Hey all, this is my first time posting here, but some of you might recognize me from some of the other rover lists...anyway...

Yesterday, I installed a new DDC (2 u-joints at each end) front driveshaft from great basin rovers on my 98 disco. It was hitting the cat, so I pounded the corner of the cat flat with a large hammer. So now it clears during normal driving, but still hits when the right-front suspension compresses. I'm afraid to pound on the cat any more, as I think I already broke a piece of the catalyst off. If I keep hitting it, I will ruin it for sure...

Anyone here deal with this issue? the situation should be the same on a 97 D90...

If I remove the cat and replace it with a straight pipe, I will have no problems. In my state (Illinois), the emissions inspection on 96 and newer vehicles consists SOLELY of connecting to the OBD2 and scanning for codes. No exaust sniffer, no visual check!. Of course, this will make my CE light go on, and i will fail the test. I have heard of a replacement GEMS chip that will ignore the aft O2 sensors.. I guess this is an option, but it doesn't sound like a cheap one.

I wonder if I just left it alone, would the driveshaft eventually wear a hole in the cat, or will it just continue to push it out of the way?

Sorry for the long stream-of-consciousness post, any advice appreciated. thanks

I am quite interested in hearing more about this replacement chip! does anyone have details?

Why remove the cat when you could just move it. There are many aftermarket cats that are smaller and could be moved behind the T/C.


Funny screen name!

Josh you can call Chris Crane at RPI for information on the chips. I believe he can alter the O2 codes for non cat applications... Its a bit $$$ and for the gems requires 2 chips. Also you have to send your box to him with a 2 to 3 week turnaround, Im going to the UK in Spring and plan to have mine upgraded on a walk in basis... I hope i will be able to carry on the Gems in my luggage?

I don't know how practical it is to move the cat behind the transfer case...at that point the exhaust is already down to one pipe, and my truck has 2 cats....I will have to see if I can find a generic cat that's smaller--this might also be a problem because the one that hits is the flat-looking one, not the muffler looking one. Maybe I can just move it back a couple of inches...

There is also the option of putting more lift on the truck--that will make it clear! :D

I did a soild Y pipe on my ** 88 RRC Provide by RPI, i also welded on 2 O2 bosses close to there orginal locations.

Aft of the Y pipe i went with 2.25 od SS pipe to the tail

I placed the cat where the old large factory muffer and I beefed up the heat shield with new one from jegs. The Cat was a performance type made by Catco i think?

I got it from a local muffler shop price was right,it was under 100.00 Jegs has them also. it was a hook up so i save thee shipping

Then just aft a few inches past the cat I place a flowmaster... It worked great a bit loud but i liked it.

It did not hang down lower than the stock configuration and there was none of that hot floorboard any more... IMO its too hot in that area even on my 97 DI I want to do the same type Y pipe setup setup

The 14cux ECU is way more forgiving as the gems is in reguard to modifications to the intake and exhaust.

I also had a RPI chip and Nology coil and amplifier... It worked great until i lunched the timing chain....

Hope it helps

I have two good friends that went about this removal of cats in another way. They simply removed the catalyst from the cats by cutting the top open, then re welded. If you did this, you could bang the cats as much as you wanted and not worry about the catalyst. One has passed emissions without the catalyst in the cat!

I would not cut and gut. VERY expensive if you get caught, especially in CO. Maybe not everywhere, but not worth it IMHO.

I would go with a LARGE single cat, and relocate. Get even more "CB" with a Glass pack!

Get trick with a supertrapp!

Y pipe can be made with flex, then straight section for 02 holes, then flex again to a y connector. TOTAL CB, but easy, and legal.

j

I guess the GBR drive shafts are wider then the Tom Woods ones. I'm running Tom Woods Double Double Cardon shafts on my 98 D1 and it is close to the passenger side CAT but, it doesn't hit it. Is there a way for you to bend the pipe in front and after the CAT so that it moves over and out of the way a little?

I know what the Darkstar screen name means! We are everywhere!

My Blazer was called Darkstar, but I didn't like the implication of the first line of the song!

Peace,
Paul

If its ~ 1/2in or so that you need and you have the room between your cat and frame, loosen the engine and trans mounts and rotate the whole thing a few degrees.

Johnathan

Hmm.. that sounds doable. I don't think I have much room betweent the frame and the cat, but there may be enough...Will have to take a closer look at it tonite. Thanks

Beware of rotating too far counterclockwise, as the tolerance between the cat flange and the frame is closer than most people think. Trust me, on this one. Depending on the rubber in the mounts, there is a considerable amount of flex in the t-case/tranny/engine when in gear, (especially reverse). Try and be mindfull of that.

j

I dont' get it...If it's the CV that's making contact, then rotating the drive-train isn't gonna' change much (if anything)...Providing the area that is making contact is the center of the CV.

