#307 going together cam timing question

[blackheart]

All:  I thought it was intuitive when taking apart, so i too no photo's or made any diagrams.  The service manual replicates what others have written.  I found the marks from the crank drive gear to the lower idler a bit misleading but here is how I set it up (photo).  However, when i checked the cam timing to make sure by setting up the way I did, the front and rear cam timing is the same.  BTW the cam duration is 196/210 at 0.050 valve lift (I did not actually check exhause at 050 only at 006 and 020).

The top portion of the cam timing is a piece of cake, very straight forward, there are just a lot of dots on the front lower idler.

My concern is set up this way the intake centerline is at 117.5 deg, which is set up retarded quite a bit if you ask me but I'm not used to 4 valve motors.  I can tell you on the victory's stock as well as aftermarket cams they are similar to HD 2 lung OHV motors and all in the 102 to 108 degree arena. 

Heck at only 0.006" valve lift the poor intake doesn't open until 3.5 degrees AFTER TDC.  Seems very late for a modern engine.

[Jumper]

H-5's change the timing some I believe. Less valve train noise and much more Torque...
Jumper

[blackheart]

I just wasn't sure if the marks were aligned correctly, but I don't see how it could be different.  I just know the cam timing is set up extremely retarded and on a very wide LDA.

[wytfut]

Rich,
Sorry I didn't answer your question.... but to be honest, you were way too technical for me.

I've timed the cams several times, but I don't note where they are lined up with TDC.... as just time them according to Jamie's process, he wrote out for me to comprehend.

You are far more experienced on the technical than I....

Got an up date?

flatlanderssupportingXworld,
Bruce

[Donkey Hotey]

I'm reading along and interested in hearing your continued thoughts on this. Rephasing cams isn't that difficult. A couple of new holes for the dowel pins and you're good to go.

[blackheart]

Sad to say I did not check phasing coming apart.  So I just went back to what I showed.   My question really was do I have the correct Mark's linesd up?  I can see for a slight confusion between the square and circle on the front,  but this condition doesn't exist on rear.  And rear matches front when checking with degree wheel.  I am going to try it where it's at and should Fire It Up this weekend.   The crank sprocket is 40T so if you move one tooth that's 9 degrees. It would make sense to advance it this much but Mark's at crank clearly do not line up for rear.  If it were carbureted I'd time to what makes more sense but with a speed density F.I. engine this will alter Volumetric Efficiency and thus mapping must change.    If it's off it'll run but probably like crap, so I'll know it.  There is no fear of piston to valve interference since lift is very low.  I picked up an Examinator but I don't think you can alter maps. You can load new maps but not alter existing.  I have no idea what maps are on the card. Does anyone know how to change the mapping on storage card which plugs in examinator?

[Jumper]

Examinator and tune is … well.. Not good for an X.... The Tune is very lean and you can not change it. Send your ECU out and have SuperXTune dropped in it. The X will thank you and You'll be glad you did this. (No burnt valves!)
As for Timing the Engine, Line the marks for the Front first and time that Cylinder. Then hand turn the Engine over to where the Rear Timing mark is on. Time the rear as well. It's been a long time since I built/Timed an X engine so a call to Jamie may be in order to make sure you do it correctly...
Jumper

[blackheart]

I had Jamie drop in an updated tune several years ago.

Yes, the Mark's line up.  It's very intuitive on how to do it, but I'm just saying it is very goofy cam timing on the intake side, exhaust not so much.  Intake opens very late and closes late for a profile this small.  We'll find out & I'll report back.

It's my estimation they were leaving alot on the table or were  battling detonation issues so they may have retarded the intake cam timing

[Donkey Hotey]

Do you think it was to reduce valve overlap? With much overlap, four valves and the injectors firing directly above the valves, it may have been burping a little too much unburned fuel into the exhaust. That would have been a huge no-no for emissions. If they got desperate for a solution, that would have done it.

Better to survive that battle, get the bikes into production and live to fight another day...

Just wondering what your thoughts are.

[blackheart]

Well yes, that's the advantage of 4V / cylinder heads, so much better low lift flow you can run a smaller cam and get the same or better performance.  If you look at the new HD M8 cams which are all emission certified they have very little overlap.  That would help emissions.   

Detroit in the 70's was in the habit of retarding cams to help lower cylinder pressure to lower NOx and allow to run on lower octane fuel.  This also adds to cylinder filling, i.e. volumetric efficiency at higher rpm.   Was EH fighting detonation?  Could have been.  But the amount I'm seeing is 15 degrees or so.  That's a lot.  My old 79 shovel I'm convinced has the factory pinion gear breached to retard cam timing by 8 degrees.  Every cam I've ever put in it is off by 8 degrees so I have to press the gear off and on trying to estimate the right amount (HD did not key the cam to cam gear, it's just a press fit)

I still think I'm one tooth off on the intake which would be about 7.8 cam degrees or 15.6 crank degrees.  The marks make sense a door in the root of one gear and in line with a tooth on the mating gear.  I went to advance the intake cams today but decided since I'd have to drop the rear of the engine I'd first try it.

