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Roller rockers, valve guide wear, offset rockers and cams....winter project?

4K views 20 replies 11 participants last post by  Don Dorfman 
#1 · (Edited)
Hi All,
I recently read on a sporty forum that a guy had N4 cams installed and then had to replace valve guides at 10,000 miles because the stock rockers were putting enough sideways force on the valve stem that the guides wore out and leaked oil. He put in roller rockers and went another 45,000 without issue.

Does anyone have any experience with this in a twin cam?

My cams certainly aren't HOT, but I'm all for making mods that will increase engine life.

So, are my stock rockers fine or should I put in some rollers for a longer living engine? This would be a pretty simple and enjoyable winter project.

While we're at it...with the build in my sig - any significant or obvious possible gain by going to some roller rockers with modified geometry to increase lift? My bike has been running a little goofy this summer so I might be going for a re tune next spring anyways. I'm not sure how this would work with the Andrews 26...might not be worth it ie. hotter cam might be a better choice?

Gosh, while we're at it....again...I've sort of considered swapping out the 26's for 37's, but I think I need a bit more compression for that. I have a .03 head gasket. Does anyone know if there's a thinner one available that would bump me up from my current 9.7 ish:1 into the 9.8 ish range that the 37's like? Right now, according to the Big Boyz calculator, I'm running 9.74:1 static compression which is 189 CCP
Pulling the heads and getting a little bit milled off wouldn't be that big a deal but if it's a simple as a gasket change, might as well save the cash.

I know my pipes aren't performers...perhaps the ideas above for bumping up power a bit aren't worth it at all unless I get some better exhaust...?

EDIT: I guess Woods makes Night Prowler conversion cams now!! I have no experience with these and the descriptions on the website aren't that obvious to me ie. Which woods cam would I pick for my engine that is going to give me good low to mid range power but not drop off too quick? The Andrews 26 drops off noticeably, it doesn't BOTHER me, but heck, might as well extend my capability a little if there's the option to without doing a full on rebuild???

Thanks for your patience and thanks in advance for ideas/knowledge!
 
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#3 ·
The 37's would help. I ran them in my 95". It was not until I sent bean my heads for the street port and skinny them to 80cc did I go over 100hp. If I remember right the 80cc with a .03 gasket put me about 9.8/9.9 for the 37 cams. It ran good!!! Good luck.
 
#5 ·
There is no NEED for roller rockers with lifts under .600, you can use them with stock lift. Bronze guides generally wear quicker than iron, the reason they aren't generally used on a street bike. Bronze is a better material, but bettervsuited to very high lift racing valve trains, you can use anything you want, 10,000 street miles and bronze guides are usually sloppy and leaking oil.
 
#7 ·
Tall Terry is right. Under .600 lift on your cam you have no need for rollers. Don told you about a very fine product. AV&V is one of the best. You already have a street port from bean. You would be fine with just adding the 37's. In the long run having the heads shaved would be the best. As far as having .020 cut off them. That is just a #. It us better then nothing. When I did my 95" with the same pistons and .030 head gasket bean took .040 off one head and .041 off the other. That set the compression for the 37's. Call and talk to bean. Good luck.
 
#8 ·
or put andrews 54 shave ur head for 10.2 compor if u want more tq down low u can modify an andrews 57 to made a conversion cam its like the 37 with higher lift that what i do on my road king got 107 tq and 98 hp with a 98 ci

for the conversion u can ask king of cubes he do it for me
really happy with the result
 
#12 ·
Thanks a lot for all the responses, guys. Looks like roller rockers really aren't needed.

Does anyone have experience with which Woods conversion cam I might look at? My combustion chambers are at 81cc, which Bean did for the Andrews 26. I could likely get a local shop to mill a bit more for 80 cc to work better with Andrews 37's, however I'd be interested in hearing if any of the Woods products like the 9.7 - 9.8 ish compression range that I'm in, as I've heard they're rippers.
Can I just get a thinner head gasket and put in the 37's and skip the milling?

