1973 GMC 26' Glacier Build
- Thread starter ScottC
- Start date
It appears main leak area was the oil filter adapter, I read "just tighten the bolts" but I figured why I am in here just change them. The Cummins part# is 0122-0771, you need 2. I also cleaned up the Oil pressure sensor adapter and a little PTFE to the threads. Next is the timing cover seal.
Attachments
Pulling timing cover seal can be difficult if it is original or been in there a long time, most screw a self tapper into the seal which is the way I started until they pulled the threads quickly, I do not have a slide hammer but luckily I have a set of heavy duty pic tools and used the existing holes in the seal to pull, with a pair of vice grips and a small hammer I was able to tap it out.
Attachments
Thanks for documenting your Onan work with nice pics. I'm sure all that work is in my future, so I appreciate being introduced to it early.
After the seal and gaskets it was time to deal with the exhaust, it was all rusted out so I started looking for replacements which was a joke, finally found a Onan part number for a kit that appeared to have the correct muffler, funny thing Cummins had it on the web for like $2,450 then it showed up on clearance for $80, came with 3 pieces, the muffler, piece of pipe and a clamp. I ordered it and this is what showed up, the muffler is a match but not the other pieces.
Attachments
I've been pondering just using a motorcycle muffler on mine, seeing if I can make it even quieter. I think I remember calculating the Onan to be about 60ci, so around 1000cc. Guys are always ripping very effective mufflers off of Liter bikes in favor of something obnoxious, so nice quiet OEM mufflers are easy to come by. Of course, it's not a bolt-in affair.
I bought this one last year off of Amazon, but have yet to install it. Comments say it's really quiet. It won't be a direct fit, though.
Attachments
GOOD DEAL! They are super proud of their Onan mufflers for some reason.
Where did you snag one for $80????
Holy Cow, they have the same kit still on clearance but now 96% off for $7.56 straight from Cummins!!!!
Attachments
Well it's a Cummins 155-1962, which is the exact kit Scott showed the contents of above. It should be the same thing. It's the same part number that comes up for $2500 elsewhere. Pretty strange price range...
Either way, I'm in for one at that price. Shipping was only $4.99. I guess we'll see.
Of course the kit did come with a tail pipe but not a down pipe, the connection to the muffler and flange are 1 1/4" and I was thinking I could use electrical conduit but could not get the bends right, the smallest my muffler shop does is 1 1/2" so I took my old rusty piece and had it bent to match, then took some of the 1 1/2" cut off split it and squeezed into pipe ends, put everything together, made some adjustments with a large crowbar and hammer (not while on generator) then welded everything up. I finished it off with some DEI high-temp.
Attachments
Now time for the Bovee Ignition Kit, followed included instructions and on his website, pretty straightforward, found my 25 degree timing mark (painted it white when flywheel was off) lined up with timing window then found nearest fin and marked it, moved module in position and clamped, marked fin at white line on module, tested with multimeter then glued magnet in. Only problems is it would not run so I double checked with meter and it turns out the magnet was just a little bit off , it appeared lined up with white mark but I ended moving the magnet out a little bit and all good. She starts right up but seems like it has a little bit of vibration not sure if it is the timing a little bit off or is it the magnet. Going to hook points back up just for reference and see if the vibration is the same.
Attachments
Scott,
You were not at the rally a few years back that we got in a gentleman that had been part of the Onan team that put together the Power Drawers. During the lengthy discussion, he admitted the fixed timing for both was retarded by 2 or three degrees because the actuation of the basic points was so bad that they saw damage to test engines related to early ignition.
I don't know if the Bovee kit suggests this, but I set mine up at +3° from base. Except for several component failures, the beast has run great since then and also uses a tad less fuel.
Matt_C
You were not at the rally a few years back that we got in a gentleman that had been part of the Onan team that put together the Power Drawers. During the lengthy discussion, he admitted the fixed timing for both was retarded by 2 or three degrees because the actuation of the basic points was so bad that they saw damage to test engines related to early ignition.
I don't know if the Bovee kit suggests this, but I set mine up at +3° from base. Except for several component failures, the beast has run great since then and also uses a tad less fuel.
