1G NPR Pistons -- No Oil Squirters?

thereef · Mar 8, 2013

Hey everybody. I am buying a N/A 6 bolt and gonna slap some NPR pistons in there... Anyone have any experience with the NPR pistons in an application with no oil squirters?

Should I rethink my approach here? Going to DDing the car, sort of..

Searched like wild, and it felt like I came up with a lot of speculation, and mostly about stock pistons. Nothing about NPR specifically.

Thanks!

Edit: Also, I have a donor 4G63T at my disposal.. So I guess I could potentially take the oil squirters off and have them installed on the new block, assuming this is possible? Worth the trouble and price?

vingasoline · Mar 8, 2013

If your non turbo, then you don't need squirters. If your converting to turbo, you would be better off using the donor 4g63t. It's not practical to add squirters to a nt block. Probably be cheaper to buy forged pistons.

Edit: I see you're turbo. Npr's in a nt block with no squirters won't work in a turbo application. Either go forged or get the right block.

thereef · Mar 8, 2013

vingasoline said:
If your non turbo, then you don't need squirters. If your converting to turbo, you would be better off using the donor 4g63t. It's not practical to add squirters to a nt block. Probably be cheaper to buy forged pistons.

Here's the situation.

- I have a 91 TSi AWD that's sitting waiting for a heart...
- I have a set of NPR pistons sitting next to me.
- I have a 4G63T 6-block that blew up.. Holes in 2 and 3 pistons.. Head is completely destroyed. Possibly deep grooves in cylinder walls. Can not confirm/deny this, but will find out soon.
- I have agreed to purchase a 4G63 6-bolt motor (non-turbo) for $180..

I want to put together the motor in a responsible manner with mild power goals in mind (~300whp)

Obviously the biggest question is whether or not the turbo block is mangled beyond usage, which I'll have the answer to tomorrow.. For now I'm just trying to make sure that no matter what the block looks like, I'm ready and have a plan.

SOOOoOoOOO... NPR pistons in a N/A block with no oil squirters is a BAD idea? Hopefully I don't have to mess with it and the turbo block is good to go.

lasthope05 · Mar 8, 2013

Oil squirters are unnecessary unless you plan on road racing where the engine is on constant load where the pisons would need to be cooled. NPR are good replacement oem pistons and I would have no problems running them. There is nothing wrong with running a NT block. In fact, I actually prefer using NT block for full builds vs the turbo.

DSM IN MN · Mar 8, 2013

Not to thread jack here but, I am in the exact same predicament (sort of, LOL

). N/T 6 bolt block, 6 bolt crank and plans to get NPR pistons as well as Manley rods (or whatever I can find on the cheap).

I've been told an N/T block can be stronger and doesn't need to have oil squirters deleted. Then this topic comes up; are oil squirters REALLY necessary?

D's GS-T · Mar 8, 2013

Wow.. I almost asked this question the other day, and have been pndering it for about a week. I ran OEM pistons with No squirters (as have others) and it ran great. I've decided I plan to do the same with the NPR Pistons as well.

WES_393 · Mar 8, 2013

DSM IN MN said:
I've been told an N/T block can be stronger and doesn't need to have oil squirters deleted. Then this topic comes up; are oil squirters REALLY necessary?

The NT block is preferred because of the lack of squirters. This provides more oil directly to the crank journals where it actually matters, not the underside of a piston where it does nothing to help cooling. The squirters are for redundancy, there's no evidence that you need them and tons of guys have run NT blocks without issues.

lasthope05 · Mar 8, 2013

Running oils squirter is really personal preference. I dont like them because they are another point of failure and are know to have inconsistent flows and pressures. Also I wouldnt say the NT blocks/cranks/rods(same as turbo) are stronger but they do see a lot less stress and cylinder pressures.

thereef · Mar 9, 2013

vingasoline said:
If your non turbo, then you don't need squirters. If your converting to turbo, you would be better off using the donor 4g63t. It's not practical to add squirters to a nt block. Probably be cheaper to buy forged pistons.

Edit: I see you're turbo. Npr's in a nt block with no squirters won't work in a turbo application. Either go forged or get the right block.

So how come what you said in your Edit is going opposite what most people in this thread are saying?

This is what I'm talking about.. There doesn't seem to be a consensus about oil squirters......

DSM IN MN · Mar 9, 2013

In my case it doesn't really matter I guess. I'm going to run what I have regardless. Lol I just wanted to see if what I've heard can be confirmed. Or what conflicting information others may have.

KevinRR · Mar 9, 2013

thereef said:
Hey everybody. I am buying a N/A 6 bolt and gonna slap some NPR pistons in there... Anyone have any experience with the NPR pistons in an application with no oil squirters?

Should I rethink my approach here? Going to DDing the car, sort of..

Searched like wild, and it felt like I came up with a lot of speculation, and mostly about stock pistons. Nothing about NPR specifically.

