02-18-2023, 11:41 PM
(This post was last modified: 02-25-2023, 08:12 PM by Terry Bentley.)
Chapter 127
For rest of the week I wanted to focus all of the time available trying to get the engines put together. So far there was not any real hold up. I gave in and decided against all of the hot rod ideas for now. Well not all of them just yet.
It was one very late nights worth of work altering the E-65 side covers so they can be used on our A-490 engines. I also drilled lubricating holes to feed the crank bushing directly. Still no reason why these were not already done this way.
These E-65 covers originally had needle bearings on flywheel side. The A-490 had a lubricating passage routed from intake manifold bypassing the flat reeds, then running thru drilled passages. For a drone engine or rotary lawn mower might be totally functional. But had such a long route to travel, I didnt think for racing would be wise to leave it that way.
After grinding out a small trough I drilled a hole from intake tract that feeds the flywheel side bushing directly. So long as fuel was passing thru, that bushing and seal would be lubricated just fine. That I am fairly certain about. Famous last words some people might say.
Why would the side cover already has cast provisions for drilling that lubricating hole? But just wasnt finished out to use that way. I still dont understand the long winded indirect way it was done before. But makes no difference now. On to more important things.
The side covers are sitting here waiting for assembly. Just like several more parts of the engines. I worked thru the problems and think the solution is going to work just fine. But this is one more thing I did not find any information about when reading all of the hop-ups for our engines.
Those articles went in to a lot of detail on some things, but never mentioned about better lubrication to the crankshaft bushing. The side cover has a place for this hole to be drilled. But I am curious why it was not done. The very long and indirect route to oil both sides of crankshaft does not look very well thought out at all. Sure hope this is not going to be a big mistake.
Wednesday morning I caught up with Mr Sadeskey right before school. He mentioned looking into that high temp epoxy, but so far nothing he could put his hands on. I thanked him for his trouble. Without all of the details i did fill him in on something I had found out.
I did a the usual coke bottle run for return deposit money up at the car wash, yesterday. This keeps some pocket change available when grabbing a snack at the 711. I was close enough to Bailey Crankshaft to stop by. If anyone might know if epoxy would work, I figured he might just be that person. I guess my grandfather may be the one other person that might know something too.
Mr Bailey didnt have a good answer, but saw no negatives about trying it out. A customer was there picking up a few crankshafts. He overheard our discussion and offered some free advice. Mr Bailey introduced me to Dave Pluebell. I have heard his name before, but the first time to meet. He explained what should work and likely work well.
From a reliable source he told me this retired dirt track racer, uses very fine aluminum powder with the best epoxy. Find the best epoxy I could buy. Mix enough in to thicken the batch up. He said it should hold up just fine for filling the piston ring grooves not in use. Make sure the surfaces are very clean and slightly rough for good adhesion.
Mr Sadeskey scratched his chin with an interested expression on his face. Hmmm, I wonder if that will work? Did the gentleman give any working examples of what he used this for?
No sir, just told me to trust him on this. It will hold up for my intended purpose. Do you know where can I find aluminum powder? It it used in anything for someone to get a hold of?
Well Rick, ur uh, Terry, that can have a lot of uses. Just none come to mind at the moment. I believe you may have some luck talking with the Chemistry teacher. He can probably offer some of it up to you. Or at least lead you to somewhere that sells it.
That is interesting. I will have to think on what he told you for a while. I wonder how much difference there is in expansion rates between epoxy and aluminum? This has peaked my curiosity. Let me know what you find out if deciding to test his suggestion. This might just be something useful to know if your results are positive.
The first bell rang, so I decided it was a good time to head across the hall and get ready for Drafting. Yes sir, I will let you know if it works or not. But might be a while before risking an engine to find out just yet. Thanks for all of your help so far Mr Sadeskey. I am going to class.
After school today I hustled on home and got right to work. Time is running out as the weekend approaches. There was one thing I had put off. One thing I had actually forgotten completely about. It is something more than just timing the engines. Well setting the points gap was not the problem.
I wanted to advance the timing slightly past the stock engine specifications. This is one engine that already has a lot more advance compared to all of the others I could find information on. The timing is at 35 degrees. That is so much more than I had expected. So one less thing I can change that could have made a lot of difference.
