Tear down and inspection...

[AcIdBuRn02ZTS]

Hey alls... I started pulling the motor apart in my parts car today and I'm not sure whats going on...

When I drove the car home... it was fairly obvious that there was quite a bit of blow-by (dip stick was 3.5" out of the tube after a 15 mile drive...) and coolant was low in the rad.

The previous owner of the car said it was rebuilt around 15k miles ago and had receipts to prove it... has had several hg jobs (stock hg and no machine work) before its overhaul... and was having an overheating problem (acted like the thermostat was stuck) however the t-stat had been replaced 3 times since the overhaul all with oem toyota parts...

The cyl. walls still have hone marks so it was rebuilt... however there are gouges in the cyl. walls and it looks like it should have been bored but wasnt...

anyways... here are a few pics...

its obvious #5 was seeing coolant considering how much cleaner the cyl. is compared to the others... I just dont know where its coming from... the hg that was on the motor looked to be in good shape (however was spary copper coated)... and when unbolting the head... some of the bolts came out with very little effort and a 3/8" ratchet where some took a 1/2" breaker bar... perhaps improper torquing of the head when rebuilt? cracked head or block?

advice/input would be appreciated..

thanks
-AcId-

 

[cuel]

Was it still running when you took it apart?

Have the head vacuum tested at a good machine shop. From the pic of the head, it kinda looks like it had combustion escaping to the exhaust side from 5 and 6. From the pic of the pistons, it looks like 1, 2, and 3 were leaking(or at least weeping) as well. Is that rust build up on piston 4?

Honestly, if I took a motor apart in my shop and it looked like this, I wouldn't bother with it. I'd get another one and start over. I'd bet that head is fried on the exhaust side at 5 and 6, and probably won't seal correctly. You should have the radiator tested as well. It could be partially plugged up, which would account for the overheating issue.

 

[AcIdBuRn02ZTS]

yes it was in running condition... I drove it 15 miles to the house and it ran decent... had a missfire but I account that to a plug wire not being pushed onto the cap at all...

im not extremely worried about the head... i ushually rebuild heads myself when I go through a motor so when I pull it apart... if the guides are shot... its going to be turned into a torque plate...

my main want overall was the shortblock.... i think its stock bore... so bore it .020 over (depending on what the shop says...) and run either gte pistons or probes... havnt decided... im just debating on machine shops... im pretty sure no shop around here will be familuar with the 7m... so I'm basically gonna have to go over every little detail with whom ever does the work.

the head will be fully disassembled and put in our washing machine at work and I'll check it over... it does have nearly 200k miles on it so it very well be due for replacement... lower mileage heads arnt too hard to find around here though...

no rust on the pistons or bores... the only spray oil i had laying around was pb so I coated the cyl. walls with it (which kinda gives them a yellowish look)

btw... by combustion gases leaking... do you mean past the valves or how do you mean?

thanks
-AcId-

 

[cuel]

The pic of the head looks like carbon buildup on the head surface from the chamber to the exhaust outside edge. Looks like its between 4, 5, and 6, and especially between 6 and the exhaust side of the head. It looks black and burnt, which would make me think it was leaking compression there.

I think it would be pretty hard to damage the block in any way that wouldn't be repairable. The head is another matter.

 

[AcIdBuRn02ZTS]

I see what your saying now... its been a long day and I didnt notice it...

considering how many times the hg was replaced before the motor was "rebuilt" (i have receipts from the po for 3 different times the hg was replaced before the motor was rebuilt... so head has been off atleast 4 times) I'd say the head is warped quite a bit...

I'm gonna call around to different machine shops in the area and see what they say and if they have any experience with the 7m... perhaps i'll get lucky but i doubt it... all I need to do is find someone that can surface the block and punch the holes... i'll be doing the rest myself....

thanks
-AcId-

 

[cuel]

It's really not that big of a deal to do what you want. I'd talk to the local racers at the drag strip or circle track, and see who they recommend.

 

[AcIdBuRn02ZTS]

found a shop that can surface the block... and punch the holes with any cut on the hone I could need.... so forged it is.... however they dont have a torque plate... is this a MUST? if so.. i can build one i believe (work has a waterjet that they would let me use...) if i make one... how thick would it need to be if i make it out of steel?

how do people avoid piston slap when using forged pistons or is it just the nature of the beast?

also... i dont know if ive ever heard this asked... but... how long will a forged internal setup last if taken care of and not beat on? will they hold up like oem stuff or will i be pulling it apart every 50k miles for rings and bearings?

thanks again
-AcId-