sweeetpete
Yes I bought my hardtop mainly so that I could mould it and make a carbon one for my track car. Once I have the mould I can make a glass one also and then work on modding that to suit the 918 style. Picked up the PPE downpipe for my 2ZZ swap today so just about have all the parts here and its getting a lot closer to completion , Finally.

Nice do you have pics

So I pulled my headers off the exhaust and being a custom muffler I Assumed the precats would have been guttered but no they hadn't the one for cylinders 1 and 2 was fine but 3 and 4 per cat was totaled I believe due to not much of it being left it had been sucked into the motor which explains why the fourth cylinder blew!
Per cats yep Toyota screwed up with those on the Mr there now guttered.

I've heard about the precats on these being notorious for collapse, but I thought being an exhaust, a collapsed precat would block that cylinder and cause it to blow rings, not have bits being sucked back into the engine..
Unless I am missing something here? Exhausts blow, not suck.

Definatly had to of sucked in because the bottom of it was intact though there wasn't much left of the top there was about a quarter of it left and the engines 4 th cyl was grinding and rattling like a aerosol can and burnt about 2l of engine oil in a 1km distance getting it home I think the pre cat sucked into the cylinder on down shift through back pressure and the little prices got on the bore and damaged the rings and scratched the cylinder wall guess I'll find out when I crack the head off!

<facepalm>
 
Okay so I understand what you are saying might sound like it makes sense, but here we go:
 
If you think backpressure can cause things to get sucked BACK into the engine via the exhaust, somehow getting past the valves and making its way into the combustion chamber, you are mistaken.
 
If you could even fathom up a scenario where this works, it will not apply to your situation, this is why:
 
If you have a blocked precat, this then means for that cylinder, for all the exhaust gases getting pushed out of your chamber post combustion cycle, there is no longer a large area where the gases can escape and go into the exhaust, it is being blocked. So for every exhaust cycle you are getting a build up of gas there, pressurising the system. Usually the pressure can slowly escape since there is not a complete blockage (or if there is, pressure will cause something to blow out, usually the manifold gasket or valve seal).
What happens is the gases there are HOT, and with a buildup of hot gases with nowhere to go, the combustion chamber no longer has adequate cooling, heat causes stress, and something has to give. The manifold and gasket would probably crack and blow out first in ideal situations, but usually the piston rings are fried and give up.
Other places could be your valve seals/guides.
 
I'm sure the rattling and grinding you are hearing is a broken piston ring. I'm sure it will still be on its guide but likely has cracked and moved around in the guide, causing bits to go around the place. Hope nothing too big has come off and gotten stuck in valves too etc.
With another engine you've mitigated the problem though so I expect you don't really care anyway.

I cannot remember the reasoning behind it but the precat breakdown does get back into cylinder. It has been proven too many times unfortunately. I know it does not make sense but it happens.
 

maj
I've heard about the precats on these being notorious for collapse, but I thought being an exhaust, a collapsed precat would block that cylinder and cause it to blow rings, not have bits being sucked back into the engine..
Unless I am missing something here? Exhausts blow, not suck.

The 1ZZ uses it’s VVT to perform EGR (Exhaust Gas Recirculation) functions without the aid of a specific valve like other cars. Under certain operating conditions the cams are timed to scavenge some exhaust gas back into the cylinders, as a way of reducing the high hydrocarbon emissions that modern petrol engines generate at certain times.
This is what you learn when you buy an mr2 spyder and hear about the nasty precats! But it's only the 00-02 Spyders with the precat issues!

i have test fitted the 2GR supercharged and made all the necessary brackets, exhaust headers etc.
There are some extensive body & chassis mods, that will require a lot of effort to get thru engineering for registration. Not impossible, just not straightforward
I plan on using it in race car.
 
I had to fix this auto-salon car some years ago. dead SMT. My recollection is the huge offset wheels and spacers on it, made it drive like crap. Strictly a "looks only" car at that time
 
 
 

Road and Track
i have test fitted the 2GR supercharged and made all the necessary brackets, exhaust headers etc.
There are some extensive body & chassis mods, that will require a lot of effort to get thru engineering for registration. Not impossible, just not straightforward
I plan on using it in race car.
 
I had to fix this auto-salon car some years ago. dead SMT. My recollection is the huge offset wheels and spacers on it, made it drive like crap. Strictly a "looks only" car at that time
 
 
 

Thanks for the info what was the exact problem with the SMT,
The one in the car now is slipping in second on down shifts but there wasn't anything left of the clutch when i took it off (maybe clutch slipping and not the gear :S!
I'm running 295 rear tires with slight inner camber but no spacers just strait to the hubs if I didn't have them cambered they would hit the guards.
I've had the suspension all set up and all aligned so it was driving a dream before the engine went.
 
Do you to a conversion kit for example plans for what needs to be cut modded, loom, engine and trans mounts, shift linkage, headers, ect?
If so can you supply a price or PM me with details?


Did you have to custom make headers so you didn't have to mod the firewall?
I thought you only had to cut and strengthen the rear cross member so the trans fit?

IMAGE TAKEN FROM http://www.primemr2.com/2/post/2014/01/prime-starts-2gr-v6-mr-s-build.html

How did you get around the passenger coolant line, you didn't run it under the fuel tank did you?
I don't like the idea of running it under there the idea of the car scraping on a curb or something and busting that line could be a painful experience!


With getting it engineered can you build the car to completion then get it all signed off on or do you have to get each part signed off on so you cut and mod the cross member do they then judge how it was done or do you recommend getting a engineer to do that job?

jezussssss 295's! with that size it will put alot of strain on the clutch, maybe thats why the clutch hasnt been enjoying life