Exhaust issue - long read, but this issue is driving me INSANE

Maintenance/Repairs
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41

Insightful - When I mention “Brand X” I’m referring to HM headers. I raised the leak/sound issue with the HM distributor (the guy who sold me the headers) and he was a great help. Can’t say the same for HM themselves though. I’ll hold off on my anti-HM rant for another time, but suffice to say HM’s service was what lead me to switch to Brand Z headers.

I’m still struggling with the possibility that the sound is a characteristic of the headers. Two different brands/designs of headers making the exact same hissratttle? Marginally different ffffffffftt sound sure.

My dilligence is now toast as I’m 99.99% sure I’m going to return the car back to stock, get rid of it and buy another car… a car that, through some force of nature, either doesn’t need headers or doesn’t have aftermarket headers available. Pretty sure I may have started balding from all of this. First the arm, now the hair.

42

Um, seriously, have you considered porting? I’m thinking that the noise might be from the exhaust gas being pushed through the smaller exhaust ports and expanding in the headers. You’re certainly capable of the work.

43

Thanks for the vote of confidence MountainBike. But, yesterday’s effort has really taken the wind out of my sails. It’s been suggested I replace the engine. But that’s a huge gamble in my eyes… right now anyway.

44

I guess this isn’t a good time for the old joke:

Ed, "This is driving me insane!"
Fred, “How can we tell?”

45

Thanks insightful… the insanity fits me well.

I kinda haven’t given up… took it for a drive to settle in the new lifters. Had a mate drive the car past me a few times while I waited on the side of the road. Cannot hear the ffffffffttt noise when the car drives past. Inside the car the ffffffffftt is as loud as day and sounds to be coming from outside under the car.

Another point - when I run this car without the “snorkel” on the airbox (hisstattle and ffffffftt noises don’t change) but man is that induction noise horrendously LOUD. Only time I’ve heard induction noise like that was on a V4 two stroke engine. I’m surprised I wasn’t sucking up pedestrians and small animals. LOUD induction noise.

46

The Ffffffttt noise is load and/or throttle position related. Not speed or rpm related. You can gentle accelerate up to any speed and any engine rpm without making the car do it fffffffffttt noise.

47

Correction to my earlier statement about the ffffffftt sound not being heard when the car is driven past you. It CAN be heard but only under load. Once the engine is in the higher RPM range you cannot hear the fffffffftt sound. Also, hissrattle from this point of shall be referred to as “fahsissle”. Ffffffftt is now known as “Fssssssst”. Current consensus is that I just live with it.

48

When I had a tube header on my '81 Accord it made a “ping” or “zing” sounds at times.
What you might be hearing is gasses blasting out of the exhaust ports when the exhaust valves first open up.
Stock cam?

49

Circuitsmith - as far as I’m aware the cam is standard.

The noise - to me - defies all of the logic my brain has stored in it with relation to fitting headers.

50

I think I have it! He said for the umpteenth time.

Drove into the driveway this afternoon after work to find my water pump puking water all over the place. So, I swapped it out (just finished) and the noise is MUCH quieter - almost gone. When I got home with the water fountain under the car the noise was LOUD. The timing belt had developed slack at the water pump pulley - between the camshafts. I don’t have the special tool to get my tension wrench onto the eccentric tensioner pulley (bad, I know) so I’ve been Macgyvering it with some circlip pliers. Tonight, after the huge job of swapping the water pump out on this thing my noise is reduced.

Just ordered the special tool to get the right tension on that pulley. I think the noise is the belt slipping over the water pump pulley. Will update once I have had at it with the right tool.

51

Wow! Let that be a lesson to me… sound propagates and it’s always the last place you look.
I’m very happy for you that the problem is solved. It’s unfortunate that you had to go through all you did before it showed itself. But just think, you now have a great story to tell that’ll be with you forever!

Sincere best,
TSM

52

A story to tell? Like the monologue of a super villain complete maniacal laughter.

Did I mention a bonnet strut broke somewhere between doing the lifters and the water pump? Broken bonnet struts, wiping memories since…since, well I can’t remember when.

53

I still say it’ll make a great story… when you’re an old man like me, sitting in the sun BSing with the neighbors like I do. Life will be better with stories to tell.

54

Okay. So THAT didn’t fix my noise either. More on that later as I have ANOTHER theory…

I replaced the water pump the afternoon is blew out. But this brings me to a side question. Please settle this for me.

On first install of the timing belt I had to tension the eccentric pulley without the special tool. Yesterday I used the special tool.

