255 cams in 96

[Mawnanian]

I'm thinking of putting 255 cams in my 09 Glide, plus a heavy duty clutch spring. The 103 stage 2 without the 103 if you like.
I already have stage 1.
This seems to be a popular move in the US judging by the various forums, giving a decent increase in torque up to 4k, but I've not heard it mentioned on this board. Does anyone know of any pitfalls or unforseen consequences of doing this?
Thanks in advance for any advice.

[MadMax]

No real pitfalls as such depending whether you intend to do anything to support the new cams. You'll need the correct tool for changing out the inner cam bearings - there is no other way without asking for trouble. It's a straight forward job as long as you're comfortable with either using adjustable pushrods or assembling the rocker gear and fuel system. Do you intend taking the heads off? The 255 intake closing is 25 degrees BTDC so the power will come on early which is nice, but as you already know it will be all over by about 4000 rpm. The 0.555 lift is ok with the 09 stock valve springs although stronger springs would give more control with such a short duration if you do get above 4000 rpm . If the heads are coming off then you could fit a 0.030" head gasket to bump your compression a little. Even at 25 degree closing the corrected compression is only around 8.9:1 with the stock head gasket. CCP is fine at 182 psi so no need for releases. Headwork will improve performance right through the rpm range and allow you to take the compression to the optimum for this grind. You'll could generate more heat because of the short 13 degree overlap, the only benefit of which is the build will be more exhaust tolerant. Retarding the timing will reduce the heat but may rob some power. Have you looked at any other cams?

[Mawnanian]

Originally Posted by MadMax

No real pitfalls as such depending whether you intend to do anything to support the new cams. You'll need the correct tool for changing out the inner cam bearings - there is no other way without asking for trouble. It's a straight forward job as long as you're comfortable with either using adjustable pushrods or assembling the rocker gear and fuel system. Do you intend taking the heads off? The 255 intake closing is 25 degrees BTDC so the power will come on early which is nice, but as you already know it will be all over by about 4000 rpm. The 0.555 lift is ok with the 09 stock valve springs although stronger springs would give more control with such a short duration if you do get above 4000 rpm . If the heads are coming off then you could fit a 0.030" head gasket to bump your compression a little. Even at 25 degree closing the corrected compression is only around 8.9:1 with the stock head gasket. CCP is fine at 182 psi so no need for releases. Headwork will improve performance right through the rpm range and allow you to take the compression to the optimum for this grind. You'll could generate more heat because of the short 13 degree overlap, the only benefit of which is the build will be more exhaust tolerant. Retarding the timing will reduce the heat but may rob some power. Have you looked at any other cams?

Thanks very much for the advice.
I admit I haven't looked closely at other cams. With the bike still under warranty they would have to be HD and the 255's seem to fit the bill.
It strikes me that on the road and with the high gearing of the twin cam the biggest noticable improvement in performance is going to be achieved by increasing low end power and torque, I rarely take it much over 4k even in first and second. I'm more of a tourer than a sprinter these days.
As I have the money at the moment I was going to pay a dealer to do it because of the warranty and because if anything does go wrong I would have some chance of getting it fixed FOC.
I was assuming the heads would stay in place (so is the dealer) the 103 stg2 uses the stock heads and valve springs so without the new pistons and barrels there would not seem to be any need to disturb them.
I guess if the lift height of the cam varies it will have to be compensated for somewhere, is that what you meant by adjustable pushrods?
The heat question occurred to me, which is one reason I didn't go for the 103. I intend to switch to fully synthetic oil so that it can cope with running hotter without breaking down.
Thanks again for your info and advice, it's given me something to think about.

[Matt FXDX]

Dont think Madmax was refering to cam lift compensation with the adjustable pushrods Mawnanian, think he was saying you would not have to remove the rocker covers & rockers using adjustabe rods!

If your having the work done by a dealer, bet theres not mutch in the way of cost in the two methods, by the time you add the extra labour & gaskets together, you could buy the adjustable rods!...

[Mawnanian]

I think I see what you're saying.
In order to swap the cams you have to slacken the valve train right off. You can either do this by removing the rocker gear or if you have adjustable pushrods you can do it using that adjustment?
Can the pushrods be removed from the bottom then? Otherwise in order to swap them you would still have to remove the rockers.

