The V8 Owners Forum -

On my SD1, the reading from the coolant sensor for the EFI as shown by TunerStudio is much more consistent than the dash gauge reading - which uses a different sensor.

I have the standard 88C thermostat fitted, and an MS log always shows something close to this, with the engine hot.

The dash gauge shows about 100C in slow town traffic, but drops back to about 80C on the open road.

OK guys, after a long time ....

Yes, I did numerous tests and I am overheating running at anywhere between 95 and 105 with probably 110 in traffic!

Then I started to get a squeal from my belt so I got a new one and now that squeal is deafening at start up - plus squeals when blipping throttle too. So I'm now changing my water pump but as I'm so busy with many house related things my car is off the road until April.

Anyway, having high-jacked this tread (apologies) I can confirm that by changing the oil to 10/40 semi-synthetic my oil temp is definitely 5 degrees less than fully synthetic.

I too had belt squeal and thought it was the pump bearings. So I changed the pump and the belt and the noise came back after a week. The noise I now think is due to slip because of the minimal wrap of the belt around the water pump pulley. I need to install an idler pulley to give more wrap.
I could get the pulley knurled I suppose.
No slip may mean better cooling also.
By the way the noise sounds like a budgie chirping.

So I'm now changing my water pump but as I'm so busy with many house related things my car is off the road until April.

If you just take the belt of I would have thought you should be able to feel the bearings to see if they are tight/rough/loose just by rotating it by hand?

Tom.

The squeal has been getting worse over the last month or two and at start-up it is now horrendous and I have to slow the engine right down by putting it in gear to stop it otherwise it just keeps squealing - very loud indeed..

On start-up revs jump to 2,000 for 5 seconds then drops back to 1,000. Unable to reduce rpm any further as throttle is on its stop.

For the whole of this year whatever I've done to sort out the cooling has made it worse. A year or two back it only got hot on motorways and three years ago the fan would actually cool the engine whilst it idled.

My belt is a W routing so I have over 180 degrees of pump pulley contact and the idle jockey is sprung loaded with TVR's standard item. Thus tension is correct.

I will agree I'm running a 5 rib belt instead of a 7 rib belt and that's only because one bracket is out of alignment so I'll fix that this winter. Earlier on this year the 5 rib belt I had been using did not appear to have a shiny back nor indeed shiny ribs. Now it does and a new belt a few weeks ago is getting shiny after a couple of hundred miles, if that..

Still think I'll remove water pump to see what's what. It's getting stupid.

You need to check all rotating parts in the front. If you have 180 degrees cover on the water pump, then it could be the alternator or P/S pump causing the squeal. It could even be the idler bearing failing...

unstable load wrote:You need to check all rotating parts in the front. If you have 180 degrees cover on the water pump, then it could be the alternator or P/S pump causing the squeal. It could even be the idler bearing failing...

I just had an alternator front bearing fail, only started squealing for a few days, getting worse until it was very loud, and I mean LOUD. Quite easy to see & feel the sideways movement when the belt is removed.

On start-up revs jump to 2,000 for 5 seconds then drops back to 1,000. Unable to reduce rpm any further as throttle is on its stop.

Your first point is related to your idle control valve and settings. What idle control valve are you using? stepper type with PWM control? You can set a number of steps for the valve to open when starting to help starting.

My belt is a W routing so I have over 180 degrees of pump pulley contact and the idle jockey is sprung loaded with TVR's standard item. Thus tension is correct.

If your belt is a different length to the TVR belt and the idler pulley and alternator is in a different position then your belt tension may well be different than the original TVR. Is your sprung tensioner acting at the same angle as in the original TVR fitment?
Can you attach a photo of your aux belt?

Tom.
[/quote]

Main cooling problem ….

OK, I’ve removed belt and no problem with alternator, water pump nor idle wheel bearings. All turn easily and smoothly. Possibly a minor play in water pump but so minor I do not think it is a problem.

