52 replies to this topic

[sdjones121]

I recently moved from Norfolk to the US and am having a heck of a time with my Mini running very hot. Before leaving the UK I took it to Peter Baldwin who put it on the rollers and got it running beautifully, and it is because of that that I am a bit hesitant to go too crazy adjusting much of anything until I get a bit of experienced advice. For the record, this is a '87 Mini Advantage with a Metro >'84 1275 lump, Hif-44, LCB, RC40 exhaust, modern 2-core rad (unsure of the exact model), and the original (running the right way) plastic fan. Of note, the car is idling very poorly right now, and I usually need to pop the choke out a notch or two to raise the idle when stopped.

 

I'm now living in Albuquerque, New Mexico which, when compared to Norfolk, is hot, dry, and high. Average high temps right now are around 90f/32c and I'm at about 5,400ft/1,600m elevation. Ever since the Mini got here has been running super hot when idling, driving slowly, or when driving over about 55-60 mph. In Norfolk the temp needle would sit smack dab in the middle of the gauge 99% of the time, but now it is often right at the edge of the red, and sometimes just on that red line. To be fair, I only had it there from November to April, so I don't know how the summer would have affected it there. I haven't overheated yet; I've been careful to slow to about 55mph to get it to cool down before it's gone to high up the gauge.

 

So far, I've flushed the rad twice, and the engine once, and replaced the thermostat (tested, working) and gasket. I got a ton of little bits of solid junk out when I did the flush, but it hasn't made an impact on my running temps. Looking around the forums, I've considered the following: 

 

1. Air in the system

2. Timing is off

3. Need to upgrade to the tropical fan

4. Corroded water pump impeller

 

I just ran the car up to temp without the radiator cap, and added water once hot. I brought the level up to about 1/2-3/4 inch over the cores. During this time (it's 75f/24c right now), the temp gauge crept up very close to the red. After I buttoned everything back up I took it for a quick spin around the neighborhood and the temp came back down reasonably quickly with the increased revs on the fan/water pump. But, coming back home and leaving it to idle, the temps went right back up. I had been concerned that my belt was a bit loose, but I aligned the alternator pulley and tightened the belt down last week to no avail.

 

As far as the timing, that's a big thing I'm a bit hesitant to touch since Mr. Baldwin just set it up. But, I'm wondering how big an impact being a mile in the sky would have on the "correct" timing, and if his hard work is now for nothing. I've also wondered if this (or mixture) could also be the cause of my idle issues.

 

I'm hesitant to drop $80 on the fan if that's not really the issue, also, I don't want to buy that and end up just covering up the real (potentially more sinister) issue.

 

In regards to the water pump, I haven't brought myself to take off the old one just yet, preferring to look at external issues first before tearing into things that may not lead to any solutions. But, I can't help but wonder if any of those little bits of rust and what not were the remnants of my impeller.

 

As I said, I haven't touched anything other than the coolant system yet. I'm game to adjust anything else, just want to get a bit of advice before I go off and undo Mr. Baldwin's great work for no reason. I've got a fair collection of tools, a timing strobe, and a Gastester+, so I should be able to give much of anything a go. I'm sure it'll come as a shock, but there aren't a whole lot of people around here competent in the tuning of these motors, so anything I jack up, I'm pretty much on my own to fix.

 

Any help you can offer is greatly appreciated! Fortunately, the Mini is more a toy than a required form of transport, so if it takes a bit to get it right, that's OK too.

 

Seth

[sdjones121]

One more thing I forgot to mention. The car has also developed a pretty strong petrol smell at just about any speed. I've rooted around for fuel leaks and haven't seen anything, and the rubber hose on the top of the tank (exact name escapes me right now) is connected and runs to under the car.

[Carlos W]

The high altitude would cause the car to run rich, not enough air for the fuel, this shouldn't cause overheating issues like running lean does

Is the fan on the correct way? (they're marked fan side)

Does the heater get hot? (If it does it means water is circulating)

What thermostat have you put in? (you could put a lower rated one in)

Edited by Carlos W, 25 May 2013 - 04:34 AM.

[Barman]

I'm not an expert...

 

Could it be something to do with the fuel being used - different octane rating, ethanol additives or something like that?

 

What colour are the plugs - a good guide to the state of tune...

[Blatherskite]

Follow Barmans advice about mixture, and if you have significant ethanol content, thst burns hotter than regular gasoline. I dont recall whether ignition timing is affected, but as ethanol burns faster, some retarding might be useful.

Otherwise, hot thin air at altitude will not give the same cooling effect through the radiator, so you should consider a tropical fan, upgraded radiator, and even high flow water pump (one at a time, cheapest first!). But start with a properly set up motor so, as you say, you dont cover up other issues.

Let us know how you get on.

[Gulfclubby]

Yeah, different fuel could be one factor. What have you been running it on in the UK? 95 unleaded?

What are you running it on in the states? 87, 89 unleaded?

Note that the US and Canada use a different octane rating than Europe too. They have technical octane rating + motor octane rating / 2, while we just use the technical octane rating, I believe.

[A-Cell]

High Altitude running.
Advance ignition 1deg per 1000 ft so for Albuquerque 5deg
Water boils at 94C not 100C, so make sure you using 15psi rad cap. Also in view of summer temps use 78deg thermostat.
Highest octane fuel available will be best. In any case you will need a weaker setting than in Norfolk. You may have to fit a weaker needle.

