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Discussion in 'Airheads' started by fxray, Feb 26, 2015.
Nice thread Ray, I am enjoying this.
Before I try to put this back together, I have a question about camshaft end-play. The Clymer and the FSM assume the camshaft is out of the engine for the sprocket replacement. Here's what Clymer has to say about using a hydraulic press to install the new sprocket onto the camshaft:
Camshaft timing sprocket to mounting flange clearance 1970-1978 models: 0.08-0.12mm or 0.0031-0.0047 inches. (My words here: Shoot for .0040 +/- .0007 inches)
After installation, check the clearance between the camshaft timing sprocket and the mounting flange with a flat feeler gauge. Readjust if necessary by moving the timing sprocket either way until the clearance is correct.
Having said that, Clymer shows a picture of the end-play being checked between a flange on the camshaft, and the backside of the bearing flange. Both these surfaces would be inside the engine and inaccessible if the camshaft is not removed. I guess the result is the same, but their words don't match their picture. I assume that doing this with the cam still in the engine, one would measure between the back of the sprocket and the surface I have marked below:
Thing is, without the sprocket installed, the cam will float in and out .046 inch. I understand putting a .004 feeler gauge on the bearing flange and then sliding the heated sprocket on there as far as it will go. My question is, how do I keep the cam pulled forward as I am sliding the sprocket on? Do I juggle the hot sprocket onto the shaft with one hand and pull out on the quill with the other hand?
A little searching found this:
So, finally, my question is -- how do I lever the cam forward as Bill said here?
Good, You found my How-To.
Levering the camshaft forward? Ideally, best time is before pull the sprocket-- lever it with a big screwdriver/prybar against the case. If the cam sprocket is removed, use Vise-Grips . Just cushion/protect the sprocket nub on the cam with cardboard or leather strap or nylon webbing and grip it with Vise-Grips and lever against the VGs. If you loosen the valve adjusters, or if the heads are off, youmay bven be able to move it forward with bare hands.
With the sprocket removed, I can move the camshaft back and forth (in / out) .046" easily with my bare hands. When the sprocket was on there, it restricted the cam end-play to .004". My valve adjusters are not in play here. The jugs are off the engine. I'm just trying to get my ducks in a row before I try to install the new sprocket. My question is how do I keep the camshaft held forward as I am sliding on the new sprocket? Maybe just tugging outwards on the quill with one hand will be sufficient, but I don't know -- never done this before.
If I read you correctly, you lever the camshaft forward and then count on the pressure of the lifters to keep it there?
Ray, I've never replaced the cam sprocket with the cam still in the engine, I've always removed the oil pump and pulled the cam. That said, if you remove the oil pan, you can gain easy access to the rear lobe. If all you are trying to do is keep the cam pulled forward, how about putting a hose clamp on the last lobe, pull the cam forward and tighten the hose clamp onto the lobe. With the hose clamp pressed against the engine block, the cam will be held, not real well but held. If the cam sprocket slips on without resistance, the clamp will hold fine, if you have to tap or push the sprocket, the clamp will slip. If you try this method, don't forget to pull the clamp when you're done.
Like I said, I've never replaced the cam sprocket while still in the block, the above is just an experiment.
The way I heat the sprockets to slip on is not with a torch or hot air gun, instead, I use a pan and hot plate then boil the sprocket in oil. This way the sprocket is heated more evenly BUT you need a good pair of welding gloves or you risk some really unpleasant burns.
This thread is a very rewarding read. Enjoying your attention to detail and thorough style. Extremely informative.
Thanks for taking the time to share your insights and experiences.
P.S. Your Triumph is gorgeous. Had a '70 TR6R back in the day and loved it.
Lornce, thanks for the nice comments. Triumph had some things worked out by 1970. A lot of people say that was their best year, and there is a lot to like about the single carb bikes. I'm pretty much in love with my '64.
