Larger Heat Exchanger for Perkins 4-108

[lexowgrant]

Thanks for the reply. over 2250, I over-heat. I'd be happy with 2600. Im looking into a new heat exchanger from Transatlantic Diesel. The old one dates to 83 I think.

[Wainui]

I have my 24,000lb boat propped to run up to 3,00rpm in gear at WOT.
I generally cruise at 25/2600rpm @6.5knts and 175/180 deg. It sounds and runs great at that rpm.

[DougR]

Hello All,
Many years ago I bought a boat with a 4-108 in it and experienced the same overheat issues which you are discussing. At the time I was employed by a major marine engine manufacturer (since retired) and I worked with our heat exchanger supplier to build me a one off heat exchanger to solve the problem.

The standard Perkins 12 inch heat exchanger that was mounted behind the engine had only a 9 inch tube bundle inside it, and the one we built used a 12 inch bundle, for an increase in heat rejection capability of 33%. This solved my problem. The new unit bolts in exactly where the old unit sat, on the same bracket, and connects up almost exactly the same. The overall length is 16.5 inches long and all of this extra length extends 4.5 inches toward the starboard side of the engine. This unit worked very well and controlled engine temp regardless of engine load.

I still have this exchanger and would be happy to sell it for a reasonable figure, but more importantly if there is sufficient interest it may be possible to arrange to purchase a number of units from the manufacturer at a wholesale price.

If you are interested, PM me and include your e mail address. I'll send you photos of the old and new HE, the new and old mounted on the engine, etc. We'll see what we can make happen.

DougR

[Wainui]

I purchased this HE and it really does make a difference! I just motored for 26 hrs at 2600 rpm and the temp never went over 155 deg (25k boat)

[CSY Man]

Originally Posted by SkiprJohn

Good luck on your project. Getting those old Perkins to cool down sometimes is a combination of a lot of things. Boiling out the old exchanger, checking exhaust and pump vanes as well as not overpropping. I used to run mine at about 1800 and if I went up to 2200 or higher needed to keep an eye on the heat gauge.

I would cruise at 2100 all day and all night.
2400 max and anything over 2400 would make the temp creep up slowly but surely.
Tried everything but concluded a bigger heat exchanger and or a bigger intake hose/through hull would would solve it.

[CSY Man]

I have my 24,000lb boat propped to run up to 3,00rpm in gear at WOT.
I generally cruise at 25/2600rpm @6.5knts and 175/180 deg. It sounds and runs great at that rpm.

At bit overpropped perhaps.?
The 4-108 on my boat was designed to do 4000 RPM at WOT and my prop would let it do just that. The 51 HP rating was also at that RPM if memory serves right.

[gjordan]

Wainui, maybe I am missing something here, but 155 degrees is way cold for a diesel to run and could cut into its life expectancy. Was that just a typo? ___Grant.

[jamhass]

I had two great heat exchanger experiences with Lenco. They help me retrofit my Volvo with an oil cooler and heat exchanger. They understood what I wanted and were able to customize one of their "off-shelf" units to meet my needs. Very quick, excellent quality and great price. Highly recommended.

Lenco Coolers - marine heat exchangers, marine oil coolers

[Wainui]

Installed a new17" HE and ran a 12hr delivery at 2600 rpms and temp never got over 160 deg.

[BigAl.NZ]

Originally Posted by Wainui

Installed a new17" HE and ran a 12hr delivery at 2600 rpms and temp never got over 160 deg.

My bowman HX on the Perkins mounts to the side of the engine block and is squarish in size. How do you mount one of those bigger round ones?

Is the ones at TAD the Sen-dure brand?

[Wainui]

It is for the older model 4108.
It mounts across the back of the engine just above the transmission.
Will not work for your engine.
I have since installed a Beta 50 and loving it.
M

[BigAl.NZ]

Originally Posted by Wainui

It is for the older model 4108.
It mounts across the back of the engine just above the transmission.
Will not work for your engine.
I have since installed a Beta 50 and loving it.
M

For the Beta were the mounting holes in a different location? Did you change the gear box or use an adapter?

Does anyone know if the 4.236 manifold mounted HX will fit on the 4.108?

[Wainui]

The engine mounts are slightly larger than what was on the Perkins.
Beta will adapt their mounting brackets to fit yours.
I kept the 72c Borg Warner Velvet Drive as it was in great condition.
Beta sent an adapter plate and transmission cooler.
I was able to use the original 2” exhaust hose.
Quieter and less vibration.
8knts @ 2,500
7knts @ 2,200 rpm.

[Msea]

Hi Doug. I know this is old post. I also have 4-108 that likes its temperature under load. Hope you can steer me in a direction to correct this.
Thanks,

[marcjsmith]

Originally Posted by Msea

Hi Doug. I know this is old post. I also have 4-108 that likes its temperature under load. Hope you can steer me in a direction to correct this.
Thanks,

I have the bowman heat exchanger on mine. that is part of the exhaust manifold.


since i woke the boat up after a 9 year slumber have not had any problems with overheating last year. one day last year did an 8 hour run from annapolis to solomons 40 miles temps in the upper 80's never went above 180... running around 2500 rpm.


I would take the HE off and clean it up and make sure none of your passages are blocked and that your water pumps are working