Advice on Y Piece fitting

[TimJM]

Following on from my other thread where I couldn't remove the old clamps (sorted now at the cost of two screwdrivers). I have had no joy at fitting the new y-piece. The old one I removed sat well on the manifolds - in fact even with the clamps off I had to use a knife to break the exhaust paste seal they sit that close.

The one I am fitting just won't marry up with both manifolds at the same time. I know some people on here have said you have to pull the manifolds in a little (although I don't know how they do that as mine are solid with no give at all) but the problem I seem to have is the top of one side not reaching across even when the bottom is in contact. I have taken a picture to try and explain the problem a little better, the red lines I have added are to indicate where the manifold and y piece faces are as the exhaust paste I have added after a few failed attempts hides them a little.



The gap at it's widest point is about half an inch. The bottom is touching and the back nearly touches but the front/top is a way off. It is almost as if I have got to rotate the manifold anti-clockwise and then pull it in or if the y-piece was longer on the top but the same length on the bottom of the bend.

Has anyone got any tips from doing this job, should the manifolds have any give in them as mine feel solid? I have pulled/pushed and lent on them and they do not move at all. I was going to try a crowbar against the chassis to try moving them but didn't know if I would end up cracking them as they do not want to move. Even if I could move them the movement needs to be more of a rotation rather than a pulling in, as I said the bottom is in contact.

I usually enjoy working on my car but this job is really starting to annoy me now. If I knew what a bh it was going to be I wouldn't have started. Four hours of swearing, two knackered screwdrivers, a fked elbow and no closer to finishing it. Worst case I will be going to the Growl in the wife's:


I could glue a TVR badge to it...

Tim.

[TimJM]

BliarOut said:

Have you tried using a ratchet luggage strap to bring them together before putting the clamps on? It's the only way my standard Y piece will go back in.

Copied in from other thread - wanted to keep on topic here.


I have heard this but do you have any play at all in your manifolds? Perhaps mine are just really old and brittle but there does not seem to be any give at all. I might try a picking up a ratchet strap to see if that helps but I think the problem is more one of rotation rather than pulling in as the bottom seems to be in contact.

Tim.

[clive f]

hi Tim, first I`ve seen this, you should have dropped me a line mate.
firstly, is the exit pipe on the y piece fitted into the exhaust pipe, if not then yes you may need to orientate the y piece a little, a small amount of movement at the bottom willl greatly alter the flange alignment at the top.

if the y piece is already in the exhaust and its in its right place, then the only explanation can be that your manifolds for some reason are slightly different to any that I`ve come across before, I`ve made quite a few decat pipes now, and thay are all made on the same jig, and fit reasonably well on peoples cars.I can cut and reweld the flanges for you to suit the fit on your car with a few measurements that you could confirm for me, but may not be able to get his done in time for the growl when you consider postage back and forth unfortunately.

give me a call 07793553602. clive.

[TimJM]

Yes, the exit pipe is in - I was going to give you a call but just wanted to see if it was me being a numpty before bothering you.

I'll give you a call, thanks.

Tim.

[V8Bart]

I had same problem with Act Y and was sure the headers would not move, it took a strong ratchet strap, muscles and alot of swearing. Also you can loosen the first mount for the main exhaust if you leave the Y in, it'll give you some more room to play with.


BTW
You'd be better off with no exhaust than the gf's mini!

Edited by V8Bart on Wednesday 6th June 16:41

[TimJM]

V8Bart said:

I had same problem with Act Y and was sure the headers would not move, it took a strong ratchet strap, muscles and alot of swearing. Also you can loosen the first mount for the main exhaust if you leave the Y in, it'll give you some more room to play with.


BTW
You'd be better off with no exhaust than the gf's mini!

Edited by V8Bart on Wednesday 6th June 16:41

Had a good chat to Clive yesterday (in-between thunderstorms on the M5) and he gave me a couple of pointers that could be causing the issue.

Just going to go and lie down in some puddles under the car for an hour or so to see if I can fix it. I wish my garage was wider so I could jack the car up in there. Oh well.

Tim.

[virgil]

TimJM said:

I wish my garage was wider so I could jack the car up in there. Oh well.

Tim.

Can't you jack it up front he front...I can now get mine on stands from the front and rear without touching the sides...

[TimJM]

virgil said:

Can't you jack it up front he front...I can now get mine on stands from the front and rear without touching the sides...

