| Author | Message | ||
     Brian Vogel Grand Master Username: guyslp Post Number: 328 Registered: 6-2009 |
Progress is slow, but steady, on LRK37110 and I'm trying to get my ducks in a row to have the majority of the exhaust pipe work replaced. The system is odd in that the catalytic converter and various mufflers all appear to be made of stainless while all of the connecting pipe work is mild steel. What are the experiences of the cohort as far as finding sources for stainless pipe work that is as close to "out of the box" installation as one can get? (At least if one is taking it to someone who routinely does exhaust work). I realize that there may be few, if any, who've sourced these parts in the United States, but if you have definitely chime in. Even when sourced elsewhere, if the maker of said pipes is an international aftermarket maker I might be able to find their product in the US. Thanks in advance for your input. Brian | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 134 Registered: 10-2010 |
Hi Brian, I put mostly Crewe parts on mine, but the Crewe downpipes and balance pipe are mild steel so I went with an aftermarket supplier for those in stainless (the ones Flying Spares sells). To I'm sure no one's surprise, the downpipes required a bit of fiddling (and the balance pipe needed cutting) to make fit. The Crewe parts bolted right up with no drama. The other thing I'd watch out for with aftermarket suppliers is the guage of the stainless used. The thinner stuff can sound tinny. (Flying Spares' stuff is fine in that department.) Cheers, Jeff. | ||
| David Gore Moderator Username: david_gore Post Number: 1263 Registered: 4-2003 |
Brian, if you want the quietest exhaust and your wallet can stand the shock; go for the heaviest gauge stainless steel available either ex-stock or preferably special order from a specialist shop who can use your old pipes as templates. If it was my car, the extra cost involved in having them fit the exhaust to your vehicle instead of DIY is an easy decision as there will always be a need for "fiddling" the installation to get the best possible fit. The best material thickness is 10 gauge [0.1406 inches, 3.57mm] but not all shops will be capable of bending this - a truck/bus/earthmoving exhaust specialist will be able to handle this job without any problems. A compromise between cost and sound attenuation would be 16 gauge [0.0625 inches, 1.59mm] material. I would use type 304 stainless steel by preference and would not use type 316 as it is prone to sigma phase embrittlement after prolonged exposure to high temperatures above 500 deg Celsius which are commonplace in exhaust systems. I would not use the cheaper type 409 grade and steer well clear of any shop that tries to tell you it is suitable. Be careful when selecting a muffler and resonator [I would fit resonators as they enhance the exhaust note especially with a dual exhaust and balance [cross-over] pipe set-up]; they may be light gauge for cost reasons and be more noisy when fitted than one made from thicker material. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 329 Registered: 6-2009 |
Jeff & David, Thanks for your input. Luckily, I live in an area where shops for heavy agricultural equipment and trucks are relatively common. I am hoping that I can keep pretty much all of the original catalytic converters, mufflers, and resonators since they look almost pristine compared to the sad mild steel pipes that connect them. Heaven knows that my finances could certainly not stand the shock of having to replace the entire exhaust system. Having the detailed information on stainless steel type numbers and suitability will be very helpful. Metallurgy 'R' not me! Brian | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 160 Registered: 5-2012 |
Jeff, I don't suppose you know the gauge of the Flying Spares stainless system. I have a 74 SY1 which has a very basic exhaust system. I replaced the rear tailpipes and boxes a few month's ago with a FS mild steel system. I now have a FS mild steel front silencer box just delivered waiting to be fitted this weekend (very simple on the SY1). The reason I went for mild steel is that I wanted to buy time until I could research and buy a really good stainless system. The gauge of the front silencer box I have just bought is 15 (0.0673"). I suspect the stainless system would be the same or less. This compares very badly with David's recommendation of 10 gauge. When my new exhaust system comes up for replacement in a few years time I will consider having a system made up by a specialist shop from much thicker gauge stainless if I cannot find one aftermarket or from Crewe. If anyone knows the gauge of stainless systems for a Rolls from whatever source, I'd be really interested to know. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 161 Registered: 5-2012 |
Brian I was checking out JEGS website that has a wide selection of stainless steel pipes and fittings for making up custom systems. Have you checked this out yet? Geoff. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 162 Registered: 5-2012 |
Brian I have just been checking out the SY2 exhaust system - I do sympathise with the costs. Sometimes I am quite grateful I have the "inferior" series 1 Silver Shadow. BTW - when you have had the new pipes welded to the silencer boxes, give them a good shake and listen for rattling of any weld beads that have dropped into the box. This was the case on my car when I bought it and it sounded awful - necessitating the immediate replacement of the rear part of the system. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 330 Registered: 6-2009 |
Geoff, I've checked out very little because I was hoping to get input from the voices of experience first, and I have. More has been better. Knowing what not to consider from the outset helps narrow the scope quite a bit, and I can't begin to say what a help that is. I hadn't the vaguest idea of what makes for a good stainless exhaust system and the information offered so far on this thread has gone a long way in helping to remedy that ignorance. I will probably end up allowing the shop I use to acquire the various bits and pieces they deem necessary. What I want to be able to do is to specify the steel type and gauge that I would prefer so that an accurate price can be worked up. I have never seen an exhaust system as complicated as the ones on my two SY series cars. At least the European spec car doesn't have (and never did) catalytic converters, so those are removed from the equation on that car. Brian | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 135 Registered: 10-2010 |
Hi Geoff, It's pretty hard to tell on the car, but I remember it being considerably heavier than my Land Rover which I did at the same time. The Land Rover is 16 gauge, so I'm going to guess ~ 13 or 14 gauge for the FS stainless downpipes. The balance pipe is much thinner, though, even a bit thinner than the Land Rover's primary exhaust. 18 gauge perhaps? Cheers, Jeff. | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 136 Registered: 10-2010 |
Turns out FS lists the specs on their website: pipes in 2mm (14 gauge) type 304; boxes fabricated from 1.5mm (~16 gauge) type 304 sheet. I guess my guessing ain't so bad. ;) Cheers, Jeff. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 330 Registered: 4-2009 |
I am not sure that 304 grade stainless is the best choice of stainless. 304 stainless does suffer from chloride attack. If you have salty roads then maybe 304 may not be the best choice for you. I have a stainless steel bodied car that sat on the beach for a few years - soon went rusty!! | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 331 Registered: 6-2009 |
I just put in a query with Borla East, an outfit in New Jersey that does full restorations on high end cars and that I've heard good things about as far as their exhaust systems go. I don't have a price quote yet, but they told me that they use type 304 stainless. Brian | ||
| richard george yeaman Frequent User Username: richyrich Post Number: 83 Registered: 4-2012 |
Hi all. My SY1 SRH19529 Has a full stainless system probably after market flying spares or such like I have the car two years in June the previous owner had it for Seven years and it was on the car when he bought it and it is still like brand new as they say, It has a Raspy sound when you rev it while stationary sounds good to me. Cheers. Richard. | ||
| David Gore Moderator Username: david_gore Post Number: 1265 Registered: 4-2003 |
"I am not sure that 304 grade stainless is the best choice of stainless. 304 stainless does suffer from chloride attack. If you have salty roads then maybe 304 may not be the best choice for you. I have a stainless steel bodied car that sat on the beach for a few years - soon went rusty!!" Omar, I presume you are referring to the exhaust system and not the car body.... I suggest the "stainless steel" used was probably Type 409 and this would rust heavily in a marine environment - it is normal for stainless steel to discolour in harsh environments due to surface deposits which may or may not be rust. A simple test to determine the type of stainless steel used is to test the metal with a magnet; if the magnet sticks, it is most likely a lower grade of stainless steel with marginal corrosion resistance however this effect can also be observed with highly alloyed ferritic alloys like type 444 or the more recent duplex austenitic-ferritic alloys. The 300 series austenitic stainless steels are not magnetic and the magnet should not stick; if the material has been heavily worked during bending, some attraction will be felt from the work-hardening process but the magnet should fall off under its own weight. The fact that Brian lives in a snow/ice region is the reason why I included the warning about not using type 316 and type 409 due to the high probability of problems after installation. Due to problems with under-body corrosion from de-icing salt, I assume the underside of the car would be washed down after use to remove the salt and this would also benefit the stainless steel exhaust system. I would not expect serious pitting corrosion in a type 304 system if the level of care required to preserve a R-R/B vehicle in this environment is provided. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 332 Registered: 4-2009 |
Dear David, No I was refering to the car body. The car is a 1989 Moon Leopard (one of only 11 cars made). The body is stainless steel and I have no confirmation of the grade. A specialist once told me that it was 304 stainless. The rust is not horrendous, but enough for me not to be able to get a shine like I can on my other Moon Leopard that was not parked on the beach for years. If the industry standard is to use 304 ss for exhaust systems, then that must be the best compromise. Surface finish is not an issue for exhaust systems. | ||
| David Gore Moderator Username: david_gore Post Number: 1266 Registered: 4-2003 |
