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Thanks guys, I will post some more pics of the carnage soon. I reckon there was just one piston that couldn't hack the pace and maybe the rest weren't far behind. Anyway it just might be that the forged piston, mains cap girdle 265 with 904 Torqueflite may be coming into service earlier than expected.

Bottom land is cracked also and had started to detach from the piston.

Oh aftermarket cheese it looks like it's been cocking over in the bore looking at the top edge of that piston

it definitely doesnt looks lean

Hey there heff0018,

Well the damage does not look bad so saving of a motor might have happened. While it is hard to say that it was caused by over expansion of the ring and binding, there is that possibility. Your other option is that the ring lan itself was too wide for the ring and therefor the ring would beat the lan support to death.

All in all the piston and thus the motor has been rebuilt in the past. I would be steering away from pistons of this construction as the oil lan is weak with the slot in it. Even if the lan had not given up you might have lost a piston crown eventually due to the weakness prebuilt into the piston. It is just the way alot of factory pistons are and thus because it is cheap to manufacture this way they will use it. Try and make sure your new pistons have drilled oil lans.... like below.



I would like to see a little more holes but this will give you the right idea. One thing to keep in the back of your mind though........DO NOT RUN SYNTHETIC OR MODERN OILS. Now there is a number of reason for this. But let me give you a really simple run down, i can explain more in detail if you like later.

1. You engine was designed to run mineral oils with a certain shear factor. New oils do not have this. [To the same degree]
2. New oils are not as detergent as older mineral oils and thus the motors do not last as long.
3. Carbon is one of the hardest elements known to man and this is what helps degrade the motors quicker particularly the new oils.
4. New pistons with the drilled holes for oil ring lubrication can get blocked with carbon which thus causes an issue. Simply you fix one issue but create another.
5. The simplest way forward and easiest fix for this is to..... run diesel oils. These are designed to remove heavy carbon deposits and clean the engine. the Shear factors of the diesel oils are alot closer to the older mineral oils and will both make your engine last longer, it will also keep the engine in a cleaner state. This is not hear say, this advise was given to me by 2 leading oil companies because a number of car clubs i have been involved with have notice more and more engine failures in the last 15 - 20 years with engines not lasting as long.

I run diesel oils in my race cars and my dailies (in fact pretty much everything i own) I had a VE s1 v6, and everyone kept complaining about the timing chain stretch. This is partly due to a design issue where the drivers side timing chain gets coated in carbon etc. I ran diesel in my and my mates cars and we both got to the 300,000 klm timing chain replacement service without premature timing chain replacement. The stuff works and all my motors are golden in colour in side. You will need to change your oil regularly (no more than 10,000 intervals) as it will pull the carbon from the motor. If you stick it into a motor that has had normal oil it in expect to change the first three in a less time frame. it will go black very quickly and you want to remove the carbon ASAP. I have fixed a number of noisy lifter cars purely by changing to the Diesel oils. The grade of oil is amazing these days so just find the right grade for your engine and wack it in!!

Good luck.
Cheers
oldn64

Thanks for that, interesting.

there is a point with diesel oils but i always say its all hearsay without oil testing done, each engine is different to

I checked all the other pistons carefully and there is no other obvious damage. The JE pistons I am looking at have the drilled oil lands

The1 wrote:there is a point with diesel oils but i always say its all hearsay without oil testing done, each engine is different to

Understand what you are saying, but when two different oil companies visit two seperate car clubs i am involved with you sort of pay attention to the advice. My testing in real world environment has shown it to be the correct advice. All who know me have watch what i have done and are now following suit. Even the guy with the mx5 that was buying oil at $120 per fill for the race car is now running supercheap topdog with better results, bot in time and in engine cleanliness. He is about to swap his daily type R civic to diesel as well. I am sold and have been for a very long time.

heff0018 wrote:I checked all the other pistons carefully and there is no other obvious damage. The JE pistons I am looking at have the drilled oil lands

Awesome, top piston failure will be a thing of the past. Make sure you gap your rings properly and also make sure the lan gap to ring is within tolorance. Personally I will only use hastings rings and king or hasting bearings. remember like timber work with measure twice cut once. make sure you assemble multiple times checking all the clearances etc before final assembly. while not entirely needed in the application you motor it intended, are you going to balance the assembly?

cheers
oldn64

The lan to ring gap is something I haven’t considered before but will be checking from now on. With change in piston weight I thought balancing The crank would be required.

What brand of diesel oil are you running?