Thermostat Question 160 deg. or 195 deg.?

It needs to warm up above 190 to be sure the inaccurate sensors actually turn on and switch the computer into 'warmed up' mode. Otherwise the computer stays in basic 'cold' mode and you burn a lot of gas.

You also will lose internal heat with a cold t-stat in the winter.

Even with no computer still working in my 86 258, I get better mileage with a hot engine.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

You mileage and engine life would go down and your emissions would go up year round.

In the wintertime your heater will function poorly.

I do not believe that an automobile engine has been commercially built in the last 30-40 years that was designed for a 160 degree thermostat.

Engine temperatures of 190-210 are normal (that is why 210 is dead center of the gauge)

Also the cooler thermostat will not allow the water vapor in your oil to evaporate, and this will promote sludge and acid formation. The main advantage to the 160º thermostats that I have seen, is that they have a larger diameter water passage and therefore, I suppose, allow higher flow for rock crawling with a big engine, which you do not have.

Knock and ping can be due to too low octane fuel, or the timing mark on your harmonic balancer having slipped. Putting in a cooler thermostat isn't going to fix that. Check TDC with a dial gauge or something before being so sure that your timing is "dead on".

Earle

The others have covered the t-stat question pretty well - don't!

As for the ping/knock, it only costs a little time to SLOWLY run a pint of water through the intake while keeping the engine at a fast idle. That will blast the carbon buildup off the heads and help with pre-ingition for hot deposits. As Mike R. says, you could also run a pint of ATF through it as well - might even work better - but the humongous smoke cloud that creates is gonna irritate some neighbors.

The others have covered the t-stat question pretty well - don't!

As for the ping/knock, it only costs a little time to SLOWLY run a pint of water through the intake while keeping the engine at a fast idle. That will blast the carbon buildup off the heads and help with pre-ingition for hot deposits. As Mike R. says, you could also run a pint of ATF through it as well - might even work better - but the humongous smoke cloud that creates is gonna irritate some neighbors.

Thanks for everyone's informative responses. I knew there were some good reasons not to go to a 160 stat, it just really bugged me that the smog police would care about that. The only reason I believe my timing is on is because every mechanic / smog tech to have ever checked it is getting the exact same reading as I am, but I guess I should check it with a gauge. I have run water slowly into the carb and am on my 2nd tank of Chevron 91 octane gas, both have helped but it still has a way to go. I think I will go ahead and remove my Air Conditioning system since it doesn't work anymore anyway, and the condensor is right in front of the radiator. Thanks again for everyone's help.

You have the dreaded Ford emissions computer running that carb and timing system.

If the knock sensor has failed or any other of the hundreds of feet (it seems) of vacuum lines have failed the computer dumps into 'limp home mode' and clamps down on the timing.

To test for this, warm it up fully and then open the hood and give the front tube of the intake manifold a warp with a hammer. The engine should stumble as the knock sensor kicks the timing. If this doesn't happen, you could have found the cause of the ping.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>

You have the dreaded Ford emissions computer running that carb and timing system.

If the knock sensor has failed or any other of the hundreds of feet (it seems) of vacuum lines have failed the computer dumps into 'limp home mode' and clamps down on the timing.

To test for this, warm it up fully and then open the hood and give the front tube of the intake manifold a wap with a hammer. The engine should stumble as the knock sensor kicks the timing. If this doesn't happen, you could have found the cause of the ping.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: N>

Of course, the harmonic balancer could have slipped. This sometimes happens on older vehicles. When it does, the timing mark moves and you can't get a real reading with a timing light.

You might check to see if you are running lean for some reason...carb adjustment, vacuum leak, etc. That will certainly make things hot and pingy.

Regards,

DAve

Kevin proclaimed:

If you live in a strict smog state, running a cooler thermostat does tend to make it harder to pass.

What do you mean by a lot of knock and ping?

Moderate accel or steady state?

Normal range IS 190 to 210 and the engine works better at that range.

I've had mild ping with regular from Chevron, most others seem to work. Midgrade or a shot of premium cures it.

Kevin proclaimed:

If you are using Chevron regular, I'd put money that is the problem. Only brand/grade I regularly get ping with. Yes I know it all comes from the same terminal in north San Jose, but the actual blend doesn't.