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Topic Summary

Posted by: Jeff_M
« on: July 03, 2014, 07:22:01 AM »

I can't wait to drive it again....and see what else I can find wrong with it...not. 
Posted by: Ryan_M
« on: June 29, 2014, 11:41:51 AM »

After a losing battle with my rebuilt carb, Scoutpilot (whose customer service has been second to none...anywhere), shipped me another carb. With it bolted on and the timing adjusted I headed out to the "test hill" for another run. Previous top speed on the straightaway leading up to the hill was just about 60mph. This time I was just under the 65mph mark and still accelerating when I chickened out and let up. I rocketed up the hill and for a split second dipped a hair below 50mph but by the time I crested the top of the hill I was holding a steady 52mph.

So the performance continues to improve by leaps and bounds since the beginning of this thread. I started at 50mph on the straightaway and can now most certainly hit 65mph. My "hillcrest" speed of 30mph has improved to 52mph. Pretty impressive percentage improvements. It just shows how obvious it is that because you simply bolted your Jeep back together does not mean it's running at peak performance. Minor tweaking to make it right can really pay huge dividends or keep you lagging severely behind if you choose not to address it.
Posted by: 1955CJ-5
« on: November 14, 2013, 10:33:57 AM »

Ryan, I'm glad all those changes have improved your performance.

All those changes, timing, new carb, new distributor and the linkage set-up have contributed.

But really, 60 mph? At night? In an old jeep?

I wish mine would go 60.... :(

I better set my sights on an overdrive.....
Posted by: Ryan_M
« on: November 14, 2013, 10:28:23 AM »

I have no complaints with the 62 year old 6v bulbs. The brand new high beam switch, however, failed when stomped on which can be a little alarming when all goes dark at 50+mph.
Posted by: Jeff_M
« on: November 13, 2013, 10:21:16 PM »

That's a significant improvement.� Funny how a simple adjustment can make such a difference, although in your case you've done a lot more than that.

I'll try to refrain from any posts for a while so you can get your sleep and save your money.� :-)

BTW, how do the vintage 6v headlights work in the dark?
Posted by: Ryan_M
« on: November 13, 2013, 09:52:36 PM »

The forum members here never stop amazing me. Earlier this week I received an e-mail from our friend 1955CJ-5 (Randy) that suggested I take a look at the throttle linkage attached to my carb. What he had discovered on his 3A is that when the accelerator pedal was pushed to the floor the butterfly in the carb was only about 2/3rds open.� I checked mine and, sure enough, same deal. It occurred to me that I had installed a new rubber boot on the accelerator pedal shaft during the rebuild. Prior to my rebuild there was no boot. Even if the PO had adjusted the carb linkage correctly at the time, the fact that I added the rubber boot would screw up the adjustment because the pedal no longer comes close to hitting the floor. As I did in many places during my rebuild, I think I just unbolted what was there, cleaned it up, and bolted it back together without it even occurring to me that adjustments needed to be made. Rookie mistakes.

Anyways, tonight I installed a newly rebuilt carb from Scoutpilot (another saga, but I can assure you his carbs are great and his service after the sale is outstanding). With the new carb installed I adjusted the throttle linkage properly. Since it was pitch black and 25 degrees out, I figured it was perfect weather for a topless Jeep voyage. I bundled up and headed out to my test road and up the test hill. What a difference. Even before I reached the hill I noticed a significant increase in acceleration from a dead stop. I hit the 60 mph mark WELL before the end of the straightaway and barrelled up the hill no slower than 46mph. I made three passes and all were within a couple miles of each other. Slower speed climbs up other hills were noticeably better at holding a steady speed too. Good stuff. Yes, I was running with a new carb but I really don't think my previous carb was all that bad, it has simply found a new home on my decrepit M38.

I need to continue fine tuning the throttle linkage and carb idle adjustments and I'd like to get my hands on a dwell meter and figure that out as well. It was just too cold for me to do much more testing tonight but I'm thrilled with the progress at this point.

When Jeff_M started this thread I was barely hitting 50mph after the straightaway and was down to 30mph at the peak of the hill. Timing was also at 10-15 deg BTDC and when I set the timing again tonight I set it at 5 deg BTDC - right where it is supposed to be. That's quite an improvement.
Posted by: stony
« on: September 27, 2013, 03:18:11 PM »

Dwell meter measures the amount of time (in degrees of rotation) that your points are closed.� Will give you much better results than setting the gap.� Just hook it up to the coil - and ground.� I have the $30 from Amazon, works fine with my 6V tractor.� Also works as a tachometer which is helpful in setting the idle.� Must have tool for working on a points ignition engine.� Oh yeah you need to set the dwell before you set the timing, because changing the dwell will change the timing.

