Dropped a Valve Seat on a 7M-GTE (Pics Inside)

RBD 305

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Aug 19, 2010
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Just to get you guys up to speed, I just recently rebuilt my 7M-GTE and had about 1300 Miles down before this happened..

Prior to this incident I was experiencing rough idles and a random clicking sound coming from the head that would affect my RPM's and Vacuum @ idle. The clicking sound progressively got worse to the point were the car wouldn't hold an idle.

A few days ago I decided to start up the car in my parking lot and try diagnosing it some more and it ran fine for about 10 seconds then started a really fast paced tapping sound reaally loud (Im sure some of you guys are familiar with this sound ::shootme:: ). So I immediately shut the car off and had it towed down to my dad's shop.

Started tearing down the engine and ran into this when I pulled the head off.














So pretty much as you can see in the first two pictures the Intake Valve Seat for Cylinder #3 was completely loose getting ready to say hello to piston #3.

The next couple of pictures was the actual damage to the head and piston for the Exhaust Valve Seat on Cylinder #4 completely disintegrated.

A closer look at the head and I noticed more of the other seats were getting ready to come loose which is a very rare occasion. I was told this only happens when a head has been overheated or ran lean for a period of time.

Checked all the rod bearings to see how they were wearing and its perfectly fine. No metal pieces or shavings were found in the OIL/Oil pan which I'm really happy with..but I do need to check my exhaust wheel on the turbine to check for any damage.

NOTE: This head was rebuilt and assembled at my local machine shop. I called my machinist up the same day with the news in a calm professional manner letting him know what happened. He told me to stop by with the head and piston for inspection..

Pretty much to sum it up the head is trash and no longer usable. Some parts inside it may be salvageable but my machinist is going to attempt to repair the piston if not replace it with a new one.

I've known this machinist for 4-5 years and always had good work from him and he decided to replace the head for free and cut me a deal on the machine work cost for the new head.

With all that being said, I'm actually kinda glad this all happened in a parking lot and not driving on the highway somewhere because it could of been ALOT worse. The buildup you see in the coolant jackets is caused from improper coolant for aluminum heads and would of caused hot spots in the head which would of ultimately lead to a BHG issue. I was also very happy with how my machinist responded to the situation and I continue to do work with him!
 

RBD 305

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IJ.;1803055 said:
That piston is NOT repairable...

I'd be surprised if the bore is usable.

These are JE's not OEM. The cylinder walls are completely fine also..I've seen worse pistons that have been repaired but that's just me.
 

IJ.

Grumpy Old Man
Mar 30, 2005
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There is a lot of "shape" to a piston below the Crown, any impact can deform them, up to you I wouldn't repair it, I'd also have the block Magged just to be sure.

I don't build Grenades so don't like taking a chance or rolling the dice on something like this as it usually bites you in the Ass later on..
 

RBD 305

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IJ.;1803069 said:
There is a lot of "shape" to a piston below the Crown, any impact can deform them, up to you I wouldn't repair it, I'd also have the block Magged just to be sure.

I don't build Grenades so don't like taking a chance or rolling the dice on something like this as it usually bites you in the Ass later on..

I appreciate the advice. I'll see if I can get a new piston at a good price from JE.
 

IJ.

Grumpy Old Man
Mar 30, 2005
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JE are good guys to deal with, can't see it being too exe, might be an idea to pull an undamaged one to Mic up.

When you're shopping for a replacement Head make sure to Hardness Test it before dropping the Coin, Most 7M heads are annealed on the exhaust side by now, all it takes is 400c... :nono:
 

RBD 305

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IJ.;1803074 said:
JE are good guys to deal with, can't see it being too exe, might be an idea to pull an undamaged one to Mic up.

Yep that's already being done at the machine shop. I just asked him if it could be repaired..if not I don't have a problem replacing it.
 

nofx230

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Jan 24, 2012
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bout to get my head worked on and was curious if this is something huge to worry bout, all the other chambers are fine but this one?? IMG_0258.jpg
 

RBD 305

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Poodles;1804880 said:
What's with the major erosion between the exhaust valve seats? That's not normal at all...

RBD 305;1802950 said:
The buildup you see in the coolant jackets is caused from improper coolant for aluminum heads and would of caused hot spots in the head which would of ultimately lead to a BHG issue.

I was told by a 7M guru to use only Toyota Red Coolant for 7M-GTE's...That build up happened within a 1300 mile break-in period (very fast) probably within 2 weeks or less of weekend driving. The coolant that caused this is from Autozone, the neon green shit lol.

EDIT: Here is the Toyota Red Coolant I will be using next time
images
 

nofx230

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Poodles;1804880 said:
What's with the major erosion between the exhaust valve seats? That's not normal at all...

was told its from running too lean combined with a BHG, only no.4 cylinder looks this way, also the water jacket by the exhaust valves is a lil pitted, but all the other jackets are fine. heads only out about .009 and cams turn very easy, thinking of resurfacing the head and putting a new toyota composite gasket in with arp head studs and tuning it unlike the previous owner! it should hold up for a while, motors only got 100k, but i know that don't matter cuz one good overheating session can FuQ a head quick

what do you think?
 

nofx230

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RBD 305;1804887 said:
I was told by a 7M guru to use only Toyota Red Coolant for 7M-GTE's...That build up happened within a 1300 mile break-in period (very fast) probably within 2 weeks or less of weekend driving. The coolant that caused this is from Autozone, the neon green shit lol.

EDIT: Here is the Toyota Red Coolant I will be using next time
images

i run engine ice in my tacoma 5vz-fe i know its $$$$ stuff but it works great in my dirt bikes and quads so why not in a car spos to keep temps down by 20 degrees on average, don't have a temp gauge on my truck, only oem gauge but on my quad and bikes they run a lot cooler and it don't gum up like regular coolants
 

nofx230

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Jan 24, 2012
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whats the issue with the 7m's cooling system?? is it the fact that the HG covers part of the water jackets on one side of the head or is it just weak water pumps or bad design???
 

Poodles

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Jul 22, 2006
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Honestly, I wouldn't use it. Some erosion in the water jacket is normal (because the car is old and most people don't change their coolant) but lean/detonation damage is a different story...
 

nofx230

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Poodles;1804963 said:
Honestly, I wouldn't use it. Some erosion in the water jacket is normal (because the car is old and most people don't change their coolant) but lean/detonation damage is a different story...

oh i fully understand, have been hunting down a donor head for my project, and a few machine shops have already looked at it (very reputable ones in the area) and said it should be fine as long as the motor don't continue to run in these conditions.