Well now; I guess I promised to work on the power train last month, now didn't I? Well, that would have been a simple matter of assembly, if I hadn't changed plans in mid stream. Since I bought the later model engine, I had to disassemble, clean and assess the new engine before Icould get started. A couple of the front engine mount lugs had been repaired, and when I split the cases, I found that they neglected to weld up a small crack on the inside as well. Nothing major, but it should be corrected before proceeding.
The transmission was in pretty sad shape, but repairable. The cluster shaft had spun the bushings due to worn out cluster bushings, so I had to bore and replace them with oversize units. Somewhere along the line, an attempt was made to separate the primary from the transmission, but I don't really see the value in that, so I reversed the procedure (which hadn't worked anyway). The thrust washer on the clutch side was completely missing, and I installed all new bearings, bushings and seals. Surprisingly, the case had not been broken during its long hard life. The kick gear tension spring had been replaced with what appeared to be a GM solenoid return spring (go figure). The kicker gears were all very good, except they are the pre 48 style, but that's okay since they always work, where the 48 and up kick ratchet wasn't always as reliable.
Engine almost done
More about Stan's Project VI Chief on the road in the Century Ride Home story in this issue
|Transmission, and gearing is a balancing act with a 3 speed transmission, and I've never been satisfied with the ratios Indian used when riding a Chief at modern speeds. So far, the only real option has been changing the transmission output sprocket from the stock 23 tooth, to 24, 25, 26 or 27 tooth. While this will increase top speed, and reduce engine RPM, it also creates other problems. First, if the final drive is geared too high for the available engine power, the chain systems tend to over run and cause chain whip, which can cause severe damage to all of the drive components. Over tightening the chains is a bad option here. Also, the larger sprockets tend to magnify the lower gear gaps. This will manifest itself as a huge jump from second to third gear, and small gap from first to second. It's almost like a gear is missing. Well, while discussing this on the Virtual Indian List, Rick Abbott stepped up to the plate, and volunteered to investigate the possibility of correcting the ratios. I proposed some configuration changes that would only alter the internal gears, and not require case modifications. Currently, Rick is working on having the cluster and slider gear sets made in this ratio configuration, which I believe will greatly enhance the gearing issue. I'll go into this further when the sets are actually constructed and finished. My intent is to use the new ratios in this bike, and couple them with a 25 tooth output sprocket to achieve the best overall gearing possible, with a stock 3 speed transmission setup. If Kiwi's new cluster rollers are available at that time, I'll try a set and see what I think of them. They looked much better than the needle bearing setup that is currently available, but I'd rather try them out for myself to see what I think of them.||
Improved ratio gears from Rick Abbott. A few sets left at $571.00 Contact Rick at: firstname.lastname@example.org
is any sign of pitting or wear, I replace the case bearing housings (races),
and they usually need it. I rarely salvage the used flywheel shafts, since
they almost always have wear and some pitting. A set of shafts aren't all
that expensive when compared to the damage that can be done from a bearing
failure, so the rollers and shafts always get replaced. Keep in mind that
I rarely deal with a running engine, so what I start with is always less
than ideal anyway. Most often the engine has been lying around gathering
dirt, dust and moisture for years before I get it. You will need to spend
a great deal of time in the disassembly, cleaning and assessment of each
part to ensure a good solid engine when you're done. Several articles have
been written on the cleaning process, so I would refer you to the Virtual
Indian Archives for more details.
Some folks will disagree, but I always use a Glyptal type sealant on the inside of the engine cases, transmission case, inner and outer primary. This will prevent any pinhole leaks from porosity in the casting, and if there are any embedded glass beads that were missed in the cleaning process, they get sealed up. I also paint the outside of the same cases with silver engine paint, to aid in clean up of oil and fuel drips, and avoid stain discoloration of the aluminum.