1.) Stepping back a bit.
Originally I had the belt going around the crank > alternator > water pump. The water pump was about 90 degrees in contact with the belt and I used a bracket to tension the belt. My problem seemed to be above 65mph on motorways as the oil (then fully synthetic) and water got hot. Water probably running above 105 if not 110. Belt did not squeal and did not appear to slip. So long as I kept speed down and non-motorway all seemed sort of fine with temp sometimes less than 90.

2.) I then fitted idle wheel with spring tensioner. Belt now W pattern – see photos below of this set-up. Water pump now in contact for 180 degrees. Still had a problem so did a few minor things such as fit a rad cowl to ensure air goes through rad 100% and removed grill. All this made no difference but gradually belt squeal developed and engine seemed to get very hot (I know it got to an accurate 109 via laptop reading) as soon as one hit traffic. Also, when it gets hot, it rarely cools down to less than 95.

3.) In last month or so belt squeal got worse so bought a new belt. More or less stopped squeal for a run or two but started again and now very noisy indeed. Part synthetic oil reduced oil temp by 5 degrees but water as 2.)

Yes, my current belts are all 5 ribs, not 7 as there is a slight miss-alignment but I’m not convinced that’s a problem.

I have noticed that when I blip throttle, there’s squeal and the tensioner moves a lot and slackens the belt. I am thus thinking that the tensioner is a wrong move and should go back to first design with 7 rib belt.


Here is the standard TVR set-up. There is a massive alternator bracket with the tensioner below on the left. There is also a fixed idler wheel on the right. I cannot fit either as just not enough space.


Here is my spring tensioner and current belt.


Here is my W set-up with tensioner on right.

Thanks guys, as usual.

Tom’s Idle question ……

Standard RV8 stepper motor is used and below are the Megasquirt settings.

On start-up, either cold or hot, engine fires and revs to about 2,000+ rpm and stays there for about 5 seconds and drops to 1,000. I would prefer an idle speed of 750 or 800rpm.

Is that normal to run the water pump off the back side of the belt??,

Denis247 wrote:Is that normal to run the water pump off the back side of the belt??,

Yes. All serp factory RV8's are like that.

A picture tells a 1000 words as they say

Your tensioner is in the wrong place. A sprung tensioner must always be the last pulley on the drive belt system, on a clockwise rotating engine that means the sprung tensioner must always be on the right of the engine with the next pulley being the main crank pulley. As it is you have the force of the water pump and alternator pulling on the tensioner which will reduce belt tension! The idea of a sprung tensioner is to keep a consistent tension in the belt when the belt stretches from the loads of the water pump and the alternator the tensioner will move to keep the tension constant , this improves belt and bearing life.
If you cannot fit the tensioner to the right hand side then you should replace the sprung tensioner with a fixed/adjustable idler.

With this change I would also use the 7 rib belt. The wider the belt the more friction and less chance of slipping.

Tom.

Well spotted Tom.
As a trial, the tensioner could be locked up and the threaded adjusting bar at the alternator used to set a belt tension.

Denis

Is it not the last? Clockwise (looking at engine / picture) is Crank > Alternator > Water Pump to tensioner > Crank again. I agree 100% out from TVR's standard set-up so I guess you mean the tensioner should be the first, not the last.

I agree this explains some things such as the tensioner being pulled in on load with a throttle blip that allows the belt to go slack. I.e. The tensioner cannot keep the belt tight when the throttle is blipped.

Since I cannot at the moment see how to lock the tensioner, it now means finding how to fit a new fixed idler and going back to adjusting tension with my mechanical bolt / bracket. Not an easy exercise.

I agree going back to 7 rib as well but the alignment is not perfect as crank does not quite align with JE alternator bracket - grinding somewhere thus needed!

Taking the above, this is why the W belt set-up does not keep cool and the reason why the original non-idler set-up did not was that you need 180 degrees of water pump contact, not 90 degrees.

Thanks for suggestions and possible (probable solution).