Andres131313 Posted June 21, 2014 Report Share Posted June 21, 2014 I have a 78 datsun 510 and the engine is an l20b. I need a new water pump but I can't fine one that does not have a clutch. And since I don't have the car I have no idea what the pump looks like. Someone help me out? Quote Link to comment
ggzilla Posted June 21, 2014 Report Share Posted June 21, 2014 The pump looks like this $38 unit: Quote Link to comment
datzenmike Posted June 21, 2014 Report Share Posted June 21, 2014 Pretty sure the A10 only came with the clutch fan. Most L20Bs did. If you don't have it this is likely the one you need. Quote Link to comment
Andres131313 Posted June 21, 2014 Author Report Share Posted June 21, 2014 What is the purpose of the clutch? I'm used to cars with no clutch. Quote Link to comment
ggzilla Posted June 21, 2014 Report Share Posted June 21, 2014 Its about performance. Clutch fan takes no HP when its not needed. Quote Link to comment
datzenmike Posted June 21, 2014 Report Share Posted June 21, 2014 Cars that are moving don't need much fan at all. Vehicle speed pushes plenty of air through the rad. When the engine is cold is another time it isn't needed. The clutch has built in slip and is limited to about 1,500 RPMs no matter what the engine is turning. If it senses being over heated, the clutch increases the friction and the fan speed will increase to about 2,300 RPMs. This saves energy moving masses of air that is not needed. Quote Link to comment
Andres131313 Posted June 21, 2014 Author Report Share Posted June 21, 2014 i guess mine has something wrong with it. last summer when i messed around with the car i would get close to 4,000rpm and the fan was still turning. I dont know why but i fell in love with that piece of junk Quote Link to comment
datzenmike Posted June 21, 2014 Report Share Posted June 21, 2014 When the engine is off you should be able to turn the fan with your finger. It should be firm and is not loose enough to spin freely. The fan does not stop with the engine running it only reaches a maximum speed of about 1,500 RPMs. If the engine revs higher it remains the same. The clutch is filled with a special silicon oil that provides the slippage. If it leaks out the fan will slip severely and the engine can over heat. They have also been known to seize and spin up higher. In this case they sound like an F-18 taking off. Quote Link to comment
Jester Posted June 21, 2014 Report Share Posted June 21, 2014 You are looking for a water pump from an early 510 with the L16. No fan clutch. Quote Link to comment
LenRobertson Posted June 21, 2014 Report Share Posted June 21, 2014 There are variations in the bolt spacing on the plastic fan blades where they bolt to the water pump. I know of three different sizes, but there may be more. If you get a non-clutch water pump there is a pretty good chance you will need to get a different plastic fan. Not a problem if you can find one at a wrecking yard or have time to advertise in the Classifieds here on Ratsun . Some of the online parts sources and autoparts stores will give a measurement for the fan bolt hole spacing. It seems like some parts catalogs show water pumps with or without AC and those may have different fan sizes. I can't quite remember. So when you shop for a new pump you should pay attention to the size of the fan you have. On my '72 510 with L20b, I had to remove the radiator to change the water pump. Nissan cleverly uses one long bolt which is captive behind the water pump pulley, so you need quite a bit of room to get the pump away from the front cover. I have a feeling you will need to pull the radiator on your 510, but look at your new pump or a pic in an online catalog and you will see the bolt I'm talking about and decide. Pulling the radiator is pretty easy except the radiator hoses are usually stuck on really tight. Be careful about just trying to pull them off as you can crack the solder joint where the hose neck attaches to the radiator. It is better to run a small screwdriver in between the old hose and the neck to free up the hose. I suspect Harbor Freight sells a special tool for this that looks like a cotter pin awl with a much longer nose. If your radiator hoses are very many years old, buy new ones and just cut the old ones to get them off. You will be much happier replacing the hoses now than doing it along side the road this summer! :D Len Quote Link to comment
datzenmike Posted June 21, 2014 Report Share Posted June 21, 2014 I have a 78 datsun 510 and the engine is an l20b. I need a new water pump but I can't fine one that does not have a clutch. And since I don't have the car I have no idea what the pump looks like. Someone help me out? You need to find out if you do, or do not, need the pump with the clutch. If you don't have the car, perhaps someone told you the pump is bad and needs replacing before you drive it? If it's the original pump it should have the clutch also. BTW the clutch is NOT removable and is pressed on. If replacing any hoses, as Len suggests, I find slitting them lengthwise with a box cutter worked better than a screwdriver. Then just peel them off. Quote Link to comment
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