What the heck did you buy? A 1350?

--D

I dont have the spicer # off hand, but according to Bill at GBR they are the same ujoints/DC yokes that tom woods uses. One size up from 344 IIRC. it is the edge of the CV that makes contact, not the center. as a matter of fact, if the adapter plate was thinner, it would clear. of course, it can't really be made thinner because it has to be thicker than the heads of the 3/8" bolts that connect to the pinion flange....

Forgive me for asking, but do you have physical contact or just noise?

j

Noise caused by phisical contact :)

Actually, with my "mods" to the cat it clears fine in street driving... it will most likely still rub when the front suspension compresses fully, but I have no way to test that, at present/

Originally posted by darkstar
Noise caused by phisical contact :)

Actually, with my "mods" to the cat it clears fine in street driving... it will most likely still rub when the front suspension compresses fully, but I have no way to test that, at present/

Sure you do. It's called "urban ramping".

Keep your eyes peeled for loading docks and parking birms. Another favorite of mine is retaining walls. There is a home depot next to my house with a fairly awesome ramp... :D

Darkstar -

You anywhere near Joliet? If so, you can probably have Mike Aedo (Aedofab.com) throw it up on a forklift for you for a minimum fee to check clearances and then solve issues while you are there.

How much lift do you have, anyway?

Tom

redrangie--yeah, I will have to do that.. I actually did find a ramp at work, but it was too small to completely compress the suspension..

Tom... man, I'm kind of disappointed that you don't recongize me, considering the number of times we've wheeled together in Attica :rolleyes:

www.asmc.net/htdocs/main_framesets/lr_set.html

Originally posted by Jtisdale
If its ~ 1/2in or so that you need and you have the room between your cat and frame, loosen the engine and trans mounts and rotate the whole thing a few degrees.

Johnathan

I would definitely be careful of this one. I have broken my fair share of Motor mounts due to Tranny/engine not being aligned perfectly. If you run lockers you will surely bust mounts if things aren't perfectly aligned. Great in theory, just not in practice.

Johnathon, didn't you bust a mount at the Rally? Or was that someone else. Something to think about. I had this problem for about a year and finally realigned everything and haven't broken one since.

Larry-

It was Troy that broke the motor mount. The reason suggested it was because my engine was canted like that at one time. Don't know if it would provide the solution, as Doug mentioned. I've since replaced my mounts and straightened it a bit.

Trying to follow your train of thought, running lockers=broken motor mounts?

Johnathan

Ya know Alex, that just gives you an idea of Rover build tolerences. Even when I busted my last GBR shaft at the TC end, and the joint was flailing around in there, it STILL didn't hit the cat. My '96 must have s***loads more clearance then yours...

Where exactly does it hit ??

Hate to ask, but you ARE putting it in with the right ends in the right places........?

keith
:usa:

Alex - LOL!

I didn't know you went by darkstar.

Well, I will just shut up then.

By the way, heading to Attica on Saturday with Mike and Tom. Tom's blue Dodge Dakota now has a front straight-axle conversion and 35's. Should be a fun maiden voyage.

Tom

keith--yeah, I put it in correctly, slip joint towards the TC. It makes no difference, as there are 2 ujoints at each end, and it is the "CV" that hits the corner of the cat--at the diff end.....

Tom--sounds cool, can't make it this weekend.. the weekend after is the club pipeline trip though, I will be going to that.. you guys should come, it is always a blast (and alcohol filled :D )

I will try to find a place to ramp it today to see just how bad it still is.. I made a bunch more room with my hammer last time, and it hasn't scraped since, in street driving, bumps and all.

To the gentleman with the T-woods drive shaft. I too have a 96 Disco and a T-woods drive shaft. I was wondering if your double carden joint is extreamly close to the cross member. I have not found any evidence that it has hit, but my god is it close!

Originally posted by Jtisdale
Larry-

It was Troy that broke the motor mount. The reason suggested it was because my engine was canted like that at one time. Don't know if it would provide the solution, as Doug mentioned. I've since replaced my mounts and straightened it a bit.

Trying to follow your train of thought, running lockers=broken motor mounts?

Johnathan

Couldn't remember who it what. In short... No Lockers do not equal Broken Motor mounts. I had just done an LT-230 conversion and the motor/tranny mounts were not lined up properly. So when both lockers were engaged the torque from the engine could not go to the slipping wheel. Thus it found the weak mount on the way back to the engine and "pop".

This problem has since been remedied. However I do believe that lockers increase the amount of stress placed on both motor and tranny mounts.

Alex,

Next weekend will be a blast....and I bet you break something! Just don't get lost overnight...