Pokie, thanks for your insights. Pulling the pan is no big deal. Right now, it is only being held on by four temporary bolts to keep things closed up while I was getting the regular hardware plated. I thought about going in there to brace the cam, but wasn't sure where to attack it. Here's a picture I had from when I dropped the pan before:
and closer in:
I see what you are saying. I could maybe also use some kind of soft bar (maybe wood) against the edge of a lobe. I may be worrying too much. If the sprocket is hot enough, it should just slip on, right?
I wondered about the rationale with heating the sprocket in oil. I was thinking of plugging in an electric skillet right next to the engine. The controls on that thing go to 450°F (I was going to heat the sprockets to 300°F). I thought about oil, but I figured I'd wind up burning the house down or making a lot of smoke.
I'm probably overthinking this. If all else fails, I can take the back end apart again. Think those single use bolts can be torqued a second time if they have never been put into service?
If the bolts are angle torqued, replace them. If they are just brought up to a torque spec. one time, I think you can go ahead and do them again.
Angle torque is when you bring them up to a low spec. then pull them to another figure like 180 degrees. Angle torqueing actually stretches the bolt to a final use figure. These must be replaced each time they are used. To angle torque a bolt more than once weakens the material and you risk either pulling the threads or snapping the bolt.
Regular torqueing is bringing the bolt up to a low torque then bringing it up again to the final torque. This method is to bring the bolt up to use tightness without damage to the bolt or the material it's threaded into. No real or intended stretching of the bolt happens, usually the bolts are re-useable. Often bolts that are in a stressed or vital situation are replaced just to guarantee or insure no or less future problems.
Pokie: thanks for explanation of angle-torque.... can you give an example of when that might be indicated and/or appropriate? All I've ever done is the regular kind.
That's not actually correct. Bolts are designed to be stretched, preloaded, when tightened, that's what provides the clamping force. If everything stopped and nothing yielded when you eliminated all the slack, there would be no preload or clamping force. It's the bolt's ability to stretch (a given amount) that provides the required preload to maintain the clamping force.
In critical applications bolt stretch is actually measured instead of applied torque (my old Mercedes diesel cylinder head bolts where tightened in this manner). Applied torque is just a quick way to estimate the required bolt stretch and therefore clamping force.
Oiled and dry threads are a whole other thing.
H-D/Buell head studs are angle torqued. After bringing them to 14ft/lbs, they're finished with an additional 1/4 turn - 90 degrees rotation.
H-D engineers already did the math on how much clamping force (preload, stud stretch) would be achieved by 90 degrees of additional screw cap rotation. Oiled threads, of course.
Its good to think it put beforehand.
When the sprocket is hot enough it will have enough clearance (.002-.003" at 300 *F) to slip on effortlessly and the cam shouldn't move. Or have someone lever the cam forward through a cylinder hole or fromo the bottom or just snag it with a hose clamp, like Pokie suggests. You could easily remove the camshaft, but the you'd need a hydraulic press and the assoc press plates to press it back on. Or just use a variation of the heat-and-shove method. I've done it both ways, and either works.
My shop is a converted carport and adjacent to the kitchen, so I was able to use the oven for heating and run quickly to the bike on a lift. The idea of a cauldron of hot oil is too Quasimodo-esque for my taste (thoI have done it many a time). I have a couple pairs of "Ove-Gloves" that I use for juggling heated parts-- they have good insulation and good tactile feel.
Quite right Lornce.
Most/ many HD (heavy duty) equipment manufacurers utilize Torque Turn currently.
I've developed "Torque Turn" specs several times for really large fasteners that are not practical (or easy) to bring to desired torque/ tightness value with a torque wrench (example, multiples of M24 hex fasteners on placing boom towers that require 1000Nm, or 738ft/lbs. Hard to pull that when several floors up on a construction job site on scafolding. 300ft/lbs applied, then an additional 60 degrees tightening (or one side of hex flat) does the deed.
