Outer Limits 4x4 Board

Help info wanted. I have a 1hz with a holset H1C turbocharger from a 6L cummins, Im running about 18lbs boost at full load and made 139hp at the wheels with 33's, I have had a ring land failure on 3 pistons. whilst looking into building a high power 1hz I noticed that all brands of pistons Ive looked at state that the piston is not suitable for forced induction. so can any one tell me if there is a company that builds specific pistons for forced induction 1hz's. Also 1hdt pistons will fit the bores but the gudgen pin diameters are different, which means i would have to run 1hdt con rods, where can i get some.....


Mabe I should just fit a gen 3 and T700.

1HDT's have direct injection and the combustion chamber is in the head of the piston, you would need the 1HDT head to go with the pistons aswell.


Wally.

shit mate 18lb? who tuned it ? i got 10lbs of boost and 142 hp? just sounds like alot of boost for what u r getting

sorry my stuff up i ment to write 139 kilowatts I think thats about 180hp, not sure Ive lost my conversion chart. yeah my dynometer read out is in kilowatts. And I tuned it Seeing as Ive been a diesel fitter for over 8 years. Yes I know i should put a 1hdt head on it soon but trying to find second hand head and rods isnt as easy as you might think (well up here in north queensland any way). A little back ground for you though, I have already installed a new boost compensated fuel pump from a 1hdt, I had the cam built up and reground more duration on the intake and exhaust and slightly more lift on both as well, (i have the specs around here some where). as for the turbo it is a non wasetgated holset h1c, running on a manifold i built using steam pipe bends (flows very well), I have not got any form of aftercooler yet...
I do relise that im on the limits of this engine but the crank has been balanced and micro polished and the main tunnel line bored and blue printed. but I am content with sticking with this engine so if you are able to help me with some info about pistons or where i can get a 1hdt head and rods please reply..

Can pistons be cryogenically treated to withstand higher boost pressures? Or would the high temps make it a useless treatment?

Dave

yeah dave they can treat them as you say, or I could also get them ceramic coated but jet hot coatings but the main problem isn't from heat. See if a diesel engine is tuned right there is know way the pistons should get the point that the melt which is the common problem that I have found speaking to most engine machining shops. The failer I have had is that the ring land on the top piston sealing ring has completely broken away from the piston. And yes before any one ask's the pump timing is spot on. but thanks cause that was always going to be an option to me when i get new pistons and possably rods to know.

if not heat then what caused the ring land to brake away?

Whats the difference between 1hz and 1hdt pistons? id have thaught the piston rod combo would only differ in the compression ratio and the physical design of the piston would be very similar.

Shadow wrote: Whats the difference between 1hz and 1hdt pistons? id have thaught the piston rod combo would only differ in the compression ratio and the physical design of the piston would be very similar.

The 1HDT has a well cast into the piston top:



and the 1HZ doesn't:



I don't know if the well alone is responsible for the difference in the compression ratio, or different head combustion chamber sizes and connecting rod lengths also contribute to it.

balzackracing, if you should ever find pistons that will suit a 1HDT head on a 1HZ block, please send me a PM. I am interested also. It would save some $$$ if the conn rods and gudgeon pins do not have to be changed to 1HDT parts.

Dave

Two things spring to mind.

What are your exhaust temps? What are the two pump numbers ie the 1hdt pump and the old 1hz pump. I think advance rates are different in both. if you give me the numbers I will look at the test plans and let you know.

Fitting 1hdt pistons in this thing wont help as you still have a precombustion chambered head. If you fit a 1hdt head then you also have to find injectors and lines as well.

Food for thought.

Andy