Airstream Forums

Airstream Forums (http://www.airforums.com/forums/)
-   Mechanics Corner - Engines, Transmission & More... (http://www.airforums.com/forums/f159/)
-   -   Classic Motorhomes running too hot ? (http://www.airforums.com/forums/f159/classic-motorhomes-running-too-hot-142513.html)

PeterH-Airstreamer 10-16-2015 05:23 AM

Classic Motorhomes running too hot ?
 
We were discussing operating temperatures on Mike thread and i would like to get input from more MH owners

Quote:

Originally Posted by Punch (Post 1697586)
....

The LY had a much more open feel around the engine, and the 345 is closed in, as I am sure are all the Classics. Whilst I am tempted to strip a bunch of metal out to make for more air flow around the engine, I read on here about people making an inner fender on the passenger side to ensure that air flows past the rear end of the exhaust manifold, so doing the opposite of what I was thinking!

I'm a little bit mystified by this whole air flow and cooling question.

This current 310 is the first Classic I have owned with a passenger side inner fender and I echo your thoughts and concerns. It does not appear to be original as the drivers side does. At least the drivers side has an open space towards the back for the air to escape. It also seems to function as a protective shield for the Master Cylinder.
I like to know if your Classic has the passenger side shield what your thoughts are about their function.

bpg_austin 10-16-2015 05:55 AM

Peter, my '78 Argosy 28' has nothing for inner fenders. I like the idea of them as discussed in some of these threads and am considering fabbing some out of aluminium eventually. However, I've never overheated or run warm. And I've had it stuck in a 3 hr traffic jam in Oklahoma in triple digit heat this summer. Ran the entire time and never overheated. So, do I think they're necessary? No. I tend to think, if my motorhome is any basis, that a good clean radiator, proper functioning fan and good radiator shroud will do far more than some inner fenders will.
Also worth noting that I'm still running original exhaust manifolds. I do have a very nice aftermarket radiator fan to replace the old viscious unit. That's it.

tevake 10-16-2015 07:34 AM

1 Attachment(s)
Engine cooling is an issue that I really dove into in preparation for a major west coast trip this just past summer with my 1989 345.
It had run hotter than I liked since it came to me a couple of years ago.
Generally around 200/205. But would run up to just over 210 in steep climbing, or hot slow traffic conditions. Apparently not too bad when reading of temps up to 240:eek:

But for this trip I was planning to tow a car along for the first time and knew there was going to be some climbing to be done in warm summer conditions .

So I pretty much did the full Monty on the cooling system to try to bring it into the best condition I could manage.
This included. Recoring the Radiator with a high efficiency core said to offer 20%+ better cooling, I installed a 180 degree thermostat in place of the 195 that it had, high flow Gates water pump, new hoses, installed a new air dam to direct more air thru the radiator, repositioned aux trans coolers so they did not block the engine radiator.
The rig also does have electric fans in front of the Radiator, and the added shroud on the passenger side wheel well.

The trip prep work also included getting the holly TBI dialed in better as both the ignition timing and fuel mapping were found to out of spec.
As well as a laundry list of other jobs including dropping the fuel tank, new sender and fuel lines thru out, welding all the seams on the tank, as there were a couple of weeps there. Doing reinforcement of the rear frame for towing, replace the toilet/ rebuild the base. Etc.

The result was a very enjoyable mostly trouble free trip up the west coast as far as the Straight of Jaun De Fuca. Back down to central Cal. For car week at Monterey peninsula , then east thru Yosemite, Salt Lake City, on to Colorado, and back down to Az. Nearly 7K miles that included some summer desert driving, and a number of 10k' + passes along the continual divide.

Now the normal running temp is just over 190, and the highest temp I saw during the trip was 205 during hard climbs. A big plus is that the engine fan clutch only kicks in for short periods to bring the temps down quickly once it reaches over 200.

I had been thru a couple of fan clutch replacements previously try to get it to not run so much. Now I realize that keeping the engine temp below its kick in temp is the key to not having it drone away in there so much.

Let me reiterate that this summers much improved cooling performance included the effort of towing an additional 2,500 lbs toad for the first time. So quite the satisfying outcome.

