Thread: 3l needing new pistons?

I used to own and operate a machine shop - we used to have this issue many times on Toyota diesel engines.
If it was not burning oil before this then it wont after this. The downward force from the valve onto the piston is straight - and not on an angle. The valves in these engines take the hammering. If the head checks out A OK then the piston assembly will be good. Diesel engines are built tuogher than petrol cause of such higher compression and it takes a massive amount of energy to break a diesel engine piston. I'm not saying its impossible but in this cause its only a valve touching - You should see them when a valve breaks and pummels itself senseless in the combustion chamber.
I'd be happy to let it run however it all depends how good it was before the incident.
The secret to long life in any diesel engine but especially toyota's is regular oil and filter changes. They used to start on new ones at 10,000kms but that was reduced to 7500kms to stop thinning of the oil - once the oi became diluted it reduced bearing clearance resulting in the con rod going up that little bit further thus allowing the valves touching the pistons and Vola - Same result as you have.
Be care on aftermarket cheap parts - they are cheap for a reason - no one ever regretted paying for good quality parts. As me how I know LOL
Parts like pistons etc are like rifle scopes. You pay for what you get.

Originally Posted by 35desoto

I used to own and operate a machine shop - we used to have this issue many times on Toyota diesel engines.
If it was not burning oil before this then it wont after this. The downward force from the valve onto the piston is straight - and not on an angle. The valves in these engines take the hammering. If the head checks out A OK then the piston assembly will be good. Diesel engines are built tuogher than petrol cause of such higher compression and it takes a massive amount of energy to break a diesel engine piston. I'm not saying its impossible but in this cause its only a valve touching - You should see them when a valve breaks and pummels itself senseless in the combustion chamber.
I'd be happy to let it run however it all depends how good it was before the incident.
The secret to long life in any diesel engine but especially toyota's is regular oil and filter changes. They used to start on new ones at 10,000kms but that was reduced to 7500kms to stop thinning of the oil - once the oi became diluted it reduced bearing clearance resulting in the con rod going up that little bit further thus allowing the valves touching the pistons and Vola - Same result as you have.
Be care on aftermarket cheap parts - they are cheap for a reason - no one ever regretted paying for good quality parts. As me how I know LOL
Parts like pistons etc are like rifle scopes. You pay for what you get.

Thanks for your response, heard back about the head and valves aren't bent but the camshaft is. Gives me a bit more confidence to put it all back together once head is sorted, was a good runner before this happened
Cheers