Correct installation of headers/extractors?

[Marce]

Hi everyone, I'm new to AULRO so first a couple of lines to introduce myself, then a question.

I'm Marcel, I'm 44 and I live in Melbourne. My partner Susy and I have a 21 month old daughter, Bindi-Rain, and a 13 year old Jack Russell, Chocolate. Last year I inherited a 1972 LWB early Series 3 from my late grandparents. It's a veteran of numerous outback trips and was looked after pretty well: kept out of the rain, serviced regularly and maintained in good running order. But this was no show-pony, it was a working vehicle and accumulated some light surface rust, some dents and scratches and a whole lot of little modifications (like the mallee root choke knob carved with a Swiss Army knife) that lend it character.

I have vivid memories of camping trips in "the Land Rover" as a kid so this vehicle is rather special to me. Just the smell of the interior and the sound of the original 2.25 motor brings back happy memories of fun and adventure on dirt roads and country highways. I've taken it on with zero experience (but learning fast) as a restoration project. I'm not after a showroom finish, I want it to be a reliable touring and off-road vehicle, to look dignified and to last another 40 years. I'm going to strip it down to a rolling chassis, get rid of the surface rust, recondition bits that need it, replace a few things, paint one panel at a time and put it all back together.
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Now to my question.

I've decided to keep the original 2.25 L motor which runs well but I want to squeeze a few more horsepower out of it. Step one is fitting a set of Redback extractors. This was done today by a local exhaust specialist, but I'm wondering if he did a dodgy job. Rather than connecting the extractors to the rest of the exhaust system with flanges, he inserted the extractor tube into the slightly larger diameter pipe going into the muffler and secured it with a bracket. This leaves a gap of a couple of mm (see photo) where you can feel exhaust gases leaking when the engine is idling. It's not a huge leak, more a gentle puff, but it's not insignificant.

Is this something I should be concerned about? Would that leakage compromise the effectiveness of the extractors by reducing 'good' back pressure? Or might it actually improve them slightly by reducing 'bad' back pressure, that is, making the exhaust system less restrictive? On a test drive I did notice a mild performance improvement. It accelerated slightly quicker and held top gear on hills a little better. But I wonder if that leak is not allowing the extractors to reach their full potential, even without modifying the rest of the exhaust (which I'm reluctant to do in case it kills low-end torque)? Any thoughts would be much appreciated.

[Homestar]

Welcome to the forum. 😊

Yes, that looks dodgy to me - a slip joint that is exhaust tight is no dramas, but one that leaks is not. I’d be asking them to rectify this.

[101RRS]

One could argue that welding the pipes together could be an issue if the joint has to be separated at a later date - particularly if the last few mm of the extractors had to be cut off.

So for me some sort of joint would be preferred - if it was me I would prefer either end be flared to fit a circular seal with a bolt together flange to hold it together. However failing that how he has done it with an exhaust clamp, whilst unsightly is Ok - my mufflers on my jag and 101 are similar, however they do not leak exhaust gas - it is actually a roadworthy issue. Your guy has either mismatched pipe sizes where one fits into the other or has not pushed them in far enough and the slots in the outer pipe that allow the clamp to tighten up are not fully covered by the internal pipe and are letting a bit of gas out.

You need to take it back and as a minimum get the exhaust leaks fixed and preferably, though not essential, have a different method to the clamp of joining the pipes.

Garry

[Toxic_Avenger]

Poor fit indeed, but nothing a $10 tube of exhaust gasket sealant won't fix.
As for the performance aspects of this engine... negligible.

[Marce]

Thanks everyone.

I took it back and he apologised, put roof and gutter silicone in the join and tightened the clamp. We'll see if the seal holds. If not I'll take it back.

Marcel

[Blknight.aus]

thats DAF.....

roof silcone wont hold... tuned and driven right you'll get the 2.25 hi comp engine to glow the manifolds.....

