Leave the rocker arms 'loose' to avoid any chance of them hitting pistons.| Return To MagSab High Tech & Customization Site Main Page |
Tony D's Cam Installation Instructions |
See the FAQ at the bottom of the page!
This area will detail my own experiences in
changing the cams, and hopefully bridge the gap between fully technical (Dave Dodge's procedure) and an inexperienced
cam-installer.
This page owes its credit to Dave Dodge, who, with infinite patience answered all
my stupid, endless questions!
Overview
As I see it, the cam replacement (degreeing) procedure breaks
down into 3 steps.
Step 1: Find TDC
Step 2: Find the spot on the cam that corresponds to TDC
Step 3: Move the cam to this location and tighten
Seems easy, Huh? Well, then why did I find
it so hard to understand? To prepare for the change, I removed the engine. That is
a relatively easy task, compared to trying to work inside the limited area when it is in
the frame. The engine is sitting on a rolling jack, to allow easy manipulation and
hopefully photographing. I also decided to do the heads separately, first doing the rear,
then the front. This way, if I get mixed up, I have the opposite side to look at.
The first step is to set everything up. By this, I mean I want to make it as easy on
myself as possible, so I turned the crankshaft to TDC with the cam sprocket alignment
marks facing inward. This is shown in the Honda manual. Upon re-installation, I will now
have a reference to install the cams. This means when I reinstall the cams, I know where
to initially place the sprockets and cams with relation to the pistons. I will not move
the crankshaft at all, and everything should be aligned correctly. Of course, this will
not save me from having to degree the cams, but it is a great starting point. So the
plan is to remove the cams, heads, and tensioners, and then to clean the pistons and
gasket area. I will stuff lint free rags in the oil gallery and in the water
passages to prevent the introduction of dirt and grime. Installation will now
consist of installing the heads and gaskets (non-torqued), then the cams, cam chain and
totally loosened tensioner. The cam sprockets will also be 'loose' but in the
'nominal' position to allow the initial alignment. The rocker arms are still loose,
to prevent any accidental piston hitting. This should not occur, because the cam and
crankshaft is sitting at TDC (plus or minus a few degrees) but why take chances.
Leave the rocker arms 'loose' to avoid any chance of them hitting pistons.
Everything now gets tightened down, except for
the sprockets, which are just snugged. Torque the heads, cam cap, etc. Again,
I will make sure there is clearance in the valves to prevent an oops. Now its time
to find TDC. The piston is in its topmost position, so the engine must be rotated to
allow it to go down. Once the piston is down in its stroke, the TDC tool is
inserted into the spark plug hole. Following Dave Dodge's procedure, the engine is
rotated back and forth until it touches the tool on each end of its stroke. The key
is to make the magnitude of the angle the same in both directions on the degree
wheel. For example, if the piston hits the tool at 50º in one
direction, then it should hit at exactly at 50º in the other
direction. Then by symmetry, the center is 0º, or TDC. Once TDC is
found, it is now time to set the cams. The specification of both the intake valve
and exhaust valve is given at TDC. So we must verify that the valve is lifted an
exact amount at TDC. This is done with a gauge on top of the valve. Notice the
distinction now between valve lift and cam lift. The rocker arms have an associated
ratio, so it will travel more (1.5 times as much) than the cam. A dial indicator is
attached to measure the lift.
But we must first get a reference, or zero lift, so we have something to compare
to. So this means again rotating the engine (now tightened) until the cam is
definitely at zero lift. When the cam is at zero lift, the valve clearance is now
set to zero. Now the engine is again rotated, and set to the exact angle as
specified by the cam manufacturer. Now, loosen up the cam sprocket, and rotate the
cam (not the sprocket) until the required valve lift is obtained.
Doing The Job
Removing
the frame from the engine went well. Since it was going to be apart for a long
time, I stored everything in plastic containers and boxes for easy identification upon
re-assembly. I got the heads and cams back from DD, along with the oil pump and a
repeat of the degreeing instructions
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I removed the rear head first. For no apparent reason
except that I figured that the first head should be the easiest, and vertical is better
than slanted anytime. I did a step by step removal, taking photos along the way.
As stated above I aligned the cams at TDC. With the cam notches aligned, I
figured all I would have to do is assemble them the same way. The photo to the right
shows the rear head. Note the positions of the cam lobes. They should be
pointing 'in' towards each other. This is shown in figure 1 from two views, the top
and the side. Note in the top view that there is a lot of oil on the cam lobe.
This is because I (of course) had done the oil mod.
Finally came the big day. Install the heads and cams! Malcolm, the fringe kid
and official photographer, and Rich D., keeper of the dial gauge were there to provide
moral support and assistance.
I installed the rear head without incident, scrounging some additional dowel pins from
the Magna Emporium. It was now time to install the front head. No more dowels! And
the dowels that remained in some spare parts were not removable. There was no way to
get them out without destroying them. So I ordered some extra dowel pins from DD,
which arrived that week. This put me a week behind.
