JNZ Shortblock Pull Apart?

[RT-AWD]

I recently purchased a 6-bolt turbo fully built shortblock from a guy who bought it from a guy who had it built by JNZ Tuning in early 2008. Since then the motor has not been cranked there are no miles at all. My question is should i pull this motor apart to check the ring gaps etc? My friend had a JNZ motor go after 1,800 miles due to a ring gap error. Some people say yes others say just put it in. I think it may be a waste to take it apart since im not the original owner of the motor, and if there is a problem I'd be screwed anyway. what are your thoughts and opinions.

thanks

 

[hostile]

I wouldn't think a motor would let go because of ring gap anyways. It would use a little more oil, but nothing that would cause the motor to fail.

The main reason for a built motor to fail early is improper machine work. If you don't own a machine shop chances are you don't have the tools to check the work done by one.

 

[Rob10_99]

Yes, I checked a ring gap after I had a machine shop put mine together(no time to do it myself at the time). And wow they were at least .004" tighter than the spec sheet read.

FYI, the only things you need to regap would be feeler gauges, some type of fine file(i used a diamond file), and a torque wrench.

 

[DSM_PWR]

If you know what your doing and have the tools... why not?

If it was me, id like to check everything else like bearing clearances, crank endplay, torque specs, etc.. ring gap would be least of my worries...

 

[RT-AWD]

well i've got the tools and the know how i just didnt know if it was really worth it or not. I dont think it has any crank end play, i tried to rotate the assembly and it rotated a little and then stopped and it doesnt move.

 

[dSmgs-T]

so the motor doesnt spin freely now?

 

[hostile]

So you have a bore gauge, a ball end micrometer , a caliper, a set of feeler gauges, rod bolt stretch gauge, dial indicator and torque plate?

I can promise you a real engine builder like JNZ has all that stuff.

 

[gsxitement]

I would deff. check end gap. If it's to tight, the ring end's can butt and actually break the ring land. Not good. Just be aware that breaking the ring is always possible while removing or installing them. Be careful.

 

[RT-AWD]

so the motor doesnt spin freely now?

well i just tried to see if it would move with my hands and it did a little. i dont want to really yank on it and do damage

 

[cfriddle]

tear it down and check it especially if your afraid of it potentially already being damaged. There is no reson why you shouldn't be able to give it a few rotations, might not be able to by hand because of compression but at least you would know it rotates! tear it down it will give you a good chance to throw some assembly lube on everything and fire it fresh

 

[jking29]

^^^^^Agreed. Well worth it for peace of mind.

 

[RT-AWD]

ok it rotates, i put more effort into it and it rotates

 

[BoredDSM]

I would call JNZ first. When they do the machine work they torque things to there specs. If you don't torque it to there specs there is a chance that end caps of rod bearings or main bearings being out of round. If you can find that info out then it would not hurt to check it.

 

[JEFFREYCASTGSX]

Dont touch it, if it ran before and a reputable shop built it, then why would you even open it up, just a waste of time. Your friend obviously just had a bad apple.

 

[RT-AWD]

Dont touch it, if it ran before and a reputable shop built it, then why would you even open it up, just a waste of time. Your friend obviously just had a bad apple.

Motor has never been started, cranked or, even in a car. When i first bought the shortblock i took it right to JNZ and the looked at it and said that it was in fact one of theirs and the guy that built it remembered the build because he built it for a friend.

 

[DSSA]

If that's Matt's old motor that was then sold to RT Tuning for a customer's Mirage build, the gaps were set @ 19 top and 21-22 bottom.

If you're speaking of Nick's motor (which consumed oil), we've recently figured out why that occured.

A former employee decided to sell Nick a customer's motor who never picked it up or finished paying for it which was being built for really high boost and nitrous--thus the ring gap being large.

Thus also why the motor he got ended up having $790 Crower Rods in it instead of the cheap Eagle units that he ordered.

Thus another reason why "former employee".

That motor was "somewhat" built by us though. Matt basically assembled it here in the engine room for his car with us guiding him, so I would say it was "somewhat built" by us.

Josh

 

[RT-AWD]

yes this is Matt's old motor. I bought it from an RT-Tuning employee. Is it safe to say the motor is to spec and ready be put in?

 

[assault187]

Matt's motor has been sitting for a good while now...well over a year. Prime it by spinning the oil pump with a power drill, toss it in, and throw some boost at it.

 

[DSSA]

Nick, yes---a year and 1/2 for that matter. Good call.

The only thing I would be worried about is if it was exposed to moisture, or if the rings bit into the cylinder walls over 1 and 1/2 years of sitting in the same spot.

I'm pretty sure that Justin walked him through the buildup for the most part, so I would say it should be done correctly.

 

[RT-AWD]

spun the assembly a few nights ago. there were no strange marks or sounds everything sounded smooth.