Possibly but for this job I have to take off the passenger front wheel to access the exhaust clamp and securing bolt easily. I couldn't do that in my garage.

I am making some progress though, I measured the y-pieces old and new and there is barely anything in it. My old one may be a few mm wider but that is all.

It looks like Clive was correct with his diagnosis of the exit pipe not pushing home as my exhaust seems to be longer than usual. I am going to try expanding the exhaust pipe slightly where it narrows to take more of the new y-piece before I resort to cutting the new y-piece down.

Tim.

[clive f]

tim, expanding the exhaust pipe will be difficult, just cut 1" off of the end of the y piece, much quicker.

[TimJM]

clive f said:

tim, expanding the exhaust pipe will be difficult, just cut 1" off of the end of the y piece, much quicker.

You would think so but I have a pipe expander and I don't have any metal cutters. Given my limited toolbox pipe expansion will be easier for me. Anyhow - Success!

I have managed to resolve the problem, a big thank you for Clive (I owe you a pint) for your advice. You were spot on. The problem was down to the exit pipe not going in far enough. I will add a few pics and a description here for anyone that has a similar problem in the future as these steps seemed to resolve the problem for me.

Just a recap - the symptoms are as my first post. When fitting the y-piece if the back and bottom of the manifolds meet up but you have a gap at the front/top then this is down to the exit pipe not being back far enough in the exhaust. When I was sliding the new y piece into the exhaust it would only go so far and then stopped abruptly. You could slide it back and forth but it always stopped at the same point.

For me the solution was to fit a pipe expander down into the exhaust where the narrowing started and slightly expand this section. Mine gave a little but not a massive amount. I then slid the pipe expander back up to make sure that the section after the cut in pipe slits was the same diameter as the slitted part.



I then noticed that the new y piece end wasn't quite round, it may have been knocked in delivery but it was slightly flattened into an oval near the bottom left side. I think the bottom of the oval may have been getting caught in the end of one of those slits. I gently re-rounded the y piece exit with the expander using just enough pressure to take the oval shape out a little.

Then I slid the y piece back into position (with some more exhaust paste applied) and it immediately slid back much easier and further. The manifolds nearly joined and were much closer all round.

I then applied a ratchet strap to try and pull in the manifolds, they feel like they wont give at all but if you put enough pressure on them then probably do move a few mm each side. When doing all this make sure all clamps and brackets are completely removed (the clamps are on this picture as I took it after pulling the manifolds in to test the fit). You want to apply the pressure equally to the manifolds as far forward as you can. Just at the front of the pre-cats seem to be the best position.



Once I did this the right hand side was sitting nice and level but the left of the y piece was slightly further back and not located. Again, it feels like it will not move at all but I put a cloth over the y piece flange to protect the metal and used a rubber mallet to knock it forward. It then seemed to clunk into the recessed location with the manifold and the ratchet strap could be tightened a tiny bit more.

Then it was all as per Clive's instructions. Clamps back on tightening both sides together slowly and tapping around with a mallet every so often until tight. Then the exhaust bolt back in (although I had to use a hammer to prop the exhaust section up slightly to locate the bolt back in) and the exhaust clamp back around where the y piece exit and exhaust meet.

Start her up, listen for any leaks (if you are lucky you will not have any), let her idle for 10 minutes to start curing the exhaust paste. Then wheel back on (I removed the passenger wheel for better access to the exhaust clamp and bracket) and go for a drive.

Here is the finished fitting after a 20 mile blast to check all was OK:



Thanks again for all advice and help, at least after this I have not decided I won't be fitting any new manifolds myself. I am no mechanic.

See you all at the growl!

Tim.

[kevd]

welldone on getting the job done. The most important bit, how does she sound?

[TimJM]

kevd said:

welldone on getting the job done. The most important bit, how does she sound?

Much better - I can hear the engine now when I am driving, I could barely hear it before. Next stop it the precats out, then I think I will have the sound I am looking for. I don't know if you saw the video I posted up previously of my car on tickover...perhaps I should post un an after one? You could have mistaken if for my wife's mini! Now the car is starting to sound like a TVR.

[MPoxon]

Well done sir

[TimJM]

MPoxon said:

Well done sir

Thank you - I think you will be parked a couple of cars up from me at the growl, I would like to have a little listen to your setup if possible. Your engine bay looks a bit tasty. And by tasty I mean expensive!