Pre cats - Gone

[450 Paul]

I had a crack in both manifolds where the 4 pipes join into one. So I bit the bullett and took the car to Warren at TopCats (top people and always have plenty of great advice. Warren reccomended take out the pre cats whilst fixing the cracks and I agreed a good idea.

When I picked the car up Warren showed me the pre cats and one had been loose for a while and was starting to break up. My lucky day as a bit of pre cat getting sucked into the engine and stuck in a valve would not of been appreciated!

The sound has changed and more metalic and it does pick up revs a bit quicker through the range. The exhaust note is louder as a neighbour noticed asked me what I had done to it!

I saw some LS engine conversions that Warren had done and the level of their engineering to fit the engine/gearbox in without changing the chasis was very impressive.

[K4TRV]

I think the pre-cat would be heading to the main cat if loose enough, not back to the exhaust ports.

I think, as in my own case, you too were lucky, as one of my pre-cat was found on top of the main cat, partially blocking it.

Thankfully hadn't been there long according to Neil Garner.

It was found when replacing the cam. The other pre-cat had partially melted!!

Yes, there's definite increase, albeit around 5/10 bhp possible after removal - plus aural improvement!!

Trev

[450 Paul]

Mine is a 2000 model and only 39k how many miles had yours done?

Warren said that the engine could such it back into the engine I guess with back pressure.

I can see how everyone has different power as there are so many things such as a loose pre cat etc that can cause problems.

[K4TRV]

An early '93 model, but with only 47K !!

[jr6yam]

My manifold is blowing on the drivers side; how much was it?

[MPoxon]

K4TRV said:

I think the pre-cat would be heading to the main cat if loose enough, not back to the exhaust ports.

I think, as in my own case, you too were lucky, as one of my pre-cat was found on top of the main cat, partially blocking it.

Trev

Same with mine, found a large part of pre-cat sat on top of the main cat.

[BillC99]

I had a perfect imprint of the lambda sensor and its boss in one of mine!!

[Badmutha]

jr6yam said:

My manifold is blowing on the drivers side; how much was it?

Just had mine done;
Indie removed,welded and replaced manifolds for £160, including cutting one open to make the repair and fitting new engine mounts which I supplied.
Manifolds skimmed to remove corrosion, £120
I supplied the gaskets which were around £25, so under £300 in total.
While they were off I took them home and removed the pre-cats, and also replaced the heat shields while the manifolds were out of the way.
You may be able to remove and refit them yourself but IMO it was money well spent,unless you're a masochist.
The alternative to repairing them is about £900 for a new set.
Bm

[Golflion]

Had manifold gaskets renewed this week as well as other things(other post on PH),was told pre-cats are well clean, and in great condition, so thought bks to it i'll leave them in for now.We'll see how it goes ,can always remove at a later date by removing in situ>

[ralphy12345]

What's the situation regarding the removal of the pre-cats and MOT time? Do the cars still pass on the emissions test?

R

[MPoxon]

ralphy12345 said:

What's the situation regarding the removal of the pre-cats and MOT time? Do the cars still pass on the emissions test?

R

So long as the main cat is still in place you will be fine once the engine is up to temperature.

[450 Paul]

I paid just under £400 for the work on mine.