Lister Engine Forum
Lister Engines => Listeroid Engines => Topic started by: gadget on December 04, 2020, 07:21:20 PM
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Anyone seen this mod or something like this? Looks like maybe a custom camshaft or is the housing removed to mount a belt drive sprocket on the end of the camshaft? Apparently this guy got tired of dealing with his idler breaking;
https://www.youtube.com/watch?v=NlXTeF0wOts
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An impressive timing belt conversion project.
The idler failure was sorted out by Dave (XYZer) over a decade ago. He found that errors in the idler gear bolt location where consistently causing grossly excessive gear lash. Once people corrected that by offset idler bolts, which Dave most graciously had made in a variety of offsets, there has never been gear failure reported on any idler lash-corrected engine. That was during the heyday of US listeroid/clone imports.
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An impressive timing belt conversion project.
The idler failure was sorted out by Dave (XYZer) over a decade ago. He found that errors in the idler gear bolt location where consistently causing grossly excessive gear lash. Once people corrected that by offset idler bolts, which Dave most graciously had made in a variety of offsets, there has never been gear failure reported on any idler lash-corrected engine. That was during the heyday of US listeroid/clone imports.
Well said.
That and bronze gears.
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An impressive timing belt conversion project.
The idler failure was sorted out by Dave (XYZer) over a decade ago. He found that errors in the idler gear bolt location where consistently causing grossly excessive gear lash. Once people corrected that by offset idler bolts, which Dave most graciously had made in a variety of offsets, there has never been gear failure reported on any idler lash-corrected engine. That was during the heyday of US listeroid/clone imports.
Well that is good news for us newbies. My 8/1 is still apart in my garage waiting for some free time to reassemble after I have given it its initial cleaning and painting. I checked my backlash and noticed it was maybe .010-.020 one way, and when I rotated it 90 degrees, It was tight. I'm guessing one of my gears is egg shaped.
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I don't believe tight gear lash or out of round gears have ever been reported here before. Perhaps valve train pressure tricked you. Your finding certainly warrants careful checking. Anything is possible in a Rajkot made engine.
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. "I'm guessing one of my gears is egg shaped."
assuming you had no valve spring load on the camshaft when you checked it is more likely the camshaft is bent or the cam gear was knocked crooked when the pin was driven in.
I am no fan of bronze gears. As Bruce said the fix is correcting the lash, not a soft gear.
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I like the bronze gears, after the problem is located
and rectified.
I have made several offset bolts with success.
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38ac's advice on the CS listeroid/clone camshaft being bent (by Rajkot's "sledge that tapered pin after boring hole off axis") is right on the mark. I found it in the 1st clone camshaft I checked via dial gauge and hardwood vee blocks on my cast iron saw table deck. This just after he posted great info on this issue about 5 years ago. My intent here is just to amplify his understated advice for newbies.
32coupe made a very nicely turned offset idler bolt for my neighbor's 8/1 propane conversion. A great kindness!
That engine has been working hard and trouble free as an off grid power and air compressor for 4.5 years now.
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My 8/1 parts are boxed up at the moment and it will be a while before I can check again. I had to move everything out of the shop I was working in last spring and haven't had any free time since.
There was also mention that the problem with excessive back lash is the snap back from the camshaft from exhaust valve going down to intake opening? Is there not any valve over lap on these motors or maybe some wrong lobe placement? I guess it could also be during intake closure or the injection lobe.
It seems like poorly made camshafts are a problem source on these motors. I'm curious to test the valve timing on my camshaft.
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The lash problem has nothing to due with overlap, although there is overlap in a CS cam. Every revolution of a CS type cam the direction of force on the teeth changes 6 times, pushing the valves open and then the springs pushing them shut, same with the fuel pump. A small amount of extra lash multiplies the excelleration, aka gear bang by many times. Extra lash is what breaks the gears, not inferior gear metal. This problem exists in the Lister built engines also. I have one in the shop with gear issues and it sure isn't the first one.
