Hot running AMC 360

FrankNB

hi boys,

well, here I am once again knocking my head against the wall. The rebuild is 5 years old, with maybe 5000 miles on it 3000 of which were put this year. It's not a daily driver so...

Anyway it's your typical mild build,
-.30 over
-edelbrock intake
-Summit SUM-8600 cam http://www.summitracing.com/parts/SUM-8600/
-Howell TBI
-MSD distributor (blue-heavy silver spring, 21 deg max advance)
-MSD Offroad ignition
-TFI coil
-.045 plugs
-bulltear timing cover and oil pump
-15w40 non-synth
-4 core rad (rebuilt after engine)
-160F thermostat
-17'' Derale fan (puller)
-oil cooler

I noticed that the advance had a good effect on engine heat so I've been playing with the advance to control detonation (pinging) and trying to control the heat. Right now it's around 5 deg with vacuum off, vac adds 10 for 15 total at idle.

Currently, idling it will keep heating up and not cool down, I need to go about 40mph at light throttle to get it to at least stay around 195. Or turn the heater on. Idling the temps will just keep climbing.

We also think I'm consuming oil cause I keep having to top it off but can't see any serious leaks. There is a light accumulation of oil in the breather pan. Would some type of blowby let heat travel into the engine and be the source of all this? Bad rings? Unseated rings?

jeepsr4ever

I am willing to bet your running lean lean lean.

FrankNB

jeepsr4ever wrote
I am willing to bet your running lean lean lean.

I'm confused, isn't the Howell EFI supposed to take care of that? The stoich gauge needle bounces beetween rich and lean as it should, no?

I mean, any of you guys that run this Howell setup have to enrich it some?

I've just ordered your water pump for peace of mind as I don't trust the guy that built my motor. I remember him mentionning having an issue with the water pump that he had blamed on the nickel plated cover.

jeepsr4ever

I havent tinkered with a Howell for a while but I take it you have the oxygen sensor welded in. As far as blame goes AMC is one of those motors that you either know or you have to learn about before assembly. We often get engine builders calling up with questions.

FrankNB

jeepsr4ever wrote
I havent tinkered with a Howell for a while but I take it you have the oxygen sensor welded in. As far as blame goes AMC is one of those motors that you either know or you have to learn about before assembly. We often get engine builders calling up with questions.

Yea, this kit has the oxygen sensor. We put it right below the collector.

tufcj

Do you get a serious sound of air sucking at idle? When I got my Howell setup, the throttle plates in the TBI were closed too far. The IAC was almost opening fully to compensate, and it was too lean at idle. If you hear a whooshing sound at idle, I can give you the procedure for adjustment, but you need an IAC control tool. Bob tufcj

FrankNB

tufcj wrote
Do you get a serious sound of air sucking at idle? When I got my Howell setup, the throttle plates in the TBI were closed too far. The IAC was almost opening fully to compensate, and it was too lean at idle.

If you hear a whooshing sound at idle, I can give you the procedure for adjustment, but you need an IAC control tool.

Bob
tufcj

Yes I do, that's the first thing I noticed is how lound the succion was at idle. And it idles at 1000 rpm, quite fast.

I'm all ears.

FrankNB

Well, I guess it's just me freaking out over nothing.. Quote from my buddy that did a bit of research today.. "BTW Normal operating temperature for the AMC line of motors is 190-210, according to most of what I read, EFI will run hotter, more complete burn, leaner. If it exceeded 210 regularly I would be concerned, Boil over is 257. " I'm just used to freak out when I see temps above 185.. not sure why.. I'd be interested to know what some of you have for engine temps..

Patf10

mine runs right on 190 consistantly, on the highway it will bump up just a tad, but never thought it to be abything to worry about. Now i just worry why i only have 20psi oil pressure at highway speeds! maybe time for a new pump

tufcj

Mine runs in the 190-200 range too. The emissions will actually be cleaner over 190. For the IAC. There's a small metal cap over the throttle plate adjusting screw on the driver side of the throttle body. You need to pop that off with a small punch. Disconnect the IAC from the harness wires and install the manual IAC adjustment tool. Start the engine. Close the IAC fully, while adjusting the throttle plate screw until the idle is about 500-600 RPM (you may stall it a few times). Shut it off and reconnect the IAC. I believe Howell sets the idle to be about 750. The IAC will open to bring the idle up, but you won't have the loud whooshing sound. Mine still does it while the computer tries to compensate when I'm lugging it at idle on the trail. That's the only problem with the Howell system, it gets no input from the speedo, so it doesn't know you're moving. The TPS says you're at idle, so the computer tries to maintain the 750 RPMs. If you lug it down (at idle), the computer opens the IAC attempting to bring the idle RPM back up. It's not all bad, my Jeep idles thru a lot of obstacles. Bob tufcj

FrankNB

Thanks for the instructions, I'm pretty sure my kit has a speed sensor, we put this little device on the t-case speedo gear and it's connected to the ECM. Put I do get the effect that you're talking about, in a parking lot when slowing down. Mine actually idles at 1000 rpm. With the carb, the best we could get was around 800. We'll try the IAC procedure. What's this IAC tool you're talking about?

tufcj

I have one similar to this that was made by MAC tools. They were popular in the early 90s when there were a lot of TBI problems. Now they're nearly obsolete.

http://www.amazon.com/OTC-OTC3320-Control-Tester-Chrysler/dp/B00063USCG

Bob
tufcj

FrankNB

Wow, that's expensive... at the end of the Howell service manual there are instructions to set your idle speed. I don't have the manual with me here, but it was along the lines of taking the cap off, jumping the ALDL A&B connectors, disconnecting the IAC plug and turning on the vehicle and setting the screw to the desired idle rpm. Turn off, plug the IAC and remove jumper and be happy. Will try and set it around 850 this weekend, don't want it too low as on the trail it's nice to let it idle around and also prevent stalling when clutching. Can barely wait to play on angles to compare with the old carbs I used to run.