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The main sprocket cannot be welded and that's the one that slips. You have to pin it. Also, we check for runout on the housing bore and sprockets. This isn't something you are doing at home.
So the main sprocket is driven by the crankshaft, correct? That is not a single machined piece with the rear cam chain sprocket, then. Correct? If this is the case, the image that was lifted from a post by Jake Raby shows the cam drive chain welded to the IMS. Is this also pinned to retain the crank sprocket?
Granted, this was from nine years ago, so maybe things are different now (how to address the issue). Picture shown again...
So the main sprocket is driven by the crankshaft, correct? That is not a single machined piece with the rear cam chain sprocket, then. Correct? If this is the case, the image that was lifted from a post by Jake Raby shows the cam drive chain welded to the IMS. Is this also pinned to retain the crank sprocket?
Granted, this was from nine years ago, so maybe things are different now (how to address the issue). Picture shown again...
Yeah, it looks like you'd end up pinning the main sprocket and welding the cam drive sprockets. I know LN pins that main sprocket, I dont think they do anything to the other sprockets
Edit: Other than checking runout, I'm up in the air about this now
Ok - so the IMS is still not fully resolved. Let me know if I have this correct. The photo below shows three separate parts. Left to right: 1) the IMS tube, 2) the rear cam chain drive gear and, 3) the main drive sprocket. Correct so far?
It's very difficult to see the separation between the main sprocket and the cam gear. I will concede that it must be there. A few questions arise. The IMSS cap that is inserted into the IMS to close off the tube from extra oil is internal, but somewhere near the cam gear. By drilling to pin the main sprocket, is there any risk of hitting that cap? I can't take measurements since I installed the stud and external bearing. There are other decisions I need to make, but understanding where that lies with respect to any drilling of the main sprocket is important. I should be able to pull the bearing, but getting the cap out might not be possible without destroying it.
Ordered some AOS parts. Should have something to report on that before too long. Also should be able to get all of the con rods closely matched soon. They are all within 1.5 grams, so it won't take much to take a little off the heavy ones.
Well while you're all formulating your answers, I have some good news. Just got off the phone with a guy named, Len. He wanted to get some numbers from me so he could release my cylinder heads. He did say they were the best heads he's ever seen.
Well maybe not those exact words. He did indicate that core shift was observed, but it was in the good direction. He also said they were flow tested and came out on the positive side of the curve. So I might just have a couple of beers to celebrate, when I get home. Then I'll probably stand out at the end of the driveway waiting for the UPS truck to arrive.
Charlie - thanks for posting this. That looks like four welds at 90 degrees. Still gathering information and keeping this under consideration. Any reason to be concerned about the front sprocket? Is that known to be an issue?
Found the thread in which this may have originated. Great stuff.
We pin 100% of all shafts for Jake and most customers send us theirs to be checked and pinned. The main drive sprocket is indeed a separate piece and is not keyed or indexed and is swedged onto the pipe with about .250" engagement.
Ok - so the IMS is still not fully resolved. Let me know if I have this correct. The photo below shows three separate parts. Left to right: 1) the IMS tube, 2) the rear cam chain drive gear and, 3) the main drive sprocket. Correct so far?
It's very difficult to see the separation between the main sprocket and the cam gear. I will concede that it must be there. A few questions arise. The IMSS cap that is inserted into the IMS to close off the tube from extra oil is internal, but somewhere near the cam gear. By drilling to pin the main sprocket, is there any risk of hitting that cap? I can't take measurements since I installed the stud and external bearing. There are other decisions I need to make, but understanding where that lies with respect to any drilling of the main sprocket is important. I should be able to pull the bearing, but getting the cap out might not be possible without destroying it.
Ordered some AOS parts. Should have something to report on that before too long. Also should be able to get all of the con rods closely matched soon. They are all within 1.5 grams, so it won't take much to take a little off the heavy ones.
FYI, If you can see the separation, the shaft has failed and is junk.
We pin 100% of all shafts for Jake and most customers send us theirs to be checked and pinned. The main drive sprocket is indeed a separate piece and is not keyed or indexed and is swedged onto the pipe with about .250" engagement.
Originally Posted by Charles Navarro
FYI, If you can see the separation, the shaft has failed and is junk.
Charles - thank you for the information. At the time of assembly, there must be a method of indexing all three sprockets. Have you observed any keys/keyways in damaged of destroyed intermediate shafts? The factory may have used a fixture to maintain proper orientation of each component and then pressed them together. I can't image the sprockets were machined after the parts are pressed together as an assembly. But that would be one way to assure proper timing.
The cam timing adjustment feature at each bank will allow for a small amount of misalignment of the cam gears with respect to the crankshaft. It should also allow compensation, to a certain extent, for chain stretch.
I still am not clear on whether either of the two cam sprockets can rotate relative to their original installed orientation. Is this a concern? If they are keyed, it seems that risk would be reduced.
"I still am not clear on whether either of the two cam sprockets can rotate relative to their original installed orientation. Is this a concern? If they are keyed, it seems that risk would be reduced." Scott @ team Harco
Charles @ LN Engineering "We pin 100% of all shafts for Jake and most customers send us theirs to be checked and pinned.The main drive sprocket is indeed a separate piece and is not keyed or indexedand is swedged onto the pipe with about .250" engagement."
^^^This seems like a fairly direct/unambiguous statement...
"I still am not clear on whether either of the two cam sprockets can rotate relative to their original installed orientation. Is this a concern? If they are keyed, it seems that risk would be reduced." Scott @ team Harco
Charles @ LN Engineering "We pin 100% of all shafts for Jake and most customers send us theirs to be checked and pinned.The main drive sprocket is indeed a separate piece and is not keyed or indexedand is swedged onto the pipe with about .250" engagement."
^^^This seems like a fairly direct/unambiguous statement...
Where does it describe how the cam sprockets are retained?
02-26-2020 | 11:11 AM
