ak

Heys guys,
Was wondering some opinions on what temp water thermostat i should be using in my 509?I am running a 160 right now and it will not run hotter then !60 and oil temp has never even seen 200-i thought if the engine ran hotter it would be better due to my car knowledge????What do u guys think?

RdRacerZ28

I've got a 170 stat in my 388 EFi SBC........ seems to be fine. Some people will say its too hot for marine use, but I like my engines to run hotter .. more efficient, better wear characterisitcs etc...

ThisIsLivin

I'm running a 160 and my heads don't get over 130. My oil is right around 200 after running hard. My engine builder specializes in marine high performance and that's what they have found to work well. It also depends on your compression and cam, I'm pushing it on pump gas so I run it cooler to prevent detonation.

ak

Thats my exact thoughts too!!!You get too many different opnions about the temp for marine use.

ak

Yes i also run it on pump gas and my total timing is pretty high as to where it works great-i will probly just leave the 160 in it.

stevesxm

there is so much more to this thermostat deal and you guys keep trying to come up with a one size fits all answer. it just doesn't work that way... the thermostat is just one component in a long line of parts that go into your motor that make it a correct combination. the metalurgical interface between the rings and the bores and the pistons and the expansion characteristics of all the parts and the thermodynamic loads generated at the various stress levels created when you run them define , in absolute terms the cooling scheme that you need. one of the massive supercharged motors that show up here making huge boost require completely different cooling than the guy with a simple 8.5 to one 502 injected mag.

beyond that, it strikes me odd that you seem to want to create problems and then solve them ... " i am running the timing on the edge of disaster so i run no tstat to keep from blowing up " or " my motor melts if i run 87 octance because i have 16 to one compression so i run no tstat to keep the heads cool " ... huh ?

the structure of the motor defines how you cool it. blocks and bores and pistons require 165 to 190 degrees of operating temp to function as they should from a structural and metalugical standpoint. the oil temp needs to operate routinely over 210. cold oil is wrong and bad for the motor in all manner of ways... anything outside of that is wrong to some degree. can you get away with 140 water ? of course. can you get away with 190 oil ? of course... but every time you do you take life and reliability out of every component and gain absolutely nothing . sort of like hitting yourself in the face with a shovel every morning just because you know that it will only hurt for a while...

the bottom line is that unless you have some compelling and genuine performance reason to run extremely cold temps, then don't do it. and if you are doing something dumb that requires you to run extremely low temps, the solution is to stop doing whats dumb... back the timing down to some intelligent number or fix the cumbustion chambers so you can run the timing you want... or run the right fuel so it survives...

getting your combination to run correctly at proper operating temps is the answer... and that will allow you to spend your time and money on women and gas instead of prematurely worn out motors...

articfriends

iTrader: (1)

Steve, you are a wealth of knowledge and a asset to this board, you are dead on. Us guys running supercharged motors run no stat and wide open cooling, we do it so we can run tons of boost on pump gas, As far as doing this for a typical engine I too agree its just creating a problem. My motor runs at 100-120 degrees with no stat and everything works well like this BUT i also rebuild it every 120 hours or so. The only thing with what I'm doing that defies logic and everything I have ever heard or read is that my cylinders have never had no ridge or measurable taper. I read years ago that Ford studied cylinder wear/bore taper on engines running below 160 and for every 20 degrees below 160 the cylinder wear increased exponentially and at 100 degrees a motor would be basically wore out as far as cylinder wear/taper and ridge on the top by about 10,000 miles. The only thing I can figure is these bbc's must have a TON more nickel in the cylinders or something that makes the cylinders tougher. Again, I look forward to the intellectual discussion you bring to the table.
On a side note I also run my motor normally aspirated occasionally with no thermostat (only because I am not going to re-rig the cooling system) I do know that I am able to run more timing and make a tiny bit more power this way. Something to keep in mind too is IF you are running a factory programmed ecu until motor goes over 140 degrees the fuel table are going to enrichen your mixture because motor will never come out of cold start up mode and this will wash the cylinders and cause a black transom, fouled plugs and crappy fuel economy so another reason NOT to try to lower operating temp unless you are going to seriously tune for it. On my own Mefi set-up i am running I have all the enrichement blended out at 80 degrees to compensate for this, Smitty

Raylar

Steve +1
Its hard to understand sometimes here in the performance boating community why there are so many boaters subjecting themselves to the pain of the "shovel wack"!
Performance boating success story- "Work Smarter, not Harder"! then take all those saved $$$ and time and go boating and really enjoy the sport!

Best Regards,
Ray @ Raylar

stevesxm

it was never my field but i spent a lot of time with engineers whose field it was to understand the metalugy of the ring/bore interface... and when they started trying to describe it , after about 15 minutes you just wanted to kill yourself... there is so much to know and understand and so many diffrent ways to approach the same problem that to actually get it right requires a clean sheet approach. remember when chomebores were all the rage and then chrome top rings and on and on and on...

in your case , you are probably right. high nickle content in the block which really increases wear resistance and you are probably running a soft ductile iron ring set so the rings don't break to bits from the shock loads. that means the rings wear out long before the bores no matter what the temps... they become the sacrificial element because they are a lifed component anyway. . i don't know if you have had many modern jap motors apart but you take a nissan or toyota motor apart and there is no bore wear at all at 100,000 miles none... zero... perfect metallurgy ... and don't even get me started on bore finishing... thats a whole other science in itself...

and like anything else... you can hone the thing in your driveway with a piece of 80 taped to a broom handle and buy a set of rings from jc whitney and the the thing will start and run when you are done. it is a pretty forgiving exercise putting this stuff together and still get away with it for a while at least... and thats what encourages all the mythology and magic bean trick stuff and why a lot of guys will never understand the benefit of learning to do whats correct or the value of hiring a real professional. why bother when the stuff seems to run ok no matter what you do to it? right up until it doesn't.

oh well... thank you for the compliment.

i would love to know whats wrong with that guys oil pressure... i can't help but think its something really basic that we are all missing somewhere ... it almost always is...its just too weird to be true ... we are probably going to find out there is a loose wire on the oil pressure gage that vibrates at 4 grand and makes the gage lie or something...

ThisIsLivin

You'll have to excuse my brevity on my previous post. I didn't take the time to give a dissertation on the thermal, hydraulic, mechanical, and budgetary calculations made in the process of building my motor. This is not my first time around the block. I passed my master mechanics exam in 1980 and gave up my Auto repair business to pursue a career in Engineering. I was simply trying to give a thumbnail overview of what works for me. The water temps I boat in, vary almost 50 degrees and have to be considered as well. I monitor every operating condition of my motor closely and given the varied ambient conditions and desired performance levels, my system as a whole is operating as it should.