Waterpump dismantle tips?
Posted: Mon Aug 01, 2022 12:35
How everyone - how do you dismantle the waterpump so I can change it using the kit. Mine is rock sold (won't turn) - do I need a press to press it out?
Esprit2 wrote: ↑Mon Aug 01, 2022 18:45The impeller used in the 907 pumps had very few, short vanes. That may (??) also apply to the 912LC. The 910 Turbo and 912HC pumps use an impeller that has more, much longer vanes. That, plus a deeper scroll housing portion of the pump housing means the later pumps can move a lot more coolant for better cooling.
If your 907/ 912LC runs a little hot, and you run a cooler thermostat to help the engine stay cool, then consider installing the impeller from a 910/912HC pump during the rebuild. It's obvious at a glance that the length of the nose on the two impellers is very different... the 910/912HC impeller being longer. As is, it will not fit into the 907/ 912LC pump housing. But take both impellers (short & long) to a machine shop, and ask then to shorten the long one to match the short one. Then the rest of the pump assembly is as per the instructions.
Also, the front engine cars use a 5.25" OD pulley on the water pump. The mid-engine Esprit doesn't get the air-blast into the engine bay that the front-engine cars do, so the engine tends to run hotter. So Lotus installed a smaller, 4.5" OD pulley on the same pumps when they're used in an Esprit. The smaller pulley spins the pump faster so that it pumps more coolant.
If you install both the 910/912HC impeller and with the smaller OD, 'Esprit' pulley, the pump willl move a lot more coolant, and the engine will run cooler. Now install a proper, higher temp thermostat to keep the engine up to normal operating temp. Consider the greater flow rate to be an insurance policy held reserve for those hot days, or congested traffic situations when the engine might otherwise be prone to over-heating. The big impeller and small OD pulley make a significant difference.
Hi Tim....I've been trying to locate the impeller with the longer canes here in the uk. SJ advise that it's no longer available....Any ideas please.
Also some clarification if I may: is it ok to use the longer vane impeller with the canes that almost spiral to the middle, with a 907 pump. I know the nose will have to be shortened but my concern relates to the length of the vanes that will NOT be in close proximity with the angled surface. (The 0.5 gap)
Thankyou in advance