About engine fans.

[Licensed to kill]

When I got the engine to put in my B61, the fan was pooched. Got bent when the truck was wrecked. The guy I got the engine from said that he had another fan that I can have. However, being the not so patient guy that I am I thought, I would just take the fan off of the 673 in my B61 and use that. Well, I don't have the fan from the engine anymore (threw it away awhile ago) but it looks like the fan off the B61 is quite a bit smaller than what I remember of the other fan. It was also fixed and did not have the clutch (that was also broken in the wreck) that the engine came with. So, my question is, is there any reason to NOT use the smaller fan from the B61 in a fixed mount out should I get the bigger fan with the clutch?. I question the value of the bigger fan since the small one is the right width for the B61 rad and going bigger would make the fan bigger than the rad and therefore IMO of no benefit. While on the topic of engine fans, why is it that they don't make the fan blades symmetrical??. There is always one blade out of sync with the others. 

[MACKS]

Just my 2 cents,the old fixed fans suck,they increase the noise level in the cab by a lot and they rob the engine of a significant amount of power..

[Licensed to kill]

55 minutes ago, MACKS said:

Just my 2 cents,the old fixed fans suck,they increase the noise level in the cab by a lot and they rob the engine of a significant amount of power..

Pretty much. In my case, the engine cruising RPM will be 1250 so I doubt that noise or power will be an issue. I certainly can put a clutch hub on mine and probably will. My question was more about the size (diameter) and also the curiosity of why they are asymmetrical. 

[Freightrain]

Is there room in a B model for a clutch fan?  

Personally I think fan noise is the least of the problems in a B.  Only time I can tell its working is when the shutters close when it gets cool on a down grade.

 

[theakerstwo]

I put a fan and clutch on my B model but i had to cut a small amount off of all blades and then balance it.I also had to move cab and rad forward some and up also for clearnce.Moving cab and rad was easy.

[Licensed to kill]

I looked it up and the reason for the fan blades being asymmetrical is to reduce noise. There are also some that suggest that it is to provide access to bolts but it seems that this is not the primary reason. Anyways, the comment about room for a clutch hub on a B is valid. Thinking on when I took the fan off of the B, there is no way there would be room for a fan clutch without some mods such as suggested by theakerstwo. I'll just run the fixed fan that came off the B and see how that goes. 

[Steve L]

The clutch fan is to help control water temp, usually on later models, whereas the fixed fan doesn’t so it has shutters to control the water temperature, both types still require a thermostat. Personally I prefer shutters, they give an audible note of how the temps are going.  The offset blades do reduce noise even at 1250 revs.

[Freightrain]

I recall the bolts are just short enough to get them out to remove the fan.  Thats how little room there is between it and the radiator.

Ive seen guys just run eelctric fans also, put on a thermo switch.

[mrsmackpaul]

I dunno about the noise of the fan, clutch fans offer greater fuel economy and power

Is this a issue for you ? only you can answer that 

 

I personally dont run a clutch fan or shutters, dont think either were ever fitted from new, so much other noise I doubt I would even hear the fan

I have collected shutters for mine but not the rest of the mechanism to operate them 

 

Paul

[Steve L]

I think yool find the shutterstat hard to find now Paul. I used to love driving through the night listening to the shutters opening and closing, brings back old memories. Remember the ole B model 711 engine rattling and knocking while idling ( that truck prolly done my hearing in ) not like my E7 now which sounds like a motor car engine and doesn’t wake the neighbours at 6 in the morning grrrrrrrr haha! Trucks are no fun anymore. Then again I could fit an air starter and remove the muffler, I’ll be at home again and won’t feel like a steering wheel attendant. Gimmee a R or B model any day. 

[Licensed to kill]

16 hours ago, mrsmackpaul said:

I dunno about the noise of the fan, clutch fans offer greater fuel economy and power

Is this a issue for you ? only you can answer that 

 

I personally dont run a clutch fan or shutters, dont think either were ever fitted from new, so much other noise I doubt I would even hear the fan

I have collected shutters for mine but not the rest of the mechanism to operate them 

 

Paul

I don't recall, ever seeing a B ,model without shutters so IMO it's safe to say that they were fitted from new. Most R models run shutters also, to many IMO to think that they are all after market. 

[Licensed to kill]

2 hours ago, Steve L said:

I think yool find the shutterstat hard to find now Paul.

