Doing away with the bypass hose between head and block

Post by **MikeNash** » Sun Oct 21, 2007 6:34 pm

Anyone done this?
As I never turn off the heater supply I don't need the bypass hose and so could elimiinate a potential source of trouble by blanking it off. I'm thinking of aralditing a short bolt in the stub under the head and ditto into the water pump casting, but I suspect others have a more elegant soloution. What do you think? MikeN.

Post by **MoggyTech** » Sun Oct 21, 2007 6:45 pm

If you do this, remember to drill a couple of small holes into the thermostat to allow some coolant flow before the stat opens.

Not sure I like the idea of having a water system blanked off using glue.
Heat + vibration could cause the glue to fracture and break. Better to run a threaded tap into the pipes and fit blanking plugs with some thread seal such as Atmos.

Post by **rayofleamington** » Sun Oct 21, 2007 7:37 pm

If you do this, remember to drill a couple of small holes into the thermostat to allow some coolant flow before the stat opens.

The thermostat only controlls the flow to the radiator. Having a permanently open heater circuit will ensure there is some flow (like on some a-series where there is just an open stub pipe on the head for the heater, not a valve, and therefore no need for a bypass hose)

Post by **MikeNash** » Sun Oct 21, 2007 7:51 pm

Yes, I like the idea of threaded bolts. I'm just going to have a rummage to see what I can find, but I wondered if anyone had already done this. I suspect that threading the water pump in place will be difficult. Will let you know. MikeN.

Post by **MikeNash** » Sun Oct 21, 2007 8:59 pm

Well, I've run a 3/8th inch BSF tap down the pipe on the water pump casting and got a good fit with a short bolt. In the head I've run a 7/16th inch BSF tap but as the stub is thin, luckily its a shallow thread. But it takes a bolt securely. I'll trim it down to make plug. Unless anyone's got an awful warning, I'm inclined to give it a go.
MT, what's Atmos and where do I get it? I'm inclined to use a Locktite product or go back to Araldite, but if Atmos is The Thing, I'll give it a go.
MikeN.
By the way, is the stub in the head a press fit? I can't move them in either of the head's I've got.

Post by **bmcecosse** » Sun Oct 21, 2007 9:03 pm

Excellent idea to eliminate bypass - took Rover 40 years to think of it! No need for holes in thermostat - and you will find your heater works better - and sooner. Just use Loctite on your threads - it will be fine.

Post by **alex_holden** » Sun Oct 21, 2007 9:55 pm

I unscrewed the head stub (with the assistance of an oxy-acetylene torch and a cold chisel) and Loctited a cap head bolt in its place, then I replaced the water pump with a Metro one that doesn't have a bypass fitting. I drilled a couple of small holes in the outside of the thermostat to make sure there's always some flow through the head.

Post by **bmcecosse** » Sun Oct 21, 2007 10:05 pm

Lucky to get that stub out! It's often badly rusted. And if you want v best heater performance - fit an 88 degree stat with NO holes for the winter.

Post by **MoggyTech** » Mon Oct 22, 2007 9:35 am

Any good thread seal will do as long as it's water resistant. Atmos is just a brand name for plumbers thread seal.

Post by **MikeNash** » Mon Oct 22, 2007 10:07 am

Thanks for all the advice folks!
I'm going out now to cut up a couple of bolts to make plugs with screwdriver slots in the ends and install them with some sealant. Another vulnerability less! Regards, MikeN.
(bmc - already got an 89C thermo and v pleased.)

Post by **Kevin** » Mon Oct 22, 2007 11:59 am

I think its possible to get a blanking plug from the Mini specialists if you can get the old stub out of the head.

Post by **bmcecosse** » Mon Oct 22, 2007 12:32 pm

Some Rover heads have that plug fitted - dunno about availablity today.

Post by **Kevin** » Mon Oct 22, 2007 1:57 pm

These may help
http://www.minispares.com/SearchResults ... ty=fi&rt=1

Post by **bmcecosse** » Mon Oct 22, 2007 2:50 pm

That would do nicely - and only £1 each. Well found!

Post by **M25VAN** » Mon Oct 22, 2007 4:36 pm

If you didn't want to change over the water pump or fit a plug into it will this do which was listed on the web page mentioned above,

http://www.minispares.com/Product.aspx?pid=32723

bit expensive but cheaper here,

http://www.hytheperformance.co.uk/index ... rod_id=724