If stock timing was closer to the 26 degree setting like a lot of other chainsaws, bumping it up that much would be very noticeable. But no such luck. Gotta find another edge here. One thing that was mentioned it two of the articles I read was the fixed air gap clearance of ignition coil to flywheel magnets.
According to these hop-up articles, this gap needs to be closed up just much as possible. Since the coil is under the flywheel, it could almost touch since the centrifugal force would try to sling it out if I am thinking this thru correctly.
Engine equipped with an externally mounted coil, when the rpm increases that flywheel has a tendency of running out far enough to hit the laminations on coil. With load, vibration and crankshaft flexing, the gap needs to be at least 10 thousands using a feeler gauge for setting the clearance.
But on the Clinton with under the flywheel mounting, it tries to sling out away from coil. So clearance can be at a minimum without any major problems. Even if it does slightly rub under certain conditions, might not even be a big problem.
One slightly major problem is making this adjustment difficult. There is no adjustment. Everything is in a fixed location and laminations are permanently riveted on to the points box. To resolve this, I have to drill out the rivets, enlarge the holes, then replace rivets with nuts and bolts.
The bigger problem is there is no way to measure the gap. The flywheel fits over everything and no way to access the underside or measure with flywheel bolted on. Since after cutting all of those stock cast iron flywheels during the summer, I decided not to use the really heavy ones that are from very early models.
So back sometime over the summer when first hashing thru and pondering all of this, I decided to cut up the old heavy cast iron flywheel. Hoping it might allow some way to make adjustments possible.
At first I was thinking about only cutting a window in the flywheel. Or get totally carried away and cut off every part of the flywheel except what holds the magnets in place. This sure sounds like a ton of work. Not to mention a ton of scrap iron and very messy job.
First thing would be to remove what is left of the cooling fins. Then machine down the outside diameter, just to reduce the bulk and weight. I could cut out a pie shape that keeps the center hub then angles out only wide enough to include the magnets.
With what is left of the cut down flywheel, I bolt it to crankshaft. There should be plenty of room to check air gap. Then rotate the flywheel around slightly allowing access to each screw so coil can be moved closer to magnets.
If I can remove all of the unnecessary sections of flywheel, maybe even cut a window right over the coil to see everything. This should make a super easy job to adjust the air gap then tighten in place. I guess notching the outer edges might also work out. I needed to make the new screws accessible after setting the gap to tighten them up.
One thing that might help is to glue a piece of brass shim stock to magnets, then would be nearly fool proof to use. Just have to find some shim stock the right thickness of air gap. Wow! So cool!
By setting the air gap close as possible is supposed to make for a stronger spark. Well so far from everything I have read. Maybe this is one of those things that doesnt hurt to do, but hard to prove enough or any significant advantage worth all of this effort.
This is just one more thing that would make sense to do a back to back comparison at the track one day when practicing. But I already have a long list to do just that. So until the engines are built and we can plan a serious practice day, I wont ever find out for sure one way or another.
I put a lot of effort into making this flywheel lighter. Just for ease of use. Also having less bulk to cut out using the hack saw. But it still ended up very heavy. It took a lot of work too. At first I wanted to rough it out just enough so adjustments on the ignition could be made. But I know from past experience nothing would get any further done past this point if the flywheel was not finished out the whole way tonight.
So if this timing adjustment does make a big difference, it becomes something that will needs to changed on every ignition we have sitting around. Also making sure we have a spare in the parts box as backup. If it does work, all that effort chopping up the flywheel would now be worth it.
Spending the evening cutting down excess bulk off the flywheel was time consuming. After finishing up with the lathe, it did make it easier to cut with hacksaw removing the unwanted section. Cast iron is not so hard to cut with a hacksaw, but the thickness sure puts a slow down of things. It took some time to cut completely across.
Machining this down, I had hoped it would be thinner, but a few hours later working the blade, well make that several blades back and forth, most of this flywheel was now occupying ground zero below the pedestal mounted vise. Cast iron dust and small chunks were spread all over the floor. But something now looking more like a counterweight was the result. Or something that would make the engine run way out of ba1ance if attempting to do anything more than spinning over by hand.
A year ago me and Steve would be all over attempting to start an engine with a flywheel cut down like this one has already been done. Watching it vibrate so far out of ba1ance would be hilarious to watch self destruct. But now realizing if it let go at any speed could kill someone. That is still a heavy piece of cast iron spinning around. I dont want that someone to me or anybody else I know.
