I remember someone re-drilling another Jap make one with
bigger diameter for this purpose but cant remember which.
Might be worth going through the wreckers to see a likely
fit to modify.

Quote:
Yes, Datsun Competition sold one 100mm/3.9"
B110: 5.05"
Newer type: 4.22"

Even better is the small-diameter crank pulley:
* 99996-H1160 SMALL DIAMETER CRANK PULLEY
This slows down both the water pump and the alternator

L-series w/pump pulleys are 100mm... I can see if one will fit on a-series pump tonight.

Rezlo. I would'nt worry about your temp if the gauge goes to centre. This is acceptable. It is when it goes higher that you must worry. I spoke to alot of people here and all of them said that their gauge on A14 bakkies lies in the centre on very hot days. So for your track use I think you are safe.

Racetech. I still wonder if your water doesn't circulate too fast.Comparing the core to a Nissan radiator core I noticed that the pipes in the VW radiator is very big.I would presume the small piping in a Nissan radiator helps to slow flow through the radiator and thus cool better. Just a possibility.
You might be loosing coolant because it is going over boiling point and then blows out.

I remember a while back that Boofhead with a Nissan Radiator has a temp of 95C on a 5 lap track day.

Thanks for the info so far.

Besides the return line from the reservoir tank that needs to move to the bottom pipe that comes from the radiator, it seems that everyone agrees that my biggest issue could well possibly be the water pump spinning to fast at high revs.

Please add your views regarding the following thread that highlights it could also be plug heat range related: http://datsun1200.com/modules/newbb/v ... ASC&type=&mode=0&start=10 look at mareospeedwagon post.

1200GXman what baffles me the most, is the fact that the temp stays constant for 3 laps and then all of a sudden it raises, in my opinion if it was a matter of boiling the temp would steadily raise and then boil.

The reason why my head is leaning in the direction of a water pump that is spinning to fast and forcing fluid out the entire 3 laps, but still there is enough fluid to keep the temps down, keep in mind the extra capacity of the rabbit system with the expansion tank, once it gets to a point where the fluid level is not sufficient to keep the temps down, the temp raises in a matter of seconds.

Isn't there a leak at the bottle cap or something?
Try the larger pully and let us know. I am curious about this problem because I also want to upgrade radiator later. VW is the cheapest option, but if you are having this problems then I am not interested and must pay a little more to go Nissan radiator.

VW radiator is no problem. Gary_P races his 1200 with VW radiator and VW overflow system.

It seems that whomever has the problem has plumbed the overflow system incorrectly.

I do agree with dd on this one, the VW rad is brilliant, and the issue is not there, the issue is related to constant high rpm operation.

What is your thoughts regarding Electronic Water Pumps like these for race applications: http://www.daviescraig.com.au/Electric_Water_Pumps-list.aspx

Hah, sorry, I didn’t see this thread moving,

My gauge going up and pushing coolant was due to my radiator being ¾ blocked from scale from my old A12 before I stuck the A15 in, I flushed the radiator a few times and not a single problem,

I run the A12 crank and water pump pulley (slow combo) and I ran her to 8500rpm for the whole 90minute spring bok series enduro without the gauge ever going past 1/3 temp, not a drop of coolant lost. Earlier that day we had 3X 10lap sprints, again not even 1 drop lost and it was 30+deg as seen below

http://www.youtube.com/watch?v=UNhRy_lI9Jw Now i just need to make a race car, running a marque car with those race cars on slicks was kak!