Messages

1

Engine compartment / Re: Running hot

« on: July 09, 2025, 10:44:22 AM »

SteveKfl & Rus- Thanks for the response.  No clue where the electrode ended up, but testing all 4 cyl for compression indicated with 5-7lbs.  Not burning any oil, etc., so assuming it ended up getting spit out past the exhaust valve, but who knows.  I'm just keeping my fingers crossed.

I might have the octane rating wrong but pretty sure it's 94.  The whole issue is around the effects of ethanol (has a higher-octane rating of around 109) and the point of combustion of 9x octane w/o ethanol vs. 87 w/octane. To be honest I do not know if one would be better than the other.  Since I have no markings, I don't know where i ended up in terms of timing before TDC.  All i do know is that the pinging is gone with the 9x octane with the timing set for max vacuum and correct dwell and rpm. It was a hit or miss operation for a while, but it's finally running with plenty of power, still hits 200 - 210 temps but no pings, so this is where it'll stay.

2

Engine compartment / Re: Running hot

« on: July 08, 2025, 09:31:32 PM »

So, it's been a while, to say the least.  Here's where I am:

Replaced thermostat to new 160, replaced water pump, flushed radiator, tried various timing settings using vacuum, dwell, and rpm. Nothing worked in terms of getting rid of ping after engine heats to 200 going uphill.  All very disappointing.

However, i may have stumbled upon a solution.  Problem is, I don't know what the downside to doing what I'm doing is, if there is one. One of the ways the effects of eliminating lead was offset was by introducing octane in gas.  Given that, I set the timing back to what ran the best and filled the tank with 91 octane without ethanol.  Since doing so, I've not heard pinging even though the temps run at 200 at times.  I tried backing off to 87 octane with ethanol (I cannot buy 87 w/o octane) and the pinging returned, although not very often. The problem is that I don't know if the pinging was because the octane level was lower or because it contained ethanol.  Because I cannot buy ethanol free 87 octane, I have no way to prove out either scenario.

So, for now, it's ethanol free 94 octane.

One other very disturbing problem occurred while testing all of this.  At one point, the engine started skipping and coughing like there was no tomorrow.  With all the changes to timing, gas mixtures, octane levels, etc., I thought for sure I'd done permanent damage of some sort. I checked for spark at all cylinders, pulled plugs and checked compression - all looked OK.  As I was putting plugs back in, I noticed what you'll see in the attached image - one of the electrodes on the spark plug was completely gone. Disturbing as all hell! 

3

Engine compartment / Re: CJ-3A vs CJ-3B radiator

« on: June 06, 2025, 07:02:50 PM »

So, finally, an update:
 1. Pulled the radiator and had it boiled again.
 2. Attempted to install a spacer between the fan blade and pump but the fan would've hit the top tank on radiator - so that was a no go.
 3. Added a bypass hose from rear of head to water pump, just because I could.  No heater to help dissipate any of the excess heat.
 4. Replaced the water pump even though the unit that was in it is only 2 years old.
 5. Replaced 165 thermostat with new one. The replaced unit was only 2 years old and after I pulled it, tested it and it started opening at around 150ish, so that wasn't the issue.
 
No difference in symptoms. Runs at around 180 under speeds of 45, or so. Then if approaching a hill of any length, the temp would quickly bounce to around 190 - 195 and start pinging (and losing power). Letting off or cresting the hill would result in the temp dropping almost immediately.

All that is to say I made no progress. Time for something completely different.

Because timing, fuel, etc. can all impact ping, and knowing I could not retard timing any more than already set, as I could sense a decrease in power.  So, the other option I'd not previously considered is the effect of increasing octane, as its effect is to retard the detonation of fuel. The question became whether to increase from a rating of 84 (with Ethanol) to 87 (with Ethanol) vs. 91 without Ethanol.  Filled the tank with 91 to also rule out the ethanol and glad to report I cannot get it to ping.  Temps still climb to nearly 200 while hitting hills, but no ping. So, as long as I can keep it from overheating, 91 octane is in my CJ's future.

For now, that's where I am.
 

4

Engine compartment / Re: CJ-3A vs CJ-3B radiator

« on: May 01, 2025, 07:17:29 AM »

And the finished product...

5

Engine compartment / Re: CJ-3A vs CJ-3B radiator

« on: May 01, 2025, 07:16:22 AM »

Not a great picture for the radiator, but it's a bottom mount for the '49 - 3A.

