How biga heat exchanger do I need,..??..??

[Bondo]

My Old Town Atlantis project is movin' forward, 'n I'm considerin' a closed coolin' system for it,.....

I've got a 22.5"x 4" heat exchanger, which I pretty sure will cool the 350 that's goin' in for power,.....
But,....
I'd like to put the exhaust manifolds on the coolant side too,.....

So the question is, will this exchanger be big enough,..??..??

More info to follow,.....

 

[tpenfield]

By the size of it, your H.E. sounds about the same size as what I have on my 7.4L's with exhaust manifold cooling.

 

[Scott Danforth]

how many passes?

should be fine

 

[Bondo]

how many passes?

Ayuh,..... That's Good news Ted,.... Thank you,.....
Maybe you could measure it for me, the next time ya lay eyes on it,..??

I'll have to look Scott,.... didn't count the tubes, nor figure out the flows,....

I do know,....
Lookin' from the end-plate(raw water side), the 4" is fulla, probably 3/16" tubes,.... maybe 1/8" or 5/32" tubes,...

The exchanger came off the 351 OMC stringer drive I took outa the hull,.....
I've also got an industrial hyd. oil cooler that's 12"x 3",... I looked it over, 'n I can run the antifreeze on the oil side, 'n of course the water on the raw water side,....
It flows the water in from 1 end, through, 'n back to the same end to get rid of the water, next to the input,.....

I'm also lookin' for whatever is the Most Popular motor driven raw water pump,.....
Ain't gotta be a Merc,..... I'm thinkin' a crankshaft mounted unit, like some of the Volvos,....

I want something "Common" for ease of replacement parts,.....

 

[alldodge]

If you got the room (sounds like you do) I would go crankshaft every time

 

[Bondo]

If you got the room (sounds like you do) I would go crankshaft every time

Ayuh,..... I'm widenin' the stringers, 'n movin' the motor forward, 18"/ 24", 'n goin' with a jackshaft to a Bravo drive,.....

Wanta be able to walk/ fight/ net fish, from aft of the motor box,....

A blank slate, long cockpit, feet forward to the 2 captain's chair seats,....

Thinkin' of usin' the forward 1/2 of the motor box as a tandem seat for guests,....
The aft 1/2 for a tackle station,....
Thanks Bob,......

So I wonder what's the Most Popular crankshaft driven raw water pump,....
Convertin' a nice dressed bobtail 350, Alpha, to a Bravo,.....

 

[alldodge]

Don't know about most popular but I would be thinking the Johnson Pump
Parts easy to come by, well made and easy to fix if it ever needs it. There are different models

http://www.depcopump.com/catalogs/current_marine/catalog111/Page-99.pdf

If your not going high HP (don't think you are) I would suggest the stainless model SHP105 which uses impeller 10615K which can be had on ebay for about $16 each (impeller only)

Or bronze model 10-24228-1 bronze model uses 09-1027B-1impeller and about $14 on ebay. It has a bit less pumping GPM but still withing limits of what you would be needing.

 

[Bondo]

how many passes?

After lookin' at it more, the raw water makes 2 passes,.....
Comes in 1 end, through 1/2 of the tubes, then back through the other 1/2 of the tubes to the exit,.....

Antifreeze comes into a top tank, with the cap, which looks to be 'bout 2 qts. into 1 end of the exchanger, then goes out through a big nipple on the other end, to the circulatin' water pump,......

 

[Bondo]

Don't know about most popular but I would be thinking the Johnson Pump
Parts easy to come by, well made and easy to fix if it ever needs it. There are different models

Ayuh,..... I'm thinkin', why not go with the F6B-9, vs: the F5B-9,..??..??

Big block, vs: small block pump,....

The F6B-9 is actually a couple of bucks cheaper at Michigan Motors,.....

 

[alldodge]

Maybe, but my thought in sticking with the SB pump, is pressure will increase with the BB pump (can only push so much thru a given size whole/channels). May not be an issue, but just thinking, that may be the reason there are different pumps. Probably doesn't matter, but bigger pump will take a tad more power to turn

 

[Bondo]

Thank you for the thoughts,..... I'll measure the ports on the HE, I "Think" they're 3/4", possibly 5/8", both in, 'n out,....

I'm gonna need a sea-**** to feed the strainer bucket I've got, 'n the riser/ elbows I'm gonna use have 1" ports, like the sea-strainer,.....

I ain't worried 'bout the extra power to turn the slightly bigger pump, this is a fishin' barge, not a water rocket,....
Though it oughta do pretty good, bein' such a light-weight hull, compared to most 25'ers,....
I think the original listed weight is 2700 lbs,....
It's the 27* Vee that I'm lookin' forward too, after 20 odd years runnin' a 10* Vee tinbarge,....

Finished the new stringers yesterday, gonna throw a layer of glass on 'em today,....
Also cut an access hole in the last 2 sealed compartments yesterday, gonna grind out the last of the ole poured foam today, 'n vacuum out the trash,....
Lookin' forward to turnin' the corner, 'n start buildin', after all this tearin' apart,.....
Atleast the transom is 99% complete,..... should be done today, other than a coat of paint,.....

Thanks again Bob,....

 

[Scott Danforth]

Bondo, post a pic of the HX's you have, if you have number of tubes, etc, I think I still have a copy of the HX heat rejection software

tubes should be .248" OD, .020 wall copper brazed to the tube sheets. the smaller tubes had a problem of plugging if used in a marine invironment

typical tubes used in HX's

O.D.	Wall Thickness	I.D.	Area
0.1940	0.0160	0.1620	0.0089
0.3125	0.0180	0.2765	0.0167
0.2480	0.0200	0.2080	0.0143
0.3580	0.0200	0.3180	0.0212

are you plumbing it as a half system or a whole system?

If I remember the OMC HX's they were vertical with the expansion tank on the end.

either of the Johnson pumps would work (VP pumps are Johnson pumps)

If you are going half system, plumbing is easy.

full system, I have a cheat that makes plumbing easy.... it uses two thermostat y-fittings to circulate water bypassing the HX until it comes up to temp

 

[HT32BSX115]

Thank you for the thoughts,..... I'll measure the ports on the HE, I "Think" they're 3/4", possibly 5/8", both in, 'n out,....

Howdy Bill, This got me thinking about what size HX I actually have.

Took a couple of pics...



This is the San Juan Engr I installed on my 454 in 2006. It cools block, exhaust manifolds and riser-extensions.

I've run it in 85 degree (F) and it still maintained 180 engine temp.


Regards, Rick


By the way, are private messages working ok for everybody?