Another operating temp question

[FreeBeeTony]

As some of you might remember, I installed a FWC system on my rebuilt 165 Mercruiser IL6. The temp of the bay is now close to 80* and as I suspected my operating temp has gone up. While running on a plane at 3000rpm, the temp goes to ~ 190-200*. When I slow down and get off plane the tem goes to about 210 then drops back down to 150-160* at idle. I think I am OK but am just looking for some assurance. Hope to get out fishing tomorrow........if the weather breaks. Thanks......

 

[crazy charlie]

Re: Another operating temp question

Hi Tony.The temp sounds to me to move around too much.You mention a 50 degree swing,thats a lot.The 10 degree climb after coming off plane is fine.Are you using a 170 degree thermostat??Charlie

 

[Skipster1]

Re: Another operating temp question

Sorry Chief.... no re-assurance here. I have the same engine and have worked on other engines over the years and this just doesn't sound right.<br />I simply don't believe the engine should rise at 3000RPMs ... at least not that high.<br />I'm wondering about timing???? Have you checked it lately?

 

[snapperbait]

Re: Another operating temp question

Little hot there, FBT.... I'd check the coolant level, and change the heat exchanger cap...<br /><br />What's the psi rating on the current radiator/exchanger cap?

 

[Boomyal]

Re: Another operating temp question

I run a San Juan Engineering Cooling system for my 302. When I installed it, I also installed a 180 deg thermostat. It runs, rock solid, at 180 deg with no variation between wot, cruise or idle. I did change the stock cap and installed a coolant recovery system as it would spit out some coolant when I shut down. The heat exchanger does not want to be totally full.<br /><br />Can you pull your supply hose, momentarily, at 3000 rpm, to check the flow fom the outdrive?<br /><br />Also, if your temperature was consistant before you installed the heat exchanger, I would contact the manufacturer.

 

[FreeBeeTony]

Re: Another operating temp question

I am running a 140* t-stat. Originally used a 160* but went to 140* to see if it would bring down the operating temp. Cap is 7lbs with a recovery system. I am cooling the block and manifold. Timing is right on...Could I check the supply in neutral at the dock? I don't know if i should rev it up to 3000 in neutral w/o a load.......

 

[Bondo]

Re: Another operating temp question

Hi Tony,<br />It's possible that the H/E you're using is a bit small..... seeing that you're cooling the manifold, as well as the block........<br />The small Spike in heat, coming back to idle, is somewhat normal.........<br />To check the Raw water flow, try pulling the Out line off the H/E..... It doesn't Need to be at 3000RPMs..... If it's Flowing at low speeds, it'll be flowing at higher speeds.......<br />Looking at these old photos you sent me,<br />It Appears that you have the Raw water plumbed into,+ Out of the H/E on the Same End.... Can you replumb it to get a better Lateral Flow, Through the H/E ????? <br />Kinda hard to see in these pics......

 

[FreeBeeTony]

Re: Another operating temp question

Hey bondo.........that's a no on the plumbing, the fittings are only on one end of the H/E.<br />If I pull the Out line of the H/E I won't have water on the exhaust flappers, is that OK?<br />What do you think about the temp? Should I be worried? The way I am looking at it is that the new cars are operating at 210, as long as I am presurized somewhat I should be ok....I think...

 

[Bondo]

Re: Another operating temp question

I think you're at the borderline of OK, <br />But, Still in the OK Zone..............<br />Pulling the Out line from the H/E would Only be for Seconds...... Just to See that you have a Good Flow...........<br />Even at Sea Level, <br />Water doesn't Boil till 212*.........<br />I'm not sure of the scale for a Pressure/Temp increase..... You could go to a Higher Pressure Cap..... <br />I think about 14lbs is about Tops......<br /><br />Maybe you should start shopping for a Larger H/E.....<br />It would be Ashame to take the Manifold Out of your system...... Just to get the Heat down.....<br />Are you getting Any Blow-Off into the Recovery Bottle ???????

 

[Boomyal]

Re: Another operating temp question

I didn't know you were cooling your manifold with the H/E. Is it possible to temporarily return the manifold to raw water cooling then see how your motor temp reacts? If your H/E is the same or smaller than mine, that would be a lot of heat to deal with, both motor and exhaust.<br />

 

[Dunaruna]

Re: Another operating temp question

Boomyal, a quick question (I don't mean to hijack the thread). Is that HE a normal size for a 302? Mine is about 2 thirds the size and I get rising temp over 3000rpm.<br /><br />Aldo

 

[Boomyal]

Re: Another operating temp question

Originally posted by Dunaruna:<br /> Boomyal, a quick question (I don't mean to hijack the thread). Is that HE a normal size for a 302? Mine is about 2 thirds the size and I get rising temp over 3000rpm.<br /><br />Aldo

Dunaruna:<br />I don't have any experience to know if it is normal size or not. It's made right up the state from me and I did not shop around before buying. Maybe, with the picture posted, others who have experience may know of other brands to compare too. The bracketry, for this unit, is also drilled to fit a 351W.<br /><br />As I mentioned, I am not cooling my exh. man's as I have the log style that I don't think you can FWC. After I installed, I went to a 180 deg stat for better combustion efficiency (no longer have to be concerned re salt plating or cylinder wall contraction/expansion) and my temp never varies but a couple of degrees whether at WOT or idle.

 

[Dunaruna]

Re: Another operating temp question

I also have log style manifolds (raw cooled). Your picture above is the first HE on a 302w I've seen in comparison and mine is 2 thirds the size. I've tried everything chasing this temp rise. I think I have the same problem as freebeetony, HE too small. Thanks.<br /><br />Aldo

 

[Boomyal]

Re: Another operating temp question

D~R~, it's made in Bellingham, Washington. If you need any contact info, let me know.

 

[FreeBeeTony]

Re: Another operating temp question

I am pretty sure the H/E I am using is from a SBC. I think it's supposed to cool the manifolds on the V8 so I figured it should handle my IL6 and the manifold, although the manifold on the IL6 is pretty BIG. I was a little low on coolant and will try it again...I'm probably not going to do anything to the set-up this year.....I will just have to watch the temp.

 

[FreeBeeTony]

Re: Another operating temp question

^

 

[yoced]

Re: Another operating temp question

More heat is in the IL6 manifold than in 6 cylinders worth of the SBC manifolds (only because the coolant flow in that manifold is notoriously bad), and it builds as you march down the six cylinders. But it should not be more than the two manifolds combined for the eight would be.<br /><br />Your heat exchanger was _probably_ not designed to cool the manifolds on the SBC. What make and model H/E are you running?<br /><br />Doom and Gloom thought for the Day: If I recall your plumbing correctly you have your water coming out of the manifold at an endplate. I am thinking that the top inch or two of your manifold near the riser (or more depending on the tilt of your engine) may be nothing but steam - which would add quite a bit of heat to your system. I know your water system goes higher than the point of exit on the manifold, but unless you were able to upend your manifold while filling the water system you may have some extra heat going on there.