6

Engine compartment / Re: CJ-3A vs CJ-3B radiator

« on: April 30, 2025, 06:41:57 PM »

In some of the very early '49 - 3A's, several parts could have been from 2A production that were left over and used.

The part number for the bottom mount radiator was either a 640146 or 640145 - with ring shroud.   If you have a side-mount, it should be 648451. My '49 has the bottom mount, but it's my understanding the side-mount was supposed to be the unit for 3As

7

Engine compartment / Re: Running hot

« on: April 30, 2025, 06:24:47 PM »

Thanks for the replies.

In trying to recall the thermostat orientation, I'm not sure it's possible to put it in upside down.  The spring and copper cylinder would hit the housing, I think.  In any event, the spring is facing the block, and I've drilled the bleeder hole to allow bypass of water to prevent overheating from an air pocket.

No bypass hoses from rear of block to water pump.

No sign of a blown head gasket: no sign of water out the tailpipe, no sign of foam around oil filler tube, no bubbles in radiator while running, compression test is consistent across all 4 cylinders.

When I had the radiator serviced, the shop boiled, and flow tested.  Much to my surprise, they stated it was in great shape - I'm sure it's been re-cored (maybe more than once over the past 75 years.

I've found a NOS bellows type thermostat and NOS waterpump.  Those are on the way.  If that doesn't work, a radiator may be in my future.

Aain, thanks for the feedback.  I'll post after I change out the parts and test drive.

8

Engine compartment / Re: Running hot

« on: April 29, 2025, 12:11:49 PM »

Thanks again, SteveKfl and Rus.

Yes, pinging is definitely a symptom, but the root cause is the mystery.

Actually, Russ, it may be time to head down different rabbit holes, as the ones I've been down, turn up no rabbits.

It's been nearly 50 years since I did a CJ rebuild but seem to recall the temp climbing after shutdown.  I can rationalize that if the water is sitting in a hot block with no circulation, it will climb until the entire block starts cooling off.  I can also rationalize that once you shut an engine off, it should be at its max temp and should not continue to rise. Given my complete lack of knowledge on thermodynamics, I assume one of them is correct but beats the devil outta me which one it is. 

Could be the water pump might be the issue.  Haven't gone down that path yet, but not far from it.

No heater in it, Steve. It has a mechanical vacuum advance that appears to work. I have a mark on the front pulley that I use a ballpark reference and when I rev the engine with a timing light on it, I can see the mark advance.  And thanks for the heads-up on the spacer for the fan.  It's worth a try ato see what the effect is.  If that doesn't work, I'll tackle the water pump.

Appreciate the help.

9

Engine compartment / Re: Running hot

« on: April 28, 2025, 05:37:15 PM »

Thanks for the reply, SteveKfl. Using the analog temp gage that has the sensor mounted directly in a port on the head.  While the absolute numbers may not be perfectly accurate, the differential is what's concerning and causing the problem.  While driving at 40 mph on relatively flat roads, the temp will range from 165 - 180.  As soon as I hit a hill > 1/2 mi, the temp will rise to >195 and it starts pinging.

As a test today, I retarded the timing so that the vacuum was just starting to fluctuate a bit and set the idle screw a bit richer to try to help with running at idle after heating up.  Took it out for a spin and no difference.

I found a spacer that was made to move the fan blade closer to the radiator.  Going to give that a try. 

10

Engine compartment / Re: Running hot

« on: April 27, 2025, 09:22:09 AM »

Thanks for the replies:

Scoutpilot - running 87 octane.  I bring timing to highest, smooth-running point, then retard about 100 rpm, and adjust idle to ~670. Vacuum is steady at 20.  I've pulled plugs and, while not full of carbon, are definitely on the darker side, so I've been assuming it's running a tad rich, if anything. I rebuilt the carb and even took it apart a second time to verify the metering rod settings, etc. It starts fine cold and when it's warm but hasn't heated over 200.  When hot, it can be stubborn. Under those conditions, where the engine has been heated, harder starting may be an issue of vapor lock (?).

Russ, yes, very early - in fact, I've found a few items that were left over from the 49-2A. Rear end is a Dana 41, not a 44.  The original engine rear plate was replaced but the plate that's on it does not have the timing hole, so it's a crap shoot.  The crankshaft pulley didn't have a timing mark, so when i was reassembling the engine, I brought the engine to TDC and notched a mark as close as I could to the 0° mark on the timing cover.  Not perfect, but it gave me a ballpark reference point.

