dodgy thermostats, or badly tuned webbers?

[wonkey eyed barmaid]

* Taken from the 'popping, spitting, lag' thread*

 

Is your car fitted with a thermostat? - i remember mine running pretty poorly last winter until i had one fitted. The water temperature never registered on the gauge unless in traffic - now runs just below 80 and runs a lot smoother.

 

Neill

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I have this popping and spitting occasionaly on my 1600 Vx as well, and had thought that the carbs needed setting up...

 

Neil,

can you explain more about this thermostat please?

I have mentioned before on this site my concerns over my water temp guage always having very low readings. never gets close to 90, where the fan should kick in? In fact today I was blatting up and down the A701 north of Moffat and the guage never made it above 60 - that cant be right!

 

Faulty guage or faulty thermostat? how can I check?

 

granteuk

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I am also interested in the thermostat bit. I have a 2.0 vx running on Dellortos. My fueling seems to be OK although if you blip the throttle on downchanges the engine starts to run on three and ocasionally stalls at roundabouts after this.

 

But it bangs really loudly whenever you back off and at any revs (this is great to start with but loses its appeal as time goes on). It is also great in the dark but I think my silencer may be suffering (I have a 3" SBD exhaust and I have been told this may be the culprit). It seems to be cured when running at track days which I would have thought would make it worse. But it runs at about 50 degrees C on the road in this weather and about 60 - 70 in the summer.

 

Michael.

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Dunno if it is any help but on the carbs supplied for the beaulieu 1600 vx's many had the wrong calibration inside the carbs (SVA ??)

 

I also had the same probs, in particular a flat spot a 3500 rpm, had the carbs recalibrated (not by caterham, who just kept balancing them) and now it runs a treat, minimal spitting and popping and better performance throughout the rev range.

 

Talk to Ian at GRL Motors on 01483 725759, he knows all about it

Jon

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* Can anyone add anything else concerning these possible dodgy thermostats, that may be causing poor running and misreading guages??

how/where to check the thermostat would be good.

 

*And what about "carbs recalibrated " - what does this invlove? is there anyone in Scotland who you'd recommend to do this?

[Super_Rich_Bernie]

I used to have one of thses cars, and it certainly didn't spit, bang or do anything else unpleasant. In fact it was amazingly untemperamental for a weber equipped car - just as smooth and easy as the injected car I have now. In 2 years and 6000miles the carbs needed balancing twice, and a loose choke tube caused a misfire - soon cured.

 

If you do a search you should be able to find some early threads on the 1600vx cooling system. Many of the cars run without a thermostat - mine did. In winter I cut a piece of aluminium, painted it body colour and blocked off a part of the radiator grille to increase the running temperature - otherwise it ran at 50 degrees on cold days. There was a good reason for the lack of thermostat, and I think the fitting of or non fitting of a heater was related to this - just can't remeber the details. On a warm day it ran at 70 degrees, though took a while to warm through.

 

The previous owner of my car had the carbs rejetted from the standard Caterham spec. The jetting seemed an odd choice - but probably compensated for the Z shaped inlet manifold needed on these engines to clear the diagonal chassis tube. The reset jetting was a 140 main jet & 34mm choke tube plus other changes I didn't note down. This inlet manifold shape is probably the reason the engines are hard to tune for more bhp - and short of sawing out the chassis tube there isn't much you can do about it.

 

I never tried a car with standard jetting so don't know how much difference the changes made. It did pull well from low revs with no flatspots and I heard that the standard spec had a flat spot at 3500rpm - though thaty may have been peculiar to that individuals car.

 

hope this is useful - a search around should reveal the thread on thermostats.

 

Jonathan

 

 

[C7JFM]

My advice is to fit a thermostat. It was the best £10.00 i ever spent on the car. Any vauxhall dealer will supply one for a C16NZ 2 engine (assuming there has been no change in the engines supplied). The car ran smoother and maiantained a healthy 80 to 90 degree temp. It never overheated.

 

Chris

[wonkey eyed barmaid]

thanx Chris,

 

how do I check firstly if I have a thermostat or not? where is it located?

 

if there is no thermostat - then what is the water temp guage connected to at the moment?!

[C7JFM]

There is a thermostat housing at the front top nearside of the engine. It will have a large pipe connecting to the radiator. You undo the top of the housing by removing 3 bolts and take it off. It may be a good idea to drain a little water from the rad before going ahead or you will get wet shoes. You will then see if you have one or not .

[Foxy Smith]

This is quite interesting.

 

When I bought my car, VX 2.0 Swindon it did'nt have a thermostat fitted and like the poster above I made up a radiator blind to try and get the engine up to temp. I was told that often thermostats were taken out of Vxs particularly for track use to boost bhp slightly. How true this is I have no idea but am sure it is not conducive to good engine wearing if the oil especially does not come up to temp. ( always had nice high and steady oil pressure tho)

 

I then fitted a thermostat as I got p****d off taking the nose off to adjust the radiator blind. Now I find that the engine comes up to temp nice and quickly. After a while the thermostat starts to do its stuff, and this can be quite alarming as the temp gauge swings up rapidly into the red then backs off to 85 or so over say 30 secs. I am told the problem is a mismatch between the thermostat(opening at too high a temperature) and the gauge ( reading too high).

 

Overall can't say I've noticed any difference in how the engine runs with or without thermostat, probably prefer having the 'stat in.

 

Did give some consideration to an electric water pump but as this really requires disabling the belt driven pump to get full advantage have'nt done anything about it as the water pump is a swine to get at. Maybe when the cam belt gets changed??

 

As regards popping and banging, air leaking into exhaust should be considered. Misfire on over run, check needle valves/floats in carbs as flooding will cause funny things to happen had probs like this with over specced fuel pump overcoming the floats/valves could get so bad as to cut the engine competely.

 

Alan

[michaelw]

Thanks for that, I have had someone look at the carbs and said it lloked OK but I think they need properly set up or go for Injection (sounds expensive)

 

Michael.

[AndreK]

To add to the comments above. The Vx 1600 cooling system is best with the triple conning tower submarine pipe, if you want to run it with a thermostat. If you search for the 'Cooling on VX 1.6 thread' in the technical archives you will find a more detailed explanantion. I believe that the current (?last of) Vauxhall Classics may have this as standard but the early cars didn't. As above, Vauxhall dealer will be able to supply a suitable thermostat. The car then runs at 80-90 deg. C even in the winter.!