Hi guys

Just a couple of quick Q's before I start putting the engine back together.

1) I'm concerned that my radiator may of had an air pocket when it was installed. When I reinstall the radiator and fill it with water+coolant, what it the best way to ensure any air get out the system - I'm not running a heater at all.

2) I'm considering removing the thermostat from the head and putting a blanking sleeve in to regulate the flow. What people's thoughts on no thermostat (head is no bypass)

3) Before I put the head on, is it possible for me to calculate my compression ratio the engine is running? If so, how do I do it?

Thanks guys
James

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Hey James,

All I do to bleed the cooling system is to fill the radiator entirely, leave the cap off, turn heater on if you have one, start the car and let it warm up. Once the thermostat opens, you'll generally get a few bubbles and gulps from the top of the radiator. Continue filling until all the bubbles are gone (I usually let it idle for 15 min or so), put the cap back on and happy days. Take it for a bit of a drive and let cool down and double check the level when it's cool. Standard warnings apply here about opening a hot cooling system and copping boiling coolant and radiators caps in the face.

As for the thermostat, I've always run one. I think that a new and correct temperature thermostat, tested to make sure it works and at the right temp, will have no negative effects on the car. I'm sure you can run without one and many people may, but I'll let them comment as to why and what the benefits are. I've driven in many a mini on a 40+ degree day and had very few problems with cooling or coolant flow. Except once when I put the radiator fan on backwards.

Cheers,
Keels.

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-Wasabi
1972 Clubman - Daily Driver
1962 850 - EW1 Powered

To figure out the compression ratio you'll need to know the volume of the head (cc), along with your bore, stroke etc.

I've got the proper gear at work to measure the heads. I can help you do this if you want? You can use the cheap plastic syringes from the chemist, but I've found they aren't always accurate.

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Running without a thermostat just doesn't make sense to me. What is the logic?
The thermostat serves a very important role in that it allows the engine to get up to temperature before opening. On colder days you may find that running without one will not allow the motor to warm up which could have some bad side effects.

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Ryan Filippi
Minis In The Gong
[email protected]
www.minisinthegong.com.au

I have never used a blanking plate, but have heard they are ok.

You need to run something as if you don't the water circulates too quickly and doesn't have enough time to cool.

I have never had air pockets. I just fill it up to the brim, Squeeze the top hose a few times and put cap on and its fine.
When circulating air will automatically go to the filler neck, So just fill it up and run it, and then check it (Once it has cooled of course so you don't hurt yourself). All my minis have the by-pass hose though.

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Cheers guys think I'll take your adv on the thermostat and getting air pockets out.



I'm quite curious to know what mine is actually. If you've got any time to help me out whenever that'd be awesome thanks Timmy

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If you're free tomorrow afternoon after 6PM I could bring the gear up to your place and check out that subframe while I'm there?

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I'll add my vote to the prov thermostat crowd. It's a must in my opinion. Quicker warm up and then maintains correct temperature.

Otherwise the cooling system has the same flow on a 40 degree day as a 5 degree morning..

+2

Air pockets aren't an issue on our cars. Only a few small bubbles are left over generally after you fill up which dissipate quickly..

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I also agree that the thermostat is a must have item on a road car.

I had a thermostat with just a 3mm hole drilled for a non-bypass head. It took AGES to warm up and ran like a pig cold. I couldn't imagine how crap it would be to have no stat at all.

Interesting ?
My 1100S (1275) has a hose from the heater connection to the radiator top tank and no bypass between the head and water pump. Also takes ages to worm up and runs terrible until it does.
It would be undrivable on a cold day without a thermostat.

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