For rest of the week I wanted to focus all of the time available trying to get the engines put together. So far there was not any real hold up. I gave in and decided against all of the hot rod ideas for now. Well not all of them just yet.
It was one very late nights worth of work altering the E-65 side covers so they can be used on our A-490 engines. I also drilled lubricating holes to feed the crank bushing directly. Still no reason why these were not already done this way.
These E-65 covers originally had needle bearings on flywheel side. The A-490 had a lubricating passage routed from intake manifold bypassing the flat reeds, then running thru drilled passages. For a drone engine or rotary lawn mower might be totally functional. But had such a long route to travel, I didnt think for racing would be wise to leave it that way.
After grinding out a small trough I drilled a hole from intake tract that feeds the flywheel side bushing directly. So long as fuel was passing thru, that bushing and seal would be lubricated just fine. That I am fairly certain about. Famous last words some people might say.
Why would the side cover already has cast provisions for drilling that lubricating hole? But just wasnt finished out to use that way. I still dont understand the long winded indirect way it was done before. But makes no difference now. On to more important things.
The side covers are sitting here waiting for assembly. Just like several more parts of the engines. I worked thru the problems and think the solution is going to work just fine. But this is one more thing I did not find any information about when reading all of the hop-ups for our engines.
Those articles went in to a lot of detail on some things, but never mentioned about better lubrication to the crankshaft bushing. The side cover has a place for this hole to be drilled. But I am curious why it was not done. The very long and indirect route to oil both sides of crankshaft does not look very well thought out at all. Sure hope this is not going to be a big mistake.
Wednesday morning I caught up with Mr Sadeskey right before school. He mentioned looking into that high temp epoxy, but so far nothing he could put his hands on. I thanked him for his trouble. Without all of the details i did fill him in on something I had found out.
I did a the usual coke bottle run for return deposit money up at the car wash, yesterday. This keeps some pocket change available when grabbing a snack at the 711. I was close enough to Bailey Crankshaft to stop by. If anyone might know if epoxy would work, I figured he might just be that person. I guess my grandfather may be the one other person that might know something too.
Mr Bailey didnt have a good answer, but saw no negatives about trying it out. A customer was there picking up a few crankshafts. He overheard our discussion and offered some free advice. Mr Bailey introduced me to Dave Pluebell. I have heard his name before, but the first time to meet. He explained what should work and likely work well.
From a reliable source he told me this retired dirt track racer, uses very fine aluminum powder with the best epoxy. Find the best epoxy I could buy. Mix enough in to thicken the batch up. He said it should hold up just fine for filling the piston ring grooves not in use. Make sure the surfaces are very clean and slightly rough for good adhesion.
Mr Sadeskey scratched his chin with an interested expression on his face. Hmmm, I wonder if that will work? Did the gentleman give any working examples of what he used this for?
No sir, just told me to trust him on this. It will hold up for my intended purpose. Do you know where can I find aluminum powder? It it used in anything for someone to get a hold of?
Well Rick, ur uh, Terry, that can have a lot of uses. Just none come to mind at the moment. I believe you may have some luck talking with the Chemistry teacher. He can probably offer some of it up to you. Or at least lead you to somewhere that sells it.
That is interesting. I will have to think on what he told you for a while. I wonder how much difference there is in expansion rates between epoxy and aluminum? This has peaked my curiosity. Let me know what you find out if deciding to test his suggestion. This might just be something useful to know if your results are positive.
The first bell rang, so I decided it was a good time to head across the hall and get ready for Drafting. Yes sir, I will let you know if it works or not. But might be a while before risking an engine to find out just yet. Thanks for all of your help so far Mr Sadeskey. I am going to class.
After school today I hustled on home and got right to work. Time is running out as the weekend approaches. There was one thing I had put off. One thing I had actually forgotten completely about. It is something more than just timing the engines. Well setting the points gap was not the problem.
I wanted to advance the timing slightly past the stock engine specifications. This is one engine that already has a lot more advance compared to all of the others I could find information on. The timing is at 35 degrees. That is so much more than I had expected. So one less thing I can change that could have made a lot of difference.
If stock timing was closer to the 26 degree setting like a lot of other chainsaws, bumping it up that much would be very noticeable. But no such luck. Gotta find another edge here. One thing that was mentioned it two of the articles I read was the fixed air gap clearance of ignition coil to flywheel magnets.
