Yes its another thread for those who love talking about disaster.
Since the pre-cats problem made it as far is being printed in the independent when they featured the MR2 in their buyers guide I thought I'd take my 2 (which still has its cats I presume as I can't get the rusted heatshield bolts out, but is showing no signs of a problem as yet) and the article to my local dealer.
Well, good news everyone, the guy there not only had never heard of such a problem but described the MR2 as "indestructible".
He told me a lovely story about how even if anything in the exhaust broke up the only place it could go would be out the back. (Do they know how their engines work? Anyone want to explain the back pressure thing to me again, I am mechanically thick, so I can easily explain it to them?)He even went off to talk to the head techie whose worked on toyotas man and boy for 30 years who agreed with him, apparently.
However, this trip to the dealer was not a total waste of time as I discovered that you may purchase an MR2 Roadster baseball cap. If anyone feels the need to make themselves look a bit simple.
*Stands back and waits for the cap wearers to reveal themselves....*
No, not a cap wearer but my brother has been a mechanic for 25 years and i asked him about the pre-cat material going back into the engine and he said he didn't see how it could either.
have none of these people ever heard about valve overlap? or exhaust gas recirculation?
they aren't new concepts. Are they aware that teh precats are only cm away from the engine?
Quote from: "northum"Well, good news everyone, the guy there not only had never heard of such a problem but described the MR2 as "indestructible".
Clearly he's never heard of the Titanic.. s;) ;) s;) s:lol: :lol: s:lol:
And as Mark said - precat material could conceivably get sucked back into the engine due to the way our engines use valve overlap to create an EGR effect (some vehicles use a vacuum controlled valve that has one end attached to the exhaust and the other to the intake tract instead). Essentially, at certain points in the rpm/load map, the valve overlap will be suck that on each intake stroke, the exhaust valve is open slightly at the same time as the intake valve - thus scavenging some of the ingested charge from the exhaust runners rather than solely from the intake tract.
This is done to reduce emissions (primarily, it reduces hydrocarbon emissions) and also as a side-effect will reduce in-cylinder temperatures by utilising a partially-dead (already spent) intake charge.
It's entirely possibly that during such an intake stroke, any free particulates in the exhaust tract could get sucked back into the cylinders. Since the particles are ceramic, they would only need to be a few thousands of an inch in size to markedly score the bore walls, leading to oil-leakage past the oil control rings and you're then in to a vicious circle (oil kills cats, cats kill engines)
It's entirely possible - it is also true that nobody knows for sure if that happens. Without doing a full chemical analysis of the oil from a failing engine, that's impossible (and none of us have those kinds of resources, really).
northum just do what i did and get them out bud, i questioned it and questioned it until finally a mr t mechanic told me "off the record" yes it can happen. so as we speak my pre-cats are getting taken out
Thanks for the refresher aaron. It is all clear in my mind now.
I'd love to get rid of them and have it off my mind, but if I can't find anyone around here who understands and is willing to deal with it then I'll have to do it, which could be a mistake!
Maybe I'll just hope to get away with it for a while until I can splash out on a Honda S2000. Worrying about this is ruining my enjoyment of the 2 a little.
Incidentally the newspaper article in question, for those that haven't seen it, suggests that the pre-cat matrix holding map was redesigned from October 2001. Even giving a VIN number 0043748, and states that a new manifold is available. As they reference mr2roc I presume they've got that stuff from here somewhere, but I thought I'd mention it as I hadn't spotted anything that specific before.
Found all the info on here now s:oops: :oops: s:oops:
Anyway, the main point was to whinge about my local Mr T having either no knowledge or giving me the brush off!
Let me know if you find anyone to gut your pre cats. Am also in Newcastle area and from what I've read so far on the forum will be having the job done myself.
Cheers,
Phil
i printed the the DIY guide off the forum and took it to my local garage, £90 which included one sheared stud and the car POLISHED and delivered
i am happy with that