Warm running Dolomite 1850

[yorkshire_spam]

Since doing the head gasket on "Binny" our 1850 Dolomite I've been slightly concerned that at higher speed/RPM she's getting a little warm (not boiling over, but above "normal")

Coolant system is in good order, nearly new sprint rad and a volvo expansion tank.

I'm wondering if it might be the water pump (which was rebuilt about 12 months ago) cavitating or something like that? It seems odd that she's warm at 70mph on the motorway (lots of airflow through the rad) but sits nicely at "normal" temp when in traffic with an ambient of about 28 deg.

Any thoughts/ideas?

Cheers, Sam

[oldtuckunder]

By chance at Shelsley the other weekend a couple of the TR7 & Dolomite guys were talking of a similar issue, It appears that the clearances in that pump housing are critical to its effectiveness, and that a number of new water pumps on the market are suspect in build/clearance quality.  Two of the four slant four engines there had already been converted to external electric pumps. Apparently another reason for doing so is to remove load from that jack shaft that drives WP and Dissy, as its also a potential failure point. The TR7 we used as a competition stop gap a couple of years also had one of the Davis Craig? electric water pump conversions and didn't seem to suffer any overheating issues (well not until the head gasket blew!)

Alan  

[yorkshire_spam]

Very interesting, thanks.

It's just a shame the water pump is such a b1tch to work on. I'm having endless "fun" getting the various water connections to seal properly every time I disturb the inlet manifold.

 

[Nick Jones]

Yes, the designers of these engines weren't nearly as clever as they thought they were! Should be regularly flogged with barbed wire for their crimes against humanity......

Add lean running and retarded ignition to the mix of possible causes, but water pump clearances are certainly a candidate. 6 vane (early) and 12 vane (late) pumps exist. Each needs to be used with matching top cover and, IIRC, there is a setting procedure to get the correct impeller to cover clearance using gasket thickness.

also worth bearing in mind that barrelling along at 70 doesn't in itself guarantee good airflow through the rad. 

Nick

 

[yorkshire_spam]

I checked the plugs and if anything it's running rich... ignition timing I'll re-check just to be sure, I think it's somewhere between 11 and 16 deg BTDC

I pulled the workshop manual off the bookcase and looked at the process for setting the clearance. Different thickness of gasket based on a feeler gauge between the case and the cover then add the tolerance and pick the nearest gasket.

Previous owner rebuilt the pump and changed the top cover, so parts should be good even if the cover tolerance isn't quite right.

Next time I'm doing 70 I'll pop the bonnet and see if it improves things :-)

 

[oldtuckunder]

4 hours ago, yorkshire_spam said:

I'm having endless "fun" getting the various water connections to seal properly every time I disturb the inlet manifold.

 

Ah, have to admit being caught with that, after we blew head gasket on TR7, replaced head and gasket, fired up shortly afterwards had steam pouring out exhaust, thought had fuc.ed head gasket replacement, removed again, all well, re-assembled, same problem! Turned out to be a leakage on inlet manifold between front waterway direct into #1 inlet tract, so yes we were just injecting water that was turning to steam!  Crappy repro gasket.

[yorkshire_spam]

I have some "NOS" manifold gaskets and some new ones. The new ones (despite being from a reputable specialist supplier) are about 2x the thickness of the NOS ones!

 

[oldtuckunder]

Ah reverse problem to me with the MK1 Vitesse manifold gaskets, original Payen's are about twice as thick as the current repro ones, and I'm down to my last couple!

[Sprint95m]

9 hours ago, yorkshire_spam said:

Coolant system is in good order, nearly new sprint rad and a volvo expansion tank.

The header tank (it is not an expansion tank) is poorly positioned on your car. I did point this out in the TDC forum thread.

If it was moved to a better position then filling up is a simple process with no bleeding required and
furthermore the potential for cavitation is greatly reduced.

 

 

 

 

Below is a photo of my preferred location. It is as high as possible (taking advantage of the skeleton of the bonnet).
All the coolant within is ABOVE the height of the engine.
To fill up the cooling system you set the heater to "Hot" and fill via the header tank. No bleeding or purging hoses required.

 

Whether position of the header alone is the cause of your problem I don't know Sam
but I do know it is easier to start with moving it.....!

 

The water pump clearance should be set to the maximum given in the workshop specifications,
advice from Sprintspares (now sadly no longer trading).

 

As an aside,
I have an electric pump for fitting to my Sprint, it is a Stewart EMP (200 litres/minute) 
but alas these aren't sold in the EU so I had to import one from the USA.
However, even allowing for all the import duty, they are really good value compared to the rubbish that Davies Craig produce.

 

 

 

Ian.

Edited July 2, 2018 by Sprint95m

[yorkshire_spam]

Hmmm food for thought there Ian, thanks. I might try a temporary move of the tank and see what's what.

Cheers, Sam

[yorkshire_spam]

30 minutes ago, oldtuckunder said:

Ah reverse problem to me with the MK1 Vitesse manifold gaskets, original Payen's are about twice as thick as the current repro ones, and I'm down to my last couple!

I have only 1 pair of NOS thin gaskets, I intend measuring the thickness and buying some gasket material to make up copies rather than using them.