Hi Omar, Did a little research on the "Moon Leopard" - one of those cars that appear from time to time to test one's beliefs about motor vehicles......... As you still have the cars referred to in the article in "The National", can you do the magnet test for me and let me know the result? If the metal is non-magnetic, I will send you details of a chemical spot test you can use to determine if the steel contains Molybdenum which will indicate if the material is type 304 or type 316/317. This test requires some care due to the chemicals involved and your background is appropriate for you to appreciate the care that has to be exercised in relation to their use and to access the chemicals. If you can send me some photos of the damaged bodywork, I should be able to send you some information on surface cleaning/finishing stainless steel which may help you rectify some of the damage to the stainless steel. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 165 Registered: 5-2012 |
David I find all this information incredibly useful and store notes for future projects. I would just like to query one of your comments above. Not that I am in any way qualified to disagree with it, just that I would like verification. You state that 10 gauge is the best thickness to use in a stainless exhaust system. Is this correct? I know it would make for an excellent quiet system but it does seem very thick - well over 1/8". Geoff. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 335 Registered: 4-2009 |
Dear David, The magnet did not stick at all. No attraction whatsoever. The car that had the beach exposure is now stored on the roof of my garage at home. To get to it to take photos will take some time. I will get round to it and then send you a PM. Thanks for your advise and help. Omar | ||
| David Gore Moderator Username: david_gore Post Number: 1267 Registered: 4-2003 |
Hi Geoff, Yes, here in Australia 10 gauge is appropriate mainly because of its ready commercial availability ex-stock; the other gauges between 16 and 10 gauge were usually "special orders" which required a minimum quantity order to justify the local mill setting up a production run. If 12 gauge is commercially available in your location, this would be eminently suitable. The reason for using heavy gauge material is based on the fact that the greater mass of the material, the better is the sound attenuation; this is why Lead is the material of choice for sound-proofing purposes. My suggestion is based on my belief that the typical R-R/B owner would prefer a super-quiet rather than raucous exhaust note [BTW, I am not a "typical" owner as I love the burble of a properly set up V8 dual exhaust]. It all depends on how much you are prepared to pay; Flying Spares have compromised between cost and performance to offer products at a price which they believe will not deter prospective customers. | ||
| David Gore Moderator Username: david_gore Post Number: 1268 Registered: 4-2003 |
Hi Omar, Based on your information so far, I am confident the body has been fabricated from type 304. However, this may change when I see the type of corrosion present. I don't think we will need to do a Molybdenum spot test at this stage. The next step is to determine the mill finish of the material used, this can range from BA [Bright Anneal mirror reflective finish], 2B [smooth matt minimal reflective finish] to a No. 3 or No.4 linished finish. Each of these finishes will require appropriate cleaning procedures. When taking the photos, please try and get both general and close-up high-resolution photos of the surfaces showing mild, medium and heavy discolouration and/or pitting [easier said than done unfortunately as stainless steel surfaces often prove difficult to photograph]; I have found the best technique is to maximise the depth of field and try to use lighting from the side to avoid unwanted reflections. I am expecting to see a preponderance of brownish discolouration due to evaporation/concentration of condensation and probable pitting of the surface beneath the heavier deposits due to differential aeration corrosion. If you can estimate the thickness of the metal sheets used, this will also be useful when considering possible reclamation. I await your photos with interest; when you are ready to send them, please PM me and I will send you an email address. Regards David | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 167 Registered: 5-2012 |
Hi David Many thanks for the information. Geoff. | ||
| Randy Roberson Prolific User Username: wascator Post Number: 124 Registered: 5-2009 |
I recall vaguely that GM used some double-wall exhaust tubing, perhaps back in the mid 1970s, and that the purpose was in part sound attenuation. Seems it would fail sometimes due to engine problems which caused overheating, and the outside pipe would be fine while the inner pipe would warp until it created significant back pressure. I bet that caused some head-scratching. I am guessing, but perhaps the higher sound level from aftermarket equipment is more from the design of the silencers than of the pipes themselves. I know I'll be doing this someday, so I appreciate the discussion. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1011 Registered: 6-2006 |
Have a look at ServiCentre exhausts if you want a great fit and far quieter than any others I have fitted and I can highly recommend them. http://www.servicentresystems.co.uk/ I don't have any interest in the company other than using them for years. I can probably get you a better discount if you wish to deal through me.  | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 179 Registered: 5-2012 |
