3" to 4" heat exchanger

[1977 SILVERLINE]

Sorry I know this question has been answered a 1000 times, but I searched and could not find any info right at the moment. I bought a used 3" exchanger on a bidding site for my 1977 470. They contacted me and said they cannot find the 3" exchanger but they do have a 4" they would sell for the same price. Ok thats fine but I know the brackets are differant for a 4", but I am unsure about the hoses that connect to the exchanger. What does it all take to convert from a 3" to a 4"? I would like to know so I can make some sort of deal. Thanks

 

[generator12]

Re: 3" to 4" heat exchanger

I don't know what is involved in the conversion, but MAKE IT. The 4 inch is what should have been supplied by Merc. from the beginning.

 

[Eric 3.7LX Alpha 1]

Re: 3" to 4" heat exchanger

i don't know what is involved in the conversion, but make it. The 4 inch is what should have been supplied by merc. From the beginning.

x 2

 

[Eric 3.7LX Alpha 1]

Re: 3" to 4" heat exchanger

i don't know what is involved in the conversion, but make it. The 4 inch is what should have been supplied by merc. From the beginning.

x 2

 

[achris]

Re: 3" to 4" heat exchanger

x 3

 

[EddiePetty]

Re: 3" to 4" heat exchanger

Just going from memory eek, besides the larger mounting brackets, the inlet water tubing from the transom to the voltage regulator/exchanger inlet increases from 5/8" to 3/4".
All other hose connection remain the same.
I also remember the 4" exchanger being slightly longer.

And while you have your replacement exchanger in-hand, remove the after most drain plug and replace it with a drain **** (napa). It will make draining the raw water side of the exchanger a snap when winterizing.

 

[wrestling coach]

Re: 3" to 4" heat exchanger

I agree with Eddie above. I made a late season purchase of a 4" heat exchanger to upgrade my original 3" exchanger. I found the inlet coming in from the voltage regulator is 3/4" on the 4" and 5/8" on the 3". I am going to add a new piece of 3/4" heater hose at the heat exchanger and place a 3/4"to 5/8" reducer available at automotive stores and reattach to the voltage regulator using the original 5/8" line. This will be a spring project. I did not measure the length of either one however.

Dennis

 

[Don S]

Re: 3" to 4" heat exchanger

And while you have your replacement exchanger in-hand, remove the after most drain plug and replace it with a drain **** (napa). It will make draining the raw water side of the exchanger a snap when winterizing.

I wouldn't do that, you can't clean out the hole of debris if it gets clogged using a petcock, with the plug you can use a old screw or something to make sure the hole stays open and the heat exchanger is completely drained.

 

[EddiePetty]

Re: 3" to 4" heat exchanger

I wouldn't do that, you can't clean out the hole of debris if it gets clogged using a petcock, with the plug you can use a old screw or something to make sure the hole stays open and the heat exchanger is completely drained.

Not arguing Don, just clarifying......

A BALL valve type pet ****. NOT the typical cone-seat valve commonly found in auto radiators.

I've used the previously mentioned pet **** for years without problems.......and the ball type can be rodded through!

Kinda like this one.......

http://aeroquip.cc/w15310draincock14malepipe.aspx

 

[zlman1970]

Re: 3" to 4" heat exchanger

I did this swap this summer. Didn't have to change any hoses. The bracket was the same just larger u clamps. Took care of my overheat issue.