Matt_C
Scott,
Another set of great pictures for a common mod and one that I have on my plate. Thanks.
I have heard elsewhere as well that Matt's suggestion is a good one.
Another set of great pictures for a common mod and one that I have on my plate. Thanks.
I have heard elsewhere as well that Matt's suggestion is a good one.
Checked the Onan vibration with the points and the electronic, both have a similar slight vibration so maybe the grinding on flywheel for the magnet?
Now on to next problem, swapped out my board for a new one from Flight Systems fire her up everything was fine until about the 10th time and then no start, looked at troubleshooting and 3B "is there 12v present between terminals 10 and 1", my answer was no so it states "replace K1 start solenoid" I contacted Flight Systems and sent board back. They tested and said board was fine and the only way they could duplicate problem was with remote switch in stop position. Got the board back installed and did not hook up the remote switch (top of board) hit start same problem, it will start with coil jumper wire or with jumper between 9 and 11 on board. I started investigating why I get no power to #10 and it appears to be the starter relay solenoid under the board, if I hit the starter button there is no power on the right side, would this be the culprit? it appears Cummins has the solenoid but $70 out the door so I don't want to purchase unless it is verified the problem.
Thank you all, stay warm!
Now on to next problem, swapped out my board for a new one from Flight Systems fire her up everything was fine until about the 10th time and then no start, looked at troubleshooting and 3B "is there 12v present between terminals 10 and 1", my answer was no so it states "replace K1 start solenoid" I contacted Flight Systems and sent board back. They tested and said board was fine and the only way they could duplicate problem was with remote switch in stop position. Got the board back installed and did not hook up the remote switch (top of board) hit start same problem, it will start with coil jumper wire or with jumper between 9 and 11 on board. I started investigating why I get no power to #10 and it appears to be the starter relay solenoid under the board, if I hit the starter button there is no power on the right side, would this be the culprit? it appears Cummins has the solenoid but $70 out the door so I don't want to purchase unless it is verified the problem.
Thank you all, stay warm!
Attachments
Scott,
I might be wrong, but as I remember from when I was starting to design a dummy Onan to test boards, that contactor (Solenoid/relay) is nothing special. It just has to be specified correctly.
Matt_C
I might be wrong, but as I remember from when I was starting to design a dummy Onan to test boards, that contactor (Solenoid/relay) is nothing special. It just has to be specified correctly.
Matt_C
My 4k power drawer acts the same way
It requires 9-11 jumped to start but then runs on its own
I replaced the board and it start/stoped fine...for a while
Then the same thing, it needs 9-11 jumped again
There is plenty of documentation for it
I replaced the K1 relay and it worked again...for a while
I also disconnected the flywheel-alt charger-wire because it was outputting 15vdc. Now the Onan battery is charged from different sources now. It continues to run so the gen-alt is supplying the run-signal
I seems like the start 12vdc choke, fuel, ignition voltage is missing or pulled low?
I am curious as to what it could be
My 1973 has the three batteries and I wonder if there is some cross connect between two batteries? There was some wiring mods by PO to add an LPG water heater
I was going to add the primer circuit but was wondering if I should source the 12vdc from the Onan battery and not the house battery
My Onan is basically used these days to cycle gas out of the fuel tank
It requires 9-11 jumped to start but then runs on its own
I replaced the board and it start/stoped fine...for a while
Then the same thing, it needs 9-11 jumped again
There is plenty of documentation for it
I replaced the K1 relay and it worked again...for a while
I also disconnected the flywheel-alt charger-wire because it was outputting 15vdc. Now the Onan battery is charged from different sources now. It continues to run so the gen-alt is supplying the run-signal
I seems like the start 12vdc choke, fuel, ignition voltage is missing or pulled low?
I am curious as to what it could be
My 1973 has the three batteries and I wonder if there is some cross connect between two batteries? There was some wiring mods by PO to add an LPG water heater
I was going to add the primer circuit but was wondering if I should source the 12vdc from the Onan battery and not the house battery
My Onan is basically used these days to cycle gas out of the fuel tank
Last edited:
