Project NashZilla: R32 GT-T NEO

[amnash]

man thats one aggressive stance. looks soo mean
that car must eat babies

you're really goin to town on your car..good work man!!

thanks man!

[amnash]

This is how some of my bearing looked(not sure if this is normal wear and tear or not..)

[nelsonmxmarc]

Looks like heat soak, or hard start ups.

Heat soak is caused primarily by hard driving in hot conditions (or not), usually when oil reaches the threshold point of 220 celsius. This has been known as the point of fail for most RB engines, and where caution is throw in the direction of purchasing an external oil cooler. Because the GTR was a track car, it was mounted with an oil cooler to prevent these temps as they were known as fatal.

The scoring you see looks more like it was done on a cold start, high revving. A lot of people don't take much time to let oil temperatures warm up before abusing their car. Much like cold seizing a piston (same vertical striations), it's almost as if the journal itself was prevented from moving. Dirty oil can cause this too, small sand-paper like particles (metal fragments, not sand) build up through use.

If i was to rate these, i'd say your bassline here would be picture number 4. The one above it saw heat, and is not bad at all. The last one, what are those black specks? And the two top ones are questionable.. Can you feel that scoring with your nail? Do you have access to a micrometer to determine if these are within spec? Measurement technique is proposed in the FSM, as well as run-off and allowable clearances.

Scoring is bad, and generally means the bearing needs replacement, and the journal needs to be polished. Assuming your crank is out now, see if you can see any markings on the crank journal. If so, you'll need to send this to a machine shop, have them order new ACL bearings and have them installed properly. Along with this, new rod bolts, because the deflection from previous deformation cannot be used. And, since you're there, new mains and main bolts (CANNOT BE REUSED, or SHOULDN'T).

Basically you'll have a new bottom end.

Can you take pictures of your pistons? You mentioned possible blowby or questionable condition. At which point, have the block spec'd and line honed (if not ovaled or out of spec), then re ring the oem pistons if money is an issue. These will work over 400 hp so no worries.

[amnash]

ya that was the plan to use oem pistons. ill be getting the block honed and ACL bearing fitted. the crank will be getting a polish.
the mains and main bolts...you just mean the head studs? i already have a box of arp head studs if thats what you mean.
i already bought oem piston rings a while ago...im hoping that after the hone i wont have to get oversized rings..

[M13]

I have a polished RB20 crank if you need one.


Should be much cheaper than polishing your own.

[nelsonmxmarc]

Main bolts are the bolts that hold the crank girdle in place (Holds crank in place)

Should be ok for size, i dont think your cylinders will need a bore.

For the journals, you'll need a micrometer as measurements with a caliper wont measure precisely the hundredth or thousandth of an inch. You need to be incredibly precise. Wear on the crank journal means a smaller journal size, means increased bearing (step 2) size. If it's not too bad, and needs a quick polish, you may be fine with the oem spec size. But this comes down to 0.0xx of an inch. Take it to a professional, they'll be able to fit the new bearings for you and you won't have to deal with the headache of measuring tolerances. It REALLY doesn't take much to mess it up..

On the journal bearing, there's a stamp. You probably wont need to, but i'd suggest giving them the FSM journal tolerances along with subsequent part numbers for all 3 bearing sizes, so that they can order the proper set from ACL. Too many headaches in this department. One guy just posted about his crank seizing all together - used rb26 bearings on the journal, never even knew.

[nelsonmxmarc]

Also dont forget, you'll need to have your rotating assembly balanced and blue printed. IT's worth the cost - 500-600$ ballpark. Guarantees reliability, but i dont think they'd let you leave the machine shop without doing it..

[amnash]

yea i was planning on getting it all balanced together. pressure plate, flywheel, pistons, rods, and the crank

[nelsonmxmarc]

No no, 3 sizes are the 3 available journal sizes. If you go into the FSM, the have 3 sizes available, almost like boring over, 1,2,3 sizes over.

You will have to change main and connecting rod journal bearings.

Balancing is just the crank, connecting rods and pistons. Check youtube and you'll find a video of a balancing station at a machine shop.

You can usually get away without balancing if you buy all new rods/pistons and etc since all equipment is balanced in factory. But your crank, being that it's not new and may need polishing, will certainly need to be balanced (remove weight from counter balances), and this is best done with the whole rotating assembly in place.

Normally they'll put the motor together, girdle in place, then simulate the engine running upwards of 8-9000 rpm to check for any shake or balance issues, then work from there.

[amnash]

And the two top ones are questionable.. Can you feel that scoring with your nail?

Can you take pictures of your pistons? You mentioned possible blowby or questionable condition. At which point, have the block spec'd and line honed (if not ovaled or out of spec), then re ring the oem pistons if money is an issue. These will work over 400 hp so no worries.

i could feel the scoring with my nail even with ruber gloves on.

and here are some pics of my pistons, i dont know if there is a visual sign of blowby but like i said, some of the pistons i removed dropped right out of the cylinder from its own weight once the rod bolts were removed, rings couldn't of been sealing very well

[amnash]

#1

#2

#3

#4

#5

#6


sorry for quality...crappy phone pics

[nelsonmxmarc]

All good man!
Looks fine! I wouldnt even bother with a line hone/rings if the compression was good. No blowby, looks fine to me!

Definitely running rich though

[M13]

Damn Pat's car ran super rich. (previous owner)

[Skym]

Translator for the GTS-R badge that was mentioned on page 4 or 5 -

http://translate.google.co.nz/?ie=UTF-8&hl=en&tab=wT#

Bearings wear could be due to cavitation (heat damages surface of bearing). Using wrong viscousity of oil or like mentioned in this thread, oil not up to operating temperature (too thick with cst rating to get to and lube bearings properly) can cause this. Also oil starvation is another.

I found using a 10w60 weight oil was way too much and actually could cause more wear on bearings due to high cst which makes it hard for oil to reach bearings. Max is w50 weight for racetrack and for most modified road cars a w40 weight is enough.

Only way to know what oil is best, is monitor oil temps via oiltemp gauge and see where it sits when engine is warm, after driving. Then choose oil to suit. Most oils seem to break down after around 120degrees. Unless it's a w60 weight that's used in some applications where oil temps are extremely high.

I ended up using a 10w40. Interesting things I found after switching to this oil from a 10w60, is engine starts, idles smoother, better engine response, cooler (haven't checked coolant temps, but notice a difference) with correct oil. Wouldn't think that oil makes that big of a difference, but it does. Also oil can rob engine of hp and make it struggle to accelerate (like I mentioned with engine response).

Opie oil in UK have a document that mentions the cst at 100 degree oil temp, so can make a informed decision -

http://www.opieoils.co.uk/pdfs/tech-articles/10w-60-oil.pdf

Factory is 5w30 (have it on a sticker on my car). Oil temps on RB20DET can reach 100-120 degrees when modified, so w40 weight is enough for street use. With basic intake, exhaust, oiltemp is around 93+ degrees on the street with 10w40. Even on the street, RB20DET can benefit from a engine oilcooler.

[amnash]

ill be running 5w40 amsoil after the break in. and during the break in ill use just petroleum based oil 10w30