I don't REALLY want to call bean for more advice, even though I know he'd have a spot on answer...as I don't want to pay the shipping to send him my heads again, and it seems kind of crappy to call with questions about more work that I'm not planning on having him do. Kinds of sounds like bad form on my part if I was to do that. He was awesome throughout my whole build, but the shipping alone was like $200, hence my desire to keep the machine work local.
 
#13 ·
Pretty hard to justify the cost.
Save the money and use the 57N. The heads are not developed enough to really leverage a cam that is more than .550 lift and 230-240 duration. Woods has grinds that are similar but the results will be close to the same and the cost is +$125.
 
#14 ·
Pretty hard to justify the cost.

Save the money and use the 57N. The heads are not developed enough to really leverage a cam that is more than .550 lift and 230-240 duration. Woods has grinds that are similar but the results will be close to the same and the cost is +$125.

Thanks.
I just stopped by my local shop and, as I kind of suspected/expected, the available gains with my current set up and better cams are minimal compared to the cost.
He said I could switch to the Woods TW6 and likely notice a bit of a power bump if I stayed with the current set up. He has experience with Woods cams and not so much with Andrews so that is the direction I'll probably go if I decide to go there.
Basically I'm now thinking that if I'm going to bother ripping it apart again, I might as well do it right ie. Woods TW6H, bigger valves, new springs, high comp pistons and a head massage to get compression right. New exhaust. He said bigger valves aren't NECESSARY, but heck, like I said, might as well do what I can to get the most out of it. Maybe with the TW6H the roller rockers would be more beneficial...?

This will cost twice or more what I paid for the original 95" conversion, however my preferences have changed a bit over the last few years so oh well.
Maybe if I get a bonus at work I could make this dream a reality. For now I guess I'll keep dreaming.

Thanks guys.





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#17 ·
I've seen heads with 100,000 on them & the guides were still in good shape.

If you're doing it on the cheap get the heads milled, a GOOD valve job & throw in the 37's or the 57. You'll see a bump in power.

Good valve job...what exactly do you mean by this? Work on the seat or new valves? Thanks.


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#18 ·
A good 4 or 5 angle valve job will help you get the most out of what you have now.
A lot of people don't realize how important the valve job is. It can make or break any build. I've resurrected a lot of heads done by different people with nothing more yhan a good valve job. Find somebody that does race heads & get your heads done there. Not the basic 3 angle that's been done for 40 years but one that really helps the heads flow.
I've gotten 100/100 countless times with stock heads & valves done up right with a 37 cam. Since you're already pulling 100 torque with the setup you have a little more cam with a little more squeeze & you're heads freshened up you will get that too. Maybe more.
 
#19 ·
A good 4 or 5 angle valve job will help you get the most out of what you have now.

A lot of people don't realize how important the valve job is. It can make or break any build. I've resurrected a lot of heads done by different people with nothing more yhan a good valve job. Find somebody that does race heads & get your heads done there. Not the basic 3 angle that's been done for 40 years but one that really helps the heads flow.

I've gotten 100/100 countless times with stock heads & valves done up right with a 37 cam. Since you're already pulling 100 torque with the setup you have a little more cam with a little more squeeze & you're heads freshened up you will get that too. Maybe more.

Thanks a lot...at his point I'm not prepared to have any amount of significant head work done so I'm just going to leave it for now. I'll probably get to this in a year or 2.

Thanks!



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#21 ·
No set number for that. The higher the shock load the higher the probability of slipping the wheels. Plus they start out at .006+ tir in many cases.
Having the crank trued and welded is a good insurance policy. The new bikes with parent metal rod small ends do not need any attention but the bushed tapered rods i would replace with full compliment rods and then a rebalance is required plus the pistons need to accommodate the larger rod end as they did with all big twins before 2007 model year.
 
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