Author Topic: 67 MK-II Moke  (Read 39704 times)

Offline MPlayle

Re: 67 MK-II Moke
« Reply #425 on: April 15, 2018, 08:18:07 PM »
It seems hot to me as well.  I think I have a 185* thermostat installed.  Unless the gauge is not as accurate as I thought from the boiling water test or the thermostat is not working correctly, it seems to want to register about 220* on the gauge with steady driving.

I have wanted an excuse to get one of the IR/laser temperature meters.  I guess I will be running off to Harbor Freight tomorrow for one to use to verify the mechanical gauge and sample places around the engine.

I am using the radiator that came with the 998.  I believe it is a standard three-core.  It was flushed clear before installation.  I do have a six-blade metal "tropical" fan installed as well.

I went out for another longer run this evening and it still read about 220*.  It ran fine with the adjusted timing.  Held with traffic doing 45-50 on main roads (not highways).  It does not behave as though ready to boil over - nothing steaming out anywhere.


Offline MPlayle

Re: 67 MK-II Moke
« Reply #426 on: April 16, 2018, 05:24:00 PM »
I did a bit more "digging" into the running hot today and think I found the cause - running too lean.

I checked through my records and I put in a 180*F thermostat when I built up the 998 engine.

I pulled the spark plugs before starting as they would show how it was the end of yesterday.  They were very light-grey-to-white in color across all four plugs. 

I enriched the carb by one full turn and did a couple laps around the complex to get another starting color reference - no real change.  I enriched another full turn and took it out for a several mile drive.  It was mid-80s ambient temps, but the Moke still ran hot (close to 230*F).  I rechecked the plugs at home immediately after the drive.  They were still very light in color, but just starting to show a hint of light chocolate brown.

I know I do not have any gasket leaks as I checked that using a fireplace/BBQ lighter to give a fuel source and got no changes.

I have a another richer needle to try.  I am also going to remove and cap off the "gulp" valve from the intake manifold and vent the tappet cover breather just to atmosphere (putting on one of those little filters).  I want to eliminate any possible source of making the mixture too lean.

I also got a 160*F thermostat and gasket as a backup option.  I think if I get the mixture more to where it should be, I will not need to change the thermostat or consider a radiator change.



Online 94touring

Re: 67 MK-II Moke
« Reply #427 on: April 16, 2018, 05:36:11 PM »
It's been my experience running lean does little in coolant temps. Some but little. We use to run lean of peak egt to run cooler in piston aircraft as one example.  When my 998 ran hot it didn't matter how much fuel or how perfectly the timing was set, it still ran hot.

Offline MiniDave

Re: 67 MK-II Moke
« Reply #428 on: April 16, 2018, 06:32:15 PM »
Buzz wanted to run that hot too - but only on the highway, around town it would cool down to the center of the gauge -  I had to add an extra radiator to cool him down. Later, I found out he had the wrong water pump pulley on, I had lowered the final drive so much it wasn't turning the water pump fast enough to move the coolant thru the system, a smaller pulley off a Sprite did the trick.

On the Racing Green, which also ran way too warm - never in the red but too warm for my tastes - I put one of those $60 Ebay aluminum radiators in - now I have a hard time getting the engine up to temp on a cold day even with a 180* thermostat, but it never goes over the middle of the gauge even on the hottest summer day, running hard on the highway.

I agree with Dan, I think the only time running that lean would make it run hot is if you were on a long highway run at high RPM. In city speed stop and go driving I don't think it would matter, but I also think you would notice terrible performance with it that lean.

I hate to ask this, but you're sure you have the thermostat in right? A lot of very competent mechanics have installed it upside down....so you don't have to feel alone if you did.
« Last Edit: April 16, 2018, 06:36:17 PM by MiniDave »
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline MPlayle

Re: 67 MK-II Moke
« Reply #429 on: April 16, 2018, 08:08:09 PM »
I put on the pulley that came with the tropical fan that came with the 998.

I know I put the thermostat in with the spring side in the head - the large copper cylinder wrapped by the spring would be immersed in the coolant chamber of the head.

I did get one of the laser-pointer Temperature sensors and verified the gauge is indeed accurate.

I'll see what happens with the tinkering tomorrow.

Any idea the diameter of the Sprite pulley for comparison against what I have?


Offline MiniDave

Re: 67 MK-II Moke
« Reply #430 on: April 16, 2018, 08:43:41 PM »
Seems like the Mini pulley was like 4 1/2 and the Sprite was 3 7/8 or so......wasn't a huge difference. I'm pulling those numbers out of my head tho........
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Online 94touring

Re: 67 MK-II Moke
« Reply #431 on: April 16, 2018, 08:54:39 PM »
The aluminum radiator off ebay is a good reliability mod for cheap.  I'd put one in either way.  You'll get more water capacity for those hot Texas days.