Thanks!

Edit: Also, I have a donor 4G63T at my disposal.. So I guess I could potentially take the oil squirters off and have them installed on the new block, assuming this is possible? Worth the trouble and price?

The oil squirters are there to help cool the pistons on turbo motor. Both OEM and NPR pistons are basically cast piston. So, having oil squirters would help cool the pistons especially when your running the car hard. I doubt Mitsubishi will design it if it didn't serve its purpose. I would sell the NPR pistons and just buy a set of forge pistons. I know people that used N/T block for their build but majority of them build it with forge pistons and rods.

WES_393 · Mar 9, 2013

thereef said:
This is what I'm talking about.. There doesn't seem to be a consensus about oil squirters......

Every automotive topic in history has some difference of opinion. I personally listen to (and sometimes regurgitate) the info from those who have first hand experience.

Here's a quote from a recent thread about this very topic. The poster is a reputable engine builder and avid drag racer.

viperlp01 said:
If an oil squirter sticks open then you loose oil pressure at the mains. They act just like a mechanical injected fuel injector. As oil pressure builds up they pulse.

With that being said if you can delete them then do so. The underside of the piston cools just fine in almost any instance. The crank supplies plenty of oil to the underside. Our 16g car that runs on alcohol and runs mid 10s had an oil squirter tip break off and that piston had no signs of burnt oil on the underside.

Another quote from the oil squirter thread (where this might get moved) posted by a Wiseman.

dsm-onster said:
N/A 4g63 motors with stock cast factory turbo pistons swapped to them are motors that go just as far and just as long without oil squirters. I've personally have had identicall success with and without oil squirters using CAST oem pistons. I've seen no difference in knock threshold or reliability. In fact, I've only cracked pistons in the oil squirter equipped block. The n/t to turbo block (no squirters) has done great, sold to a friend with big boost on a 20g. Daily driven, and he's an unsafe driver.

I could go on and on, but my point is clear. There will be a difference of opinions, but rarely amongst those with the highest reputations. And the consensus between them is that oil squirters are not needed whether it's cast or forged, turbo or NA, street or track. Not to imply that squirters are bad and we should all go out of our way to remove them, but if you have an NT block and are wondering if they're absolutely vital- They aren't. Be aware that oil pressure will be higher and prepared to deal with that properly, but extra steps like that come with the territory.

thereef · Mar 9, 2013

Thank you so much. I will seek out this oil squirter thread, read until my head explodes, but I already feel adequately reaffirmed that I am not doing myself (or my unborn motor) a great dis-servitude by not having oil squirters.

Thanks again, and with that I'll call this thread closed. :applause:

erkitner · Mar 9, 2013

thereef said:
Hey everybody. I am buying a N/A 6 bolt and gonna slap some NPR pistons in there... Anyone have any experience with the NPR pistons in an application with no oil squirters?

If there's any question on whether or not NPRs are good pistons or not, the answer is yes. To a point.

Ever wonder why they're so cheap? Because you're not buying them from Mitsubishi. NPR supplies Mitsubishi with those pistons. They're the manufacturer. And then Mitsubishi puts their stamp on them, marks them up and sells them at 3 to 4 times what they paid for 'em.

N/A you're fine with those. Boosted with squirters, you're fine (my setup), Boosted NO squirters, no bueno. Go forged then.

thereef · Mar 9, 2013

erkitner said:
N/A you're fine with those. Boosted with squirters, you're fine (my setup), Boosted NO squirters, no bueno. Go forged then.

A lot of information I've been given, found while researching & been lead to believe states otherwise. I'm sure forged would be the safer bet, but with my modest power goals I'm confident that these NPR pistons will suffice if I need to use the N/T block.

I'll know whether I need to use the N/T block for certain later on today.

Thanks for the input, I appreciate you taking the time

DSM IN MN · Mar 9, 2013

lasthope05 said:
Running oils squirter is really personal preference. I dont like them because they are another point of failure and are know to have inconsistent flows and pressures. Also I wouldnt say the NT blocks/cranks/rods(same as turbo) are stronger but they do see a lot less stress and cylinder pressures.

Just to clarify, when I said block I meant the block and the block only. I am not so ignorant to think the N/T 6 bolts have differing parts from turbo 6 bolts.

dsmchevyguy · Jun 4, 2013

Like they said oil squirters are not a necessity but what would probably be ideal to running it for some insurance a oil cooler should be installed and for piston temps wouldn't running a tad rich cool egts and piston temps?

Jeff99GS · Jun 4, 2013

I have that exact setup. NPR 7.8:1 pistons in a 6 bolt N/T block. I run the balls off this engine and its always been great! I haven't had any problems in the 4 or 5 years since I built the engine! I daily drive my car in the summer and race it often. Seems to handle not having oil squirters just fine.

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1G NPR Pistons -- No Oil Squirters?

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