MA70 Supra has pooped its pants

[c_royce]

Hey all,

I took posession of a MA70 supra with the 7M-GE engine in it about 3 weeks ago. Anyway, the night I picked it up (pricate sale) it had a pretty severe problem. Whilst sitting at lights, it started running and idling like crap, and the temp was bouncing up and down a bit.

When I pulled over, it stalled (Automatic gearbox). I managed to limp it home, and the next morning the oil was the colour of coffee with milk in it (caramelly brown). First thought was BHG, but after a bit of investigation and dismantling, while still possible, it's less likely.

First test was to fill the radiator and run the engine with the radiator cap off. Well... I poured and poured water in and it kept dissapearing, so I started it, and it ran quite sweetly, and nothing even gurgled out the radiator. Where was all this water going? When I checked the oil, water poured out the dipstick hole like a hose had just been turned on.

So, we pulled things out and checked things. There's compression in all of the cylinders 150psi+ which doesn't rule out BHG but certainly helps it's cause.

Took the radiator out, and tried to remove the sump pan (which isn't easy without pulling the engine or dropping the k-frame evidently), and took off the water pump, as there's evidently a gasket between where the timing case/water pump housing bolt to the block. We poured water into the block through the waterpump's hole, and it dribbled out (under no pressure - didn't go up through the head or anything) in front of piston 1, straight into the sump.

So that's where I'm at. Anyone got any suggestions? Is it likely to be a cracked block? I'm hoping not, because that would cost lots of money - engine swap pretty much inevitable.

Suggestions questions and comments welcome. Cheers,

[TcmaBoy]

It sounds like it could be a cracked water jacket. A used 7MGTE isn't a bad option.

[c_royce]

Originally Posted by TcmaBoy

It sounds like it could be a cracked water jacket. A used 7MGTE isn't a bad option.

Is there anything I can do to be sure of that? I mean, if I don't have to replace the engine then that'd be a good option to at least know about, but if I do have to, then so be it.

Also, how in the heck does that happen??? All mechanics I've talked to are stunned that all evidence points that way especially as it's only 20 years old - blocks of this kind don't normally corrode or deteriorate until 40years+, so I'm trying to remain hopeful, but realistic.

[Jeeves]

No clue, that's a first for me.

Sorta like my block Crank walking. Who's ever heard of a 7M Crank walking?

[shaeff]

that's just weird. i'm going to jump on the cracked waterjacket train.

and a 7m crankwalking? wtf!?

-shaeff

[Jeeves]

Yup, the main crank pulley was rubbing on the timing cover when I pushed in the clutch, it was fantastic.

[shaeff]

holy crap! what kind of clutch was in there? what clamping force? even so, i've only heard of one other 7m crankwalking, and it was so long ago that i cannot remember who it was!

-shaeff

[Jeeves]

BONE Stock. BONE.

Like I said, total freak occurrance.

[willtotheumm]

Sounds like a cracked water jacket to me too. Find a decent, low milege 7mgte and swap it in

You can find them for a decent price and normally in pretty decent conditiion.