Datsun Roadster Forum-311s.org

I purchased a reproduction water pump for my 1966
1600 roadster, the install and fit look good but I ran into the issue that the four original bolts that attach the pulley and fan to the
Flange don’t fit the new pump(seem to be of a larger size) Wondering if anyone has had this issue, I purchased the pump from Datsun roadster parts
They so far have not replied to my requests.
Any help, thanks.

Mario.

pictures help with diagnosis.....

One of the differences between the early and late water pumps is the spacing as you have discovered. The early used the deep dog bowl pump pulley and the two piece metal fan. The late used the double row pulley and the plastic fan with either a fan clutch as original or a spacer.

I’ll check on the spacing
But for now is just the bolt size
The pulley is the double row with the plastic fan

Metric vs SAE? 1/4" fine threads vs. 6mm

Left is pre-smog, Right is with smog.
I hope this helps.

calito_spl311 wrote: ↑Mon Aug 23, 2021 7:26 pm I’ll check on the spacing
But for now is just the bolt size
The pulley is the double row with the plastic fan

It sounds like you have a late 1600 68 - 70 engine with the double row pully and plastic fan in an early car. If you bought an early pump from them 65 - 67 1/2 then it will not work. The pump below is the correct pump for the double row pulley. We were the first to offer aftermarket late year pump's that don't require and exchange to swap out old parts to rebuild. Ray's pictures illustrate the difference. The spacing of the holes on the WP flanges between the two are different as well.
It is important to get the customer service you deserve and to use vendors that are not only responsive to your needs, but sell good products and have fair pricing. We are one of the largest and oldest vendors ands sell tons of new parts and do not get any returns.
It is actually on sale right now.

www.datsunparts.com/1768 Shop and compare

Dean

calito_spl311 wrote: ↑Mon Aug 23, 2021 5:32 pm I purchased a reproduction water pump for my 1966
1600 roadster, the install and fit look good but I ran into the issue that the four original bolts that attach the pulley and fan to the
Flange don’t fit the new pump(seem to be of a larger size) Wondering if anyone has had this issue, I purchased the pump from Datsun roadster parts
They so far have not replied to my requests.
Any help, thanks.

Mario.

What is the Engine number on the block to verify Dean's suspicions?

I am glad that so many of you know all of the ins and outs on this water pump issue. I got very confused with trying to determine my configuration (not original) and I knew the pump fit on the motor, the belt lined up, and it worked (except someone stacked up a bunch of washers on some bolts). So, I sent mine to Flying Dutchman and had it rebuilt and installed it with proper fasteners. The price was reasonable and turn around was quick. He did a nice job and knew roadster water pumps. I will attempt to determine what configuration I have for future reference. This thread is a great resource and Dean always seems to have the right answer.

calito_spl311 wrote: ↑Mon Aug 23, 2021 5:32 pm I purchased a reproduction water pump for my 1966
1600 roadster, the install and fit look good but I ran into the issue that the four original bolts that attach the pulley and fan to the
Flange don’t fit the new pump(seem to be of a larger size) Wondering if anyone has had this issue, I purchased the pump from Datsun roadster parts
They so far have not replied to my requests.
Any help, thanks.

Mario.

Hi Mario, I'm sure Paul will help you out once you figure out what you need. You probably got a "correct for 67.5 pump" which is a little different from both a 66 and a 68-70 pump.

If the "larger bolt" difference is 1/4-28 (used on the 66 fan ) vs. 6mm on the pump....all the current production pumps use 6mm.

The 64-66 pumps used 1/4-28. The only way to get 1/4-28 is find an original 64-66 pump (Paul probably has that too) or drill/tap the flange to 1/4-28 if metric bothers you.

However as pointed out above, if you have a 2-groove pulley, it's either the wrong pulley or the wrong engine in the car. The 2-groove pulley also was drilled for 6mm bolts....so that doesn't jive with a bolt problem??

If you need any help figuring out the solution, we have pumps for every year or can help you and Paul find a solution

Upper pulley and balance, engine number also.

Pulley, Balance and engine number

A simple photo of the front of the engine will show the aluminum spacer behind the water pump if he has a late engine or no spacer signaling an early engine. A photo of the old pump would finalize what's up with this toot sweet.

D-

calito_spl311 wrote: ↑Fri Aug 27, 2021 11:23 am Pulley, Balance and engine number

Engine number seems to indicate it's probably came out of a 1967.5 Roadster, metric 5 main. Per Rallye data.

"Upper pulley and balance, engine number also."

OK, that is helpful. So the crank pulley is incorrect for R16 all years, that may be part of the problem.

The WP pulley is correct for early cars/fan/pump, so no problem there, but you probably will need 6mm fasteners.

You do not want a late style pump or the spacer for that, it would just compound the problem.

I can't see much more, but the lower wp bolt is wrong-its English threads, should be a 10mm stud. Sin of the PO.