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Slotted cam gears, opening overlap; Any experiences? Worth it?

Started by Pat Conlon, August 08, 2009, 11:37:26 AM

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Pat Conlon

Hello folks, I came across this info. while cleaning out my old e-mail files. I recall this post was from the FJ YaHoo forum but I don't recall the author. In a continuing effort to make my FJ's run cooler in the hot desert summers I thought this may be a good idea.

RPM Randy, what do you think?   Can this be done without removing the engine? I can't see how you could accurately index the cams with the motor still in the frame.     Thanks Folks  

Pat Conlon, Palm Desert, CA

If you take time over the winter to re time the cams by slotting the sprockets
you simply will not believe how much that picks the Yamaha 1100 and 1200 up

Both cams are extremely retarded due to emissions . this does alot of things to
include increasing the heat in the exhaust valves . springs n seats .
On the exh side lobe center angle is above 115 . Bring exhaust back down to 108 ,
intake 104 will make for lower oil temps and carbs easier to tune . Oh yeah , much much
more midrange without sacrifice in top end power .
I was doing this to mine and friends bikes back in 1985-86 and we had the king
of roll on power with smoother all-round drivability


1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

SlowOldGuy

Pat,
I degreed the cams on my '85 quite a few years ago; 104 degree intake and 105 degree exhaust.  At the same time, I installed a Wiseco 1198cc piston kit, so I can't really separate the performance improvement from the overbore and the degreed cams.  However, back in '01 I also degreed Hoffman's cams and he reported minimal difference in the Butt-Dyno (tm) feel.  

My '85 is slightly stronger than my '93, but that could just be sprocket size differences.  I personally don't think degreed cams is worth the trouble (might be worth it for racers).  For instance, I've had an extra set of slotted sprockets for my '93, but I've never thought it was worth the effort to install them.  Also, when I finished installing new valves in my '85 last year, re-degreeing the cams added an extra day of labor to the job.

FWIW,
DavidR.

Pat Conlon

Ok, thanks David. Were you able to dial in the index with the motor in the frame? Or just eyeball? Wait a minute, who hell am I talking to....Of course the motor was out on a bench with a degree wheel.

How are YOU doing amigo? On soild food yet? Getting your strength back or still on your follow up chemo?

You've been in thoughts, I'm wishing you a complete recovery.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

SlowOldGuy

Hi Pat!
The first time I degreed them, the motor was out of the frame.  When I replaced the valves last year, I just pulled the head and left the motor in the frame.  It's tight, but there's room to get enough dial indicators to monitor both piston TDC and valve lift.  I think I have some pictures somewhere when we did Jeff's cams.  It's a pretty busy photo.  Yes, I did use a degree wheel, it's not something you can eyeball.  Every measurement needs to be performed several times to make sure nothing is getting screwed up.

Thanks for the positive thoughts!  I finished all the treatments 5 weeks ago.  The recovery is in full force, although it took a while for any significant progress to begin it's ramped up nicely.  I started back to work last Monday and actually began eating solid food about mid-week.  Still using the feeding tube some as my mouth is still very dry and most of my taste buds are still AWOL.  Mostly cheezy noodles and watery soups.  Nothing spicy yet.

In a few months I'll get a baseline scan and hopefully I can maintain a clean bill of health and put this all behind me.

Take care all.....

DavidR.

Pat Conlon

Great news David! Thanks for the tips. How about this idea? Say I mark my cam chain, take my cams out  and send them to someone (hint) who would install (on the cams) a set of slotted cam gears and have the cams then dialed in at their shop and locked? Then I just reinstall the cams, on the marked chain... Kinda like plug and play...

Then again maybe not. Is the FJ motor a interference design? I could see me kludging the reinstall, getting the cams out of sync and bending a valve or two, or four...

Also thanks Randy, no hurry...
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

andyb

Wouldn't be perfect what with manufacturing tolerances and such, the total distance between the cam centerlines and the crank centerline, the condition of the guides, and so on.

I have adjustable sprockets on mine, had to go into the motor to get a screw out (always leave the plugs in when you're working on it, now you know!), and I simply lined up the stock markings when I put it back together... it must have been "adjusted for torque" or something silly before, because I picked up a good bit in the >6k range.