Cheers Richard

tevake 10-16-2015 07:43 AM

1 Attachment(s)
I love posting pics of my rig! Proud papa

bpg_austin 10-16-2015 07:52 AM

Late 80's SC euro with a 3.2? 😊

dznf0g 10-16-2015 08:02 AM

I do not have any personal experience with the MH, but I was involved form a MFR standpoint 20 years ago. I specifically recall the absolute need for inner fender closeouts for both sides. When they are open there is a lot of turbulence in that area which prohibits a flow of hot air out of the engine bay. You want a smooth stream of air from the grille opening, back and down and out through the rear. Having no inner fender closeout "balls up" all the hot air and leads to overheating and fuel boiling issues....especially on carbureted models.

bpg_austin 10-16-2015 08:09 AM

Tevake. I forgot to mention, and I think it might be worth noting, is that I also have a hi flow waterpump and 195 deg themostat. I've never seen temps above 210. ever. Runs on the highway at 195, even in triple digit heat here in TX.

tevake 10-16-2015 08:51 AM

^^. That's interesting to hear Bpg. That you are having the good results that you are with the higher temp thermostat . I had been crediting the lower temp thermostat for lots of the improvements. It's hard to know where the better performance comes from when making the changes all at one time.

But it is clear to see that comfortable engine temps are possible even on the larger classics.

I had wondered about the added shroud on the passenger side. As mine is a bit of a cobbled together deal that I had thought of removing. I guess not, thanks dznfOg!

My Porsche is A 1980 S C euro. with a 79 big port 3.0. It was good fun having it along on this trip tho I was really hoping to get on track at Laguna Seca while camped there for the Historics. So Want to drop down the corkscrew in it.
Really enjoyed Cruising some of the mountain roads in colo and Washington with it.

ALANSD 10-16-2015 09:01 AM

I have had a 911sc for 23 years. Never towed it though. It is a wonderful car and a blast to drive.
As for cooling on my 280 I added a can of super coolant stuff from NAPA. It brought the temp down on very hot days to under 200 consistently

Punch 10-16-2015 09:02 AM

Richard.... as a scientist, I would have hoped that you would have changed just one thing at a time, and then taken a 5000 mile trip to test the effect of just that one thing!! You'd get a government grant to do it, and each experiment would lead to more questions and another government grant. You'd be able to retire before you came to any firm conclusions, but who would care!

=======================

However, it is very interesting that you seem to have cured the hot running, especially towing heavy.
1. You added a left inner fender you say. Did you make it so there is an air outlet built in?
2. The lower temperature thermostat sounds like a great idea, ditto the water pump.
3. How did you structure the air dam to get more air through the radiator?

Peter: I removed my left inner fender, but I have decided to replace it since my engine did not run any cooler, and possibly the opposite(?) But I shall build in an access plate for the MC.

One little point: I have no popped manifold studs on my right-side head, and those are often thought to be due to overheating, and yet my cool-running LY popped right-side manifold studs twice. Hmmm!

PeterKV 10-16-2015 10:56 AM

I soooo want that little black beauty you are towing, perfection on 4 wheels.

mayco 10-16-2015 10:59 AM

Quote:

Originally Posted by tevake (Post 1697690)
I love posting pics of my rig! Proud papa

Richard,
Thats about as sweet as it gets!! Good on ya buddy!

bkahler 10-16-2015 11:36 AM

Lots of good information so far and hopefully more to come.

I've often wondered how effective the louvered vents found on the newer Classics are at reducing engine temps.

I know my old 84 310 always ran in the 180-200 range even when towing a 14' trailer with Spitfire race car on it. Dash A/C was used often. The temperature would climb slightly when going up hills but would drop back down on the way down the hill. This 310 did not have the louvers and I'm certain did not have a right side passenger shield. I believe it had one on the left side however. No electric fans, just the fan clutch which would kick in from time to time. The engine was a new GM crate engine with about 15k on it.

