Steering Column Issue

[Mudder]

The steering column on my LHD S3, 1700 Xflow runs in between No3 and No4 exhaust pipe.

The clearance to either one of them is minimal.

Minimal as in .5mm (.020 in) territory. I tried rotating the steering rack in it's mounts, but despite changing the location/angle of the column ever so slightly, I don't seem to be finding the sweet spot in between both stacks.

At around 1500 RPM and then again at around 5000RPM the column reaches some sort of resonance and starts creating this awful sound while hitting the exhaust.

 

Does anybody have a fix for that? Others must have a similar problem.

 

I am thinking about having a slightly smaller diameter steering column machined from Titanium rod or getting my exhaust modified.

[toldfield]

I used a torch and a big hammer to create a little more clearance between the header tubes and the steering column.

[MV8]

New engine mounts should reduce the total engine movement.

[Kitcat]

New engine mounts fixed a multitude of problems in my 1997 1700ccX-flow Caterham. The engine was so loose that the intake stack rubbed against the bonnet cutout and pulled the webbers in a way that affected A/F ratio. It also made an incredible racket on high G turns at the race track. When I checked them they were falling apart. After that I replaced them every 5K miles and never had another issue.

[7Westfield]

Just out of curiosity, what do Cat's use for engine mounts with a xflow?

My pre-lit Westfield uses Mk1 Cortina mounts on a welded up pedestal 

 

[MV8]

Jag XKE mounts from what I've seen.

[Mudder]

Thanks to everybody.

I have a new set of rubber mounts on order.

Will report back.

[wdb]

I'd look at the transmission mount too. It may also be possible that the exhaust is hanging at an odd angle and causing the header pipes to flex.

[Mudder]

22 hours ago, wdb said:

I'd look at the transmission mount too. It may also be possible that the exhaust is hanging at an odd angle and causing the header pipes to flex.

Great idea! Thank you.

[IamScotticus]

its not unusual to space the mounts with washers to level things out.

This is very much a hand fitted car.

[Mudder]

New rubber mounts are ordered for tranny and motor.

I'll report back.

[Mudder]

New Engine mounts are in.

It took a little wiggling. I loosened all main bolts (3) including the transmission (T9) and jacked the engine up slightly.

The new rubber mounts slid right in. The tranny mount hasn't arrived yet.

The new mounts appear to be a little beefier. Then on the other side, the 25 year old ones might have settled a bit.

(the new one is the one on the right)

 

[wdb]

Looks like the mounting holes on the old one have been drilled out to a large size. Wiggle room maybe?

[MV8]

The old mounts look serviceable. You can also look at the column and rack mounting for adjustment. The rack could be shimmed at the front to rotate the pinion down if that helps. A torque strap could be added to the left side of the engine to limit max movement Could be a simple as a saddle strap over the left mount and a screw in the center to provide a fine adjustment to total movement. I can draw something if it isn't clear.

[Mudder]

MV8,

 

Thanks for your input and kind offer.

I am a little bit between a rock and a hard place here.

Any which way I move things, there will be interference.

The steering column has about .5mm wiggle room.

I showed it to Josh Robbin’s the other day and even he scratched his head.

IMO there are 3 options.

1. Build new headers. That’s my least favorite.

2. “Malletize” the pipes in the problem area.

3. Design a new lower steering column. Retain the attachment points but go slightly smaller diameter with tubing instead of solid stock.

 

Please let me know your thoughts.

 

 

[Mudder]

On 5/16/2024 at 8:09 AM, wdb said:

Looks like the mounting holes on the old one have been drilled out to a large size. Wiggle room maybe?

Most probably.

It took a little coaxing on the new ones.

[MV8]

I'll assume your car is no different from other S3 cross-flows I've seen, with 1&4 Y and 2&3 Y into a slip fit Y exhaust.

Since a sharpie won't fit, I'd spray some paint on the area to coat the shaft and adjacent primaries, drive the car, then pull the upper section to place over a bag of sand and dimple #3 in the scratched area with a deep socket bigger than the shaft duct tapped to an extension (as a handle out of the line of fire) or use a piece of gas pipe and a short handled 10lb mallet. Pull the column and you can do the same to #4 on the car. If you use heat, it will be easier to dimple but it may not fit back on the car without extra work.

 

The problem with going thinner shaft is the welding at the ends which will anneal the thinner shaft. Better to go after the root cause imho.

 

Most of the ones I've seen are very tight but here is a pic of an '81 cat LHD that seems to have plenty of room. It even has a fat chevy 12SI alternator.

Edited May 18, 2024 by MV8

[Mudder]

My setup is completely different.

see attached pictures.

The real trouble makers are no3 and no4 down pipes, but no2 could ply a role, too.

Very annoying!

 

I hate to rig things, but….

 

 

Edited May 20, 2024 by Mudder

[MV8]

You could add joints and a support hanging off the chassis but the best fix is to make a header that fits between the slip joints and the head flange. Until then, I'd dimple the tubes as needed. You may not notice any difference in performance.

[Mudder]

MV8,

Thanks for all your great advice.

I need to find a shop which can do some custom work on the ex-manifold.

I’ll check with Josh.