There is an argument that can be put forwards for a certain type of venturi setup in the exhaust that draws fresh air in post extractors to help "clean" the exhaust coming out the back of the pipe BUT.. for a series of that vintage... not an issue.

More than happy to do a meet and greet with you at some point and close that exhaust up properly for you if you'd like.

[101RRS]

I am with Dave - the exhaust guy should have fixed this properly.

[Marce]

He also put a small bead of sealant - presumably the same stuff - over the new manifold gasket that came with the extractors. So far it doesn't seem to have burnt or peeled, it looks OK.

Internet forums are divided over whether ordinary silicone is OK for exhausts. Some people suggest it should be OK against the head, which is kept relatively cool by the cooling system, and downstream of the muffler where the gases emerge cooler. In my case it has been used just upstream of the muffler.

In any case I found another reason not to trust the person who did the work: he left an inlet manifold bolt loose. It just needed a couple of extra washers and he either overlooked it or couldn't be bothered doing the job properly. After being charged $350 for the installation, which he said would be a bit tricky and time-consuming (that may well be true), I expect is a job well done. So I won't be going back to him.

Thanks for the kind offer to meet up sometime and help me fix this properly. Send me a private message when it suits. Happy to pay for your time and any parts required and I'll throw in a case of beer as well. I do need some expert advice on this 'restoration lite' project and this is best done with someone having a look over my landy.

I've booked in a full service with Series specialist Fred Smith in Bayswater. He seems to have a good reputation.

Marcel

[Blknight.aus]

which he said would be a bit tricky and time-consuming



In retrospect,

That probably should have been your first clue while keeping one eye on your wallet, the other on the owner for you to engage R/lo and back slowly and carefully out of the place to a safe distance before giving it all available beans towards the specific direction of somewhere else.

Im a hack and I dont think a set of extractors and a muffle joint for a series is that hard to make up.

[whitehillbilly64]

'Roof silicone wont hold'
Experience, or Theory ????
But I agree, the work should have been done correctly.

whitehillbilly

[Marce]

This story has a happy ending.

On Dave's suggestion I took it to a certain exhaust specialist next door to Jaycar in Thomastown. They replaced the dodgy joint with flanges and put in new custom-bent pipes downstream of the extractors, plus a new muffler (the old one was beginning to deteriorate and it wasn't optimised to match the extractors). They did a great job. It's louder than the old set-up. For better or worse it sounds a bit more like a V8 now.

What's really pleasing is the power boost and the smoother responsiveness of the engine from the combination of the off-the-shelf Redback extractors and the new exhaust system. The extractors by themselves were a mild improvement, but together with the matched exhaust it's a quite substantial improvement. I took it for a test drive with my brother, who has a late-model Defender and drove my Series 3 before and after the changes. He was impressed: it climbed a steep hill in high ratio second that it could only manage before in high ratio first, and that was without an adult passenger, a child and a dog on board.

I told the exhaust shop I wanted the sweet spot between too restrictive (too much 'bad' back pressure) and too free (not enough 'good' back pressure, if I understand it correctly). They said 2.25 inch diameter tubes were optimal: any bigger might kill low-end torque. They also advised against a hot dog style muffler (too free) and recommended a baffled muffler, which is freer than the one it replaced yet still provides the necessary back pressure. I went with their advice.
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As for the more grunty engine note, especially on acceleration, I don't mind it but as a family touring vehicle I'll have to do a bit of sound deadening down the track.

[Blknight.aus]

'Roof silicone wont hold'
Experience, or Theory ????
But I agree, the work should have been done correctly.

whitehillbilly

Both, the temperature ratings are on the packaging.

if you use a low temp sealant it can burn through you get a path for the hot gasses and then you have an exhaust leak.

Roof sealant also wont withstand some of the coolants so while, (in theory) you should be able to use it as a waterpump or core plug sealant... its not typically rated for heat, chemical pressure and component creep all at the same time.