Pre-cats: The Official MR2-ROC Information Thread

muffdan · June 10, 2009, 21:54

Yes, you don't have to pay for any work they've done on your car. Hopefully they're not spiteful enough to do anything to your old car before returning it. The problem with having them repair the '2 is that they'll probably take short cuts. It needs to be repaired properly otherwise it's going to go wrong again 6 or 12 months down the line and you'll then be paying for the replacement engine.

Anonymous · June 10, 2009, 21:56

what would be likely to go wrong 6months down the line? the pre-cats would be removed, i probably already need a new engine now.

Anonymous · June 10, 2009, 22:01

Quote from: "sarahlr3"what would be likely to go wrong 6months down the line? the pre-cats would be removed, i probably already need a new engine now.

The main cat will be blocked with oil and precat debris, unless this is also replaced it will simply ruin the new engine.

Sarah, you are here for advice, please believe me, the advice is not to accept the car.

Anonymous · June 10, 2009, 22:10

oh yeah i know and thanks for all the great advice - i was just tryin to get a good picture so i can tell them exactly what the score is, wasnt bein funny in my response. thanks again

darkday · June 10, 2009, 22:17

Quote from: "nelix"
Quote from: "sarahlr3"oh Im dissapointed now I dont want to give it up now I have it! But I know what you're saying it makes sense. Thanks

Give it up, it's a pile of dog faeces, always some for sale on here, you know then you are buying an enthusiasts car.

^^What he said. That's the best advice anyone could give you.

Anonymous · June 10, 2009, 22:28

ok then time to get lookin for a new one haha better luck this time i hope!

loadswine · June 11, 2009, 09:10

Its not just the precats and main cat unfortunately. The bores will probably be oval due to the earlier design of piston and ring issue on some cars, and that is probably what sets off a lot of the precat failures, and is certainly what causes massive oil consumption. Often the crank would need checking out as well.
So botton line is, reject that car if at all possible.
A lot of the cars for sale on here ( not all) have been owned by enthusiasts, as has been said, and you can also trawl through the posts from that owner and get a flavour of that car's history.

Anonymous · June 11, 2009, 21:55

ok just to update went to the garage today they checked the precats when i asked - and I was indeed victim to this fate!! engine was also ruined, so have therefore managed to get my old car back thank god! Im now on the look out for a new one but there aint so many in the south wales area for 4k and am also worried about this happening again. I loved that car though so I think im gonna have to get another. Thanks for all the advice and if anyone sees any that they know of id be grateful. cheers.

Wabbitkilla · June 11, 2009, 22:04

Well, not a total loss, but a worth while learning experience!
Glad you've got things sorted for now and good luck with the search s:D

s:D

Anonymous · June 11, 2009, 22:13

no on the whole a very lucky escape! and bang on the mark, im not such a novice now when it comes to the inside of an mr2 haha

uktotty · June 11, 2009, 23:04

WOW!
A success story, really pleased you got it all sorted.
Welcome to the club, lets find you a nice example

Anonymous · June 11, 2009, 23:08

Thanks uktotty! yes please do, I need my faith in mr2s restored!

uktotty · June 11, 2009, 23:18

Stick with the TottyMan, I will look after ya s;)

s;)

philster_d · June 12, 2009, 15:04

i think sean put it best recently when he said....

Buy on condition

He was refering to TVR's but i am going to apply this logic to every and any car purchase ever!

Philster

Carribdis · June 20, 2009, 20:25

Removed my Pre Cats today......... great thread, though it kinda makes it sound alot more simple than it was lol. Unbolt this, unbolt that, done.......... My experience was more, round off this head, round off that one, take a drill and a hacksaw to it, cut your hands and bang your head a few times, get a load of crap in your eyes, swear, swear, swear, swear, swear, swear, swear *5 hours pass* swear swear swear swear....... remove manifold.......... but then take sweet revenge on them dam cats!!!! MAAAAA HAHAHAHAHAAHAHA!!!!! Good times!

enid_b · June 21, 2009, 00:04

Quote from: "Carribdis"Removed my Pre Cats today......... great thread, though it kinda makes it sound alot more simple than it was lol. Unbolt this, unbolt that, done.......... My experience was more, round off this head, round off that one, take a drill and a hacksaw to it, cut your hands and bang your head a few times, get a load of crap in your eyes, swear, swear, swear, swear, swear, swear, swear *5 hours pass* swear swear swear swear....... remove manifold.......... but then take sweet revenge on them dam cats!!!! MAAAAA HAHAHAHAHAAHAHA!!!!! Good times!

but if the 'how to' was like that, no one would be brave enough to take them out. its a simple enough job if your nuts are well lubed, and given a good hammering (missus)

manchestermatt1986 · July 2, 2009, 11:50

Hi guys, done my research on the precats and know i need to get them out as i have a 2000 mrs and its just ticked over 86000km which im guessing tghe ticking time bomb is ticking louder. s:scared: :scared: s:scared:

my question is, insetad of knocking the precats out is there anything i can replace them with. (this may have been covered but i must of over read it). maybe they can be replaced with a de-cat?

but what is the specification for a pre-cat to de-cat. a pipe? s:lol: :lol: s:lol:

cheers

roger · July 2, 2009, 11:54

You can't replace your pre-cats, only buy a new manifold. Buy a MrT one with new pre-cats, or aftermarket without. Plenty available - search will bring up quite a few with pros & cons.

manchestermatt1986 · July 10, 2009, 17:44

can you buy a decat pipe? iv seen them for sale or are they for replacing the normal cataytic convertor?

markiii · July 10, 2009, 17:47

Quote from: "roger"You can't replace your pre-cats, only buy a new manifold. Buy a MrT one with new pre-cats, or aftermarket without. Plenty available - search will bring up quite a few with pros & cons.