Engine with Glyptal sealant inside and silver paint outside
oil pump was pretty rough. The casting was broken at the inlet nipple,
but I was able to clean it up, and have it welded. The pump gears had "eaten"
several indigestible items over their life, so they will get replaced when
new gears are available. Obviously, some of the gear damage in the photo
shows moisture pitting, while the big damage is FOD (Foreign Object Damage).
Fortunately, I was able to clean the pump up and bring it back to life.
So far, no one has reproduced an aluminum pump outer housing, and the pump
body and plate are extremely expensive. Pump gear sets are often "out of
stock", so I advise ordering early. Just another reason to use a filter
The custom made forged pistons weren't finished after 7 months, so I canceled them. I decided to run standard cast pistons, and when I looked at the heads from the new engine, I was surprised to find that they were already relieved for 80" piston clearance. That led me to check the flywheels, which were in fact 74" wheels! Hmm, that's strange! Why anyone would run stock flywheels with trenched heads is beyond me, but they did. Anyway, that's good news, since now I don't need to have the heads machined.
Damaged oil pump gears
Kiwi's 80" flywheels, and Kiwi's new forged Chief rods. I have to say that
the flywheels and rods were worth the wait! The finish is beautiful, and
the quality is unquestionable. The rods will save you a pile of money over
the commonly available Carrillo rods, and look to be every bit as high
quality. I assembled the flywheels with new Jim's shafts. At this point,
I set up the rod end play, then trued and balanced the flywheels. With
all the various arguments about balance factors, I avoid the whole mess,
and use the factory knife edge balance, which always works just fine. This
is well covered in the military manuals, so I won't go into it other than
to say you install both rods, rollers, etc., and ONE piston assembly. The
wheel should balance in any position when you're done. One thing to take
note of here is that Kiwi's new rods felt slightly lighter than the old
originals, so I had them weighed. The results were that the new rod set
was 41 grams lighter than the stock 74" originals. This isn't really an
issue in this case since I am using new wheels, and the assembly will be
re-balanced. In the case of a straight replacement, I suggest that the
assembly balance be checked and corrected if necessary. The new rods are
undoubtedly better built, stronger, and of superior materials. The fact
remains that you should always check the balance when working on the crankshaft
I was very impressed to find that the Kiwi flywheels trued and balanced very nicely. In fact, there was ZERO balance correction required, using the static balance method. One correction that I did make was to relieve a slight amount of material from the front cylinder case baffles. Due to the improved web design and strengthening of the female rod when coupled with 80" wheels, the web will make contact with the baffles. This would not be an issue with 74" flywheels, but you need to take this into account when using the 80" wheels. This isn't a big deal, and the increased strength of the rods overshadows this minor alteration. The information I was given on the rods is that they have a 34% higher tensile strength due to forging with aircraft grade E4340 materials.
Next up is fitting the flywheel assembly to the cases, and setting the end play. This isn't rocket science, it just takes a lot of time. Then I set up the transmission clutch sprocket to flywheel (motor sprocket) alignment, by bolting up the inner primary, and transmission to the engine. This can be adjusted with flywheel thrust washers, and the transmission thrust washers and the various shims. The alignment is critical to have a smooth running power train, and avoid excessive wear on the primary, engine and transmission components.