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Butch,
That is interesting. I didn't think those problems would exist in the original Listers. I must
admit I have never seen an original Lister.
So is the "fix" the same as the clones ? Offset ider bolt ?
Just curious.
Gary
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The Listers have the idler bolt properly located. While history of operation seldom comes with the engines that see my shop it's a pretty easy guess what happens. The gears wear over the years and when they reach that critical point of excessive lash and accerations the forces break the gears. Much more common in the twins but singles suffer to a lessor extent also.
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I keep forgetting about the "slapback" in the gear train.
I remember a fellow here awhile ago that posted a pic of a bronze gear with the teeth worn to a razor edge.
That appeared to be a definite case of the idler bolt being in the wrong location. Funny thing is I offered to
send him an offset bolt but he never got back with me.
I think the list of problems with the clones is endless. That is the reason when I got my twin I didn't even
try to run it. It was completely torn down and rebuilt.
On my twin the bore for center carrier in the block for the cam was large enough for excessive play. I repaired
that with a brass shim that wrapped around the carrier I JB welded in the block. I used material that gave
the carrier a snug fit when in place. A pin holds the carrier in place and it seems to be fine so far. I haven't
run the engine much ( maybe 75 hours or so ) so I guess time will tell.
Again, on the clones everything has to be checked. One of the heads on the twin had the valve guides reversed !
And yes they are different.
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I think the list of problems with the clones is endless.
No way! They all come with a sticker that says PASSED??????
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I think the list of problems with the clones is endless.
No way! They all come with a sticker that says PASSED??????
I picked up an 8/1 "KIT" last year from D.E. Tore it apart and hot soaked. Blocked looked pretty good, no holes! Found I had a steel piston and used cylinder bore. Also, one of my lifters has an unusual chatter type pattern on the face surface. Also, my back lash feels way off. Everything else passes visual inspection
I ended up going with one of their stamford type gen heads. I figured I would have enough on my plate getting the lister polished and just wanted a turn key gen head. It looks really well built!
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I'm grateful to have my 6/1 Listeroid for a working off grid power source; so is my neighbor with his 8/1.
38ac's knowledge and experience on the camshaft issue was something sorely needed back in the heyday; people just accepted that some engines barked out the intake, etc., when what they needed was a straight camshaft and setting lash to get the timing right.
My memory is beyond bad lately. 38AC can you remind us which two valve timing events are the critical ones to set lash to? Intake open and Exhaust open? It's a good one to remind us on a thread for a newbie with an engine to go over, after he checks his cam for straightness.
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32 coupe, can I ask what eccentricity you built into your idler bolts? Also, I'd really like to hear a bit about the correct location of the bolt, if you'd care to comment.
Thank You,
DK
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I'm grateful to have my 6/1 Listeroid for a working off grid power source; so is my neighbor with his 8/1.
38ac's knowledge and experience on the camshaft issue was something sorely needed back in the heyday; people just accepted that some engines barked out the intake, etc., when what they needed was a straight camshaft and setting lash to get the timing right.
My memory is beyond bad lately. 38AC can you remind us which two valve timing events are the critical ones to set lash to? Intake open and Exhaust open? It's a good one to remind us on a thread for a newbie with an engine to go over, after he checks his cam for straightness.
Anyone ever price out a custom cam? I know there was a project at one point they died on the vine. I've read some of 38AC's cam threads and agree with the importance of proper timing.
I'm planning on marking out degrees on one of my flywheels and to make sure everything is timed correctly. I know it has been debated before but I would also suggest some port work on the head.
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I'd be very curious to hear the advantages of any port work on the cylinder head of a diesel engine that has a top speed of 650 or 850 rpm. The ports in the head seem to be of ample area for such a slow speed. Cam timing fine tuning on the other hand, at least to intended specs seems quite important.
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DK,
I have one in the shop I did a few years ago and I will try to find it tomorrow and get a measurement.
People would ask for a range and I would get it close and I always got good feedback and
everyone was happy.
