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Author Topic: timing belt conversion on youtube  (Read 1140 times)

BruceM

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Re: timing belt conversion on youtube
« Reply #15 on: December 13, 2020, 11:10:55 PM »
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.

dkmc

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Re: timing belt conversion on youtube
« Reply #16 on: December 15, 2020, 01:16:51 AM »
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
« Last Edit: December 15, 2020, 01:31:07 AM by dkmc »

gadget

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Re: timing belt conversion on youtube
« Reply #17 on: December 15, 2020, 02:18:50 AM »
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.

dkmc

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Re: timing belt conversion on youtube
« Reply #18 on: December 15, 2020, 03:51:48 AM »

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.

32 coupe

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Re: timing belt conversion on youtube
« Reply #19 on: December 15, 2020, 04:13:45 AM »
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



Metro 6/1 turning a ST 7.5 KW gen head
Changfa 1115 turning a ST 15 KW gen head
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"I was sitting here reading this thinking what an idiot you are until I realized it was one of my earlier posts !"

gadget

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Re: timing belt conversion on youtube
« Reply #20 on: December 15, 2020, 12:26:55 PM »
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.

gadget

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Re: timing belt conversion on youtube
« Reply #21 on: December 15, 2020, 01:00:24 PM »

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