Anonymous · July 21, 2009, 09:52

Hi
I bought an Import model this Feb, love it to bits (I previously drove an MX5 for 5 years, must say the MR2 is much more fun and considerably lighter on the juice).

However I've noticed a touch of blue smoke from the exhaust (maybe 3 times in the last 6 months) seems to be when I set off again after I have been going a little faster than I should. Also noticed that she drinks quite allot more oil than the MX5, I do about 300 miles a week and I am putting in about 1L oil a month (MX5 was about 1L every 6 months), tho some of the forums I read said this was normal so I wasn't too concerned, but after reading a few posts on the precats I'm a bit concerned, The car has done about 55k and was serviced regularly.

I'm going to remove the sensor tonight and have a look to see if the precat is still intact (the MR2 has an aftermarket stainless manifold and very loud twin exhaust, which I was going to get changed as it wakes the neighbours but a mechanic friend says its worth about 700 so I'm not now).

Obviously with the blue smoke there is oil being burnt somewhere, if the precats are ok / have been removed before / weren't in there in the first place, Then I assume its the oval bore problem. So my question is, having read on another forum that the piston rings cant be replaced on an MR2, can someone tell me if that was rubbish. Hopefully if the precats are not the issue then I can just have a re-bore and new rings?

Im also planning to do a compression test this weekend if my mate can borrow the kit from work.

Any advice is greatly appreciated.

Cheers

StuM · July 21, 2009, 10:09

Quote from: "donnyladjr"I'm going to remove the sensor tonight and have a look to see if the precat is still intact (the MR2 has an aftermarket stainless manifold and very loud twin exhaust, which I was going to get changed as it wakes the neighbours but a mechanic friend says its worth about 700 so I'm not now).

Hi, and welcome.

Pre-cats only live in the factory manifold, so if yours has an aftermarket one, you'll not have them - just before you look in the sensor hole and get scared that they have gone!

High oil consumption can be experienced and is not always oval boring - but you are doing the right thing getting a compression test done. I seem to recall that in some cases others have slowed down their oil consumption by using a different viscosity oil - I'll leave it to others to advise on this.

Cheers,
Stu

Anonymous · July 21, 2009, 10:11

Quote from: "donnyladjr"Hi
I bought an Import model this Feb, love it to bits (I previously drove an MX5 for 5 years, must say the MR2 is much more fun and considerably lighter on the juice).

However I've noticed a touch of blue smoke from the exhaust (maybe 3 times in the last 6 months) seems to be when I set off again after I have been going a little faster than I should. Also noticed that she drinks quite allot more oil than the MX5, I do about 300 miles a week and I am putting in about 1L oil a month (MX5 was about 1L every 6 months), though some of the forums I read said this was normal so I wasn't too concerned, but after reading a few posts on the precats I'm a bit concerned, The car has done about 55k and was serviced regularly.

I'm going to remove the sensor tonight and have a look to see if the precat is still intact (the MR2 has an aftermarket stainless manifold and very loud twin exhaust, which I was going to get changed as it wakes the neighbours but a mechanic friend says its worth about 700 so I'm not now).

Obviously with the blue smoke there is oil being burnt somewhere, if the precats are ok / have been removed before / weren't in there in the first place, Then I assume its the oval bore problem. So my question is, having read on another forum that the piston rings cant be replaced on an MR2, can someone tell me if that was rubbish. Hopefully if the precats are not the issue then I can just have a re-bore and new rings?

Im also planning to do a compression test this weekend if my mate can borrow the kit from work.

Any advice is greatly appreciated.
Cheers

If your manifold is something like THIS then you don't have any precats, so it looks like you could have oval bores, re-ringing won't cure this problem unfortunately so it looks like re-bore/sleeve (depending on wear) & pistons s:(

s:(

Be interesting to know how long (if it is a Che header) the manifold has been fitted?

Les

Anonymous · July 21, 2009, 12:40

Thanks for the advice, just had a look and its a Che manifold, its been on the car as long as I have had it but that's only 6 months, why do you ask, are there problems with the exhaust manifold also?

I noticed some white markings on the engine block, the kind they use in scrap yards, so perhaps the engine has been replaced, I will check the log book tonight.

If the engine does need reboring how thick are the walls, is it possible to rebore or will it need reshelling? And can anyone recommend any good garages in Doncaster or Manchester?

I've been using 20 - 50 oil as I had some left over from my old car, what's the recommended oil for the MR2 please?

Many thanks

intheend · July 22, 2009, 17:14

hey guys, i'm relatively a new member too and about to buy an import. i took my mechanic friend to view the car, he checked it over and said it was fine... although he did mention he saw a little blue smoke and smokey smell (car was in showroom also) the car has an aftermarket exhaust, i dont think this has anything to do with it, but i hope that my pre-cats will stay in tact! what do you guys think?