I wasn't overly motivated today and just got the beefed up key switch bracket mounted and the batter box / electrical components mounted.

Tomorrow I will mount tank, prelube the engine, hook up exhaust,  set battery, & fire it up!  For break in I'm running Rotella T3 15W-40 which is wet clutch compatible. We'll see how it acts.

[blackheart]

Well I got it all set up, took longer than I thought, but it fired off right away once fuel made it to injectors.  I heat cycled it, sorta, like some of the big performance people for HD advise,  not sure its necessary on a stock engine.   It acts normal so I'll have to ride it later on in the week.  Sure sounds good, we'll see how it goes.  I still have to post pics on the various mods I did. Some could be viewed as good or bad, we'll find out. 

Changes: Hi lead bronze for mains (#936) with left side not grooved and made with integral thrust face (orig thrust washer must have gotten tight and ripped anti rotation tabs off). Right side main grooved.  Both set at 0.005" interference fit at room temp, bored to size with 0.0015" oil clearance.  Had piston skirts recoated by Swain and crown ceramic coated (it's not much more when you do both) had chambers and exhaust ports ceramic coated as well as valve faces.  Running total seal gapless top ring set (Ive never ran a set so I thought I'd try one) replacement teflon scavenging pump bushing had failed, tried aluminum which came in spare engine I never used.  Finish honed opening up 0.0005" with 180 grit Sunned AN followed by Sunnen plateau hone inserts. Factory head & base gaskets with stock head bolts.

Its amazing this engine ran the way it did with as much that was wrong with it.  I came away with a different opinion in the design as it appears to be well made other than the mains which may come loose due to loss of fit.  I was really impressed how straight and round the cylinders were.  Hardly any scoring evident, which for a demonstrator bike is impressive.  Although this bike was only #14 on build list it has the later crank and  compensator drive, so question begs was the factory engg. team evaluating the new parts??  In 14k miles the exhaust valves were not looking new anymore,  had Atlantic EH tune dropped in shortly after I got it at about 7200 miles.  I didn't realize it at the time but right side main had already spun at that point so I rode this machine 7800 miles with bearing out spinning in case......  who knows when it started....talk about lucky...... if it were the right side the rods would have smoked as both are fed from right side.  It didn't hurt crank at all, main opened up case bore a few thousandths.  Truly amazing it didn't shell out one way or another.

[Donkey Hotey]

I'm a total n00b when it comes to things like changing cam timing or what good and bad numbers look like. I only know some general things like the overlap being bad for emissions, etc.

What I am familiar with though is engineers leaving easter eggs behind for people to discover. You suggested that one full tooth of change on the cam timing would be too much. What if you flipped the gear over and used the same dowel hole?

What I'm thinking is if I were designing such a part and I knew that a certain cam timing was good but, some other factor was keeping me from accomplishing it, I might split the gap between the teeth with that locating dowel. You understand what I'm suggesting? Flipping the gear might only index the cam half a tooth instead of a whole tooth. Or something closer.

Even if that's totally not the case, it might work out that redrilling a new alignment hole in the cam and the gear is a simple fix to advance that cam a bit.

Are you saying the duration numbers look good but the timing is all that seems wrong?

[blackheart]

DH:

If I could advance it one tooth without worrying about a total remap I would.   It would be more normal compared to a bout any engine set up I've seen.

You are right increased overlap increases emissions at low speeds.  Retarding the intake such as what I found radically reduces overlap.

I've got bigger problems than that.  I took it out and rode it.  Runs fine just like I remember.   However it smokes white something fierce especially after running low speeds.   Cant believe it is rings but could be.  No blow by or carry over into breather (I still run stock set up).  I'm not sure where to start, but will start verifying both sides of scavenging pump are functional.   Oil level is low.  Lower than i typically run it, and i did not change the fill hose.  I've never used the total seal gapless top rings,  but this shouldn't cause oil consumption issues.  Second ring is a reverse torsion type.  Set was not what I'd call low tension either.   Very disappointing to say the least.  I'll start with the easiest and work my way back, verifying valve stem seals are not damaged, that oil can drain back from head, etc., prior to pulling heads & cylinders.   Later this week it will warm up some so I can verify scavenging pumps first then ride again and see if fully warmed oil helps.

[Jumper]

I seem to remember that when Jim McCarthy made the "H-5" cam's, he changed the centerline of the Exhaust along with different duration and a bit more lift. This quieted up the Valvetrain quite a bit and gave the X some good pep and pull... Not sure what the spec's were but the X sure likes the different cam profiles... (oh yeah... The H-6's pull even better in the upper RPM ranges) They are rare and require some extra head attention )
Jumper