Offline MPlayle

Re: 67 MK-II Moke
« Reply #432 on: April 16, 2018, 10:53:23 PM »
Any link available to one of the aluminum radiator listings that you guys have used before?


Online 94touring


Offline MiniDave

Re: 67 MK-II Moke
« Reply #434 on: April 17, 2018, 08:15:36 AM »
I always get one that has the screw in plug on the bottom corner, that way it still makes a mess but it's easier to drain.
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline MPlayle

Re: 67 MK-II Moke
« Reply #435 on: April 17, 2018, 10:06:33 AM »
I was apparently not entering the right keywords to easily find the ones for classic Minis.  My search last night was getting lots of entries for various new MINIs.

Thanks for the direct link Dan.  I'll get one of those ordered asap.

I'm also going to find a smaller pulley and might as well replace the water pump while in there.

Things I should have done while it was still out of the car ...  :-[



Online 94touring

Re: 67 MK-II Moke
« Reply #436 on: April 17, 2018, 10:29:32 AM »
I'll bet this will fix you right up.

Offline MPlayle

Re: 67 MK-II Moke
« Reply #437 on: April 17, 2018, 11:36:31 AM »
Turns out 7Ent was the only place I found that had the older small water pump pulley in stock.  Ordered the pulley and a new water pump from them today as well as the new radiator from ebay (Dan's link).

In discussing the issue with Jack at 7Ent, he indicated the mixture will have a significant impact - if way too lean (like mine has been) it will run hot.

I am going to work on the mixture and timing some more while waiting on the cooling system parts.

Also going to keep trying to improve the brake pedal feel if I can.


Offline Jimini II

Re: 67 MK-II Moke
« Reply #438 on: April 23, 2018, 01:49:17 PM »
An old trick i was taught when working at SU in the 70's was to push the needle farther into the piston thus making the car run richer through the range, works great and lets you decide if you need a needle change. Also pull the choke out slightly when driving through the gears this will verify if you do need a richer needle.
Not sure which filter you are using but if you changed it from the factory one it will need a richer needle.

Offline MPlayle

Re: 67 MK-II Moke
« Reply #439 on: April 23, 2018, 02:33:56 PM »
Jimini-II,

I have a K&N cone filter on it.  I have put in a richer (ABD) needle and seem to finally have it adjusted about right as per the "lift-pin" method.

It ran a little bit cooler once I finally got the mixture about right - in the 200* to 210* range.

The new radiator arrived today.  I will begin changing things out to new water pump, new (smaller) pulley, new 160* thermostat and the new radiator this afternoon.

Still have a bit more diagnostics to do on the brakes - see the other "brake bleeding" thread.

Offline MPlayle

Re: 67 MK-II Moke
« Reply #440 on: April 23, 2018, 09:11:34 PM »
Started the cooling system upgrade today.  I got the old radiator, thermostat and water pump out.  Not an easy task on a Moke as it has the early style fender shroud that limits the room to maneuver things.

It turns out I already had an upgraded water pump - the cast impeller and the deeper 1275 style that also fits later 998s.  (I had ordered the cast impeller, but shallow depth for small bore engines not knowing exactly what year my engine is.)  I will be putting it back in with a fresh gasket.

I also had to make some minor modifications to the 2-piece fan shroud for fitting to the new radiator.

Tomorrow will be the bulk of the reassemble process for the cooling system.  I plan to let it set overnight before putting the alternator back on so the new gasket seal will be fully cured first.

I still have to do a bit more troubleshooting of the brakes.


Offline MPlayle

Re: 67 MK-II Moke
« Reply #441 on: April 24, 2018, 06:27:01 PM »
Cooling system is back together.  Had to also make some "mods" to the fender shroud to get enough room for getting the new radiator in place with flex to be able to reinstall the fan.

Putting the fan back on took a couple of tries as well - first time I got it on backward.

I did get a bit more clearance between the fan and the radiator as I did not need the spacer for the fan with the new pulley as the nose of the pulley was smaller diameter than the old pulley.

Water pump pulleys come in three diameters: 4.75" (my old one), 4.2" and 3.875" (my new one).  The 3.875" used to be the standard, but got replaced with the larger ones along the way.

Tomorrow's agenda:
- fill the cooling system,
- get a friend to help examine the rear brakes for a possible leak
- attempt a test drive of the revamped cooling system

Offline MiniDave

Re: 67 MK-II Moke
« Reply #442 on: April 24, 2018, 07:13:30 PM »
My fan was on backwards too, so when I changed the water pump I put it on the right way - it doesn't seem to make any difference in the cooling but it sure is a lot noisier!
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT