Exhaust Manifold Problems

[margie2000]

Well!! I have now attempted to repair the manifolds twice after they split.

The second time I had hardly got more that 20 miles from home in Paignton in Devon when it happened again.

I need to find a suitable permanent solution to this before I throw any more time and expense at it.

The car has a 3.9 v8 Range Rover unit.

If anyone could share with me a solution to this which has worked for them, I would be pleased to hear from you. I do believe that there has been some success.

Regards

Mark

[greyV8pete]

Re: Exhaust Manifold Problems

Well!! I have now attempted to repair the manifolds twice after they split.

The second time I had hardly got more that 20 miles from home in Paignton in Devon when it happened again.

I need to find a suitable permanent solution to this before I throw any more time and expense at it.

The car has a 3.9 v8 Range Rover unit.

If anyone could share with me a solution to this which has worked for them, I would be pleased to hear from you. I do believe that there has been some success.

Regards

Mark

Hi Mark.
Have a look at my post as per link below

http://www.marlinownersclub.com/forum/showthread.php?5639-Stainless-Manifolds-for-Hunter-Rover-V8-engine&highlight=manifolds

Several members have had to replace their V8 manifolds due to welds cracking with the earlier type of stainless, so you are not alone.

The O/E 4-2-1 manifolds are not correct as the way the branches are configured they are on the "wrong" side of the engine so there is conflict between the ports. Do not copy these if having new ones made! The later type of 4 into 1 set up is much better anyway.

I live in Exeter so you are welcome to come and look at my car and I can talk you through it all. Drop me a PM with your tel number and I will give you a call. Peter.

[dave_kitson]

Re: Exhaust Manifold Problems

Hi - I recall from somewhere that stainless is not a good idea for manifolds. Fine for the silencers, but not the manifolds. My V8 has mild steel manifolds and has done nearly 30k with no cracking. I did get them chromed to make them look better, but that didn't last, so don't waste money there. In the end I had to lag them to try and get heat out of the engine bay, so that hid the grotty chrome. I guess that the high temperatures in the manifold make stainless too brittle. Dave

[greyV8pete]

Re: Exhaust Manifold Problems

Hi - I recall from somewhere that stainless is not a good idea for manifolds. Fine for the silencers, but not the manifolds. My V8 has mild steel manifolds and has done nearly 30k with no cracking. I did get them chromed to make them look better, but that didn't last, so don't waste money there. In the end I had to lag them to try and get heat out of the engine bay, so that hid the grotty chrome. I guess that the high temperatures in the manifold make stainless too brittle. Dave

I think that referred to the "earlier" type stainless. Mine are the "later" type stainless, but I can't remember the code numbers off hand. Also the O/E Marlin tubing was quite thin. My replacement tubing was noticeably thicker walled. Peter.

[Michael Turpin]

Re: Exhaust Manifold Problems

MGB HIVE do a set for a 3.5 but not sure if they are the same for 3.9IMG_7313.JPG

[dave_kitson]

Re: Exhaust Manifold Problems

Hi - The manifolds were made specifically for the Cabrio as far as I know. The offside set was particularly special, as the steering column went through them. Any other aftermarket ones will probably mean extensive rerouting and multiple UJs in the column. Also the final pipe needs to go backwards, not down as in the picture. You could ask Marlin for some new ones as they are supposed to support existing owners, or ask them where they got them from. If they know - don't hold your breath!
Dave

[Michael Turpin]

Re: Exhaust Manifold Problems

The pipe does go backwards - back up and out through the side under the wing

IMG_7496.JPG

MGB Hive supplied the manifolds through EBay for £325 the pair. I was fairly happy with the product but they did require some finishing and polishing to bring them to a good standard.
The remaining piping was made from six 90⁰ bends (Clamco SSB3890 38mm 90 Degree Stainless Mandrel Bends) £10.25 each - three for each side. These were cut to length and then fastened together using strips of mild steel and a jubilee clip on each side of each joint, this enabled me to remove the three pieces of pipe as a whole keeping them in the correct orientation. The joints were then TIG welded (tacked) at three points to avoid distortions, the clips were then removed and a run of weld ran around the whole pipe to finish job.
You could of coarse only use two to make the pipes go backwards. you can find an article in pitstop PITSTOP 188 the first upgrade of c883 cwy pt 2 page 15-16

[margie2000]

Re: Exhaust Manifold Problems

Thank you all for the help and advice. Really helpful. I am currently looking at full stainless steel replacements. It might help if Marlin could share details of contacts and suppliers. I await a call back.
I will keep you posted re progress and make available to club members full details of the solution I find so that we have it for anyone else in the same position.
Watch this space.
Mark