Any other suggstions are welcome.

11

Engine compartment / Re: Running hot

« on: April 26, 2025, 09:21:06 AM »

I know this is an older thread I haven't updated due to being out of commission for a while.  Warmer weather returning to the Northeast has allowed the CJ out of the barn.

Still same issues and I'll (finally) respond/answer prior questions. all of the following done during the rebuild before the jeep was ever run after rebuilding:

  1. The radiator was boiled and flow-tested before installing
  2. Two different 160-degree thermostats with the bleeder hole drilled. Both tested before install and opened at 160.
  3. Antifreeze is ethylene glycol based Prestone, mixed at 50/50.
  4. New 4# cap
  5. New water pump
  6. No sign of the lower hose collapsing

There are actually 2 things that I conflated into a single problem:

  7. After running the Jeep to normal running temps (<180) and parking, the temp increases while parked and the cap will release fluid as soon as the temp reaches approx. 220.
  8. When driving uphill for more than 5 - 10 minutes, temp will approach 200 and engine starts pinging.  Stopping for a minute, brings temp down so that pinging stops and power returns to normal.

What's been done to try to correct overflow at rest:

  9. Changed out cap. to the 2nd 4# cap to be sure it wasn't a cap issue.
10. Adjusted timing by retarding slightly (without timing marks, it's a crap shoot). I've been on both sides of optimal running - either too much pinging or too little power.  As it sits now, the power is excellent until the hill issue pops up. Dwell at 39, tach at 670, vacuum steady at 20
11. Added the shroud to the radiator, which helped somewhat, but did not resolve the issue.

Because the cap releases when parked, I've just ordered a 7# cap. While reluctant to put a 7# cap on, I'm hoping to see if it prevents the overflow, figuring the loss of fluid may be contributing to the overheating.

ScoutPilot - if you're still monitoring - running an engine lean could contribute but I'm not seeing any indication of running lean. If anything, it's probaby running a tad on the rich side.

Any comments are greatly appreciated.

12

Engine compartment / Re: Running hot

« on: August 06, 2024, 03:07:51 PM »

Hmmm, interesting.  I worked in an automotive machine shop for years where we rebuilt engines, including a number of L4-134s (only shop within 150 mi. that could pour babbit bearings and line bore), and never ran into an issue.  It's been too long (over 40 years) since then, so don't recall original wall thicknesses.  Not suggesting you're wrong, just an observation.

So, if that's the case - where it's a matter of poor transference of heat - have you had any experience with running a larger radiator and/or flex fan, which should provide a bit of relief. If you can transfer heat out of the radiator, it should run a bit cooler. 

Maybe someday, I'll drop the pan and mic the walls, just for the helluvit.

Thanks for your comments

13

Engine compartment / Re: Running hot

« on: August 06, 2024, 08:16:10 AM »

.060

14

Engine compartment / Re: Blade Question

« on: August 05, 2024, 08:55:11 PM »

I know this is late reply, but 50 years ago, I had a 3B that I put a flex fan on.  It was loud, but very effective at cooling the block.  I've seen flex fans t O'Reilly's, so I think they're still available.  It's not stock but if that's not an issue...

15

Engine compartment / Running hot

« on: August 05, 2024, 08:37:00 PM »

I have a '49 - 3A that was rebuilt 2 years ago (less than 2,500 mi.) and always runs hot.  I've swapped the thermostat out from a 180 to a 160 and have tried the thermostat with and without the drilled holes. The change from the 180 to 160 brought the temp lower but still not where things should be running.

the issue is that under 35 mph, everything runs at around 175 - 180, but as soon as speed is increased or if there's a long hill, temps will hit 190 -195.  Although it never overheats to the point of blowing off steam, there are side-effects.  After running at those temps, shutting off the vehicle results in the temp jumping to 220 - 225, which causes the radiator to spit water out of the overflow tube - not a lot, but always. While it will start when it's been overheated, it's always harder than a cold start or when it remains below the 180 level.

I've futzed around with timing using tach, dwell and vacuum, as there are no marks on these.  Dwell is 40, tach 670, vacuum 20.

Any suggestions?  I've tried every trick in the book I know of. Maybe someone has a different book?

Thanks

PS radiator cap is new 4lb.