I am trying to decide on a cam to put in my 2011 FLHRC 103". I am liking the Andrews 48H and 54H and the TW-555 and TW-777. A majority of my riding is in the hilly/twisty country so the powerband of the all these cams certainly fit. I hope that there may be some head work later, but for the immediate future, I will be running the stock valve train. Whatever I go with I want to make sure it is suitable to work well in the stock motor should finances push any other future work off. With that in mind I would like have some confidence that my cam swap is not going to create a situation where I am just waiting for an inevitable stock spring or lifter failure.

One of the things that is confusing with the TW-777 is that most cam manufacturers recommend a hi-lift spring when the lift gets over .560 or so. So how is the TW-777 a bolt in using stock springs with .575 lift? And if it truly is a bolt in, and has nearly identical performance to a TW-555 in a stock motor with the option to really let it show its true potential with an increase in compression and head work later, why would you even consider a TW-555 unless you truly are just asking for trouble with the amount of lift on the TW-777?

The 54H seems very similar, on paper anyway, to the TW-555 so I would assume between the 2, it probably really comes down to price, and availability I guess?

The 48H I have really read nothing but good things about...but usually on 96" motors, so I do not know if the 103" would be much different, and whether or not the .555 lift cams are better suited in the 103's?

I know there are a lot more options out there in addition to the ones that I have mentioned, but these seem to have a lot of happy customers.

Thanks!

 

The stock springs in the new engines will handle a 575 lift cam. That being said, the 555 and 777 and 54 all really work a lot better with an increase in compress to 9.8 or better. The 48 is a good cam for the stock configuration, as well as the T-man 525 , HQ 500 and others.

 

+1 on the 48 in a stock configuration; truly a "bolt in" application with very good results. OEM springs are specified to accomodate lifts up to .575". I have checked some that would accomodate .600" before coil bind. I suspect that is the reason the MoCo specifies .575" to provide a built in margin of safety as well as accomodating for manufacturing tolerances.

If you don't have compression realeases, you should add them if you use the 48s. JMHO.

 

Agree with djl and Dalton.
Those Wood 555's as well as the 777 need to have the compression brought up to witness the full effectiveness of them.
Scott

 

Coil bind is only one aspect that needs to be considered. The stock beehives will theoretically handle lifts over .600 without going into coil bind, but maintaining enough pressure to control the valve as it comes back to the seat is another thing. More radical cams need stronger springs to control the valves as they return to the seats, and without enough pressure, you will encounter valve float at a much earlier rpm than you'd otherwise expect. You can shim your valve springs to adjust seat pressure, but none of the home mechanics that I know ever go to that length.

Bottom line, I tend to follow the cam manufacturer's recommendation for springs. Woods says the stock beehives are enough for the TW5, 555 and 777, so I wouldn't have a problem running those cams with stock springs. The TW8 cams, even though they are still under .600 lift need beefier springs, according to Woods, so I'll be useing the SE beehive springs when they go in my bike this winter. (Tman just came out with a .600 lift cam that they say will work with the stock beehives).

I haven't any first hand experience with the Andrews 48, so I couldn't offer any real opinions. I do know from first hand experience that the Woods 5, at .575 lift does work well as a bolt in cam for the stock 103ers.

The moderate lift on the Andrews 48 should make them suitable for use with stock beehives, and Andrews describes them as having a "broad tip", which I'd guess means a conservative profile, which would also help with valvetrain noise.

 

Manley offers a very good beehive as well.
Scott

 

I have been spending a lot of time thinking about and researching cams. I have talked to one local shop and they were pushing S&S gear drives, the dealer of course is pushing SE's, and I am trying not to believe everything I read on the internet(present company excluded!), however one of the posts I read was a response from someone at andrews suggesting that the 48 needed lower compression 9-9.2:1 than the 9.6:1 that my 103 has and the 54 needs more. So the 48 needs less, the 54, 555 and 777 need more. I have the factory 103" power pak so the heads already have automatic compression releases, so I am good to go there.

I know dyno sheets do not tell the whole story, and that I am riding my scoot on the road not a dyno, but without trying all the cams with my own butt dyno, it is the best measurement I have to compare. That being said, all the sheets I have seen on these 4 cams seem to be close. close enough that differences could probably be dyno calibration and environmental. So it seems to me, in my twisted mind anyway, it makes sense to go with the cam that offers the option of future mods.

HEHE...maybe I should consider a turbo or blower...that should get me over 10:1 compression right? Or maybe I should just stick with a stage 1, I mean it is a big ol' heavy bike...does it really need more power...of course it does!

Seriously though, thanks for your feedback, I really appreciate it.

 

You are confusing static compression with the more important measurements of compression, i.e., corrected and cranking. Static CR is the ratio of static cylinder volume compared to combuction chamber volume. If you don't change either, the static CR remanis the same. Dynamic., or corrected compression is the same ratio but measured dynamically, in other words, calculation is based on the position of the piston in the cylinder when the intake valve closes. If you make a cam only upgrade, you do not change cylinder or chamber volume, so your static CR of 9.6 will not change. However, corrected and cranking compression will change as they are functions of the intake valve timing of the cams. The Andrews 48 intake closes at 29* ABDC compared to the intake close timing of the other cams which close much later; the 555 closes at 41* and the 54 and 777 close at 42*. The earlier the intake close, the higher the corrected CR.

JMHO, others may have their own, but a reasonable corrected CR target for a street build is 9.3 and somewhere around 190psi for cranking compression but not more than 200psi. The reason I like the 48 in an otherwise stock 103" is that by simply bolting in the cams, the corrected CR comes in about 9.3 with 193psi cranking. Right on the money without removing the heads, changing head gaskets, changing valve springs and/or using advance/retard sprockets, just changing cams.

Nothing wrong with SnS cams but they are available for chain drive applications as well. As for the SE cams, some 103" guys are getting good results with the SE204.

JMHO but select the cam for your current configuration, not for a "pie in the sky" future configuration. Cam selection is the cornerstone of a build; select the cams and build around them. In your case, you are backing in to a set of cams so you should be looking for cams that will produce reasonable corrected and cranking compression with a stock configuration.

Sorry for the long response but sometimes I think a logical explanation should be provided to support a suggestion.