Teapot in My Engine Bay!

[Aldwyn]

I have been hearing a slight high pitched wistle from time to time from my engine bay. I figured, ok... figured a hose had a leak or something. Ignored, thinking I would look at it later.

Well, it's not much later, but the whistle has become MUCH louder now. It seems to increase in pressure, volume, etc... when I accelerate, and I can hear it drop back as I decelerate.

Popped the hood, and even at idle it was getting louder, and then softer as I stood there trying to find where the noise was coming from. Front of the engine is best I can tell..

Stopped the car, checked the belts. Both look fine, and feel fine to me, though I am a novice at this, so I could be poorly judging.

Hoses look old, but not in bad shape.

Anyone have an idea what could be causing this? Where I should be looking?

I have a 76 with the air pump intact, BTW...

Thanks!
Aldwyn

 

[BritCarFan]

Check the air filter. Something may be in there

 

[AltaKnight]

Could be that air pump or related plumbing given that the whistle changes pitch with the engine speed

 

[Guest]

I don't have an air pump and mine whistles after it warms up. Engine noise, not tranny or rear end. Perplexed. Hope it is not my cam talking to me.

 

[Brosky]

Sounds like a classic air leak from the pump side, but you should have noticed more of a buzzing noise. Did you notice any increase in idle, or is all else normal at this time.

Normally, the noise on deceleration is vacuum related, but that would definitely cause an idle or really lean condition.

 

[Aldwyn]

Nothing has changed as far as idle goes, but then again I didnt really pay attention (I'll have to check tomorrow after work)... Warm idle is normally at about 1K. Timing is a little off (and has been for a couple of months). Carbs could stand some tuning as well.

Thanks gents!

 

[Brosky]

How dumb am I!! Disconnect the belt to the air pump and see if the noise is gone. If you only have one belt, get one for a TR6 without an air pump and bypass it.

Air pumps are why they make shiny brass plugs, you know!

 

[Banjo]

If it's not the air pump, then closely inspect for a vacuume leak. while the engine is still cool, spray some carb cleaner around the various gaskets, like the carb mounting gaskets, the intake-to-head gasket, and any vacuume lines coming off the manifold (things like the vacuume advance in the dizzy and those hard plastic lines under the manifold). it spraying in a certian spot changes the idle, or stops the whistle, you've found the leak.
You can also use a length of rubber hose. hold one end to your ear, and probe around the engine with the other. you'll know when you find the sound
Vacuume leaks tend to be louder at idle and deceleration when the vacuume is at it's highest.
good luck

 

[Guest]

Are your air cleaner housing bolts tight? Air cleaner housing to carb(s) gaskets good?

 

[Aldwyn]

Air cleaner bolts are tight. Gaskets could use replacing, but dont seem rough... just well used. That could be an issue.

I'll have to spray as suggested to see if the sound goes away, but it comes and goes anyway, so hopefully I can catch it when it's noisy.

Speaking of coming and going, the sound was only occasional tonight, and again back to the softer rather then as loud as it was on Tuesday. Making it hard to track down, once again. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

I will have to try pulling the belt off... I would eventually like to remove the air pump, but I am confused as to how to re-route hoses and such!

Thanks!
Aldwyn

 

[tomshobby]

Just remove the pump and all related equipment. Cap the vacuum vents on the intake. and make a plug for the EGR hole in the head and secure with a jam nut.
https://smithtr6.com/images/forum_pics/exhupgrd/01.jpg

Then make these short plugs from solid steel for the original cast header and grind them to the inside contour. secure them with set screws.
https://smithtr6.com/images/forum_pics/exhupgrd/manifold_plugs.jpg

https://smithtr6.com/images/forum_pics/exhupgrd/inside_manifold.jpg

Or better yet, install headers.
https://smithtr6.com/images/forum_pics/eng_assem/eng_053.jpg

 

[vettedog72]

Tom
That last picture looks pretty nice and it would surely eliminate any, no all air injection problems.

 

[Brosky]

Someone makes a cheap kit to block all of the holes in the manifold. Now if I could only find the link. Hardware stores sell the brass plug for the head.

 

[Aldwyn]

Brosky,

If you can track that down, I'd be much obliged! That sounds like the easiest route if the stuff is already made!

 

[Aldwyn]

Oh, BTW, going back to my whistle, it almost always happens when down shifting into 2nd, or when I am in second going down a hill, and the gears are holding the car back.

 

[Brosky]

I just saw this post and I'm logging off now. I'll look for it tonight when I get back on.

 

[AltaKnight]

Oh, BTW, going back to my whistle, it almost always happens when down shifting into 2nd, or when I am in second going down a hill, and the gears are holding the car back.

That sounds more like the whistle is only occuring under conditions of high manifold vacuum.
That would tend to indicate a vacuum leak probably from the distributor advance/retard hoses/fittings or it could even be from the intake manifold at the head or at the carb(s

 

[TR3driver]

Might also be from the distributor vacuum unit itself; or possibly the brake booster. Easy test to disconnect/plug the lines and try a test drive (keeping in mind that your brake pedal effort will be higher).

 

[Aldwyn]

Ok, I will have to look up what all of those things are first! /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif