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1G Shop that can machine 1g rods

dwb

Proven Member
305
152
Sep 9, 2021
Broomfield, Colorado
I've been scouring locally for a shop that can machine my 1g rods to fit 2g pistons and install the pistons. The shops who have responded do not instill confidence. One was asking me about bushings, which I do not believe exist on 1g rods.

So what machine shop can I ship my pistons and rods to who have this process down pat?
 

biglady112

15+ Year Contributor
1,800
323
May 20, 2004
Commerce City, Colorado
The 2G piston and pin offers you no advantage. You are literally wasting your time attempting this. Larger diameter does not mean more strength. Wall thickness does.

Unless you have a problem with your rods or pistons, you are going down the wrong path here. This is 2022, not 2001. There are superior parts that are affordable even if you want to piece some stock junk together. Don’t be cheap here. You will get cheap results.
 

CrackedDSM

10+ Year Contributor
2,166
816
Dec 17, 2009
Pensacola, Florida
I’m not sure about your neck of the woods, but it shouldn’t be too hard to find a shop that can mill it 1mm over. BogusSVO has fallen off the face of the earth or I’d say he could do it.

What you’d probably have to do is just bring the rod and the wrist pin and tell them “this needs to be 1mm over, and it’s press fit” and see what they say.

Maybe try the big name shops that do engine work? Idk.


Also: we get it people. You think he should do something else. This has been established. We don’t need 17 replies consisting of the same exact comment. Good grief.
 

dwb

Proven Member
305
152
Sep 9, 2021
Broomfield, Colorado
Thank you @CrackedDSM. You're the only one who actually kept it on topic. :thumb:

<rant>
Here's the deal, I hashed this out over the last few months on this forum. I didn't want to spend a fortune on this build as it's just a stock rebuild. Everyone gave their opinion, which I appreciate, but it's not like there is one clear and obvious path. Most opinions were from people who run higher HP than this engine will ever see. So with this in mind, I did a lot of research on my own as to what would be the best bang for the buck with current available parts and what would work for ME. Maybe some of this information was a bit outdated, but that's besides the point.

I needed to buy pistons so my machinist could fit them to the bores. I wasn't going to fork out cash for forged pistons (overkill) and compression ratio was a concern due to only running stock 1g fuel trims. I didn't like the 1g stock piston options as they all seemed like sketchy knockoffs. It was suggested on here to run Nippon 2g pistons. As far as I could tell they are as close to OEM as possible but with the caveat of slightly higher compression and larger wrist pin. They fit the bill and I guess I can live with turning the boost down until I get off stock timing maps. So I ordered them and had the bores honed to fit.

Now I'm at the stage of needing to fit these pistons to the rods. In my research, there was thread after thread that one could reuse 1g "big rods" and have the small end machined to fit a 22mm pin. This was even mentioned in the description of the pistons. I really didn't put much thought into this, it just seemed like something that was fairly common to do and I could save money on having to buy new rods.

After calling around to various local machine shops and them not really understanding what I am needing done, I created this thread for advice on MACHINE SHOPS. Only to be met with a bunch of negativity and finger waving that had nothing to do with my question. The same scenario has occurred numerous times with my previous posts and frankly I've had enough. I don't know about most people on this site, but I came for constructive discussions, answers to specific questions by knowledgeable people and to leave the flame war out. I also enjoy offering my opinions and experiences to others but I try to be as unbiased as possible. Now time and time again people are going off on unrelated rants because they want to get their biased opinion in edgewise and rarely have something constructive to add. I'm honestly starting to feel like I should go back to my cave and do things how I want to do them to avoid such negativity.

Just because I'm not an "old timer" here, doesn't mean I've not been in the game for a long, long time. I'm simply venturing into uncharted territory and I thought this site would be a great resource. While that has been mostly true, there's a few shiny turds out there that muddy up the water. I don't care to swim where people shit.
</rant>
 

CrackedDSM

10+ Year Contributor
2,166
816
Dec 17, 2009
Pensacola, Florida
People have always given crap for the 2G pistons/1G rods even back in the day. Back then it was “too expensive” or “waste of money” and these days it’s “oh just spend 2-3x more for a built engine that you don’t need”. Best not let it get to you, man. DSM guys have always been this way (though it’s for sure gotten worse over the years).

You should’ve been around when the whole ECMLink vs Ostrich thing went down. LOL


But honestly I’d bring the rod and the wrist pin and just say “this needs to fit into this, and it’s press fit. It has to be bored 1mm over. How much to do this?”
 

DSMPT

DSM Wiseman
2,174
1,758
Jun 12, 2014
Japan / Mexico, Arizona
Put aside if it's worth or not for now, the process is not complicated. Long time ago, a couple of times I did this even with a local industrial machine shop by telling them what to do.
Basically what you/machine shop need to do is to measure the interference amount for press fit between 6 bolt 21mm wrist pin OD and 1g rod small end ID. And set the same amount of interference when you enlarge the small end for the 22mm 7 bolt wrist pins.
There is one more thing you need to do. You need to narrow down the small end's width a few mm to give clearance between small end side wall and piston wrist pin boss.
 
Last edited:

biglady112

15+ Year Contributor
1,800
323
May 20, 2004
Commerce City, Colorado
If you would have stuck with the correct piston from the get go you would not be making this thread. Your research mislead you. How does removing material from an inferior part give you superior results?

There is nothing wrong with your stock rebuild approach. It is just wrong.

With that said, any machinist can handle this. At least they can here in Denver. Unless it isn’t convenient for you, you are best advised to physically make your way to the machinists near you. And after seeing what you need for themselves and they still cannot handle it, well, sounds like a rough road.

If you want/need results, take action. Complaining to strangers on the internet isn’t going to help you. Go speak with someone in person. Everyone around here is an old timer and has been around the block. The mechanics of what you are asking are simple and easy to accomplish. Even if they are not a great path to go down.
 

bastarddsm

15+ Year Contributor
5,480
1,309
Aug 26, 2003
Mendota, Illinois
Jesus, this was done all the time back in the day. Like super common. IDK why everyone has thier pants in tizzy over it.

OP i think anyone with a bridgeport can do this. We did a set for my little brother, actually narrowed the big end too, so we could use them on a 7 bolt crank. I'd offer, but we are not really 'good enough' that I'd want to for someone else.

Forget about most of these guys here. They all have tunnel vision, and half couldn't build a paper airplane.
 

Spleen8urLSX

Proven Member
268
173
Dec 26, 2017
Elyria, Ohio
Jesus, this was done all the time back in the day. Like super common. IDK why everyone has thier pants in tizzy over it.

OP i think anyone with a bridgeport can do this. We did a set for my little brother, actually narrowed the big end too, so we could use them on a 7 bolt crank. I'd offer, but we are not really 'good enough' that I'd want to for someone else.

Forget about most of these guys here. They all have tunnel vision, and half couldn't build a paper airplane.
I’m with you, maybe I’m old but I didn’t realize this “wasn’t a thing” as we used to do this all the time. Hell I have a damn plaque on my wall out of Buschur’s shop with Shep’s 1gb on it from an article in Turbo magazine from 1998. Car was going 11’s with primitive engine management, street tires, and a bolt on 20g set up and a bunch of ported stock shit. The ONLY thing done to the bottom end, 2g pistons on 6 bolt rods. YES we get that was 24 years ago but it worked well then, worked well 5 years ago, and guess what? Still works well! Same crowd who’s never accomplished anything worth mentioning im sure will have some detailed explanation on how Shep was wrong for that in the late 90s and should’ve used other parts (that probably didn’t exist yet) instead. Based on the OP’s other posts he’s obviously doing his research, he didn’t ask how to buy rods that cost triple of what he had in mind, he asked for a machine shop that can do this (holy crap breaking that down made me feel like I’m back on all the extremely dumb DSM Facebook pages).
 

steve

DSM Wiseman
14,864
1,720
Feb 3, 2002
Boulder, Colorado
This might help explain to the machinist what you want done. I'm surprised it hasn't been posted in this thread yet.

You must be logged in to view this image or video.
 

bastarddsm

15+ Year Contributor
5,480
1,309
Aug 26, 2003
Mendota, Illinois
Thanks steve, i forgot that drawing was floating around out there still. makes it easier with a drawing.
 

TheBrownMike

Proven Member
45
31
Apr 9, 2018
SAN DIEGO, California
I have a set that were freshened up like 6 months ago, I was gonna do the same thing for a "stock" rebuild but once I put them in, I realized the machine shop ordered NT pistons. So if you want, I have a set for a decent price, and you can keep the NT pistons for a paperweight
 

DSMPT

DSM Wiseman
2,174
1,758
Jun 12, 2014
Japan / Mexico, Arizona
It was suggested on here to run Nippon 2g pistons.
If you would run 7 bolt pistons, here is info about OEM style pistons and OEM EVO piston/rod/crank as much as I know, I would share for future reference.
* I don't know all the variation of EVO pistons and differences, there are many. This is just as far as I know and IIRC. Excuse me if I'm wrong or missing some.