Ain't broke, don't fix it?

FWIW, I asked Hank Scott this question a few years ago, and I believe he suggested putting the cams in at 107/108.

It seems to me that you're not going to gain power to speak of by playing with cam timing, but you can definitely shift at which part of the tach the power sits on.  Just remember that you'll need a way to measure piston/valve clearances, if the valve is sticking down and the piston comes up you will definitely do decorative modification to things internally...

andyb

Double posting FTW!

Was digging through my notes and I found this tidbit that I'd saved from the one of the mailing lists:

QuoteDate:          Mon, 06 May 1996 22:58:18 -0700
From:         

I've seen a lot of discussion in the past few days about cam timing and the
duration of overlap that the factory dials into our beloved FJs. Last year I
peeked under the valve cover in search of a few more ponies. Though the
results I got were mixed, I did
record the stock valve timing before I slotted my cam sprockets. That way I
could return it to OEM specs for resale or whatever. This is what I found
stock on my FJ. The measurements were taken at .045 inches checking clearance.
In other words when
the cam moves the valve down .045" I called it open. When the cam is .045"
from no movement, I called it closed. All measurements are in degrees crank
rotation, with respect to the exhaust/intake stoke's Top Dead Center.(TDC)

                                           INTAKE
EXHAUST
OPEN                              13*   BTDC                       141*   BTDC
CLOSE                           215*  ATDC                         26*   ATDC
LOBE CENTER            102*  ATDC                       108*   BTDC
MAX LIFT                         .332"                                   .350"
DURATION                     228*                                    235*

TOTAL VALVE OVERLAP=39*

*=degrees

I looked around for the stock valve timing but could not find it. I remember
hearing about an article called "Fire For The FJ1100". I guess somebody
degreed the cams on an FJ and documented it but I could not find it anywhere.
(anybody seen it?) Anyway I
called Vance and Hines and they had the stock timing specs. I don't know what
lift they used for checking clearance but here it is.

INTAKE       .330" lift with 228 degrees duration
                     and 104.5 degree lobe center.
EXHAUST  .350" lift with 217 degrees duration
                     and 104 degree lobe centers.

If you do some quick math, that means the intake valve opened at 9.5 degrees
BTDC. The exaust valve closed at 32.5 degrees     ATDC. Therefore the overlap
is 42 degrees in duration.

This was not the same as my FJ numbers but I attribute that fact to the
differences in checking clearance used and the expected    variation that
comes when mass producing anything.

I slotted my cams and moved both intake and exhaust lobe centers to 103
degrees in hopes of finding a little more juice on top without killing the
FJ's natural stump pulling ability.

What I got was an engine that does okay below 4000PMs. But not as powerful as
stock. At 6500 all the way to the rev limiter she screamed! I could hit
redline in fifth (on a closed circuit course only (Ha!Ha!)) in no time at all
with stock gearing. It was still
pulling hard when the rev limiter cut in, or cut me out! The only down fall
was the HUGE power lost between 4000 and 6500. If you have ever ridden your FJ
on the highway, you will know that that is where the engine cruises. That's
what gave it the "roll-on" power that makes our bikes so much fun. I turned my
lovable FJ
into a dreadfully serious not so streetable road rocket. This summer I plan to
move the lobe centers back to 105 degrees each. I'll let you know. Oh yea, my
FJ wore a Vance and Hines Supersport exhaust system. The airbox was stock and
I was at about 1000ft ASL (above sea level).  I'm wondering if anybody else
has tried this.

Mark Olson

Pat,

how's the retirement going? :blum1:

geez not  even a week yet and now you are digging into the fj for more  power.

seems to  me you  were the biggest advocate for leaving the engine alone because it made great power and didn't need to be messed with.

The times they are a changing. :wacko3:

anyway wasn't the hot tip to use an exhaust cam on the  intake for more power? :unknown:

try it you will like it.
Mark O.
86 fj1200
sac ca.

                           " Get off your ass and Ride"

andyb

Might be true on the 1100, I mic'd the cams on my 90, unless the duration is different (and it doesn't look like it is), the lift measures the same.....


