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Hamish

Water flow restrictor - jobs you shouldn’t start

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Whilst in the garage changing my sprinting tyres to my  vredestiens  I thought that On the back of Jonathan’s over heating tr2 thread I thought that there would be little harm in doing the flow restriction mod on my TR3a. The temps have been ok 185 to 207f with the elec fan bringing the temps down but perhaps they could be improved !

so off came the short L  shaped hose with little loss of coolant and I found a tight fitting Ali pipe/sleeve to go in the water pump housing. 

However, ( its never good if you have to add an “however”) the tight fitting aspect of this engineering feet was due to a little furring up of the hole.

with a little extra pressure, just to make sure it was a good fit you understand,  the bloody thing pushed right in.

it turns out that things put in here end up at the bottom of the bottom hose / rad junction.

Bu@@er. 

I have a skid plate under my car as it hold my anti roll bar so the only access to the bottom hose clip is with the near side wheel off and in through the limited space  where the steering arms come through.

luckily - sorry with brilliant fore thought. The last time I had the rad out I had all the jubilee clips the right way to allow me to get a socket on this lower junction and I was able to retrieve the sleeve. Whilst dumping all the coolant.

I needed to change the anti freeze anyway (3 years).

i then decided to concentrate on the thermostat housing and after measuring decided on a copper 22mm blanking cap  cut down and 8mm drilled at the top.

This tapped on to the housing nicely with the hole at the top to let air out and it’s short enough that the hose holds it in place and yet the hose is still sealed to the housing by the jubilee clip.

all done up and system refilled, with Heater hose off and front of car jacked up and cap off to let any air out  it all back together and running.

Moral of the story if it ain’t broke don’t fix it !!!

 

 

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Edited by Hamish

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As a restrictor, I use an old, brass, plumbing fitting which already had an appropriate hole through the middle.

To ensure that this fitting, which was a snug fit, would not migrate round the bend, I clamped a Jubilee clip round the hose at the position of the fitting.

Ian Cornish

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A mod often done over here is to use a copper 3/4" pipe cap with a 3/16" hole drilled in the center. It's pushed into the water pump end of the bypass hose and reconnected as normal.  Lotta folks report very good results with this.

'Course, our plumbing is still inch-based, so it's a piece of cake to get the right diameter plug.  About a £1 modification.

https://www.lowes.com/pd/NIBCO-3-4-in-Copper-Slip-Cap-Fittings/3680874

i-ZNBkBXd-S.jpg

 

Edited by Don H.

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Hi Hamish, 

a very nice and honest story

:D

Thanks for sharing.

Marco

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After all your hard work has the temperature reduced?

Jonathan

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Yes - Using waxstat thermostat and the 8 mm restricted bypass flow.

It the temp is more stable and reliable.

Peter W

Edited by BlueTR3A-5EKT
mm added

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I used an old coin with a hole drilled in it clamped next to the top bypass outlet with a second jubilee clip. 

Rgds Ian

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I still have the bellows thermostat in mine with no restrictor and it seems to work well.  Any reason to go with a modern stat? There still seems to be a few of the bellows type around as NOS at a reasonable cost. I bought a few at a car show a couple of years ago.

Tom

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On 8/24/2019 at 9:40 PM, Jonathan Smith said:

After all your hard work has the temperature reduced?

Jonathan

Doing the oulton trip today  to and fro and it’s a very hot day the temps are a little better. But not enough to warrant all the “extra” work imo. 

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Coincidentally, I was going to do this job today using Ian V's method. I pre drilled a suitable coin some months ago. Before starting, discovered I did not have a spare jubilee clip of the right size (had every other size!). So just cleaned the car after Stratford instead! Sounds as if I had a lucky escape.

PS the job does need doing as part of my ongoing list of mods to manage high temps. 

Miles

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