Keith6110 1999 Reincarnated Galant

[Silvertune]

The 6g7 is not a 4g6, they make power very differently and different blocks take the machining differently. The 6g7 series motors are very sensitive to geometry and use a different alloy in the sleeves, they're put together with great factory quality and that it why they last for a long time but when you start messing with it they go south in a hurry. I myself have pulled apart a pair of 6g7's that were built with hand honed cylinders and drop in forged pistons that both ending up going up in smoke. You're dealing with 2 cylinder planes here, any amount you are off is going to cost you exponentially more.

Now, if the OP had the correct bore micrometer in hand I would have hesitated to say anything. I personlly don't believe in hand honing anything other then a daily motor you're reringing but with the right mindset and knowledge I also believe that to each his own. However, when going after large amounts of performance and spending lots of money to do it going about it properly is worth a whole lot more then the difference in price. The vibe I get here is an engine that goes from stock to built without leaving the garage and that just doesn't lead to success. The ARP mains don't typically tweak the girdle (though it's always a must to check) but the rods ALWAYS need resizing and while the pins may look like they fit the rods well they may need rebushing anyway.

I'm not calling anyone stupid but I've spent a lot of time and money in these motors and would like to see success for anyone else who chooses to do the same because contrary to popular believe there is a lot of payoff to be had.

[fatal1]

not to mention the surfaces mist be PERFECT in order to run the cometic MLS head gaskets otherwise there will be sealing issues causing hot spots and even leakage

[keith6110]

I rebuilt an excavator engine this way, but maybe its different in boost =/ what's a typical machining and balancing run? I assumed since the pistons are the only thing I'm replacing other than bolts, then the rods and crank is already balanced. What do I know lol, you're the pro.

[Galanttuner10]

not to mention the surfaces mist be PERFECT in order to run the cometic MLS head gaskets otherwise there will be sealing issues causing hot spots and even leakage

decked about 10 blocks with a cookie wheel and none have ever leaked, just have the heads done at the shop

[Galanttuner10]

if you want it all done, they will balance everything as an assembly. a good shop would probably be ballpark 700 with honing decking and cleaning, the align honing is very expensive, it was 250 for my block so maybe 1000 at a good reputable shop.

[keith6110]

Good reputable shop in starlight pa please! Lolz.

Thanks for pointing me in the right direction. I only want to do this once and I'd hate to learn the hard way by making mistakes.

[Silvertune]

Chances are you won't have an issue with the mains (though there's always a chance...), I've had my hands in 2 built 74's and neither of the girdles tweaked with the ARPs but the rod will need to be resized guaranteed. Boring and honing at my shop was 150$, decking was something like 120$ for a minimal cut. You'll spend a grand or so on machinework if you get everything done right but it's seriously the best grand you will spend on the whole build. Take it from me, pro work is price; going into boost is a big enough adrenaline rush when you don't have to worry about your engine, let alone when you do and you're going to worry about it anyway.

Putting that engine together without balancing would spell death immediately, it would rip itself apart before it was done with break in. The factory balance job on the 74 is good for 6k on the stock internals, it spins rod bearings religiously at 7k. Change the mass of ANY crank, rod, bolt or counterweight by more then a few grams and it needs rebalancing again. That said, putting in aftermarket pistons without a rebalancing will literally eat your bearings.

Building motors IS an exact science, dimensions and parameters have to be perfect in the world of performance and it's not for the sake of gaining horsepower but for the ability to support it and for a long time. DSM guys can whine about doing it cheaply when the fact is most of those motors simply get by because they don't make much torque and can make a lot of power on stock components. You with your V6 can make a crap ton of power and torque or barely anything at all on the same shortblock but if it isn't built correctly neither level of output will make it down the block more then a few times. I am eyeing your parts list with contempt but I will now shut my mouth unless otherwise called upon.

[keith6110]

Hmm... It seems like if I were to dump a grand into machine work, then I might as well get Manley/Eagle rods and a new crank. Then it would be the best grand I'd ever spend lol.

[Corey2kG]

Geez! Reading all of this is awesome. Um yeah sorry for the random post but yeah good work Keith. Does it right the first time lol

[spdracr]

Keith if u r going that far then like u said just do it once. No sense in rushing it. If u decide to get the machine work done then save up for the pistons and rods as well. I wouldn't think it is necessary to get a new crank but I'm still new to this correct me if I'm wrong please.

As far as decking the block with a cookie wheel isn't really the way I would do it. Cleaning the surface before a new gasket is what I use a cookie wheel for but not decking.

If there is so much money going into this then a lil more won't hurt.

[keith6110]

Lol, let's just say this is becoming project 10k for just the power end of it. I think I need a 2nd job xD

I'll look around for some rods and see where I can send my block to. Like most of you know, I hate other people working on my shit. So having it even machined by someone makes me want to stare them down saying "don't fuck it up". The thing I've learned is: if you want it done right, than do it yourself. I'd like to keep it that way.

[spdracr]

Then buy the necessary machines and machine it all yourself lol

[keith6110]

lol! I contacted a guy that builds big block v8's for race cars about 3 hours from me. He's done a 455 for my dads car and a 350 for my brothers truck. Both running very strong now and these were done 3-4 years ago.