To the OP's question, don't believe re& re of the crankshaft bolts is going to be an issue, not aware of track record problems? I've reusued without issue, probably comes up in other posts.
Love your thread here!
Bill, if I tried to use the kitchen oven to heat bike parts, well it just wouldn't be a wonderful thing in our household.
A barbeque works great, you can set/ control the temp to bring an item fully up to a desired level (checking with one of the readily available infa red thermometers).
Don't use it often, but when I need it.... the garage already had 30a, 220vac, so Craigslist oven, and home depot wire, and an afternoon... used it mostly on my son's bike to powdercoat, but it's been handy for other preheat. Nice tool to have!
I knew I'd get some guff on that and yes, everything has a stretch and compression rate. My thought was not to muddy things too much, so much for that. Reasonable and re-useable was my intent.
You guys site Buell, why not BMW? The oilheads call for a torque of 15 foot pounds (14.75 actually or 20 NM) on the head nuts then pull to 180 degrees. They also say not to re-use the studs and to not angle torque them again, for obvious reasons. Anyone here that is into auto engines can attest to angle torqueing having been used for years.
Thanks for all the input, guys. The bolts are not torque/turn in this case, but I am familiar with that process. It is usually a more accurate way to get the desired amount of bolt stretch (which provides the clamping force) on critical and/or heavy duty fasteners. I glanced back through my notes and found that the guy at Bob's BMW had told me that the clutch bolts should be single use items. Clymer and the FSM are silent on it. In my collection of old MOA articles by Parkhouse and Glaves, Matthew says that if you have the earlier, heavy style clutch, reuse the bolts if they aren't beat up or stripped at the allen heads. If you have a 1981 or later, order six of the bolts and washers.
However, they all say to replace the flywheel bolts on my /6. Clymer says, "Discard the flywheel bolts, as they are of the stretch type and must be replaced whenever the flywheel is removed. Never reuse these bolts as it can lead to expensive engine damage."
So, O.K., I guess I'll reuse the already new clutch bolts, but get another set of flywheel bolts. We don't want any expensive damage, now do we? (What isn't expensive on these old beasts?)
The moral of this story is . . . do things in the proper order. The reason I digress here is that I guess I will be removing the camshaft, which means taking the flywheel back out. I wasn't originally planning to change out the cam sprocket, or I would have done it earlier when the oil pump was apart. Here's what happened yesterday.
I took the engine off the stand and carried it up to the kitchen. It's not too heavy in its current stripped-down mode. I don't have a stove in my workshop like the one bpeckm showed , but that would be a good idea (nice shop he has!). Instead, I threw a carpet sample on the floor next to the oven and set the engine on that. I packed the crank nose with ice bags and heat soaked the sprocket to 325°F in the oven. Here's my engine looking like it has a hangover:
Even with heat and cold, the sprocket did NOT just rattle on there and have to be held in place while the temperatures normalized. It went just a short way and locked up. The Cycleworks tool kit has provision for this, and I had it right there at hand. It worked well enough and the sprocket seated properly, but I did have to lightly press it nearly the whole way on. The tool uses the threads in the nose of the crank to accomplish this, and I was a bit worried about that, but it worked just fine:
I used the same tool to press on the bearing, but didn't bother to heat the bearing. It went on fine:
Next up was the cam sprocket. Here is where things went awry -- process FAIL! I did go ahead and remove the oil pan, and rigged a cedar wedge under a cam lobe inside the crankcase. I had my wife hold light pressure on this to keep the camshaft levered forward. It didn't matter, the sprocket needs some means of pressing it into place. Four tries, with successively higher temperature each time did not expand the sprocket enough to slide it all the way on against a .004" feeler gauge. I used 390° on the final try. Maybe with a "blue wrench" it would work, but I'm just going to remove the cam and use a hydraulic press for the sprocket.
