Position of fresh air inlet pipes. | MG MGA

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MG MGA - Position of fresh air inlet pipes.

I asked a question about this on Steves "Quick release grille" post a day or two ago but I thought it really deserves it's own post.

When I removed my front grille recently I noticed that the fresh air inlet pipes on my car were positioned quite a long way away from the outer edges of the radiator duct.
I wondered
(1) If they are in the normal position for the MGA?
(2) Would moving them fully to the outside edges allow any more cooling air to get to the radiator?
(3) If they were moved fully outwards, would the pipes still get the same amount of fresh air going into them?

Any opinions would be appreciated.
Thanks
Colyn

Colyn Firth

Another picture from the front which shows the inlet pipe position a little bit better.

Colyn Firth

C,
For what little it is worth, my (unguided) approach was to place the open ends somewhat wider apart than yours appear to be. My objective was to 'straight line' the flow as much as I could. Truth is that, having struggled to attach them at all, I also wanted to align them so as to reduce any lateral strain / twist which might tend to dislodge them at the radiator end.
David

D Smith

Colyn

I think mine are several more inches outboard. I also think the brackets are round the wrong way and should use floor holes about 3 or 4 inches outboard than where you have them bolted.

Steve

Steve Gyles

Hi Colyn
As Steve says, your tubes are about 1 tube diameter too far inboard; the air hoses should only have about half their diameter fouling the clear air flow to the radiator..
If I get a chance, I'll post a photo.

Regards
Colin

Colin Manley

Thanks everyone,
I kind of expected you would all give that answer.

Colin, a picture would be much appreciated, so long as you can get your camera in there!

I wouldn't want anyone to go to the trouble of removing their front grille for this!
Cheers
Colyn

Colyn Firth

Sorry,
Don't know why that message went out so many times?
Although now that I am geting older, I apparently do have a tendency to repeat myself 😁.

Colyn Firth

This is where I fixed mine....................Mike

Mike Moore

Colyn

Mine is the same as Mike's. You can also see in his photo that he has capped the ends in split black tubing. Not original but a nice finishing bit of detail.

Steve

Steve Gyles

I don't understand the purpose of the cold air pipe extensions in front of the rad. I don't have them and all is fine. I fust have the heater intake pipe going as far as the rad.

Art Pearse

Art,
I think the air is a little cooler (and fresher) near the grille than it is near the radiator as there is a little bit of a recirculation of air from the engine compartment into the radiator duct.

I noticed this once when the front section of the heater fresh air pipe fell off and made the air coming through the heater smell distinctly fumy.

Colyn

Colyn Firth

Colyn

The upside of your present position is relatively easy access (when needed) to the wiring loom, especially with your self confessed large mitts. I guess the down side is slightly less airflow to your radiator. I found it an absolute pain getting to that loom last winter when I modified my flashers.

Your scuttle pan appears to have gained a few more holes than standard, so if you move to the correct position you should find existing holes there for the bolts. You will probably want to blank off those rogue holes with grommets or weld in patches patches underneath, fill and repaint to make good.

Art. Not having the trunking on the carb side allows air to by-pass the radiator, affecting the cooling capability.

Steve

Steve Gyles

On the heater side the front hose brings in cooler air from the front. On the carburetor side it brings in cool air for the carburetors.

If one duct is left open with no hose attached, then hot air from aft of the radiator can blow forward through the duct opening to be recirculated through the radiator (not good for cooling in hot weather). Same problem if you omit the air block pad under the bonnet above the radiator.

The 4-inch P-clip securing front end of the forward hose(s) is (originally) bolted through a hole in the far front corner of the horizontal air pan (where it is difficult for access). That will show you where the hose was originally positioned, well off to the side. I turned the clip around and drilled another hole just inboard of the hose for easier access to the bolt, but kept the hose in the original outboard position.

Barney Gaylord

On the carb side, the fresh air to the carb bypasses the rad either way, hose or no hose.
And I may be lucky but I never exceed 180F even in the hot Ontario weather (30 C).
And I don't get any engine bay smells in the cab with the fan on, so I'm leaving as is!

Art Pearse

Colyn,
At last I took some photo's just now.
The first shows the position looking through the grill.
2 more to follow.

regards
Colin

Colin Manley

and this from looking between the gap between the rad and the front shroud.

Colin Manley

and this last one viewing the opposite side.

Both hoses are about 1.5" set back from the grill.

regards
Colin

Colin Manley

Thanks Colin,
it looks really clean in there, in comparison my car looks as if it needs a full resto! ;-)

As Steve said, my air pipes seem to to be at least a diameter width too far inboard.
(Once its sorted, maybe my car may even qualify to join Steve and Dominics "Cool Runners Club" :-)

Whilst the front suspension being rebuilt and the valence is off being repainted, I will repaint the duct panel and re-position the pipes at the same time.

Thanks everyone

Colyn

Colyn Firth

I've got mine wide, as Barney suggests and added a bilge fan to the carb side to help with vapor lock sitting still. Had rather high temps (220+) before adding fans to the situation. The main radiator fan is 12" from Moss. The radiator was Moss but I recored with a 4 row Maine.

As with many posts here the temp comments vary greatly depending on how each drives. I have no problems at all in most situations, but do when driving long hours (e.g.5+) in warm climates (80+) then hitting traffic or short (45 minutes at 90+) in stop/go. Then we need fans blowing on both radiator and carbs.

Coming back from GT-38 in Asheville, we were stuck for hours in 85 deg stop/go in NYC traffic and never went above 212 with both fans blowing. Now living in South Carolina, with less traffic but often in 95+ we are still fine. Many thanks to Barney for posting about the bilge fans which were the final key to the overall problem!

- Ken

KR Doris

Just to show you all that I have replaced the old air hoses and moved each of them
approx 4" further outboard.

I have also positioned the front of the hoses as close as possible to the grille and fitted some edging strip around the front of the pipes to tidy them up.

It will be interesting to see if this re-positioning has any effect on the running temperature.

Thanks everyone for your input.

Cheers
Colyn

Colyn Firth

Nice tidy job Colyn.
Bruce.

B Mayo

That looks more like it Colyn! My first reading of this thread - I think if you had an oil cooler up front, it may not have squeezed in before.

Graham V

I thought in the original official workshop manual or special tuning manual,maybe under adding an oil cooler that there was a reference to the measurements from those clamp holes in the radiator panel to where to place the cooler. I know I just didn't guess where they went when I replaced that panel. Anyway get those clamp mount holes in the correct spot,the hoses will "fall" into the right place with a little bending.

gary starr

Thanks for that,
I have relocated my oil cooler underneath the duct panel and cut an air duct into the front valance to get airflow to it.
I have just had my Sebring style valance repainted and I should be able to take a picture of it after I refit it over the weekend.

Gary,you should just be able to see the bolt heads of my oil cooler on the duct panel back near the radiator.
Cheers
Colyn

Colyn Firth

This thread was discussed between 14/01/2017 and 03/03/2017

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