On my 74 Argosy with 454 I plan on the rubber air damn in the front above the radiator, engine cooler and transmission cooler along with two 10" cooling fans in front of the A/C condenser. I have the louvers for the wheel wells and will install them whether they do much or not mainly because I like how they look :)

I don't currently plan on running any side shields in the wheel wells but will add them if I have cooling problems. The 454 has slightly over bored and sports an RV towing cam with Edelbrock 600 CFM carburetor.

Too bad I can't give any real world results yet :(

chiefair 10-16-2015 12:44 PM

My 310 with the 454 ran temps of 180 -210 with no right inner fender and just the fan clutch. It did have a separate oil cooler mounted in front of the radiator. The transmission cooler is in the radiator. After it blew up, I checked the thermostat and it was a 160 degree unit.

Because my temps were good, when I installed the 502, iI went with the 160 thermostat again. My temps now run way too cool, around 100 degrees with occasional trips up to 160. I installed a complete new oil cooling system (with no oil temp thermostat) a Banks powerpack and the right inner fender along with the 502. Not sure if any one item, or a combination of all caused my dramatically lower temps. Probably none of you with high temps want to hear this, but I will be making some changes to get mine to run hotter. Hopefully just a thermostat change but if necessary; I will add a temperature controlled bypass for the oil cooler.

Punch 10-16-2015 01:26 PM

Quote:

Originally Posted by chiefair (Post 1697823)
....when I installed the 502, iI went with the 160 thermostat again. My temps now run way too cool, around 100 degrees with occasional trips up to 160. I installed a complete new oil cooling system (with no oil temp thermostat) a Banks powerpack and the right inner fender along with the 502. Not sure if any one item, or a combination of all caused my dramatically lower temps. Probably none of you with high temps want to hear this, but I will be making some changes to get mine to run hotter. Hopefully just a thermostat change but if necessary; I will add a temperature controlled bypass for the oil cooler.

This is way too counterintuitive for me.

PeterH-Airstreamer 10-16-2015 02:42 PM

Quote:

Originally Posted by tevake (Post 1697690)
I love posting pics of my rig! Proud papa

Damn Richard, your Rig is looking fine, I may just copy that dark color going beyond those windows. Makes it look like some real cool Limo.
And congrats on your successful trip after doing all those incredible upgrades.
Going East soon?

PeterH-Airstreamer 10-16-2015 02:45 PM

Quote:

Originally Posted by dznf0g (Post 1697700)
I do not have any personal experience with the MH, but I was involved form a MFR standpoint 20 years ago. I specifically recall the absolute need for inner fender closeouts for both sides. When they are open there is a lot of turbulence in that area which prohibits a flow of hot air out of the engine bay. You want a smooth stream of air from the grille opening, back and down and out through the rear. Having no inner fender closeout "balls up" all the hot air and leads to overheating and fuel boiling issues....especially on carbureted models.

Now there is a perfect example of my cluelessness:sad:
Thanks for posting that info!

chiefair 10-16-2015 02:56 PM

I am guessing that most of my low temp issue is due to the new oil cooler. It is bigger than the original and is fed through bigger lines. The old one was fed through an adapter on the oil filter base. The 502 has factory oil cooler ports in the block. The old adapter was GM part #326098. I have not been able to determine if it included a thermostatic bypass. The new setup does not have a bypass.


1982 310 motorhome 454
Henniker New Hampshire

Punch 10-16-2015 05:25 PM

Quote:

Originally Posted by chiefair (Post 1697853)
I am guessing that most of my low temp issue is due to the new oil cooler. It is bigger than the original and is fed through bigger lines. The old one was fed through an adapter on the oil filter base. The 502 has factory oil cooler ports in the block. The old adapter was GM part #326098. I have not been able to determine if it included a thermostatic bypass. The new setup does not have a bypass.


1982 310 motorhome 454
Henniker New Hampshire

I can be clueless too, in fact I am getting more proficient at it: is your 502 the same as the Workhorse 8.1?

chiefair 10-16-2015 06:17 PM

No, the 8.1 is a different block than the 502. The 8.1 is a "tall deck" with a longer stroke than the 502.


1982 310 motorhome 454
Henniker New Hampshire


All times are GMT -6. The time now is 09:57 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.