In the FWIW category, I did measure the sprocket and bearing I.D.'s and the shaft O.D.'s before I started. The new cam sprocket has a slightly smaller internal bore diameter than the original one, and this may have been why I did not succeed.
By my measurements, the interference fits are .0006" for the crank sprocket, same for the nose bearing, and this was the same for both the old and new parts. The old cam sprocket had .0007" interference, and the new one was marginally tighter at .0010" interference.
Unlike the crank sprocket, which can be pressed into place, there is no way I see to install the cam sprocket except to get it hot enough (big enough) to slip on easily, or remove the cam and use a press. I am headed toward the press. Your mileage may vary.
Good job Ray! Whatever works.
The clutch, flywheel, oil pump cover, and all four lifters came back off the engine in just a short time. That let me remove the woodruff key from the back end of the camshaft and then slip the camshaft out the front. I don't have a hydraulic press, and the nearest one I can use is temporarily inaccessible. But . . . I do have this:
So, the cam went into the freezer for an hour or two, and the sprocket went into the oven till it was at 400°F. Then my wife held the camshaft vertically, with its oil pump end resting against my trusty tree stump. I started the sprocket onto the cam, slipped the pipe over the quill, and drove the sprocket home with the hammer.
I didn't have to drive it very hard, but there was no way it was just going to slide onto the shaft due to thermal expansion / contraction. The plan was for my wife to also hold a piece of .004" shim stock in the right spot to set end-play, but that was expecting too much from a non mechanic. I lightly drove the sprocket all the way on, then used my Cycleworks puller to pull on it till it just lightly popped. My lucky day -- the .004" feeler gage was a snug, sliding fit. Here you can see the gauge levitating.
You can also see the little key that makes it necessary to disembowel the back of the engine to remove the cam. Later engines changed the cam to have two flats to engage and drive the oil pump rotor, and they eliminated the key -- good idea!
While I'm waiting on my new flywheel bolts to arrive, I can go play with the master link e-clips on my new timing chain. I've really been looking forward to that!
FWIW: I forgot to mention last time that I did remember to block the crank before I pulled the flywheel back out. I'm running out of ways to do that, but here is yet another method, using the puller bolt holes for the front crankshaft main bearing carrier and a scrap of steel:
I never should have mentioned those e-clips on the new IWIS timing chain . I got one of them on there without much trouble. The second one didn't feel right. I pulled it back off with a seal pick and -- sure enough -- it was spread. It never would have stayed on there. I thought when I opened the box that it was overly optimistic for them to only supply two of those clips. They should put at least four in with each chain. Ten would be better.
So, I searched all over Advrider, eBay, Amazon, google, and everywhere else looking for how to get a spare e-clip -- or even just a master link. I figured they would be available at an inflated price somewhere. I found one thread where a guy was told he had to buy another chain to get another e-clip! Yeah, well, whatever!
I inquired with Moto-bins and got this back, "Sorry we do not have the clips or link separate but I would have thought you should be able to get a clip the correct size from a motor factors."
Eventually I remembered that I once bought some e-clips from McMaster Carr for my CL350. I even found the leftover ones that I had stored. They were close, but no cigar.
So, what size to get? I didn't want to do it, but I pulled off the e-clip that I had successfully installed, and then removed the master link. Measuring as accurately as I could (not easy on this tiny part) I made a selection from McMaster Carr. In case anybody else needs to do the same, I ordered a pack of these. They come 100 pieces for $3.15, so I'm thinking IWIS could have thrown in a couple extra with their chain. I would have happily paid them another dime or so.
More trivia: McMaster Carr says that these clips meet DIN 6799. That led me to google that spec, which brought up more than anybody would want to know about these evil little clips. It also brought up the tool that is normally used to install them. How would you like to do that for a living 8 hours a day?
Here's the info on the tool. I know I'll never be doing this job again, but I had to see if it made it easy to install the clips on this airhead chain. I couldn't help myself, so I have one coming. I'll let you know if it works.