18 replies to this topic

[gazza82]

So having searched on here for an answer, what is the best option? Without like A+ or with?

 

What are the advantages and disadvantages to removing it? (I guess the big disadvantage to leaving it is leaks ... I owned an A35 and remember the faff replacing it ... and I did several on mate's Mini's in 70s and 80s).

 

 

[Gremlin]

How do you mean, should you forget it?

[Nick Warwick]

One less thing to replace/repair!

[dsgoody]

Both have their pros and cons. I voted no, it takes longer for the engine to warm up with holes drilled in the thermostat.

 

It shouldn't cause you any issues if you use a good quality Kevlar or Silicone hose with decent clips.

 

Dave.

[gazza82]

I'm building a 1330cc engine ... I have two options: large valve heads with or without the bypass, and then a water pump to match.

 

Basically trying to decide which type to go for ... A+ ones tend to be without ...

 

As you can get different thermostats to open at different times I can experiment with them and ones with and without a small hole, etc.

[mikespicooper]

I believe you should use the bypass as you intend to build a modified engine so you will keep the water circulating all the time in the engine and use a higher thermostat such as a 82 degrees which is a std fit one an alloy radiator all over silicon hoses and a bronze nipple where the bypass fits on the cylinder head to avoid corrosion of the std iron one and the right amount of correct antifreeze!

[ado15]

All Mini's have a bypass system. The later ones just do it via a different route.

 

As mikespicooper suggests, it is best to retain it. People 'get away without it' but it's not really a good idea. It is important to keep water flowing around the engine when the thermostat is shut. Drilling holes in the thermostat doesn't do the same thing because water is always passing through the radiator, hence why it takes so much longer for the engine to warm up. The longer the engine takes to warm up, the more damage you do to it.

[tiger99]

The only things I would say are firstly, that if your head expects there to be a bypass, use it, or you may get uneven cooling resulting in poor running and damage, and secondly, NEVER USE ANY BODGER'S ACCESSORY, which includes such awful things as oversills, but in this case means a convoluted bypass hose. What you want is a short length of heater hose and two nice, new Jubilee clips, preferably stainless. It will last for many years. Remove the water pump to be able to fit it (unless you are having the head off, which is not that hard), and use a new water pump gasket afterwards.

 

In an emergency, if the bypass hose fails, you can just shorten one of the heater hoses (there is usually plenty of length) to get the material to make a new temporary bypass hose. The last one i did that way became permanent, as it lasted for years, and maybe 70k miles.

[gazza82]

If I had a bypass on this head/pump, I'd use a silicon pipe ... I've had a bypass hose go on the road in my old A35 and fitted one in a lay-by! Not fun but lucky I had one in the boot with some tools!!

 

Any way poll results as of today is 4 for not using, 5 for using!

Edited by gazza82, 01 May 2014 - 09:27 AM.

[minilee94]

Fit one just use abit of silicone hose will take many years to go wrong

Edited by minilee94, 01 May 2014 - 07:37 PM.

[gazza82]

Might be difficult as my A+ head hasn't got the fittings ... nor has my new water pump obviously

Nice timing gear by the way. What make?

Edited by gazza82, 01 May 2014 - 10:35 PM.

[AVV IT]

Hmmm both my mini's are Metro engined and as I understand it, Metro engines didn't have bypass hoses in the first place. Did Metros therefore have some other form of bypass system though? If so, should a bypass hose be fitted to a Metro engine that's been transplanted into a mini?

[Twincam]

Hmmm both my mini's are Metro engined and as I understand it, Metro engines didn't have bypass hoses in the first place. Did Metros therefore have some other form of bypass system though? If so, should a bypass hose be fitted to a Metro engine that's been transplanted into a mini?

Does the thermostat not have a little bypass on it? If my reasoning is correct, they would've either had a bypass in the form of a hose, or a bypass in the form or a small hole in the thermostat (there would be a little metal moveable piece within the hole) but correct me if I am wrong.

[AVV IT]

Not that I'm aware of. I was thinking more that the plumbing on a metro was different to that on a mini, with a front mounted rad and different thermostat housing etc. I therefore assumed that this somehow incorporated some type of bypass when such engines were fitted in metros. In my case it's probably not an issue, as both my minis have a form of bypass by way of there being no valve/tap on their heater circuits.

[Ethel]

Metros, and later minis have a sandwich plate under the thermostat that provides a bypass. In the Metro's case it's also the heater take off as there's no heater valve. Actually it's the heater take off on some Minis too, but they use an extra hose to bypass the heater.

You head may have the bypass, with a blanking plug fitted, but it may well be too corroded to just unscrew. I doubt there's much to choose on cost to go either route, if you can't find a sandwich plate kicking about.