all. Thanks again....
Hoist!

I’m good Hoist, thanks and sorry for the delay; I would go ahead and run the 18401-03, + .030 pushrods with the SE251’s and a stock configured 110” cylinder head. That really sounds too easy and I know how much you like to screw around; I’ve seen pictures of your hydronics….does that sound too personal? 

Make a pushrod gauge by taking a stock pushrod and cut off the bottom 40%. Cut the short section of pushrod own to approximately 1 inch long. Find a piece of tubing that just slips over the pushrod and solder, weld, glue or otherwise attach it to the short piece of pushrod. Cut the sleeve to a length that allows for a reasonable overlap (1” or so) when the gauge is in position and fully extended.  Locate a suitable compression spring to slip inside the sleeve to keep tension on the gauge when it is in place. Locate a couple of witness marks on the gauge using the original intake and exhaust pushrods as a “standard”. Allow for approximately 0.100” to 0.125” of lifter compression. You could also just run a set of adjustables….or not.

djkak

[Hoist!]

I’m good Hoist, thanks and sorry for the delay; I would go ahead and run the 18401-03, + .030 pushrods with the SE251’s and a stock configured 110” cylinder head. That really sounds too easy and I know how much you like to screw around; I’ve seen pictures of your hydronics….does that sound too personal? 

Make a pushrod gauge by taking a stock pushrod and cut off the bottom 40%. Cut the short section of pushrod own to approximately 1 inch long. Find a piece of tubing that just slips over the pushrod and solder, weld, glue or otherwise attach it to the short piece of pushrod. Cut the sleeve to a length that allows for a reasonable overlap (1” or so) when the gauge is in position and fully extended.  Locate a suitable compression spring to slip inside the sleeve to keep tension on the gauge when it is in place. Locate a couple of witness marks on the gauge using the original intake and exhaust pushrods as a “standard”. Allow for approximately 0.100” to 0.125” of lifter compression. You could also just run a set of adjustables….or not.

djkak

Thanks dj, and as always, you're a plethora of information! I like the answer in the first paragraph. I can see my dealer now, making a pushrod gauge and charging $90/hr to do so! It appears from everything I've gathered from this that the .030" over pushrods are the right ones. It'll be interesting to see what the dealer picked. Adjustables are the easy way out. Too many horror stories about nuts backing off. My preference would be fixed. Chit, if we only had easy questions, this place wouldn't exist!

How nice you noticed my hydronics! I had an old 1-pipe steam system in the house. I wanted to convert to HW. Then all of a sudden, I started developing that whole Radiant thing and I couldn't stop! Next thing you know, I built an Engine Room in my basement! Complete with Thermal Storage, instantaneous everything and full property Snow Melting! For me, that was as much fun as the bikes!

Again, thanks for your help. I gotta get out there and meet you sometime. Always enjoy our chats! Maybe next summer on my way to the Rocky's!

Hoist!

[Twolanerider]

Too many horror stories about nuts backing off.

Don't you hate it when that happens..... 

[Hoist!]

Yes I do hate when that happens! I spoke with the dealer today and all parts for the job are not in yet. So, the bike now goes in next week. They did confirm that their research indicated the use of the 18401-03 Perfect Fit Pushrods (.030 over) go with the SE 251 cams on a stock 110. That made me feel better, even though I asked them to confirm this again before they install them, by measuring the Base Circle Diameters of both the 255 and 251 cams. If we don't like what we see, I guess I'll use the adjustables. Not liking that idea, I'm optimistic the the .030 over pushrods are correct. I'll let ya'll know when we finally go thru it. Hoist!

[GMR-PERFORMANCE]

I really have issue's with a part called a perfectfit. Being that we build in the range of 200 engines a year, there si nothing that is perfect. You run into cylinder height varations, case height varations, and head thickness varations. Now the normal lifter has a range of 180-200 travel and you like to have it in the middle when you look at stack up or down you can end up on the short side. We have custom push rods made for us. They are adjustable made from 4130 chomemoly .065 wall and are not 7/16 but 3/8,.. 32 TPI mae west ends. We are also having a quick install made now that is going to cure the rubbing issue's with the cheap quick install's on the market now. It will be 7/16 at the base and taper to 3/8 at the top, made from the same steel, but with out maching flats in the extending portion to prevent flexing and weaking of the lower portion. It will come as a kit with 4 rods and new chome covers to allow you to adjust them easily.