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Figure 2 |
Remember to have some extra dowel pins hanging around,
just in case!
Installing the tensioners went rather easy. There are a few things to be careful of, and a few techniques which will help. When installing the tensioners, use a 'pin' Now to install the the camshafts using the DD patented 'Pop goes the camshaft' method.Only I couldn't figure out which way they came out!!! Oh No!!!! And I took photos of everything, and diagrams, and I still couldn't resolve it. So I installed them the way I thought they should go by lining up the slots in the cams.
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Figure 3 |
Well, this doesn’t fit too good, maybe if I turn the engine a little, the cams will go in easier. Well, they went in OK. First check: rotate the crankshaft. It went ok for about 90 degrees and then BIND!!!!! Oh NO!!!!
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Then I heard a big CRASH! Was it the engine falling off the stand? Valves shooting out of the retainers? No, it was Malcolm, throwing my tools all over the garage!! In his most innocent 'Rodney Dangerfield' impression he said 'did I do that????'
A quick panic call to DD. Off the top of his head he instructed me in what I did wrong. I lined up the 'Lines' not the 'Dots!'' The rear head you line up the lines, but the front you line up the dots! DOTS!! DOTS!!!! DDOOOTTTSSSS!!!!! Reading closer in the instructions, I guess I overlooked this part. An important part to miss!! Whew. I'm glad I stopped when I felt the least resistance or -- Pop goes the bent valve. More instructions from DD on how to properly line up the correct TDC and we're back online! Rich commented "I can't believe he (DD) just knew that (all the numbers and positions) off the top of his head." I have to admit I was kind of amazed also.
Remember that in aligning the cam
gears, the rear cams use the 'lines' and the front cams use the 'dots!'
Its great how easy things can go when you have the cams in the proper position. After finding a correct TDC, the cams 'Popped' right in. Of course I had to remove all the bolts I had so carefully torqued in. Which added another hour or so to the already massive amounts of overtime I have been putting into this project. Then, the fateful test. Will the engine rotate without binding? Yes!!
Next was finding TDC. This was easy, after making a pretty good pointing device. Jeez, I love geometry!
Set up the dial gauge and measure duration. 252. Oh no, the cam spec is 242. Measure
again. 252. OH NO!! DDDAAAAAVVVVEEEEE!!!!!!
Well, it wasn't as bad as I thought. I sort of figured it out anyway, but I just wanted to
consult DD about this.
Again, DD has the patience of a saint. For those who have met me, can you imagine the
hyper-mode that I was in while trying to figure things out? And talking to a very mellow
and soft spoken person on the phone? I feel bad for anybody who has to talk to me in that
state!!!!
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Anyway, the way the geometry works, if the dial gauge is not exactly parallel to the valve stem (orthogonal to the retainer) then some error can occur. I have to work out the magnitude of this error sometime. Or leave it to the Pelican. In any case, that’s why DD instructs us to use the cam lobe center method, not just set the cam at a lift at an angle. The cam lobe center method takes out all the variation, and assures that the cam opening maximum is where it should be. So, even if I measured 252 degrees at .040 lift, if the cam lobe was 'centered' at the proper angle, then the cam is set correctly.
After verifying that the cams were placed exactly, I re-took the readings with a better dial gauge. The results were:
Front Exhaust: 108º
Front Intake: 108º
Rear Intake: 107.5º
Rear Exhaust: 108º
With this done, I breathed a sigh of relief. My helper, Carmel, was going bleary-eyed since I had her read the numbers for me. It took a long time, about 3 hours, because I wanted to get it exact. Then Dave Dodge asks: are you sure you got the firing order correct? Good time to ask! Not really, he warned me before starting that there were 2 ways for the Magna to run. The first is the normal way, or 1-2-3-4. Rear-Front-Rear-Front. However, if the front cam is 180º out, it will still run, however the firing order will now be 1-4-3-2. Theoretically, there is really no difference. But in practice, there is a 20 hp loss by running it this way. Why? No one knows, but it is an observed fact. So, now that I have the engine buttoned up, how do I tell? First remove the spark plugs and the alternator cover. Then find cylinder #1's TDC at the compression stroke. This can be done by putting your finger on the plug hole, and feeling for compression. Rotate the engine until the T-24 mark lines up. This will be 270 crankshaft degrees. The #2 cylinder should now be at its compression stroke, verified again by the thumb on the #2 plug hole method.
When installing the cam gear bolts, use
locktite 242 or equivalent to prevent loosening.
Next Step: Install The
Engine
I was supposed to get the heads and cams around Xmas time, but
DD was really backed up and I told him not to worry about it. Unfortunately, since getting
the heads & cams back about a month or so ago, I have only been able to put small
amounts of time here and there into the rebuild. But the timely demise of the snow,
(Translated: The driveway from hell is now passable) with the drastic increase in
temperature, has given me the extra priority I needed!