H profile Kiwi rods
|At this point, I should offer all of you DIY engine builders a couple of cautions. Three areas that are often damaged, and easily overlooked are the threads in the engine cases where the transmission bolts to the cases, the lower rear primary bolt that threads into the transmission, and occasionally the cylinder studs. Inspect these threads very carefully, and if there is any sign of weakness or damage, repair them with high quality thread inserts. These are all areas of high stress, and over the years, vibration and loose bolts may have taken their toll. Repairing these areas when the cases are bare is a simple process, but when the engine is assembled, the task becomes very difficult, and in most cases requires disassembly. Since I have rebuilt several of these engines, I check them carefully, but since I changed engines in mid stream, I thought I had checked the lower primary bolt, but actually I was recalling the earlier engine. This caused me to have to remove the inner primary (and every part of the primary drive) to repair the threads in the transmission case. This is the only course thread bolt in the primary assembly, and it's common for it to be stripped. Fortunately, I assemble the entire drive train, and all covers on the bench, so it just cost me a little time to correct the problem. Had I decided to install the outer primary cover with the engine in the frame, the time could easily have doubled or tripled, because of having to work around the frame and fixtures.||
waiting for the cylinders, eh? Well here they are! I took pictures of them
before and after paint, to prove that they actually are aluminum. I did
add some steel inserts in the head bolt holes, since the original bolts
are fine thread, and you NEVER put fine thread bolts in aluminum or the
threads won't last long, and they aren't able to hold the torque that steel
or iron can. They needed considerable clean up of work on the castings,
and I had to relieve a them to clear the valve covers, because of the full
sized base flange used in the casting. I also had to install longer base
studs, due to the added base flange thickness. Now, I should remind you
that these are strictly experimental, and there are no plans for production.
That being said, here is why they aren't for everyone; Being prototypes,
the finish was far from ideal, they obviously were never test fit to a
set of cases, the machining was only "fair", and there were several hours
of work involved just to get them to fit on a set of cases. In defense
of the maker, the casting work is very nice, and I'm sure it was a monumental
task to make these things. Other than the items mentioned above, I had
them finish honed for piston clearance, installed the valve assemblies,
and bolted them up. After several discussions with a number of engine
Guru's, I decided to go with .004" piston to cylinder clearance. The cylinders
required .003" and .006" material removal to achieve the .004" clearance.
I was told that I could use .0025", but that just seems a bit tight for
a flathead, so I chose to stay on the conservative side. If I planned to
ride this thing like a blue hair, I might have gone a little tighter, but
that isn't the plan so I went the safe route. With cast iron cylinders,
I usually stay in the .005-.006" area, because I tend to ride these things
like they were designed to be ridden, instead of babying them along. The
advantages to these cylinders are weight savings of 15 pounds per cylinder
(9# versus 24#), and far better cooling than cast iron. The disadvantages
are....... well, we'll have to wait and see what happens when I fire it
By the way, I'm using James' silicone beaded base and head gaskets on this project. They're more expensive than the common paper type, but I thought I'd give them a try just to see how they work. I can't report much about them at this point, other than to say that the base gaskets are a lot less fragile than the paper variety. Let's just hope they seal well.
Prototype aluminum cylinders
|In the photos of the assembled engine without the cylinders installed, you will notice two white plates over each cylinder opening in the cases. These are simply protection blocks that I made a while back out of 1/4" nylon sheet. These allow me to rotate the engine during assembly, without having the rods hit the cases. They're a simple device, and when you are doing the assembly work, I suggest that you provide some sort of cushion material to avoid direct contact between the rods and cases. These can also be cut from wood if you choose, but nylon is easier to keep clean. Also be sure to pack clean rags around the rods after assembly to help avoid the possibility of any dirt or debris getting inside the sealed cases. Or you can do like I did, and drop a base stud during removal, which found the only void in the rag and went straight to the bottom of the cases. Normally, I tape off the cylinder holes, but I hadn't done that yet :( I guess that's what magnetic retrievers and flex lights are for, eh?||
Assembled engine with rod protection blocks
also included a close up of the MotoValve breather installed on the cam
cover. The MotoValve looks like the original breather when installed, but
it provides far superior breathing for the lower end. They're designed
to improve breathing to the extent that oil leaks from worn engines are
drastically reduced, and internal engine pressure fluctuations are controlled
without loss of oiling efficiency. A very nice addition to any engine,
whether well worn or freshly rebuilt. I supply them with an adapter to
fit the timing hole on post war engines if you choose to run dual breathers.
The MotoValves, Repro Batteries, Battery Minders, KING clutch kits, spin
on oil filter kits, Indian tools and several other related items are available
on my web site at www.geocities.com/kingclutch/
MotoValve breather on cam cover