[Blatherskite]

Just received Mini Magazine, where p8 has an entry about European 10% ethanol gasoline. They say retard the ignition, and the mix runs hotter due to the etanol; alternatively, use 98 octane fuel. Hope that helps.

Edited by Blatherskite, 25 May 2013 - 09:15 AM.

[Captain Mainwaring]

I run a mini is the tropics - as hot as where you are, not quite so high (we can get up to 1750 MSL just outside of town, but our humidity is a fair bit higher.

 

If the mini is sat in traffic for ages with the AC on then the temp will creep above "N", but apart from that no issues. We also run an ethanol mix fuel (can buy good stuff at double the price) and I tend to run slightly less advance than standard.

 

Running too far advanced or retarded can both cause issues - I have had real grief with a Bonnie because of just that. 

[A-Cell]

The issue here is the altitude and maintaining a reasonable stoichometric ratio. The A series is very tolerant and will run with a very wide range, just not performing well. Modern cars are able to modulate themselves for altitude.
Running at 1 mile high is the issue here. See my post for the resolution.

[Captain Mainwaring]

The issue here is the altitude and maintaining a reasonable stoichometric ratio. The A series is very tolerant and will run with a very wide range, just not performing well. Modern cars are able to modulate themselves for altitude.
Running at 1 mile high is the issue here. See my post for the resolution.

He is going to lose around 15% power whatever happens - one thing that may help is to ensure that all fuel lines and carb are kept as cold as possible.- there is a tendency for fuel to boil directly as it passes through the metering jet on the float bowl.

 

Whilst modern cars are able to modulate themselves because many will use a MAF...unless they run forced induction, the power losses remain an issue.

[sdjones121]

Wow, thanks for all the help. I was hoping to wake up to a reply or two, never expected such a good conversation. I'll try to respond to each point:

 

The fan is set with the blades "cupped" toward the radiator, from what I have seen around the forums, this is correct. The heater does get hot, and I've noticed that if I leave it on, there is an ever so slight improvement in the engine temps. The thermostat is a 160f/71c I believe.

 

Something I, foolishly, didn't consider was the effect of lower octane ratings. Regular gas is 85 (90 RON) here, and just out of habit, that's what I've been grabbing. Also, all fuel here is labeled to contain "at least" 10% ethanol. As I recall, I was using 95 RON in the UK. I haven't popped out the plugs yet, but simply judging by the smell, I'd definitely think it's running pretty rich.

 

I'm not sure what rating the current rad cap has, I'll have to check that.

 

It's looking like my first step will be retarding the timing a few degrees and fill it up with a higher octane fuel.

 

Thanks again for all the help, I'll let you know what happens!

[Ethel]

The jet is held by a bimetallic strip to help regulate for temperature and reduced atmospheric pressure could allow the carb float to expand and mess with the float level. A heat shield for the carb may be an idea.

[A-Cell]

If you retard the ignition then this will make the problem worse. Whilst this works with ethanol laced fuels at or close to sea level it is unfortunately going the wrong way for continued use at a mile high!
As I said more advance is required and a leaner mixture.
Ask the locals who run older classic cars, same principal applies.

[sdjones121]

Update:

Ok, I went out and checked the timing and it was very retarded, off the charts on the pulley, if I had to guess, I'd say it was about -10 degrees. That reminded me that Mr. Baldwin had noted my distributor was worn and would likely not hold timing long term (he said it was ok, but that I should adjust the timing a bit more often than normal). I decided to start with +4 degrees, and that instantly gave me a vastly improved idle. In fact, it started to run as well as it had when I left Wilshire's.

 

Took it out on the road and noticed a few things: A) noticeably better throttle response, I know I lose a fair bit of power at this elevation, but I got a good chunk back now, B) idles perfectly, no more dying at stop lights and looking like a complete tool every time I come to a stop, C) a bit cooler running. To be fair, it is coolish right now since it's early in the day and I was running without the grille in place, but I'd ran under those conditions before and this was cooler still.

 

My first stop was a gas station where I filled up the last half of the tank with 91 (95 RON), and noticed it wasn't 85 but 86 I'd been using. Within about 300 yards of leaving the gas station, I noticed a big difference in engine temp. I'd not expected such a rapid change, and am still wondering if it's a bit of placebo effect, but for the first time ever here the temp needle was dead center while running at 40 mph. Around town it was right around the middle, moving up while stopped, but perhaps not quite as quickly as before.

 

I took it out on the freeway, up to about 75, and the needle began to creep up toward the red like before, but again, perhaps a bit more slowly this time (could be due to the grille not being present). Once I pulled off the freeway and came down to about 50, it cooled back down very quickly. I then made a few stops at parts stores (no radiator caps for an old Mini, shocking!) and then got in some stop and go traffic. While in traffic it was running hotter than I'd prefer but nothing too crazy.

 

So to recap, timing at +4 gives me a great idle and much better running, 95 RON fuel gives me noticeably cooler running. An improvement, without question, but still not 100% there. I think I will run down the tank (which I would imagine is at about an average 92-93 RON right now with the two fuels mixed) refill with 95 RON and then do my commute, which is where it really gets tested. 25 miles, frequent stop and go traffic, 90 degree heat, and then the final 10 miles at 70 mph. I'll see what happens under those conditions, and then report back.

 

I just want to thank you all again for your massive help! While It's not fully there, the car is at least drive-able now.

 

Oh, and while I was out I got a smile and wave from a dude driving a Dodge Viper GTS. That felt pretty good.