I completed the engine March 1999. Remember, I not only pulled the engine (Really pulled the frame off the engine) but I disassembled just about the whole bike in an attempt to do everything at once.
This included:
Frame Strengthening Modifying the mount on the
Pichler Fairing Shortening the kickstand
and centerstand to match the lowered bike Installation of a 50W
stereo CD system Full digital gauges Re-Relocation of gas line
& Dial-a-Jet system
And other things I forget right now. The bike has been apart since December, so I hoped my memory served me correctly on how to put everything back in the proper spots. Joel H came over to help out, with his wife, who proceeded to tell us exactly what we were doing wrong. Of course, everything that didn’t go smoothly was because we didn’t listen to her! Unfortunately, she was right most of the time!!!!
I was going to ask Carmel to help out, but her eyes were still seeing double from reading the degree wheel for four hours straight last weekend!
Trying to put the frame on the engine was an exercise in manipulation. I was still unsure (UNSURE??) if the frame mods were going to hit anything. I made the measurements and everything, but the true test is only when the whole thing is assembled. We had a little trouble at first with the frame, and all I could envision was not having enough clearance from the swingarm brace. I had nightmares of hacksawing away at my so carefully engineered braces to make room for the engine...
It was all for naught. The engine slid in with a minor amount of persuasion. Of course, with every added piece that I put back on the bike, Joel was getting madder and madder since I had to clean every piece (again) before putting it back on. We put the carbs back in using the patented ‘sticking it in’ technique, and it was giving us just a little trouble. But wait! What I needed was a little shoehorn. Into the ‘box of doom’ and I found the perfect thing. A .030 ‘bent’ feeler gauge. This is the missing piece in the carb installation puzzle. Photos to follow.
I re-located the gas line so that it wouldn’t stick out the left side of the engine. I think it’s really ugly there. Anyway, this meant splicing in the line at the top of the carbs. I had to snip the modified line coming from the carbs to have it meet the existing line in the frame. All it took was a little ‘snip!’ ... WRONG LINE! Oops! Well, I succeeded in snipping the air vent line pretty well, let’s see if I can get the real line this time.
Anyway, it was a long day (polishing and cleaning the parts before re-assembly take a lot out of you) so we broke away for dinner.
The next day (yesterday) I was raring to go. This was going to be the day! I put on the wheels, ignition, and all the little stuff, ready to go! I poured in the gas (aux tank) and proceeded to fire that baby up. It cranked a lot, but no ignition. I figured it would take time to fill the bowls and stuff, but after a while it still didn’t start. OH NO!! Quick inspection. DUH! It helps if you TURN ON THE GAS!
After turning on the gas at the auxiliary tank, a few more cranks, and Vrooomm!! It started right up! Careful to keep the RPM’s high for the first few minutes, the engine sounded fine. It also sounded different. I guess that’s because of the cams and head work, but somehow it sounded meaner. It had a sort of ‘whirring’ smooth quality, almost like hearing a turbo or something.
After running for a few minutes, I noticed the engine getting really hot (5 bars) and the fan didn’t kick on. The rear exhaust was glowing red! Oh No! I shut it down, and called DD with the good/not so good news. He agreed with me that everything sounded normal, and that the exhaust glow was probably due to the excess heat caused by the extended RPM running with no fan. Plus running a little on the lean side. Open the radiator cap. Mistake! Anti-freeze all over my nice clean engine!!
Re-adjust idle mixture. Why wasn’t that stupid fan working? Check the fuse. Blown. Replace, short the fanstat while measuring the current with an ammeter. Turn on fan. 5 amps, 10 amps., 15amps, boom! Fuse gone. Bad fan. Into the Magna emporium to get a new fan. Measure the current. 5.6 Amps. Good. Replace fan without removing radiator. Restart. All is fine!!
Restart engine. Music! Pure Music!!
The engine sounds great, as I said, it has this smooth, whirring quality that is definitely different that it was before. I think I can hear the larger volumes of air being sucked into the heads. The next thing is the test ride. I still have a bit of re-assembly, cleaning, and chrome polishing before bringing it down the driveway, but all should be completed this week.
50 degrees, possibly 60 by Friday! I can’t wait!!
Initial Startup
Coming Soon.
Up and Running
After running the bike for a week or so, it started to make this noise that I never heard
before. When I first started it a few weeks ago, it sounded 'different'. According to Dave
Dodge, it shouldn't have sounded different, but at the time, I wanted to get the bike on
the road, and it seemed to be running fine. This week, the noises got worse. I attributed
it to valve clattering, which led to a lot of back & forth conversations between DD
and myself.
"Are you sure you adjusted the valves correctly?"
"yes"
"Are you sure you installed the cam chain tensioners?"
"yes"
Etc. Etc. So anyway, I was mystified, and DD gave me the troubleshooting procedure. At
this time, I assumed that the noise was valve chatter, so we were both convinced that this
was the way to start. DD can amazingly diagnose these things with just the phone up to the
bike!
Anyway, Saturday I re-adjusted the valves, with some help from Malcolm, the fringe kid. In
doing this, I forgot to even check the cam chains, since all the valves measured about
.008". I attributed the 'clacking to this.
Starting the bike after adjusting the valves, it sounded even worse than before! Well, not
worse, just different and not good. It wasn't really obnoxious or anything, but it was a
noise that really shouldn't be there. I stethoscoped it and localized it to the rear
cylinders. So it was on the phone to DD again, and he listened to the bike long distance.
"did you adjust the valves correctly?"
"yes"
"Did you put in the cam chain tensioners in the correct direction?"
"Yes"
"Did you check the cam chain tension like I suggested when you re-adjusted the
valves?"
"well, er, I sort of forgot. It was Malcolm's fault, he made me drink"
"did you install the oil pump correctly"
"yes"
"Did the cams look OK when you adjusted them?"
"yes"
"did you take out those little pins from the tensioners when you assembled the
engine?"
"yes"
"did you remember to install the cotter pins in the tensioner sliders?"
"yes"
"did you make sure the cam chain tensioner arm was properly seated in the receptacle
inside the engine?"
"……………………………..!!!"
"errr, what receptacle? There's a receptacle?"
Right then I had a sense of foreboding. "receptacle?" "Does this mean I have to take out the tensioner to check?"
Well, I wound up taking off the rear valve cover again today to do a step by step DD
engine analysis. The first thing was to check the side to side travel of the rocker arms.
Loosen the lock nuts and move the rocker arms from side to side to feel the 'spring.'
Checked out OK.
Now check the cam chain tension. This was a little hard for me to understand, because I
was unsure of how 'tight' it really had to be. DD said that if you could tug down on it at
all (with anything but a relatively large force), there was something wrong. This is where
I had a problem. How hard to pull down? Since the chain is covered with oil, 'pulling'
with fingers is out. So I gently slipped a screwdriver between the cam chain top guide and
the chain and pulled down.
It moved about 5 inches! No Mistaking This!
I could never consider this tight!! This seemed to be the problem, now what
was the cause? I noticed that the tensioner arm was 'back' as far as it would go.
(direction of maximum tension) It was back so far it was hitting the head.
Now I like working on the bike, but this is getting ridiculous! So, remove the cams, which
meant removing the water, gas tank, and lots of other stuff. I tried to look down into the
engine to see the receptacle with a flashlight, but I couldn't see anything. So it's off
with the tensioner.
Then I noticed the end of the tensioner arm. There is supposed to be a little metal 'loop'
at the end that fits into the receptacle. (there's a receptacle?) This was ground off. It
seems that in installing the tensioner, I missed the receptacle completely, and the
tensioner arm was rubbing against the chain the whole time. There was the 'cam gear' noise
I heard. And this would explain the whole thing. The bike was great at startup, since the
tensioner was not yet ground down. The 'cam gear' noise was present because of the arm
rubbing. As the arm wore away, the tension got less and less, until the chain was really
loose and started to ''clatter' like valves.
So I replaced the tensioner, reassembled the engine and-
Vrooooom! It sounded exactly the way it should! No valve noise, no clattering, just the smooth V-4 rumble!Lessons learned:
I want to give a heartfelt thanks to Dave Dodge for all the help he's provided in the past few months, and for putting up with my constant questions.
Dodge Racing & Promotions should be the model for customer service for the entire motorcycle industry. After this experience, there is no question in my mind that there is no higher authority on the workings of the V-4 engine."When you can snatch the tensioner arm receptacle from my hand, then it is time for you to leave."
FAQ
Why use a degree wheel to find TDC?
Can't I just use the timing marks (T1-3, T24) or just look to see if the piston is
at TDC (maybe with a dial gauge)?
The reason for using a degree wheel is that any other way is not precise. The
piston is actually at the top of its stroke for a few degrees. Up to 5 degrees
according to Dave Dodge. Thus, if you want a precise location, the only way is the
degree wheel.
How do you make the
cam 'move' in relation to the sprocket to allow for degreeing?
The bolt holes in the sprocket are 'widened' to allow a limited amount of rotation.
Doesn't this cause
alignment problems? How are you assured that the sprocket is centered where it should be?
There is a machined surface in the cam where it attaches to the sprocket. This
centers the sprocket on the cam.
Will the widened holes
cause the sprocket to have a tendency to rotate with respect to the cam?
No. This is the way it has been done for years. The tightening of the sprocket to the cam
at the proper torque will hold it in place.
