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Major Neo Rb25det Engine Damage

drgnball34

By drgnball34,
in Engines & Forced Induction

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drgnball34 Rising Star

drgnball34

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thanks for all the input guys. Damage was done on piston no. 1. He is a qualified mechanic and has prevously worked at a high performance workshop. He has has had many cars thats he has worked on enter numerous car shows. I dont know why, but he must of cranked it over many times as the valve looks like its been chewed up and spit out! He must of had the timing belt on when he cranked it over otherwise there would be more then one damaged valve. But i was not there to see. How could the valve seat dislodge itself in the 1st place? Cause that is also what he has stated. Hard to tell coz there was pretty much no valve seat left! Other then the broken valve, would anything else in the vavle train need to be replaced? Someone mentioned retainer? Also i have heard that the rods are GTR. Would the force and stress have damaged or weaken it in any way? My friend said that i may need the rod resize which also means a balance bottom end! ouch!

I will take this as an oppurtunity to rebulid my engine with forgies etc. Since the block needs to be honed, i will get oversized forgies (40 thou),

new big end bearings and rod and main bearings. Along with a thicker gasket ( 1.2mm ), heavy duty valve springs and head studs. Any other suggestions and advice/feedback would be greatly appreciated. i have a GCG highflow and NOS kit both still in their boxes along with all other supporting mods. As the GCG maxs out at around 260rwkw ( what a shame coz the engine package can handle way more! ) ive decided to make the most out of my NOS. Love it or hate it boys!!! Any idea as to the max jet size i can run providing the clutch is up tio scratch?

GTRgeoff Grand Master

GTRgeoff

Posted
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Valve seats don't just pop out, or disappear. Get the fragments and photograph them clearly on the broken surfaces.

Rods should not need a resize unless the bearings have spun and damaged the journals. Get them x-rayed though for cracks. Costs about $20. You would balance it while it is apart. Again, doesn't cost much but doing all the right things adds up. Also get the crank checked for straightness.

I don't see the need for a 1.2mm gasket for the low power you will be running. It will just hurt engine response. Use a stock gasket and O ring the block. Same with valve springs (unless you are using a big big cam) and studs. They are not a normal point of failure on engines running upwards of 300 rwkw and I assume the NOS is just a 50hp shot, so unless you have plans of a big kW engine they will be just bragging goodies.

GTRgeoff Grand Master

GTRgeoff

Posted
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Forgies are pretty well mandatory in RB25s but I think the Neo is a bit better built considering only a few ringland issues recorded, plus they come stock with GTR spec rods. The head stuff is unecessary unless wanting to rev beyond 8000-8500 regularly and even then the valves will be a limiting factor, as well as the hydraulic buckets. Just putting into perspective why you would need to install such items. I'm all for a completely tuff engine, but only if you will actually use the expensive items.

Abo Bob Grand Master

Abo Bob

Posted
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Damn. I wanted to be the one to tell you that. hehe.

I smashed my ringlands.

With NOS if you are running a lot of it you need pistons with bigger clearances and make sure you have good quality headstuds. How much are we talking? I'd hate to have to drill for bigger head studs.

Also you mention valve springs but not cams. :happy: Tomei type B Poncams work with stock valve train. I don't think you should go any bigger with that turbo. You might like bronze valve guides but for the money I don't think they are worth it unless the aforementioned hit of nos is really big.

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