Here is a nice thread from our friends on the CJ2A Forum: http://www.thecj2apage.com/forums/timing-light_topic8053.html
Posted by: 1955CJ-5
« on: September 27, 2013, 03:04:23 PM »

I bought a tester at Sears long ago..it had a tach, dwell and who knows what else...and you could set it for four cylinder engines...of course 4 bangers are pretty common..it's the 6v that messes things up...maybe a shop that specializes in old Volkswagens?
Posted by: Ryan_M
« on: September 27, 2013, 01:35:46 PM »

Quote
Ryan, the left side of the bulge is 5 degrees BTDC, not top dead center.� If you get the timing advanced too much, you should be hearing detonation (spark ping) in the motor when you get in the higher RPMs.� If the engine won't idle, you may have your idle screw set too low on the carb.

Yep got it. I said the left side of the bulge is "IGN" which on some flywheels is equal to 5 degrees BTDC.....just easier to type. I'm probably another 5 degrees beyond that now. I did mess with the idle screw too and it didn't seem to help.

Quote
Did you use a dwell meter to set your points?� Setting the gap with a feeler will get you close but you need to check the dwell to make sure you are getting the max out of your coil.

I used a feeler gauge to set the points (.020"). I have no idea about using a swell meter.....yet another variable to chase down.....
Posted by: macrisel
« on: September 27, 2013, 01:11:26 PM »

[Anyways, I really spent some time setting the points and finding what I think it TDC on the pulley and painting corresponding marks on the timing cover. The bulge on the timing cover is hard to read. If the left side of the bulge is indeed IGN then something is wrong. My motor will barely idle and definitely isn't right. If I advance another 5(??) degrees it settles in very nicely, which is where I ultimately left it. If I am indeed advanced to 10 degrees, is that an indication of compensating for something else that's failing? [/quote]

Ryan, the left side of the bulge is 5 degrees BTDC, not top dead center.  If you get the timing advanced too much, you should be hearing detonation (spark ping) in the motor when you get in the higher RPMs.  If the engine won't idle, you may have your idle screw set too low on the carb.
Posted by: stony
« on: September 27, 2013, 11:07:50 AM »

Did you use a dwell meter to set your points?  Setting the gap with a feeler will get you close but you need to check the dwell to make sure you are getting the max out of your coil.
Posted by: Ryan_M
« on: September 26, 2013, 09:48:29 PM »

I picked up a timing light today. It's a battery operated one which wouldn't have been my first choice but it's the only one I could find in town and even it had a heavy layer of dust on it. My guess is pretty soon we'll only be able to find timing lights in antique shops. Turns out the battery-only feature is pretty handy for quick roadside timing checks. Hook the one clamp to the #1 plug wire and you're ready to go. Pretty slick.

Anyways, I really spent some time setting the points and finding what I think it TDC on the pulley and painting corresponding marks on the timing cover. The bulge on the timing cover is hard to read. If the left side of the bulge is indeed IGN then something is wrong. My motor will barely idle and definitely isn't right. If I advance another 5(??) degrees it settles in very nicely, which is where I ultimately left it. If I am indeed advanced to 10 degrees, is that an indication of compensating for something else that's failing?

I have a "test" hill that I've been using to determine changes in performance. Prior to this thread I know I would reach roughly 50mph through the gently downward straight just before climbing the hill. By the time I crest the hill, I'd be down to 30mph. This is all in OD 3rd. I could downshift but the end result really isn't any better than just slogging through it in high gear.

With my freshly tweaked timing I now hit 58-60mph through the straight and crest the hill at blazing 42 mph!!!! That's a pretty significant difference and I am extremely pleased with the result.� It feels a lot peppier at slower speeds too.

All of this testing still involved a fair amount of trial and error - several sets of points, new rotor, new condenser, back to old condenser etc. At one time during my "roadside adjustments" I managed to * things up so bad I had to take a charity tow back to my house -� Good thing I have at least one friendly neighbor with pick-up truck who travels home from work at roughly the same time I idiotically disable my own vehicle. Never a dull moment.

I did spend a good amount of effort earlier this year after my initial rebuild adjusting timing by "feel". I think I had it pretty good at one time but it so gradually fell out of time I didn't really notice it. I'll be paying closer attention to it now. I have a pretty long drive over some serious hills this weekend so I'll see how it holds up.

I'm still curious about the possibility of having the timing too advanced. Any input on that? And is there an easy way to gauge RPM's on these Jeeps? I'm curious to know what my idle engine speed is as I'm adjusting the timing.

Posted by: Ryan_M
« on: September 25, 2013, 12:27:24 PM »

Excellent info. Thanks to all. Let me see if I can scrounge up a timing light and make a mess with some white paint.
Posted by: 1955CJ-5
« on: September 25, 2013, 11:51:43 AM »

Well, there you go!

All questions answered....!
Posted by: athawk11
« on: September 25, 2013, 11:20:59 AM »

Quote
Something is odd there as you should be able to see the entire opening in the engine plate, your's appears to be partially covered by the block casting. Just off the top of my head I'd say that your rear engine plate is for a different year engine.

For the production of the M-38, the engine block cast was changed.� It had a larger flange that would cover a portion of the timing hole.� Ryan has a late engine casting.� This was around the same time that they added the timing notches to the front of the engine.

Here is a pretty good discussion about this at the 2A...

http://www.thecj2apage.com/forums/whats-the-deal-with-my-timing-window_topic21461.html