Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing GDI Heater Bypass Fitted

So, I found a cheap 4 way bypass online.
https://www.amazon.co.uk/dp/B07V45J99R

I liked this one as it completely bypasses the heater, the ones for Taxi's are only 3 way and leaves the possibility that hot water can leak back into heater from the outlet, they are Brass though which is good. I don't like that mine is plastic but thought it should be ok as a prototype and if it works I would look for something more robust.

Diagrams show how it works, link provided by Gambalunga.


It comes with a Vacuum actuator, which I didn't want, but it is easily removed, see picture. It should also be pretty simple to make up a bracket to fit a Bowden cable, solenoid or other actuator in the future. The Lever in the middle isn't spring loaded so can easily be switched On/Off by hand.


It fits between the back of the engine and the heater box, I was going to attach it to the heater box but couldn't find any diagrams of the inside of the box so refrained from drilling/screwing anything into it.

It is simply suspended with 4x cooling pipes clamped to it and feels secure, so we'll see how it goes.

This picture is from is from low down on the offside and shows the pipe from the engine to the Bottom of the Bypass. This is the easiest access for your arm to get to it.



This picture is from above with the heater box to the left, the engine is to the right. It shows the new hose from the Bypass looping round underneath the bypass.



This picture is from the Nearside and shows on the right the 2x hoses from the bypass to the heater box.




Fitting

After draining some fluid from the system, I
- Removed the big Air Intake pipe between the Filter and the Throttle Housing.
- Cut the pipe running from the back of the engine to the heater box roughly in half and fitted the ends to the bottom left and lower right.
○ I purchased a brass straight through connector in case I want to put it back together.
○ NB the pipe I cut has a metal Spring in the end where it bends back on itself, it pulls out easily. I trimmed it and replaced it before fitting the Bypass.
- Simply turn round the heater exit hose so it goes to the top right of the Bypass instead of the T piece in front of the Expansion tank.
- Run a new piece of hose from the higher left port doubling back to the T.
- Replace Fluid and Air Intake Pipe.

So far have just ensured I have no leaks and it works, ie the heater inlet pipe does not get Hot with the Bypass On, but does get Hot with it Off.

The Inlet pipe does go up in temp a little! Could be a leak from the valve letting small amount of water through or just the heat from the engine bay, Have to let the system cool down now so will continue the Air Temp test when all is cooled again and post results here.
https://www.talkmorgan.com/ubbthreads.php/topics/793193/4-gdi-air-temps

Switching the Bypass On/Off means feeding a hand between the Pipes and Engine, which get Hot, so picking a state before starting up is a good idea. If the Bypass stays I'll be looking to fit some sort of remote actuator.

Could you fit longer pipes and fix to the bulk head/ firewall. I assume that silver cylinder is an actuator so then you could fit it and wire it in, though it looks pneumatic on Amazon. Or do the by hand approach without the actuator & not get burnt.

Neat mod Mark . Good call going for the four way diverter valve. I would have been tempted to search for an electrically actuated one if I felt I needed one, but Bowden cable operation will be simpler still. Spare cables for OE heater control on 60's and 70's classic cars are available on eBay.

Maybe some more pics when you have the installation completed.

There are lectric ones on ebay with 4 way control here. Not sure about the spiogt diameter required though

Obvious issue here is that the lever not being spring loaded, and in the absence of a positive actuator , the valve is not being held firmly in the closed position. You don’t need much of a gap to allow enough water to flow to warm up the heater.
As an example, if you shut the valve off on your household radiator, then just very, very slowly turn it until you can only just hear water flowing, you will find the inlet pipe gets hot very quickly. At this point, the valve seal has only just lifted off its seating by a whisker.
So fit a Bowden cable or similar and I think it will be much better. As a test, you could apply an elastic band or a spring to the lever to see if it makes a difference.

Or a tie wrap.

But the valve is a butterfly valve, it is extremely difficult to get one of those to seal 100%. You have to go to measures like “soft seats” which will up the price a lot. I would suggest that one will have to accept some degree of leakage.

Edit: For 11 quid what do you expect?

Cheers
John.

I guess you could use the bypass and after a shut off valve.

Hi,

I seam to have created 2 threads covering this topic, so apologies for that, I just wanted the title to reflect the content to aid anyone searching in the future.

Thanks all for the ideas generated, they are all welcome.

I will probably retest with an elastic band on the valve lever, it makes sense and inexpensive (not counting Petrol), so appeals to the Yorkshireman..

I accept that the Bypass was cheap and therefore this was almost inevitable, but it is a replacement part for an Explorer so I thought it should work. The obvious difference is I fitted it without the Vacuum actuator it came with, which backs up the theory of needing some pressure on the valve lever..

I had a really good look at all the pics of the Bypass identified by John, I don't want to stifle any ideas and thanks for bothering to search, but I don't think its a 4 way. To me it looks like the Valve sits at the junction of 3 ports with one going to a T, which makes it very similar to the Taxi one in concept. It's really hard to tell when they don't provide enough detail, not even the ID diameter of the ports.

More sophisticated Bypasses do exist, more in the States such as this one which Gambalunga found.

https://www.thermotion.com/4-port-electronic-heater-control-valve-pn-354-69694

But it also needs a control module, a potentiometer and is a bit OTT for my needs, a simple On/Off valve will suffice. interesting to me was that the basis of it looks very similar to the cheap one I purchased, everything is made in China!

Thanks again.

Looks interesting for me, but only if it works as an on/off valve.