H/M 351 thermostat

[YoAnthony]

Hello fellow motor heads. I have some questions about the Holman Moody motor.

It appears that the previous owner left out the thermostat. Is there any good reason for doing that?

Does anyone know where to get H/M 351 thermostat? What is the running temperature?

Lastly, Where can I source the water pump impeller?

1971 GT 21, H/M 351 ford, no circulator pump, crank driven sea water pump.

Thank you,
Anthony

[KDG]

Good Afternoon,

I'm not sure of where to find the T-Stat Cover, but I did find a replacement impeller for my 351 windsor crank mounted water pump at Boat US. I don't recall the part number but you could remove the impeller and take it along to match it up.

Good Luck.

Kurt

[Moody Blu']

heres a good thread for the pump

http://www.donzi.net/forums/showthread.php?t=1164&page=3&pp=15&highlight=jabsco+water+pump

[Ted Guldemond]

Yo Anthony, I like your taste in Donzi's. I have a 1970 GT-21 with a 351 Windsor. I run a 160 thermostat with closed cooling. The crank mounted water pump has a part number on the cover plate. Any marine store should be able to match up the number. By chance are you running the original 351 Cleveland engine?

[YoAnthony]

Thanks Kurt, Broque and Ted.
I will match the impeller at boatus.
I assume that the thermostat is standard size and I can get one at an auto store???
Lastly, is there a fuel filter mounted to the botom of the fuel pump on these motors?
Ted, I have the H/M 351, I believe they were all windsors. Bought a manual, well a copied manual, online from this registry. Not really worth the bucks, a little light on information.

[Moody Blu']

what drive is on your boat? the clymer manuals are great. I have one for my volvo and it has alot of stuff thats valuable,like timing of different motors, firing order, etc

I run in salt water and dont run a thermostat in case something gets clogged I can catch it on the temp gauge before i hurt anything. I believe 160 in salt water is ok and 170-180 for closed cooling motors.

I added a fuel/water separator/filter to my boat there worth the 240 bux.

[YoAnthony]

I have the Volvo 250. Not sure which prop. I can use some reccomendations and will do some testing in the spring.

I will also add a fuel filter/separator. Are you running stock fuel pump or electric?

[Moody Blu']

Im running a marine style holley 110 gph model

http://marineparts.com/mpf/mpf344.aspx

[YoAnthony]

Thanks Broque, Nice website. Have you gone pointless with your distributor?

[JimG]

Yoanthony, yes there is a filter attached to the bottom of the fuel filter. The canister is threaded.

I run a 160 degree thermostat (raw water cooled), and my motor runs VERY COOL. I used to worry about it, but it runs so good I don't bother with it.

I run a Volvo Ultra with 23 inches of pitch.

JimG

[Moody Blu']

jim what speed are you seeing with your setup? I believe we have similar setups, aside from my bottom paint. :-/

yoanthony, im running a MSD magnetic, mechanical advance distributor and love it. It isnt a marine distributor though,
http://www.msdignition.com/dist_17.htm. I set the timing and advance up with the smallest bushings and a combo of a light and heavy spring to get the most torque and rpm's out of the motor.
I do plan on buying a new marine distributor for it but this thing works fine for now. I think you can get the marine dist the same way, not sure.

I run a MSD 6t ignition with a rev box and a accell coil.
there looks to be a new version of the msd 6t with a diff colorand possibly multiple spark added.

http://www.msdignition.com/ignition_11_6400.htm
http://www.msdignition.com/ignition_8_6470.htm

This ignition seems nice because you can control the timing a bit to give you the extra rpm's for top end and the torque you need to get on plane.

http://www.msdignition.com/ignition_7_6462.htm

the new model is sweet, I love msd's stuff have never had a problem with it, and the boat fire's up on the first starter rotation everytime once warmed up.

[JimG]

Moody, I saw 54.7 @5200 rpm with my 23 Ultra, half tank of fuel.

[Moody Blu']

sounds like you could use a little more pitch have you loooked for a 24 ultra?

I gps'd my boat with a crap aluminum 21pitched prop and was doing a honest 53.1mph at 5300 rpms. the ford valve train does NOT like to be revved over 5000 rpm's for to long. Unless you change the valvetrain setup to roller rockers. I plan on it soon.

I havent gps's the bronze prop i got from M.O.P's buddy but my buddy raced me with the same jetski(all modified) and i was pulling on him at a pretty good rate and with my old prop we were dead even. I was running about 5100 rpms and around 55mph .

Then i got my headers and had the prop repitched to 24 1/2 with a cup to 25. the boat is running about the same speed but at 4700-4800 rpm's so I gained fuel economy. Once i get my Heads done i should be up to about 5500-5600 then its time for a CAM change OR i may go straight to a 408 or 501 stroker windsor

I have also thought about putting a themostat in to see if I can bring my rpm's/HP up a bit with the higher operating temperature. Not sure i want to do this with raw salt water cooling, maybe in fresh water

do you have any plans for your motor jim?

[MOP]

An old post on Tstats that may be of interest.

http://www.donzi.net/forums/showthread.php?t=36141&highlight=winterizing

[JimG]

Moody, no plans. I'm pretty happy where it is now. I don't see high rpms in my Donzi very much, it's happy cruising at 3500 rpms or so.

Jim

[YoAnthony]

An old post on Tstats that may be of interest.
http://www.donzi.net/forums/showthread.php?t=36141&highlight=winterizing

MOP, Interesting thread. I have wondered about higher temps giving added power. The thread does not say for sure. I think I have no thermostat in engine right now. It ran at 100 degrees the first and only time i ran it this year.

[MOP]

I have run in salt a long time with 160's never seen a problems, my 16 had a 302 mildly worked it ran a tad over 170 at cruise and up RPM's. No Tstat does not let the engine get hot enough to close up its tolerances, it will not run up to what it should and will have accelerated wear.

Phil

[JimG]

I've got a t-stat in mine, and have never run much above 100 degrees. Search this forum, this seems to be common with HM's. I changed everything: senders, t-stats, etc. It just runs cold on the gauge. When I shoot the engine block I get 140 or so. I've always thought that the crank mounted pump dumping directly into the y-pipe somehow forces the t-stat open. As far as accelerated wear, my engine looked great when I tore it down. I don't know how many hours were on it, but let's just say it wasn't fresh...