Oh, nice pic http://www.asmc.net/img/LR/pipeline/pipline_nov_01_6thumb.jpg

someone needs to chop this up.

Ya, Untrakdrover mine is real close to the cross member and so was the GBR shaft that I also had in there before going to the Tom Woods. Neither of them have hit it so far.

i also have a GBR CV front shaft with no rubbing ...

Well, I managed to compress the front suspension yesterday by driving my RF wheel up on a big rock at the end of someone's driveway until the RR wheel was way off the ground.. crawled under there, and the driveshaft was very close (looked like it was within 1/16th of an inch) to the cat, but did not touch. However, it did look like it would have touched if the DS was rotated 90 degrees. In an case, I think I should be OK from that aspect. The contact should be momentary, and superficial, as I cant really drive with the front right spring compressed for any length of time... I guess I will find out for sure when I take it up to Wisconsin in a week.

On another note, I have a nasty vibe at speed (65-80 mph) that wasn't there before. Seems to be coming from the front DS, and happens under power, not when you let off like with the last one. At 80 it shakes so bad that its downright scary... What is the deal with that?? The double double cardon shaft is supposed to fix that! How are other peoples experiences with the DDC driveshafts at speed?

Thanks for your advice guys

Ive driven my Tom Woods front double/double shaft up to 80/90 mph(by GPS) on trips no problems....I have also driven customer trucks with that set up no vibs....you do have to check the tightness of the bolts after several weeks in the alum adapters as they will work loose, I like to run them several weeks then re-tighten using loctite at that point. Checked your bolts on the rear shaft?

Bolts on the rear DS are tight... anyway, the vibes really seem to be coming from the front... I will retighten all 16 bolts with locktite, and see if that changes anything. If not, I guess I will take the DS and adapters off and have it balanced.

I noticed some vibs lately, felt like they were coming from the front also, checking under the truck, the bolts had worked loose on the rear shaft at the transfer case adapter...tightened them up, smoothe as silk again. Rear vibs can transmit right thru the TC and seem to be up front. If you have it checked for balance let us know if the GBR shaft is out of balance.

Did you check your tcase output shaft flange bolts (they can sometimes work loose), and the pinion flange nuts as the source of the vibration? I would not expect that you would get that bad of a vibration from the driveshaft at speed (although it does weigh a fair amount).

Billster

(logging in for the last time from Mike's - off to SEMA and then plane ride back to Houston.)

Originally posted by Serious One
Did you check your tcase output shaft flange bolts (they can sometimes work loose), and the pinion flange nuts as the source of the vibration? I would not expect that you would get that bad of a vibration from the driveshaft at speed (although it does weigh a fair amount).

Billster

(logging in for the last time from Mike's - off to SEMA and then plane ride back to Houston.)

Can you change his avatar befor you leave?

j

If it's not the bolts let me know what you find out that makes it stop. I have tried about every thing that I can think of except getting a new transfer case to stop the vibes that I get. Over 70 mph and it starts to feel like a blender.

I think I have solved the vibe problems.. It turns out that the driveshaft is balanced together with the adapters, and I put one of the ends on out of alignment (Bill marks them with a punch, which I didn't know until I spoke with him on Friday night). D'oh!

I unbolted the diff end of the driveshaft, rotated it 90 degrees and bolted it back on. I took it on the highway for just a few minutes saturday morning, and it seemed to be fine. I will know for sure tomorrow when I drive it to work.

Well, that seems to have solved the majority of the vibes. there are still some minor intermittent vibrations, but those can probably be attributed to driving on worn out mud tires... nevertheless, I will try to isolate them over the next month or so (remove front DS, then rear, etc)... just like everything else, a neverending project...

Alex, I was 100% vibe-free with the original GBR shaft. When it broke and was replaced, it was still vibe-free. Then, when I installed the TruTrac, I finally got around to tearing off that mud-plow vibration damper hanging off the front diff. Now, I have occasional vibe at varying speeds from 50-70 MPH that comes and goes at random.

So, that damper does do something...or it's the TruTrac causing the vibe. I figured I would just get used to it and if it changed pattern I would start paying more attention then.

keith
:usa:

Could also be the input shaft bearing...Heavy loads (big shaft) and a center diff don't mix very well. Timm C mentioned that the bearing isn't very happy with a heavy shaft (and the stock center diff)...Of course replacing the center diff with a super beef mini-spool cures this forever (and the subsequent t-case diff slop. :) Ahhhhh how I looooong for near zero back-lash in my t-case!

--D

key poin there looooooooooong. I might go the same route with the part time lt-230, however, I will tyr and wait until things settle down over in the robles. Finally slade hunk of metal is outta there and he might get to us little people! I still gotta fix the rear link problem!