Excuse my slowness but I've only worked on old Brit bikes in the past, I don't know in detail what Harley internals are like or what complications the hydraulic adjustment might cause.
I'm also aware that I don't need to know all this if a dealer is going to do it, but for peace of mind I like to know if possible exactly what they should be doing.

[Matt FXDX]

Originally Posted by Mawnanian

I think I see what you're saying.
In order to swap the cams you have to slacken the valve train right off. You can either do this by removing the rocker gear or if you have adjustable pushrods you can do it using that adjustment?
Can the pushrods be removed from the bottom then? Otherwise in order to swap them you would still have to remove the rockers.

Excuse my slowness but I've only worked on old Brit bikes in the past, I don't know in detail what Harley internals are like or what complications the hydraulic adjustment might cause.
I'm also aware that I don't need to know all this if a dealer is going to do it, but for peace of mind I like to know if possible exactly what they should be doing.

If they take the Standard pushrods out without removing the rocker covers, they simply cut them out with bolt crops, as crude as it sounds!..

[Mawnanian]

Ah, I see - I won't ask you how they get the adjustable ones back in the tubes
Thanks

[MadMax]

Sorry, I thought you were doing the job yourself. When changing cams your pushrods have to come out because when your motor is stopped there is always at least one valve spring compressed which is pushing a lifter against a cam lobe. This pressure has to be relieved in order to be able to remove the cams. The stock pushrods are one piece and the length is non adjustable. They are sized so that when the motor is running, the lifters are filled with oil from the pump and they provide a hydraulic ‘cushion’ that the pushrods ride on to transfer the camshaft events to the valves. To remove the stock pushrods and keep them intact you have to remove the rocker supports from the heads and withdraw the pushrods from their tubes. They cannot come out from the bottom. Afterwards they can be reused. If the rocker supports are not coming off and the heads are going to remain on the bike then the only way to change out the cams is as Matt says with bolt croppers. The stock rods are cut and discarded, cams changed out then adjustable pushrods are fitted. These are adjusted to length so that they ride within the ‘cushion’ that the lifters provide when pressurised. Sometimes adjustable rods can cause noise depending on where within the lifter they are set to run, cam lobe profile and the skill of whoever sets them up. It’s better to reuse the stock ones if possible as long as your cam base circle is the same as stock (the 255’s are) as they are more rigid than adjustables. Limitations will occur if the heads have been skimmed as you may approach the bottom of the lifter’s travel. No reason why you shouldn’t go ahead as long as you are happy with your Dealer’s competence. Dealer’s labour runs on a time code system though so the techs will be in a hurry as they have to get onto the next job. A concern of mine would be that they don’t have the time to perform all the work that I consider essential when changing cams. Examples that come to mind are: inner cam bearings changed out to Torrington B-168’s, lifters changed, accurate oil pump alignment, crankshaft run out measured and a dyno tune to address any extra heat. They definately won’t address stock head air flow issues. I’m not trying to scare you away from the Dealer but if it was my engine I would want more than they can realistically give considering their environment.

[Matt FXDX]

Very well put Madmax,

When i had my 2001 TC converted to gear drive, before i joined HDRCGB, so had no free tool hire option, i did not trust my local dealer to do the job!

My main concern was they would'nt change the inner cam bearings to cut labour time!

knowing the S&S bearings are superior in the fact they have 25 rollers compered to the 23 rollers OE!

Just did not want to take the chance that they did not change them, call it a piece of mind thing, with no confidence of the dealers workshop!

In the end got a local harley trained mechanic with a good reputation to do the work in my garage, which meant i could see the work being carried out!

But having said that my bike is well out of warrenty, but if it was not i think i still would have done the same!

[MadMax]

Originally Posted by Matt FXDX

Just did not want to take the chance that they did not change them, call it a piece of mind thing

Exactly the concerns I would have .. I've never had anything done at a Dealer but I think you'd have to be pretty trusting to give your bike to a stranger, let them take it away behind closed doors then get it back a few days later hoping that they had, but knowing that they hadn't given it their best .. Call me cynical if you like ...