New Engine Blown Up At Tuners

[StevenCJR31]

maybe you had better have a chat with them then, but get it (the problem) in writing from the tuner shop first

[Legionnaire]

Aren't Mahle pistons shipped with rings? If so, I would expect them to know what rings to use and to be gapped correctly.

[joe blo]

maybe he gapped em as per the application they were intended for? that being a non turbo rb30. tuner guy said that they have expanded on boost and grabbed. something like that. he also said its common for it to rip the whole top of the piston off when it does it

[DVS JEZ]

Always have to check ring gaps Legionnaire.

I cant picture a ring gap inproperly set causing the ringlands to break but thats just my opinion

To me it would crack the rings and kill the bores

[Room42]

To summarize you used cast pistons and they broke. You didn't check a bunch of stuff that engine builders check. Lesson learned. Use forged pistons next time. Make sure you know what to check and NEVER take anyones word on clearances.

[joe blo]

i didnt install the pistons into the block therefore wasnt responsible for setting the ring gaps. what other stuff is in the bunch of stuff i didnt check?

[Harey]

If he paid someone to build his engine, why should he have to check clearances?? Isnt that why you pay someone to build an engine because you dont know how to?

To me its either the requirements were not laid out well enough by the customer or the engine builder is at fault.

If its possible a good idea is to go to a place that can build the engine and tune it, that way theres no passing the buck.

[Room42]

  On 08/09/2011 at 1:38 PM, joe blo said:

i didnt install the pistons into the block therefore wasnt responsible for setting the ring gaps. what other stuff is in the bunch of stuff i didnt check?

If you are going to build an engine then you should check everything, not just the stuff that you put together. Its your motor and you are responsible. You cant trust that someone will put it together right unless they build the whole thing and warranty their work. It happened to someone I know recently. The machinist ground the crank and supplied bearings and said it would be fine to put it together as supplied without checking. He did and it lasted less than a week before it needed pulling down. The bearings were scratched. From this thread it sounds like you probably know enough about what to check when putting an engine together. At the end of the day whether or not the engine was done right and from the thread it's likely it was, it sounds like the new cast pistons weren't up to it. The bunch of stuff to check is available in a car or engine building manual. I'm not having a go mate but why didn't you spend the extra $500-$700 and get forged pistons?

[femno]

Using forged pistons isn't the solution to having an engine hold together mate. It's about screwing it together properly. Are you forgetting that standard rbs handle 300kw++ all day? They hold together because theyre built well.

[Room42]

  On 12/09/2011 at 9:45 AM, femno said:

Using forged pistons isn't the solution to having an engine hold together mate. It's about screwing it together properly. Are you forgetting that standard rbs handle 300kw++ all day? They hold together because theyre built well.

True true.

[Rolls]

  On 12/09/2011 at 9:45 AM, femno said:

Using forged pistons isn't the solution to having an engine hold together mate. It's about screwing it together properly. Are you forgetting that standard rbs handle 300kw++ all day? They hold together because theyre built well.

This couldn't be truer, it is all in the assembly, you set the clearances/tolerances wrong and your shiny $10k pile of parts becomes a $10 pile of parts. The most expensive parts in the world aren't immune to poor tuning or incorrect assembly.

This is the reason I will trust a second hand motor over a random rebuilt one unless it's been built by one of the few pro workshops that build motors every week.

[Beer Baron]

yes that's normally true but don't forget in this case he was using aftermarket cast pistons meant for NA applications that in all probability are less suitable for a boosted RB than factory pistons. so it's quite possibly it was a combination of the build AND the poor quality/unsuitable pistons.

[Rolls]

Yeah I was just talking generally BB, I think what you said is the case here, a combination of things.

[r33_racer]

  On 12/09/2011 at 11:33 AM, Rolls said:

This couldn't be truer, it is all in the assembly, you set the clearances/tolerances wrong and your shiny $10k pile of parts becomes a $10 pile of parts. The most expensive parts in the world aren't immune to poor tuning or incorrect assembly.

This is the reason I will trust a second hand motor over a random rebuilt one unless it's been built by one of the few pro workshops that build motors every week.

I would also add poor machining. If the machine work is no good and the assembler doesnt double check then there could be a problem.

[Rolls]

  On 14/09/2011 at 8:05 AM, r33_racer said:

I would also add poor machining. If the machine work is no good and the assembler doesnt double check then there could be a problem.

I was assuming the assembler, builder, machiner were all the same person in that post.

[r33_racer]

Not very often that is the case though, actually hardly ever is that the case.

[Rolls]

  On 14/09/2011 at 8:14 PM, r33_racer said:

Not very often that is the case though, actually hardly ever is that the case.

Which is why shit goes wrong, no one is accountable or cares what happens in the other steps. If you had a company doing 95% of the work I bet there would be better results.

[r33_racer]

Yeh that is very true.

[Gtir-keiron]

Ouch!

dont worry i have seen worse happen recently.Not blaming any one for a lunched motor but this is why you find a mechanic who has experience with rbs in the first place.My mechanic is the biggest pain in the ass but he is f**kin awsome and so anal about how he puts his motors together,If its not perfect he will pull it down and regap the lot.

Its like any trade tho there are hidden tricks and things that a hand book do not show that should be done.

Thats why there is engine builders and Engine builders.

My tuner always tells people when they bring in a motor,IF its stock or unknown,Shows them what a factory motor makes and then tells them what they could get out of the combo they have on the motor,As good as what motors are jap ones never have the ks on them shown on a cluster and when your taking a motor that makes 200 to 280hp atw to 400 to 450hp atws its makeing almost 2 times the factory power on parts not rated for it so its a luck of the draw how long it will last.

Hell my skyline was making 470 hp atw for 2 years all happy and running pretty good and finaly at power cruise after 3 days of flogging it down the strait like a dead horse she finaly droped comp on a piston.

My really good mate just lunched a 26/30 that was fully forged engine had not even done a 100ks droped a vlaved and smashed his piston and head maybe killed the block also but the jun head is a write off............

I think at the end of the day what you save in the short term you pay a hell of alot more when she goes bang......just do it right the first time.

Sorry for your loss tho mate im not looking forward to pulling my engine out either.