Thermostat

[Guest Mr Pid]

I know this is probably a stupid question but ive been readin alot recently about a few cars who's thermostats have decided to remain closed during openning hours resulting in seized/overheated engine warped heads etc etc.

 

I understand the function it does but is it really necessary? Can i scrap it and let my engine have the benefit of the water 24/7? Has anyone done this and encountered any problems.

 

Sorry im just paranoid about overheating, ive just finished fitting my third fan!!!

 

Cheers

 

Stu

[Guest Guy]

Hi Stu,

 

I took the thurmostat out of my Cavalier, it took an age for the engine to warm up and so the auto choke stayed on and my MPG went tits' up! Also, in the winter it was cold in the car!.

 

If you want full power you'll need a warm engine even if you can switch off a manual choke.

 

I put a new one in and life was good again!

[Guest Ant]

My new thermostat for a EFi 2.0 pinto was only £2.33 including VAT. If you're that worried about it staying shut simply change it when you change the oil.

 

Running without one means that you're essentially running a cold engine permanently. This means more friction, more fuel usage, colder (and hence thicker) oil, and very rapid engine wear.

 

Ant

[Big Jim]

The biggest problem with thermostats in the Pinto, is people putting them in arse about face. You should use a stat. You can get stas with different opening temps, I use one that starts to open at around 76º and the engine runs nicely all day at 80 - 82º (see build tips on NW web site) make sure that you have a true reading on your temp gauge, remember the sender must match the gauge not the engine / car.

[Guest Mr Pid]

OK cheers chaps i shall look for one with a lower opening temperature.

 

Just for peace of mind - is the correct way to fit them with the domey bit facing away from the engine? and does the seal go before the stat, behind it or around the outer metal bit?

 

Thanks again

 

Stu

[Big Jim]

Try themostat QTH370. They will not have one in stock, so get them to order it for you. When it comes, it will have a baffle plate attached, this in the engine it was designed for, closes off an internal waterway as the thermostat opens. Remove this plate (usually just held with a small wire circlip) then grind down the 'peg' that it was mounted on. Do this slowly, don't get the peg hot. Then when you fit it into the housing, the copper 'bulb' should be in the engine side, not the hose side.

[Guest Mr Pid]

You're are star, cheers Jim

[Guest Mr Pid]

Jim, just reading your other post on sender being correct for guage etc, and after looking at the guages you mentioned on ebay, i emailed the seller and hey says they are all cut very short with no senders, he doesnt know what they are for, from or who made them.

 

I know they are still pretty cheap but will they be really worth the hassle if they do have the correct senders with them?

 

Cheers

 

Stu

[Guest Ant]

That depends! Here's my knowledge speaking as someone who bought their gauges on EBay.

 

Temp gauges are the most important. For mine I took the number off the gauge, phoned a smiths instrument restorer, and bought a sender unit - 12 quid. Works a treat.

 

Fuel gauge is the next one. This is less important to me, so I did a few tests on the gauge, noting its current requirements for different gauge positions. Then I measured the Sierra sender resistances at various levels. Then I added a few resistors to the basic circuit so that it goes from min to max with my sender. The only problem here is that it doesn't do it linearly ... instead it falls really quickly just after filling up, but stays about the 1/4 mark for an eternity when heading for empty. The net result is that the mileage dictates when I fill up, and the fuel gauge is a reminder. I could buy a sender unit for about 25 to 30 quid, but it's usable as it is so I've not bothered yet.

 

Rev counter - no problems so long as it's not pre 50's ish. Same wiring as the Sierra one.

 

speedo - may need re-calibrating, and you'll probably need a new cable with the correct ends. Cables cost about 20 to 25 quid. Calibration is 60 quid ish, but it's only necessary if the speedo is way out. SVA is an issue here, but the requirements have a huge margin of error so long as the speedo over-reads not under reads, so it's a 50 50 chance really.

 

Oil pressure - put a T piece in between the electronic sender and the block, and run a pipe up to the gauge on the dash. If the gauge comes without a T piece and line then replacements shouldn't be more than a few quid.

 

Vacuum gauge - great fun to watch this one! Simply put a T piece in the vacuum line to the brake servo and run it to the gauge.

 

Volts - a doddle. Connect an ignition live and an earth to it and away you go.

 

Amp - More trouble. Older gauges are 30Amp max, but Sierra alternators are 55Amp approx. Yeah, I know it doesn't kick out 55Amps all the time, but the day you need a jump start it will coz it'll be charging a flat battery! Solution is to either put the alternator directly to the battery rather than through the gauge, in which case the gauge reads current consumption rather than overall battery current, or design a circuit which halves the current, and then double the numbers on the gauge. Third option is to fit it to the dash, make it light up, and don't connect it at all ... that's what mine is like at the moment!

 

A couple of other things to watch out for ... non-electrical temperature gauges are a nightmare as they have a mercury connection to the cylinder head. I've no experience here, but they're trouble. Electric oil pressure gauges will need a calibrated sender unit so they're also best avoided.

 

That's my 2 pence worth. I bought two sets of gauges on EBay. One set are in the car to various degrees of completion, and the other set I've just re-sold on EBay and come out about quits on them. The set in my car cost about 150 quid total, this is for all matching smiths gauges, speedo, revs, temp, oil pressure, vacuum, volts and amps. Speedo was recalibrated (unnecessarily!), had a new cable, and I bought a temp sender. I was given the volts, amps, oil and vacuum gauges though Not bad when they'd total over 400 quid new.

 

Ant

[Big Jim]

I agree completley with Ant!

 

The only thing is, I wouldn't put an amp gauge in, I fitted a voltage gauge instead.

[Guest timswait]

At the risk of stating the obvious, the rev counter needs to be for a 4 cylinder car, it counts pulses, so if it is expecting 6 or 8 per revolution it will read 3/4 or 1/2 what iit should.