5m-ge future engine mods?

[Mk2guy]

Originally Posted by mechrider89

Got everything back together today and went to start the car..........it burst into flames!
I would have took pictures if I hadn't been so busy putting it out, have no clue what went wrong never had something like this happen to me before at all!

It burst into flames. Are you leaking fuel? I have a degree in automechanics so, if you give me some more detailed information. Maybe I can help you figure it out. such as did it back fire. This helps rule things out.

[mechrider89]

Ya it was a fuel leak, I had a couple injector seals blow out. The fuel problems fixed and my cars up and running but I think I just confirmed my suspicion that I have a cylinder head problem.........piss me off. got to do a leak down and compression test first but I'm sure my head gaskets gone or the heads warped.

[Mk2guy]

Now, those head gaskets seem to blow every 60k miles. I don't know why. I had to have my block shaved on mine, but that is unusual too.

[Mk2guy]

Also, I was wondering if.... See I bought big bore pistons, the ones from 1985 (toyota racing) and I was wondering if anyone has any experience with them. I am not going to install them for quite a while, but I was wondering how unreliable would a 5mge engine be with them in it? I have no idea, but have you heard anything?

[CanadianBak'inSupra]

if they are 85's i would assume dome topped. you will notice no differnece in reliability, but a small compression difference.
the 5mge is a great engine. hands down.

[mechrider89]

CanadianBak'inSupra is the guys to listen to man, I'm still very much new to the supra so I'm not the best guy to ask hahaha.
But higher compression pistons shouldn't cause the engine to be unreliable, might have more HG failures because of more stress on the HG then what its designed to take which could be solved possibly by torquing it tighter.

I went out sliding the supra last night (couldn't help it!) and after coming out of my first drift the engine died out...... never had that happen! My gut feelings saying more and more that my HG has failed. White smoke when its rev'd (weird there's none when idling), sluggish rev and I don't get how but there's what has to be coolant seeping out of the exhaust manifold gasket on to the header, yet I've looked all around the bottom of the head and found no leaks, its definitely coolant seeping out of the exhaust gasket because i'm going through coolant. So I'm thinking its most likely failed in two spots on the exhaust side (cylinder 2 and 4), but what I don't get its why it only smokes when rev'd shouldn't it smoke at idle to?. I've topped it up the coolant started it up and watched to see if it started to bubble and nothing.... so I might have to pull the plugs and borrow the inspection camera from work and take a peek to see if there's coolant in the cylinders.

[CanadianBak'inSupra]

alum heads on cast iron blocks do weird things.
not 100% sure but at higher rpms the cylinders may be under greater pressure, forcing exhaust gases into your coolant, once it initially happens its going to go the other way and coolant will go into your cylinders.

get a compression check like you planned.
if you do a tear down, give the cylinder head a fine inspection for cracks, what may look like a casting turd/line could be a fatal crack. then go from there...
if it turns out your head is cracked, i do have 3 in my garage... and last i checked lordco can still get rebuilt heads for about 500$

[Mk2guy]

My pistons were made by Toyota Racing Development they are 85mm wide and give a 10.5 to 1 compression ratio. Toyota made these pistons to compete, using the 5mge, but that was eons ago. I heard reliability would tank if I installed tham...? I was just wondering how bad and if anyone new anyone else that did that. (my hp would be upgraded to about 240hp)

On mechrider89,s car, I would just replace the head gasket because it doesn't sound like he over heated the engine. It just sounds like the head gasket went. I depends on valve stem seals, last rebuild, maintanace, basically engine health. Only he would know that.

The one thing I know toyota did was make the torque specs to were you torqued the head to a certain ft lbs and then turned it so many degrees, rather than using the ft lb mark. (such as: 43lbs and then 3/4 turn) You have to watch over torquing the heads though, because I had a guy that over torqued his head bolts and he stretched the threads. (that's bad)

You might want to buy some new head bolts too, but I am pretty confident you just need a new head gasket. I hope you get back up and running soon, these cars are so fun!