I did 2 for myself and they worked fine.
My machine skills are not nearly as good as many of the folks here. I took a stock bolt and machined
the area that met the block then created an eccentric sleeve that rotated on the bolt so you could
rotate it to get the proper backlash.
I used JB weld to hold the eccentric to the bolt after a test fit. That made sure it wouldn't move when
making the final adjustment but still allowed the bolt to be removed later with eccentric still firmly attached
to the bolt
You want to remove the push rods and IP so you aren't getting any spring or back pressure on the cam
while checking/setting backlash on the gear train. If you have a twin you should remove tje oil pump as it
has a stiff spring as well.
Also check the backlash in several spots around the gears not just one area.
I think I have a pic of one of my bolts on the site somewhere. I'll see if I can locate it and post it.
I hope I answered your question. If not I can always add more confusion !
Gary
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DK,
I have one in the shop I did a few years ago and I will try to find it tomorrow and get a measurement.
People would ask for a range and I would get it close and I always got good feedback and
everyone was happy.
I did 2 for myself and they worked fine.
My machine skills are not nearly as good as many of the folks here. I took a stock bolt and machined
the area that met the block then created an eccentric sleeve that rotated on the bolt so you could
rotate it to get the proper backlash.
I used JB weld to hold the eccentric to the bolt after a test fit. That made sure it wouldn't move when
making the final adjustment but still allowed the bolt to be removed later with eccentric still firmly attached
to the bolt
You want to remove the push rods and IP so you aren't getting any spring or back pressure on the cam
while checking/setting backlash on the gear train. If you have a twin you should remove tje oil pump as it
has a stiff spring as well.
Also check the backlash in several spots around the gears not just one area.
I think I have a pic of one of my bolts on the site somewhere. I'll see if I can locate it and post it.
I hope I answered your question. If not I can always add more confusion !
Gary
I have heard that knowing what backlash change is needed is necessary before the offset is drilled? Your eccentric adjustable sounds like a good idea. I always thought a slide type adjuster that moved in an angle between the cam and crank gear would work perfect but a fixed hole would not "fall" out of adjustment vs a slider setup (if there is room for one?)
I'm not sure if I'm picturing it correctly since its been a while since I tore my motor down for initial clean up. The good news is, it should only have to be adjusted once since it doesn't sound like wear is to excessive on these gears if they are working correctly.
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I'd be very curious to hear the advantages of any port work on the cylinder head of a diesel engine that has a top speed of 650 or 850 rpm. The ports in the head seem to be of ample area for such a slow speed. Cam timing fine tuning on the other hand, at least to intended specs seems quite important.
I don't have any test experience to verify on Lister heads and I don't know what kind of CFM they move but I have done lots of port work years past. I use to port small block chevy heads for a well known company. I've also done port work on side draft carburetors, very intricate work.
Its not about "RPM". Any engine that has "low flow" at its designed working RPM is going to run poorly due to low volumetric efficiencies. The swept volume on these engines is pretty good for the valve size. That is a massive size piston. Its going to move a ton of air even at very low RPM. When I use to port heads for a living, The slightest bump in an otherwise perfectly smooth port wall can make a noticeable difference in CFM.
Out of all the heads I have ported over the years, these listeroids are the worst I have ever seen. Mine was really bad. Even just some very basic clean up of casting protrusion should help. Its a good idea anyway since you don't want your motor to ingest a loose piece of casting. I was able to pull off a piece of casting in my intake port with my finger. I would not go as far as smoothing the ports, just clean up anything sticking out or protruding into the runners.
If your hand skills are good, blending the seat area to the port (throat area) would be next. There is risk of damaging the seat area so you have to be very careful. There is no valve shrouding work to do since there is no combustion chamber pocket. I would NOT blend this area. I would leave the valve stem alone.
Make sure there is no protrusions where the intake or exhaust manifolds bolt up that can create turbulence in flow direction only. Keep it simple, just take the large bumps out of the road