I had a 1987 Ford LTL9000 with a 3406 CAT that had factory shutters and the shutter stat was still available. Might have to look outside of the B model mack parts to find one but there should be some out there yet. A shutter stat is a shutter stat, doesn't have to be from/for a Mack to work. 

[Rob]

Most newer equipment uses either electric, hydraulic, or pneumatic fan drive. These are compact and generic installation kits used to be offered. I've retrofitted both electric, and pneumatic and both work well. Proper shrouding is paramount to any good cooling system. A fan blade spinning freely and not shrouded is wasting a lot of energy as it takes a lot of power to drive the assembly.

[mrsmackpaul]

6 hours ago, Licensed to kill said:

I don't recall, ever seeing a B ,model without shutters so IMO it's safe to say that they were fitted from new. Most R models run shutters also, to many IMO to think that they are all after market. 

You are most likely right, my R model has been very molested from the previous owner, if I was to compare it to what you blokes would scrap in the states it would of been scrapped, even by most peoples standards in Australia it was never worth buying all those years ago

But throw enough blood sweat and dollars at something and you can save anything lol

I feel it would of most likely had shutters when new, I'll keep my eyes out for the rest of the parts 

 

Paul 

[tenfive0]

My truck runs a direct bolt fan (without a clutch) and shutters. That is the the way I prefer it. The noise I hear is music to my ears and my truck does not have a radio.

[terry]

Another demise of the shutters was the inter cooler in front of the radiator.   terry

[Steve L]

True terry, my understanding is all Mack’s had shutters until the 4 valve was introduced when the intercooler was mounted in front of the radiator. I’m sure the thermostatically controlled fan hub saved fuel. I remember my 237 F model belts would screech when the shutters closed if belts weren’t tight enough. Imagine how much the load increased on the fan at 2100 revs, I noticed the later cool power still had shutters but also had 3 belts. 

[mowerman]

always thought they hadda really cool growl to them....but yes they do cut down the horsepower for sure but for recreational use,,who cares..bob

[Freightrain]

On 7/9/2021 at 5:13 PM, tenfive0 said:

My truck runs a direct bolt fan (without a clutch) and shutters. That is the the way I prefer it. The noise I hear is music to my ears and my truck does not have a radio.

You couldn't hear anyway....Lol.  I put a separate speaker for my CB and I still have to strain to understand some people.  I used to have to lift off the throttle to make it quiet enough.

[mowerman]

difficult to talk to someone riding with you as well ...you have to scream at each other...bob

[tenfive0]

15 hours ago, mowerman said:

difficult to talk to someone riding with you as well ...you have to scream at each other...bob

Occasionally, I don't mind taking the old lady along. I just nod and pretend I can hear her.

[Licensed to kill]

On 7/11/2021 at 5:16 AM, Steve L said:

True terry, my understanding is all Mack’s had shutters until the 4 valve was introduced when the intercooler was mounted in front of the radiator. I’m sure the thermostatically controlled fan hub saved fuel. I remember my 237 F model belts would screech when the shutters closed if belts weren’t tight enough. Imagine how much the load increased on the fan at 2100 revs, I noticed the later cool power still had shutters but also had 3 belts. 

I was out getting a few parts from the guy I bought the engine from. He said that whatever parts I need I can have. He has a veritable wrecking yard of Mack trucks and sheds full of parts. Anyways, He was showing me a truck he just got and said that I can take whatever I wanted from it. As we were looking it over he said that it was probably a 350 as it has the intercooler in front of the rad. It also had shutters but the shutters were behind the rad instead of in front like the older models. His son was mentioning that he had never seen an engine like the one I bought before. The turbo is tall and skinny as opposed to short and stout like all the others, and he never seen a 350 with the cooler on the intake, always in front of the rad. 

[terry]

I am not to sure but i think some of the early hard nosed macks had shutters on the back side of the radiator.   terry

[Brocky]

I am thinking that the 300 series Brockways had the shutters behind the radiator also????

[Rob]

It really doesn't matter much whether the shutters are forward, or rearward of the coil; the scenario is to block airflow through the coil which removes heat.

The early E6-350 engines did use a "tip turbine" type setup that preceded the air to air intercooling setups commonplace now. These used a combination of water, and air in the cooIer housing. I think in 1982 the air to air started being released and the hoods were lengthened to accommodate the cooling coil.