Use of a adjustable pushrod can help with valve train noise as well. We do not run them down into the middle of the travel,.. but we have found that extending the pushrod into the 60-80 thou range works better and will stop much of the valve train noise. This works on stockers and after market cams.

We refuse to use the 7/16 straight style pushrods. Even on mild cams you will see issue's with the large pushrod hitting the push rod tubes in the upper portion near the head.

[Unbalanced]

GMR,

To be sure I understand what your saying are you saying that you want the clearance to be 60-80 off the heal of the cam from lifter bottom?  Are you saying this for all types of pushrods or just yours?  Please clarify for us.

In mine and other poeples experience setting of the pushrod depends more on the manufacture of the push rods and the metals used to know what clearances actually work best based on expansion depending on the metallurgy of the rod vs. the components, heat and travel.   For example on the Zippers pro tappered push rods with stock lifters they are to be set at 20 off the heal from lifter bottom.  This yields better power and quieter running with no issues.  When it comes to setting adjustable pushrods there are a lot of opinions on this topic and if you frequent tech talk you will find that you can find many many hits on the subject. 

[GMR-PERFORMANCE]

No I like to see 60-80 thou  depsression from base circle  on the cam with lifter> pushrod at zero lash.  I have tried the bottoming method for pushrods and do not like it. AS well you can bottom the plunger in the lifter and then it will pump up .... FULLY so then you can have a valve hit a piston.  You want the lifter to be a cushion and keep valve train in correct tension

. If you want a lifter to act like a soild use them or a hydo/soild ring.  And you can set any adjustable to what spec you want.  P.S zippers does not make there pushrods take a look at ours.  So that method is one way, do I think it is the way to set them ?? No,.. and will it make less noise?? No ,..more power?? Well maybe if you are collapsing the lifter then I guess you could say that you would gain power by making the plunger bottom in the lifter bore, and not have the valve fail to lift to it's max.

 But that goes back to what I said previous. If you bottom a lifter it wants to fill back up with oil. It is a pump so will it try to fill up then bleed down.   A missed shift could cause it to bottom, over revving the engine, sorry but with the amount of engines we build in a year,  we like the method we use.  But that is just my Opinion, Zippers has there own , ...... I guess i will stop there, before I say some thing that I should not.

[Rhino]

If you bottom a lifter it wants to fill back up with oil. It is a pump so will it try to fill up then bleed down.   A missed shift could cause it to bottom, over revving the engine, sorry but with the amount of engines we build in a year,  we like the method we use.  But that is just my Opinion, Zippers has there own , ...... I guess i will stop there, before I say some thing that I should not.

Hello GMR,

No please don't stop. I was just going through this issue and it solved some of my probs.  Anyway, if the lifter is going to fill, won't it fill whether it's close to the base, or close to the middle, etc?  And if the lifter was stronger than the spring, wouldn't it make the valve hit in any event?  Seems that if the lifter tops out and locks up, the damage would be done no matter what.  So, could you continue please?  Personally, I value the education, and if more insight is gained, we all benefit, don't we?

Rhino

[GMR-PERFORMANCE]

The reason I stopped is I have nothing good to say about zippers.   I will leave it at that as I do not want to air dirty laundry over the net.   They as well as other big shops seem to have forgotten why we do this. I am about customer service, making sure I go the extra mile to ensure the customer ( the people who pay my bills , put food on my table, cloths on my childrens back) are taken care of , have a build that runs well, makes the power it should and in the RPM range that the customer rides.   Customers can call me and ask me anything they need to , get tech help over the phone. I have spoke to shops that have taken care of a customer needing help.

That may be off the topic a bit but it goes back to the lifter issue. Unless you are running a large cam, over 200 lbs of seat PSI , I myslef would not run the plunger in the lifter to that postion. AS I have seen first hand what can happen. The chances of you pushing the plunger to the bottom when set in the 80 thou range is almost NILL now the chances of you bottoming the plunger out when set  very close to the bottom are much greater. I am not a betting man never have been. And I value my customers, a set up such as that has a greater % of breaking parts then our set up.  The lifter "wants" to keep oil inside that is the design, you empty the lifter it will pump up again that is it's job.

 Now that should be clear as  ahhhh mud?? HA Ha   hope you all have a great day gotta get back to work.