Replacing camshafts

[billwill]

I think it would be pretty obvious if it was sticking. You should be able to rotate the pump easily by hand when there is no belt on it.

[rgh0]

Two questions: 1) Could the belt be slipping at low speeds, but not at faster speeds? 2) Since its a removable water pump, is it possible to check and adjust if there is too much clearance between the impellor face and the housing without pulling the engine? What would I need to do to check this? Thanks. Dan

Unlikely to be belt slipping at low speed, torque required to be transmitted by the belt increases with speed so slip always occurs at higher speed and you would hear the squeel if signficant slip was occuring. I also presume you have standard 4 inch diameter crank and water pump pulleys so water pump is running at engine speed as designed.

You should be able to pull the cartridge pump unit and measure the clearance between the face of the impellor and the cartridge housing with feeler guages. I think the required dimension is given in the workshop manual if I recall correctly. You adjust it by pressing the impellor further on or off the shaft. You also need to look at how the bearing is located in the cartidge housing, if this is not a positive location then that may move causing the impellor clearance to change. Lotus originally used a spring clip to locate the bearing via a groove in the bearing and a hole in the housing the cartridge unit you have may do it in another way. Some of the replacement bearings I have seen have the groove in a different location and the spring clip cannot be used and you have to just rely on the press fit of the bearing in the housing to locate it.

regards Rohan

[collins_dan]

Thanks. I will check everything else first and hope it doesn't come to removing the pump and measuring. I know that the chap that rebuilt the end and installed the pump had some issues fitting it, but he's a by the manual kind of guy and has done many of these, so hopefully this is not the issue. Thanks for your help. Dan

[reynard]

Hi, I have been watching this thread on and off, and I am new to the Discussion Group so go easy on me.

I had similar symptoms (overheating at odd times) twice. The first time (Europa) it turned out to be a small baffle in the crossflow radiator had fallen out and the water was simply circulating through one side tank, rarely making it over and back. at idle. The second time (1969 Elan plus 2) the lower hose was collapsing under high speed/load suction. All appeared well when inspected at idle (with BOTH situations) but when you really started moving coolant, the hose would flatten out. Both were discovered randomly, reading comments in monthly Lotus magazines (pre internet). I thought it was the pump, the timing, the cams... So, there it is, for whatever its worth.

Good luck.

Andy
Fort Worth

[Carlos A]

... the lower hose was collapsing under high speed/load suction. All appeared well when inspected at idle (with BOTH situations) but when you really started moving coolant, the hose would flatten out. Andy
Fort Worth

Andy: Dan's car overheats at low speeds:

it only takes a couple of traffic lights in quick succession and I can watch it creep up into really hot temps. When moving, no issues what so ever, ... Dan

Could be still the lower hose?

Best

Carlos

[collins_dan]

It's been rainy for days and days over here (I feel like I am back in London), so I ran the car in the garage. I let it idle until it got up to temp, then thermostat opened, it stayed at that temp for awhile, then crept up until about 90C, when the fan came on (blowing the correct direction). The fan seemed to be doing a good job of holding at that time, but I did notice that the left side of the radiator was quite a bit hotter than the right side, so I moved the fan to better cover the left side. I'll try that for awhile and let you know what happens.

Dan

[ecamiel]

I have had both relatively new and old hoses have the INNER liner collapse at low speeds and the water flow kept it open at high speeds.
Replace the lower hose with a proper reinforced suction hose and see what happens.

Eric
64 S1 Hart

[twincamman]

are you sure you have not mixed up the drive gears on the cams?????[ ie intake gear on the intake side] there is a difference ---ed

[rgh0]

You measure the temperatures at the radiator inlet side it is about 90c while idling with the fan on. You say cooler on the LHS which is how it should be. It should be around 20 degrees more than the ambient temperature say around 50c on the LH outlet side.With your cross flow radiator the left side will always be hotter than the right.

You need also to check if much temperature difference between the top and bottom of the radiator core at the left and right. If the flow is evenly distributed the temperature top to bottom each side will be the same - 90c on the LH side and around 20c above ambient on the RHS.

If you have a temperature drop across the radiator of around 90c down to 50c at idle and the temp is still going up at then engine outlet and you have no leaks into or from the water system then it is alomost certainly a low water circulation rate problem due to a restriction or faulty pump assembly

Do you have the heater valve switched on or off - at idle a signficant proportion of the flow will go through the heater core bypassing the radiator and if the heater fan not running then you will not remove much heat from this stream. If the flow is low to begin with due to a restriction or faulty pump assembly this would potentially make it worse

regards
Rohan

[paddy]

I just re-fitted my re-cored Marston radiator (which has a top-to-bottom flow) and brought it up to temperature for the first time today. I had taken the opportunity to change the electric fan since the old one fitted by the PO was a pretty clumsy arrangement. The new one is a 11" Spal slimline one and, based on Rohan's advice on this thread, I fitted it on the side of the rad where the top hose enters.

Idling at 800 RPM, once the engine was up to temperature, it is remarkably efficient - coming on for less than 10 seconds and then staying off for over a minute. This was at 27 degrees ambient temperature (hot for us here...).

Anyway, with the components in good condition it can quite comfortably keep an idling engine cool. We have a few warmer days coming apparently so I'll see what kind of duty cycle it needs then, but so far I'm pretty pleased with the result.

Paddy