running without a thermostat?

[matt k]

Can I use normal ford 351 water pump gaskets (like these: http://www.rockauto.com/catalog/rafr...&parttype=2148)? I love skidim, but they want like 20 bucks for the pair of gaskets

Actually, can I use a normal car water pump? Rock auto wants like $30 for one ( http://www.rockauto.com/catalog/rafr...&parttype=2208 ),while skidim's is more like $120. I guess I just don't have a clear idea of what parts need to be "marine versions" and what parts don't.

[sydneyACE]

I see no reason to use anything other than automotive gaskets. They still do the same thing (keep water in the engine) whether they're in a boat or not.

Same thing with the water-pump. Just make sure to paint it if it's bare metal. Cast Iron rusts pretty-much instantly if it even sees water.

That skidim pump is bi-rotational, so that adds some cost. It doesn't specify, but it may have some brass parts or something to make-it more corosion-resistant for open cooling systems. (Antifreeze helps to slow corosion in automotive engines.) Even if it does last longer, you could buy 4 of those $30 pumps for the price of one of the ones from skidim.

I don't know much about Ford engines in boats, but I think you will be fine with automotive parts in this case. Maybe someone more-familiar with 351s can chime-in.

[suprasam]

Not sure about the auto, but I just purchased (this morning) a new circulating pump from skidim. It is bo-rotational, but delivered to my door cost 132.66. I have an 86 351 PCM. It comes with a gasket, that is needed so you don't need to buy a new one and you use the same pulley you currently have. I should have it by Friday and I will install that night if time allows. If needed I will keep you updated on it if you want. Good luck.
**On a second note, I just looked closely at the pictures of each online. I don't know if its just the pictures, but look at where the pulley bolts up. The marine one from indmar has bolts on it. The one from RockAuto only has spots where you put bolts thru pulley an then tighten into the pump. Im not sure how much difference that will make, or how you can change it but thought I would throw that at you.

[matt k]

as far as the bi-rotational thing goes, does anybody know if the ford truck motors turn the pumps the same way my boat does? Maybe I'll ask this question in the main forum and see if any of the motor gurus know...

[DAFF]

Do not use the automotive style water pumps.... They will not hold up to the sustained rpm of the marine engine. They will be fine for a while but eventially fail due to the bearings walking out of them. I too think this is where the problem lies.

As for the T stat issue..... There is something wrong. If your boat is in the water the manifolds should be more less cold to the touch. I would pull the waterlines running to the manifolds off and start the engine the water running out of the hoses must be massive amounts and equal. With the price of fuel where it is I would get her running correctly with the t sat in place. You will see a huge improve,ment in performace and effeciency.

[matt k]

yeah, I'm not thrilled running it the way it is. It seems fine, but I worry that there are hot spots somewhere and I'm causing damage. I should have some time this weekend to poke around a little more, disconnecting lines and flushing things out (again!). If I can find the gaskets locally, I'll have a look in at the circulation pump as well.

[matt k]

Small update: I replaced the sender and cleaned the contacts at the gauge. The sender didn't seem to make any difference, but cleaning up the gauge contacts dropped the gauge temp by roughly 10 degrees. With no thermostat, sitting at the dock with the boat running around 1800rpm or so in neutral, the temp gauge reads about 135*. With my temp gun I get ~105* on one riser and 110* on the other. Readings from various areas on the block are all around 100*. I'll take some more readings tomorrow when we go out and actually run the boat hard for a while. My gaskets haven't showed up yet, so I haven't had a look at the circ pump.

edit: roughly similar while running after an hour or so of wakeboarding. Block temps in the 115-125* range. Guess I'll go ahead and open up the circ pump when I get a chance, seems likely that that's the issue.

[matt k]

pulled the circ pump, compared to te replacement, and it looked fine. impeller was all there, with all blades intact. no shaft play or anything like that, so i put the old one back and will return the new one (boats are pricey enough without wasting money). I also replaced all rubber water hoses, since mine were looking kind of ratty, and i was thinking maybe they were letting air in. all of that and the boat still runs exactly the same

does anybody know how I can test the gauge? Can I read volts or ohms from the sender to the block, and compare that with the gauge reading? That's about the only thing I can think of that might not be working right, at this point...

Do you guys use any specific procedure to clear air out of the system, like you do in a car? I haven't been doing anything like that, just assuming the raw water pump will purge any air on it's own...

I'm also going to check timing when I get a chance. I seriously doubt that's an issue, but I know with cars if you set the timing WAY off you can generate a lot of extra heat, so I guess it won't hurt to check..


side note: the gaskets I ordered from rock auto (for a 1987 ford pickup with a 351w), the plate-to-block gasket worked fine, but the plate-to-pump gasket was different and interfered with the pump impeller, so I had to use the one that came with the replacement pump.

Any other thoughts or ideas?

[sydneyACE]

I think you should try putting the thermostat back-in and then check all those spots with your infrared thermometer. (Just for a good reference.)

Try doing a google search on testing the sending-unit/gauge. The resistance in the sending-unit should change as the temperature varies. The gauge references that resistance and the needle moves accordingly. It seems-like maybe your gauge is displaying incorrectly. (Can't know for sure, but having a reading from the infrared might give-us a good idea if the gauge is reading correctly.)
The fact that your gauge says 135* while your block is about 100* (you could touch that with your bare hand right?) makes me think that your gauge is still reading high. I have no facts to support this theory, but I would think that the cast-iron of the block would be HOTTER than the water in the block.

Keep at-it. You've got us all wondering what's up now.
I don't think you're hurting your engine by running without a thermostat, but you are probably loosing fuel efficiency and your oil isn't really getting up to temp.

[cadunkle]

Can I use normal ford 351 water pump gaskets (like these: http://www.rockauto.com/catalog/rafr...&parttype=2148)? I love skidim, but they want like 20 bucks for the pair of gaskets

Actually, can I use a normal car water pump? Rock auto wants like $30 for one ( http://www.rockauto.com/catalog/rafr...&parttype=2208 ),while skidim's is more like $120. I guess I just don't have a clear idea of what parts need to be "marine versions" and what parts don't.

Gaskets are fine, I use automotive gaskets for most marine uses, though not head gaskets or any other gasket touching raw water and containing metal.

Do not use an automotive water pump. Marine circulating pumps have stainless shafts, stainless backing plates, and bronze impellers. Automotive pumps typically use regular steel or iron and in those cheapy pumps the impeller is stamped steel. It will rust quickly.