lobe center on fk 89

[bang]

hey got my 2779 ccm oxy running now and went to the dyno last week. it did 255 hk at 6000 rpm and 280 nm on 4000 rpm. when we did the cam messure we put it on 106` on my cam card it says 104`but think it is wrong.
how do i check it. and dont you guys think 6000 rpm is to low rpm for an fk 89 to peak.
my msd in now set at 24,5 degreas if i go higher it "knoks"

on another fk89 cam card it says 108`so think my engine in running on 110`at the moment.

thanks.

peter bang
denmark

[Udo]

Hi
the best way is to messure lift @0,5" . The hp looks good and rpm is ok too i think . Normaly the fk89 has 108 lobe center . What dyno was it ?

Udo

[bang]

okay udo thanks. then my cam is set for 110`will change it to 106 and see where i am at. how many hp can i see if i go 1000 rpm up? 

[Roman]

Modified due to language barrier..

No, it isn't 108 lobe center on a normal FK-89 straight up - if you are talking about the lobe centerline, the point at which the valve is fully open. There are some good explanations under web cam homepage:
http://www.webcamshafts.com/pages/degreeing.html
110 degrees is definitely too much. Try to set it at 106.
The lobe separation on the other hand is 108 degrees.

FK-89 is quite mild for such a big engine. I had a FK-98 on my 2789.
Lobe SEPARATION is what you can't change.... You can change the lobe center and that is the same as lobe centerline...

[Jim Ratto]

I check for lobe center by dial indicating .005" off to either side of peak lift and taking degree readings at both points.
I would think that big of cylinder displacement, the hp @ that rpm is about right. If it were smaller cc then I would expect rpm to be higher (with relationship being smaller cyl cc= higher peak rpm where HP is achieved.)
I also think if you advance from your current 110' setting you will not raise rpm that peak HP is achieved, but you may pick up HP, and also broaden power and torque curve.

[Jim Ratto]

Yes, it is 108 lobe center on a normal FK-89. You can´t put the lobe center on something, it is what it is from the cam grinder.
I think you are talking about the lobe centerline. The point at which the valve is fully open. There are some good explanations under web cam homepage:
http://www.webcamshafts.com/pages/degreeing.html
110 degrees is definitely too much. Try to set it at 106.

FK-89 is quite mild for such a big engine. I had a FK-98 on my 2789.

I agree, I usually set cams up @ 104' ATDC, not 108' or "later" (intake)

[bang]

okay thanks for the reply. will follow the link on webcams homepage.

[Ohio Tom (DdK)]

I'd like to add that having your cam dialed in a few degrees off won't make too much difference in the motor's power.
I think you may be  looking at the wrong things.

If you have an fk-89 and she's giving up at 6,000rpm, then something's wrong with your head flow #, or valve trane issues.
Maybe your carb/venturi size is too small?
What's the jetting like?

A cam a few deg off won't cause that kind of powerband killer.
The -89 will pull well past 8,000rpm in the right motor.


I remommend timing the cam "straight up" and moving on to other possible causes for the low power band.

[Airspeed]

No offense, but the self made exhaust (iirc) could be not optimal for this extreme combination if we're looking at options.

[Shubee2 (DSK)]

What Ratio Rockers are you using?  I have seen A few guys over the Years use an FK-89  with stock ratio rockers thinking they were building a killer motor  because of the cam Just wondering

[bang]

running jpm heads with his rockers. have almost 16mm lift on my valve. i know the 51,3mm cabs is a bit small for this engine, but my 58 berg still need parts. now i at running with 46 vinturies.
as roger crawford says.. 1 cfm = 1 hp so 255 on my engine with the heads out of the box with too small cabs.

[Roman]

I think you are just fine. People would kill for 255 streetable hp. Add more cam and carbs and you will have 270-280! The torque on a 4" bore engine is insane.

[bang]

now i set the cam at 108 and it feels so mouch better.  have been out testing in the car today and fuck i love that torq

[TexasTom]

4" ... right ON! I can't wait to do the same!

[RMS Boxer Service]

Here is a little update on Bang's 2789 cc oxyboxer project:
Roman you pin pointed the problem, I got comfused by terms When Bang and I put the engine together. We was told (by Roman and others) to set up the cam with 106 degrees lobe center (intake lobe) and I was so confused by the cam card for the FK 89, it says: Lobe centers 108 degrees (or lobe seperation). lobe center and lobe centers are NOT the same term. FK89 have a lobe center of 105 degrees when using 0 degree shims in the cam gear.
I did used a degree wheel but we ended up advancing the cam 4 degrees on the cam gear instead of retarding the cam 2 degrees . Yes I know I should have seen the error back then, but I did'nt...  So the engine was dynoed with 101 degree lobe center and made 255 hp, maybe there is a few ponies yet be picked up.  We then changed the lobe center to 105 degrees this weekend and wow what a difference !!
The engine is much smoother now and idle is nice at 900-1000 rpm.  The engine felt much more alive and the timing was readjusted to 29 degrees at 3000 rpm without knocking. Before the reindexing of the cam max timing was 24-25 degrees at 3000 rpm, more timing gave heavy knocking. Those poor slicks had to stand up for some abuse on a nice spring sunday

/Rolf

[bang]

yes it is like getting a new engine..