OEM Style Pistons :
Our OEM pistons are Art pistons (Art Metal Mfg), and OEM style replacement pistons are NPR (Piston is NPR of America, Ring is NPR Japan), EngineTech, ITM, DNJ, Topline, Nippon Racing, YCP etc. Not all of them are from the same factory but some companies share the same pistons like NPR pistons and EngineTech pistons are the same. If you see a logo with a "S" inside of a "C" at the back side of piston skirt, those pistons are manufactured by the same factory as NPR pistons, which is Cheng Shing Piston Taiwan.
* P.S. Riken (Mitsubishi OEM piston ring) and NPR will integrate their management and will become NPR-Riken Corporation in 2023.

Don't confuse Nippon Piston Ring Co Ltd (NPR) and Nippon Racing Ltd, they are two totally different companies. (I even doubt if Nippon Racing Ltd really exists) I am not talking which one is better, but the one that have been proven by many DSMers for long is NPR, not Nippon Racing. Many people are confused because of the word "Nippon" and Nippon Racing piston kits are often combined with a NPR ring set when they sell. Nippon Racing is basically a eBay brand. The box says "Made in Japan" but they are not.. (I am not here to discuss about their product quality)

EVO Pistons :
EVO 1/2 pistons directly fit in DSM 7 bolt. They would make the compression ratio 8.5 the same as 2G DSM.
EVO 3 pistons directly fit in DSM 7 bolt. But they would make the compression ratio 9.0 and those pistons are well-known as problematic with ring land, so you should avoid to use those pistons.
EVO 4 pistons are forged (I haven't confirmed it by myself by Mitsubishi service manual, but it's commonly said in Japan). The pistons were supposed to be revised from EVO 3's but it didn't work well and are still well-known as problematic, so you should avoid those pistons, too.
EVO 5 pistons returned to be cast. Piston skirt coating, and the shape was changed from round skirt to reduce friction and weight.
EVO 6 pistons started to have oil cooling channel.
EVO 7 pistons have more durable (thicker) ring lands and thinner 2nd and oil ring to reduce friction than EVO 6's.
EVO 8 pistons are made with better material and coating on top ring land. More durable reinforced piston skirt than EVO 7's. Piston top dish volume is reduced and compression height is lower than previous pistons.
EVO 8.5 pistons have better oil cooling channel and better oil controlling than EVO 8's by having different shape between 1st and 2nd ring land and different material/tension with 2nd ring.
EVO 9 pistons have different oil control ring.

The proper way to safely use the late EVO pistons in DSM/Early EVO is enlarge/deepen intake valve pockets for DSM/Early EVO (I am not here to discuss if it's necessary or not). And should replace the oil squirters with matched ones with the pistons for the cooling channel if you have a 1g or early EVO's block. If your pistons are DSM/EVO 1~5's, 1g 7 bolt oil squirters should work fine. If the pistons are EVO 6~9's and if you want to have better piston cooling effect, then you need matched EVO's longer nose oil squirters. Without using the cooling channel, you are not maximally using the late EVO piston's ability but it's not a must.
The static compression ratio with the late EVO pistons in DSM should be somewhere around 8.2~8.5. EVO 8.5 and 9 pistons would make a couple of tenth higher than EVO 4-8's.
(It would depend if the valve pockets are enlarged/deepened, piston size, gasket thickness and how much material you have removed from head/block)
As for the piston weight, the late EVO's pistons are technically lighter than DSM/Early EVO's since design is more modern and they are not steel strut pistons like ours. A EVO 9 piston itself is about 25g lighter than a DSM/Early EVO's piston but the EVO 9 wrist pin wall is thicker and heavier than DSM/Early EVO's. So in total, usually a EVO 9 piston w/ a wrist pin would be approxi 14~15g lighter than DSM/Early EVO's.

OEM Rods :
DSM 1G 7 bolt, 2G and EVO 1/2/3 rods are the same.
EVO 4/5/6/7/8/9 rods are shot peened, and about 15% more durable against metal fatigue than DSM and EVO 1/2/3's. (There are different ID marks on rods but they are basically the same. There is no difference on performance)
OEM Crankshaft :
DSM 1G 7 bolt, 2G and EVO 1/2/3/4 crankshaft are the same.
EVO 5/6/7/8/9 crankshaft are slightly lighter than DSM and EVO 1~4,'s and rod journals are induction hardened.
 
Last edited:

Spleen8urLSX

Proven Member
268
173
Dec 26, 2017
Elyria, Ohio
I have a set that were freshened up like 6 months ago, I was gonna do the same thing for a "stock" rebuild but once I put them in, I realized the machine shop ordered NT pistons. So if you want, I have a set for a decent price, and you can keep the NT pistons for a paperweight
Put out over 400whp and 20k miles of boost on some of those paperweights, and the kicker is the seal blew on the oil filter mid pull and blew the oil out and wiped out some other stuff, but the 130k mile paper weights still look great. I have a brand new set pressed on to some rods ready to go for my new 6 bolt but I’ll take a spare set if you’re giving them away!
 
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