So I think I'll have him machine my block, balance the crank, and do the rods. Then cross my fingers for another successful block lol.

[fatal1]

you really dont need the crank....also, the 72 rods are plenty strong however, it isnt a bad idea at all to go and get some eagles etc....it will just further guarantee the life and performance of the engine. at this point its really just pennies on the dollar really.... not to mention if you decide to go bigger or whatever, you know the motor is capable.

[keith6110]

I don't need to balance the crank? I thought silvertune said definitely yes for this lol. I don't understand balancing the shortblock otherwise.

[Dominicano]

well i think once you attach new rods and pistons to the crank that's where you have to balance it

[fatal1]

sorry keith i meant to buy the eagle crank, you absolutely need to balance the crank.

[keith6110]

Chances are you won't have an issue with the mains (though there's always a chance...), I've had my hands in 2 built 74's and neither of the girdles tweaked with the ARPs but the rod will need to be resized guaranteed.

Rods resized for the ARP's?
I'm not sure what everyone usually orders for the build but I got all the ARP's for a 3000gt vr4 as I couldn't find anything for the sohc specific 6g74. They seem to be identical to the oem bolts.

[Silvertune]

The ARP block hardware is identical for all the 24v 6g7's, this includes the rod bolts, main studs and head studs. Now the first generation 3/s block came with 2 bolt mains as the 3g/galant did, 3sx sells a "custom" main stud kit for those who wish to build the 2 bolt motors. The second and third generation 3/s and every 6g74 and 6g75 came with 4 bolt mains.

When you torque the ARP rod bolts they stretch less then the factory rod bolts do and the rod cap deflects differently, it goes out of round. Under the stress of compression this oval will cause the bearing to contact the crank surface causing it to spin and if not it will work away at the surfaces until it does spin. The same thing can happen with the main girdle when you put the ARP's in it. The shop will machine the journals in the rods and girdle to perfect round with the ARPs.

Look at the crank shaft, see the big counter weights? The entire lower end is balanced as an ASSEMBLY. When the piston/rod go up and down the counterweights on the crank swing the opposite direction so that the force is equal and opposite (or in factory trim, close enough that the strength of the internals can withstand the deflecting force). This takes out vibration and makes the engine rotate smoothly. This balancing is sensitive down to a few grams. When an engine is out of balance there is a net force on the rod journals on the crankshaft. This force causes the bearing to sling down against the crank shaft, eating them up until they spin. When the engine is balanced it is 100% unique. Each piston/rod combo gets a single orientation on a single journal on the crank, switch them around and the balancing is gone unless the weight is perfectly matched between them, and it never is. That said, the shortblock is something the machineshop should build unless you are a pro builder yourself. By the time they've measured and machined and measured again, putting the internals together and torquing it all down is only a few more bucks and you get the warranty with it.

The cylinder bore is equally as sensitive. If the fitment is not the correct tightness the piston can twist and flex in the bore, this makes quick work on the honing and wears down the skirts. Any significant amount of play will destroy the rings very quickly, especially under boost circumstances. This was the fate of Bj's 3.6, I know this because he sold me the pistons out of that motor and the skirts were tapered beyond anything I've ever pulled out of a motor that hadn't blown.

If the bore is too tight when the piston expands under heat it creates a type of super friction. This was the fate of the two 6g72's I have torn apart that were built by Ripp Modifications with drop in pistons. The pistons expand beyond the bore and create a massive amount of friction that creates more heat, more expansion and more friction. It completely destroys the cylinder bores and eventually cracks the crown off the piston.

The same can happen if your rings aren't gapped properly, if they expand too much then you get the friction and the same destruction.


As for the integrity of the 74 internals, the crank has been a part of a few 4 digit 3000gt builds so a magnus forged crank would really be the worst thousand dollars you spent on the motor. The rods never hurt to upgrade but they don't ensure anything under detonation and the factory 74 rods are good for a properly tuned 500whp. The OP's parts list needs some intense reconsideration to hit that number. Peak numbers are not a good goal with these motors, they are not designed with that in mind and take more reengineering then it's worth to try to make them do it. What they are designed for is a broad power band and adding the displacement of the big blocks only extends that. If you do it right you can spin a big turbo quickly and still get it to breath up high and achieve more area under your torque and power curves then people with engines making hundreds more horsepower. THAT is why these cars move so well given even a moderate level of peak output.

[keith6110]

The intercooler I'm using is 3in wide and with the JDM bumper I am only left with 1.5 in of clearance. So to keep the same bumper without making major mods to its appearance, I had to turn to the extremes.



Don't mind the bug lol!



Off with the original lower radiator support



We forgot how un-level the original radiator support was, so we made this level instead to make sure the radiator sits even as well.



Obviously couldn't keep the lower engine beam either without modifying it.




Shaved off for Intercooler clearance



Showing how much was cut off



Original radiator bracket was used over and welded on angle steel



Support for the upper radiator. This was so flimsy after the center "support bracket" was taken out. I couldn't believe how flimsy is felt and couldn't imagine it holding up my bumper without another support bar.



Welds on the back side of the new lower support



Finally, put some paint on it




Basically every thing has been moved back 2in. Btw, this box bar is wayy stronger than the oem crash bar.




Big thanks to my brother as always. He's a pro welder lol.