According to these hop-up articles, this gap needs to be closed up just much as possible. Since the coil is under the flywheel, it could almost touch since the centrifugal force would try to sling it out if I am thinking this thru correctly.
Engine equipped with an externally mounted coil, when the rpm increases that flywheel has a tendency of running out far enough to hit the laminations on coil. With load, vibration and crankshaft flexing, the gap needs to be at least 10 thousands using a feeler gauge for setting the clearance.
But on the Clinton with under the flywheel mounting, it tries to sling out away from coil. So clearance can be at a minimum without any major problems. Even if it does slightly rub under certain conditions, might not even be a big problem.
One slightly major problem is making this adjustment difficult. There is no adjustment. Everything is in a fixed location and laminations are permanently riveted on to the points box. To resolve this, I have to drill out the rivets, enlarge the holes, then replace rivets with nuts and bolts.
The bigger problem is there is no way to measure the gap. The flywheel fits over everything and no way to access the underside or measure with flywheel bolted on. Since after cutting all of those stock cast iron flywheels during the summer, I decided not to use the really heavy ones that are from very early models.
So back sometime over the summer when first hashing thru and pondering all of this, I decided to cut up the old heavy cast iron flywheel. Hoping it might allow some way to make adjustments possible.
At first I was thinking about only cutting a window in the flywheel. Or get totally carried away and cut off every part of the flywheel except what holds the magnets in place. This sure sounds like a ton of work. Not to mention a ton of scrap iron and very messy job.
First thing would be to remove what is left of the cooling fins. Then machine down the outside diameter, just to reduce the bulk and weight. I could cut out a pie shape that keeps the center hub then angles out only wide enough to include the magnets.
With what is left of the cut down flywheel, I bolt it to crankshaft. There should be plenty of room to check air gap. Then rotate the flywheel around slightly allowing access to each screw so coil can be moved closer to magnets.
If I can remove all of the unnecessary sections of flywheel, maybe even cut a window right over the coil to see everything. This should make a super easy job to adjust the air gap then tighten in place. I guess notching the outer edges might also work out. I needed to make the new screws accessible after setting the gap to tighten them up.
One thing that might help is to glue a piece of brass shim stock to magnets, then would be nearly fool proof to use. Just have to find some shim stock the right thickness of air gap. Wow! So cool!
By setting the air gap close as possible is supposed to make for a stronger spark. Well so far from everything I have read. Maybe this is one of those things that doesnt hurt to do, but hard to prove enough or any significant advantage worth all of this effort.
This is just one more thing that would make sense to do a back to back comparison at the track one day when practicing. But I already have a long list to do just that. So until the engines are built and we can plan a serious practice day, I wont ever find out for sure one way or another.
I put a lot of effort into making this flywheel lighter. Just for ease of use. Also having less bulk to cut out using the hack saw. But it still ended up very heavy. It took a lot of work too. At first I wanted to rough it out just enough so adjustments on the ignition could be made. But I know from past experience nothing would get any further done past this point if the flywheel was not finished out the whole way tonight.
So if this timing adjustment does make a big difference, it becomes something that will needs to changed on every ignition we have sitting around. Also making sure we have a spare in the parts box as backup. If it does work, all that effort chopping up the flywheel would now be worth it.
Spending the evening cutting down excess bulk off the flywheel was time consuming. After finishing up with the lathe, it did make it easier to cut with hacksaw removing the unwanted section. Cast iron is not so hard to cut with a hacksaw, but the thickness sure puts a slow down of things. It took some time to cut completely across.
Machining this down, I had hoped it would be thinner, but a few hours later working the blade, well make that several blades back and forth, most of this flywheel was now occupying ground zero below the pedestal mounted vise. Cast iron dust and small chunks were spread all over the floor. But something now looking more like a counterweight was the result. Or something that would make the engine run way out of ba1ance if attempting to do anything more than spinning over by hand.
A year ago me and Steve would be all over attempting to start an engine with a flywheel cut down like this one has already been done. Watching it vibrate so far out of ba1ance would be hilarious to watch self destruct. But now realizing if it let go at any speed could kill someone. That is still a heavy piece of cast iron spinning around. I dont want that someone to me or anybody else I know.