Hi Folks I have finally got round to fitting a new front silencer box to SRX18501. The old box is off the car and I have cleaned up all the olives, clamps and other mating surfaces. They are all quite good - hardly any pitting so I should get a good seal when I fit the new box. Can any one advise me on the best jointing compound to use on these joints? Regards Geoff. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 180 Registered: 5-2012 |
To be more precise, I know you can get a tube of compound that usually comes with exhaust pipe repair kits, however these tend to harden much too quickly. I was thinking of using red high temperature RTV sealant as this should allow me an hour or two to assemble the exhaust system and tighten all the bolts. Is this suitable for exhaust pipe joints? I'd be grateful for any advice or opinions. | ||
| David Gore Moderator Username: david_gore Post Number: 1281 Registered: 4-2003 |
Geoff, the front end of the exhaust system can get very hot [500+ deg Celsius] depending on the operating conditions. The Permatex Red RTV sealant is only rated to 350 deg Celsius by the manufacturer and no mention is made regarding its use in exhaust systems. If or when the sealer breaks down due to the service conditions, the exhaust system will most likely leak from the gaps originally filled by the sealant. My experience with exhaust joint sealing compounds has been less than satisfactory due to cracking and spalling problems over time. Satisfactory results have always been achieved with best possible smooth, clean and uniform mating surfaces on all components and careful alignment of the entire system before final tightening of the fittings working from front to back along the system allowing for expansion and contraction of the system in use. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1022 Registered: 6-2006 |
as David says, good condition ones should seal themselves. copper grease on the ring and clamps helps them seat more tightly. tighten again after running. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 181 Registered: 5-2012 |
Wow - thank you David, that is very useful. The mating surfaces, as I mentioned, are in good condition with very little pitting. I will pay a little more attention to them with some 600 wet and dry and then reassemble. Many thanks Geoff. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 182 Registered: 5-2012 |
Paul - Many thanks - I will go with the copper grease also. Geoff. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1023 Registered: 6-2006 |
unless you have cats afterwards , them make sure anything used is act friendly. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 183 Registered: 5-2012 |
Paul - 74 SY-I - no cats, so will be ok. Geoff. | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 149 Registered: 10-2010 |
Hi Geoff, One of the main determinants of a good seal is that things can line up correctly, so it's important that the pipes can move easily on the olive (ring), and that the half-clamps can move easily on the flared pipe-ends (to even out the clamping force). I know Paul already said this, but just to reiterate, 3 surfaces need a bit of lubrication to facilitate this: the outsides of the olive, and the V-grooves of each half-clamp. I was a bit nervous about getting a good seal and so used Firegum on the olives and Copaslip on the half-clamps, but it sounds like Copaslip on all 3 would be fine. Cheers, Jeff. | ||
| Geoff Wootton Prolific User Username: dounraey Post Number: 184 Registered: 5-2012 |
Hi Jeff Many thanks. This has all been very good news to me. I had envisaged a race against time in getting the system bolted up whilst the sealants were all rapidly hardening - so glad to hear that sealants are not the way to go. I shall spend plenty of time making sure all the parts are correctly prepared and positioned before clamping it all together. Geoff | ||
| Randy Roberson Prolific User Username: wascator Post Number: 125 Registered: 5-2009 |
I don't know it all but I've never seen anything used on exhaust pipe joints to seal them, at least downstream of the manifold connection. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1024 Registered: 6-2006 |
Randy , often on very poor rings and clamps. It's also useful in heavier gauge slide fit joints. You can seal them without distorting the tubes too much. Makes future disassembly so much easier. | ||
| Randy Roberson Prolific User Username: wascator Post Number: 126 Registered: 5-2009 |
I understand. I just replaned the B-bank exhaust manifold on my Car and got a new clamp etc. It was in nice shape anyway and it sealed off fine at the pipe. I do need a pipe or two 'down there', though, to make things really pukka. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1025 Registered: 6-2006 |
Randy, nothing more satisfying than fitting new exhaust boxes with new clamps and olives. Unfortunately they double the cost of a system  Randy : If your B Bank manifold cracked I hope you jacked up and checked your rear engine mountings. Failing engine mounts are usually the cause of B Manifold cracking. All: No paste on manifold to head joints. If they will not seal with new gaskets then the manifold will need skimming. Check the manifold bolts every year. The left hand ones are always attempting to escape and frequently do! |
