Engine temperature ?

D

Dochie

Member
Hi guys
I have a late 1972 p6 v8 with 58,000 miles on the clock (documented) but since I have had it I have always thought that it runs too hot.
When running down the motorway the temp guage sits in, or just slightly above, the centre of the guage but when I come into town in stop start traffic the needle is right at the end of the green sector almost touching the red sector.
The previous owner must have thought likewise as there are receipts for a new water pump, temp sender, temp guage and thermostat.
I have fitted a triple core radiator with two electric fans, another temp guage and new voltage stabiliser and I run with the heater on.
The car also suffers from fuel vaporisation and I have insulated the fuel lines and fitted an electric pump under the bonnet which has helped but it is still there. I am running out of ideas so I would like to ask if anyone else's temp guage behaves like mine and maybe this is normal or if not normal where do I go from here?
Just to add the timing and the mixture are good and the car runs well otherwise with plenty of power.

TIA

Dochie
 
Check that the coolant bleed hose between the top of the inlet manifold and the top of the radiator is clear and flowing freely. The metal pipe that comes out can get totally blocked and cause all the symptoms you describe.
 
Thanks harvey
The hose does get hot when the engine is running but I will remove it and check all is clear
 
The TDC marks on the front cover have been known to be a long way out, are you sure the timing is correct?
 
I am sure I set the timing with the timing marks and the engine ticks over smoothly and accelerates without pinking. I will have a look at it again but should I try advancing or retarding the timing to solve the problem?
 
The point quattro was making is that the pointer can be in the wrong place, so however you set the timing, if the pointer is incorrectly fitted, the timing won't be what you think it is.
 
PS Retarded ignition timing tends to cause overheating, and as you're not suffering with pinking that might indicate that the timing is retarded.
 
Thanks
I will try advancing it until it pinks then retard it a tad (technical term) and see if this helps
 
had same issues. now fitted up rated radiator (Wins ) . tower bleed is always my first check . 15 psi rad cap fitted . block reversed flush and heater matrix removed . cleaned ( needed desoldering as 90% blocked at far end) refitted. new hoses ( to ensure no internal restriction.s .coolant flow checked with rad cap off(Good) now using Evans waterless coolant ( seem sot help a bit) and advanced my timing more than spec as modern fuel burns a tad slower so needs more advance than normal ( no pinking-plugs good after 8 weeks running check) used electric fan but found not needed ( it was poor flow anyway) currently runs midpoint on gauge and in heavy traffic/hot stops/lights etc climbs to. approx 3/4 of way to red mark. if it got to Bottom of red section ..would stop -cool engine and investigate! still get odd vapour issues ( bubbles in fuel) even after fitting electric pump and insulating fuel lines. Used to be nightmare eg drive ( cold ) =good.stop /start =OK , but when hot and leave car for more than 10-15mins. bubbles appear .. and though car drives off normally ..about 1 minute later (or less) power. drops and car is sluggish and give appearance running on 3-4 cyls. after 2-3 driving ( slow acceleration holding traffic back) it suddenly kicks in with power liek a switch being flicked . I assume that is fresh fuel being delivered and bubbles in fuel line .carb gone. rover P6 seem to be notorious for hot engine bays.
 
Harvey, I disconnected the hose between the tower and radiator. I blew through it and it was clear, stuck a piece of stiff wire into the inlet tower, also all clear. Ran the engine and got a good flow out the end of the hose, so I think I can discount this.

Quattro, I think you get the gold watch. I tried setting the timing by ear, I advanced it until the engine got a bit spluttery and then back a tad. Took it for a run and pulling ok with still no pinking however the temperature is down. Still a bit of fine tuning to do but on the right track;

Thank you both for your help, much appreciated
 
Once you are happy, or more importantly, the engine is with the timing setting use a timing light to adjust the pointer on the timing case to the appropriate mark on the pulley.
 
classicalgreen your description of of fuel vaporisation is exactly what mine does. However with an electric pump and insulated fuel lines and hopefully a cooler running engine if I still get it I will live with it.

Thanks
Dochie
 
Re vapourisation I have fitted a length of Firesleeve over the pipe that runs from the pump back along the block and over the bellhousing to the reserve/main switch to try to keep the fuel temp down.
 
^Thats excellent advice. I’ve use similar material to beef up the heat shield on my 2000TC because of boiling fuel in the float chamber (HIF6s and Ethanol fuel). Makes a huge difference.
 
Dochie said:
Hi guys
I have a late 1972 p6 v8 with 58,000 miles on the clock (documented) but since I have had it I have always thought that it runs too hot.
When running down the motorway the temp guage sits in, or just slightly above, the centre of the guage but when I come into town in stop start traffic the needle is right at the end of the green sector almost touching the red sector.
The previous owner must have thought likewise as there are receipts for a new water pump, temp sender, temp guage and thermostat.
I have fitted a triple core radiator with two electric fans, another temp guage and new voltage stabiliser and I run with the heater on.
The car also suffers from fuel vaporisation and I have insulated the fuel lines and fitted an electric pump under the bonnet which has helped but it is still there. I am running out of ideas so I would like to ask if anyone else's temp guage behaves like mine and maybe this is normal or if not normal where do I go from here?
Just to add the timing and the mixture are good and the car runs well otherwise with plenty of power.

TIA

Dochie
Click to expand...
 
Check the engine temperature with an independent thermometer.
Check the ignition timing, running retarded can cause overheating.
I know you say the rad is a replacement, but check it for cold spots.
Make sure that the electric fans are drawing the air in the correct direction.
 
I don't have a P6 V8 anymore but I used to run a 1973 MGBGTV8 and that was always overheating. I agree with other comments that retarding the timing is likely to make the engine run hot (as does modern fuel), so it's better to stick to factory settings and add an octane booster if the engine pinks (eg. Valvemaster). The worst case in the MGs was slowing down after a fast motorway run (as you describe), when the motorway airflow suddenly disappears but the fan doesn't react until the temperature has already surged. A lot of MGB V8 owners added a manual fan override switch on the dash, to flick on as soon as they noticed the temperature gauge climbing. I've also had two V8 TVRs and they both overheated in the same circumstances, and habitually blew their fan fuses just to rub it in.
 
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