Pat Conlon

Heh heh, quite observant Markus me lad, you seem to have put your finger on it. Alotta time on my hands. It's all good.
You were right (or I was) the 'ole FJ is just fine (for my abilities) power wise.  Andy's right: "If it 'aint broke....."
I was thinking about a simple mod which, if true, would (perhaps) help the bike run a bit cooler.

Funny that you mention swapping the intake cam for the exhaust cam, it's a hot topic over at the Miata Forum.
http://tinyurl.com/mctloh

Those Russell SS brake/clutch lines work out ok amigo?

Pat

Quote from: Mark Olson on August 09, 2009, 12:29:54 PM

how's the retirement going? geez not  even a week yet and now you are digging into the fj for more  power.

seems to  me you  were the biggest advocate for leaving the engine alone because it made great power and didn't need to be messed with.

The times they are a changing. :wacko3:

anyway wasn't the hot tip to use an exhaust cam on the  intake for more power? :unknown:

try it you will like it.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Pat Conlon

Thanks Andy for this info!!!  Good stuff.  We should ask Marsh to put this in our files for future reference.

I understand what you said about different tolerances between motors and setting up a cam gear in a shop on a FJ motor then transferring that cam and gear to a different motor would be inaccurate. I can imagine just the differences in the stretch of the cam chain  between the 2 motors could throw off the numbers....

Thanks again for the info Andy and sharing your experiences, it's very helpful and enlightening.

Pat Conlon, Palm Desert, CA

Quote from: andyb on August 09, 2009, 07:45:42 AM
Was digging through my notes and I found this tidbit that I'd saved from the one of the mailing lists:

1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Mark Olson

Pat,

the brake lines are bitchin, I didn't realize how spongy the old rubber hoses had gotten.

Not a lot of time to ride right now with work and the temp high.

Just celebrated my 25th wedding anniversary on the 4th. good times.

bought swmbo a new car so now she will quit complaining about me buying a parts bike and working on the fj.

good luck with the retirement and stay busy or the oprah will get ya. 
Mark O.
86 fj1200
sac ca.

                           " Get off your ass and Ride"

threejagsteve

Hello, Mark,

I'll be needing new brake lines fairly soon...

Russell doesn't list any FJ applications on their website.

Would you be so kind as to post the part nos. you used?

Also, did you get them locally or online, and if online, where?

TIA,
threejagsteve
"If you wanna bark with the big dogs, you can't pee with the puppies!"

Pat Conlon

Hey Steve, Mark got the Russell SS lines from me.
I took them off my '84 when I converted the front end to FZR1000 USDs:  http://tinyurl.com/lxj6hu
I bought the Russell lines in '85, they were my first mod. on my '84. Alas, Russell no longer lists them for FJ's.
I suggest Spiegler SS lines, the ability to rotate the banjo fittings are handy: http://tinyurl.com/9ynv7
Expensive, yep, but after all, it's the BRAKE system we're talking about....

FYI, Yamaha strongly suggests that the oem rubber lines be replaced after 7 years....

Cheers
Pat Conlon, Palm Desert, CA

Quote from: threejagsteve on August 10, 2009, 03:36:52 PM
Hello, Mark,

I'll be needing new brake lines fairly soon...

Russell doesn't list any FJ applications on their website.

Would you be so kind as to post the part nos. you used?

Also, did you get them locally or online, and if online, where?

TIA,
threejagsteve
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

threejagsteve

Thanks, Pat,

Yeah, those Spiegler lines look nice, and the price isn't so bad when you consider that Pasadena Yamaha's online parts finder says $200 & change for the OEM parts - Zanotti is likely to be significantly cheaper, but that'll probably just bring the tab down to Spiegler's range (I haven't checked Zanotti's prices yet). And OEM rubber vs. braided stainless? Jeez, I hate that phrase "no-brainer" but sometimes it's the only term that fits.

Russell does have roll-your-own lines; I'll likely price them out when I get closer to actually doing the job and see what's what.

Aside from pads and fluid, nothing has EVER been done on my brakes. They're still fine around town, but I'll completely rebuild the fronts, master cylinder to caliper seals, before I take up canyon carving again. ;)

Cheers,
threejagsteve
"If you wanna bark with the big dogs, you can't pee with the puppies!"