My side question is in relation to the eccentric pulleyand its relationship to the hydraulic tensioner/damper.

See attached Pic;

QmXZjGR.jpg800×937

No. 1 Image is how I tensioned the eccentric. In that I went in the opposite direction recommended in the workshop manual. I did this so that, as I turned the eccentric (with the special tool), I was applying downward pressure onto the hydraulic tensioner rod - pushing it back into the tensioner body. I only applied enough pressure on the rod to loosen the locking pin holding the tensioner rod in place. I then torgued the eccentric holding bolt down.

No. 2 Image shows the recommended direction that I apply pressure to the eccentric. This, to me (and my limited experience), would take pressure off or away from the tensioner rod.

No. 3 Is an image from an FTO workshop manual. I’ve included it because it shows that as pressure is applied to the eccentric pulley the tensioner arm acts on the tensioner rod. This to me seems to be the correct way to do things.

Am I thinking outside of the box here or what? Is there an expert on Mitsubishi timing belts here that can set me straight?

fmTKaSs.jpg960×1280

Now, back to my exhaust leak and my NEW (and improved) theory. The stock headers, where the y-pipe flange meets the header flange, has a raised or extended section of pipe that fits up into the headers. Neither of my aftermarket headers have this extended/interlocking arrangement. See attached hand sketch - top sketch = my new theory, bottom sketch = the stock headers pipe vs’ flange arrangement. My new theory is to press in a short section of pipe, into the aftermarket headers y-pipe, to recreate the arrangement seen in the stock headers.

I dont think I’m getting the sealing action at my flanges and/or my two mating flanges are moving about too much. I “sort of” tested this theory by running tape around the flanges… sure, it melted and made a mess, BUT I think it proved my theory correct.

Going to have a crack at it tomorrow.

55

I’ve seen header flange leaks before and they always seem to leave telltale carbon streaks.
Did you see any of those when you took the header off?

56

I’d say figure NO. 2 is correct. If the 48Nm bolt is the “eccentric holding down bolt” (the bolt that holds the eccentric idler hub to the swinging tensioner plate), the counter-clockwise rotation shown in No. 2 would push the idler into the belt and thus push the tensioner rod down into the dampener. The only way I see getting “No. 1” to work is if the idler hub were rotated about 90 degrees clockwise from the position shown. Is the idler hub in the position shown in the images?

I like your pipe extension trick…good luck.

57

CircuitSmith - I’ve scanned both sides of two out of the three gaskets in question. Both sides.

Today, before I make up my inserts, I’m going to attach a vacuum cleaner to the tail pipe, then run around the flanges with a hose, to see if I can hear anything. This is a new trick I found Googling around. I haven’t tried this before.

This doesn’t explain why previous “wrapping” attempts didn’t affect the noise though.

ALBUM HERE on imgur

Insightful, I’ve uploaded an image that might clear up the eccentric’s position.

I didn’t use a tension wrench to “torque” the eccentric around to 4.4nm. I did however torque the locking/centre bolt of the pulley. I had an assistant rotate the eccentric around and hold it in position once pressure went off the locking pin in the hydraulic tensioner. Doing this would have been much easier out of the car, but I got everything to work out. Timing marks were correct after two crank rotations, a ten minute wait and a further two crank rotations.

ERAAVFA.jpg748×876

58

Sorry, I’m still confused. Did the tensioner end up in the position shown (in yellow) in image 2 or 3?

59

Insightful, The image is a bit deceptive, in that I have spun the eccentric around at different angles Image 1to Image 2. The graphic is not an accurate representation of how far I have spun the eccentric around, it just shows a general position of the eccentric.

In answer to your question though, Image 1 is better representation of how the direction in which I rotated the eccentric. I’m damn sure I didn’t need to spin it around that far.

I’m about to start cutting pipe ands fitting it into the flanges of the y-pipe. The car is cold - has not been started in more than 12 hours - so I’m going to pop the front timing cover off and check my timing belt. I’ve been lead to believe that the timing belt should have some play in it if the car has been allowed to sit - the tensioner bleeds down apparently. If I find a tight timing belt I’ll have reason to disassemble and refit the tensioner eccentric.

60

“In answer to your question though, Image 1 is better representation of how the direction in which I rotated the eccentric.”

Image 1 is at the end of adjustment, isn’t it? If it’s really in that position, I’d say the belt is stretched and should be replaced. I’d expect to see it end up close to as shown in the original shop manual position.