A few questions about rebuilding a 6G72.

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10-13-2010, 01:39 AM
terrets

A few questions about rebuilding a 6G72.

Ive got a few questions about rebuilding my 6G72. As some of you may know, I will be installing a T70 with all supporting mods this winter. I plan on also getting front and rear LSD's, an output shaft, drive shaft, and new T-Case. I plan on running AEM EMS Series 2 and would like to tune it myself but will probably be bringing it somewhere unless I can find some good starting maps.

1. So heres my first question....Anyone got and AEM maps they wouldn't mind sharing? Along with information on your car. Should I start an AEM thread or would someone else like to?

2. Whats the best way to break in my motor...I know you've got to be pretty heavy on the throttle and do engine braking...But I am getting a new clutch and I want to know if this is alright for it without being broken in?

3. Would you suggest that I rebuild my motor and keep the stock twins on it for the break in period, or would I be alright with putting the T70 and all on right away and throwing her on the dyno or driving it right away????

4. What do you guys suggest for rebuild lube when I'm putting everything together?

5. How hard is a tranny rebuild with installing new synchros, LSD, and output shaft? Ive never done one but Im pretty smart and a quick learner. Anyone got and good guides?

6. How do I know what bearings I will need? I will be using a forged crank from a 94 N/A motor with about 128k miles on it and probably no rebuild....I will most likely be getting 3sx H-rods.

7. Is it easier to pull the motor out the top of the bay, or remove the front bumper and stuff and pull it out the front?

8. The motor thats in the VR4 has about 187k and I was told it was rebuilt last summer and I know this to be true because I looked at the bearings and they had virtually no wear...It looks like its been stock all its life....What do you guys consider to be part of a normal rebuild? I plan to at least bore the cylinders and possibly shave the heads...Also polish that crank from the N/A of course. Is there anything else I should have done?

9. Relates to #8. Is there anyway to check the valve seats to see if they need to be machined or not?

10. Do you believe it is imperative to get new crank and head bolts? I probably will anyways just to be safe.

I think thats it :lol: I'm sure Ill have more later on. :D

Thats a lot of questions but hopefully this thread will also help out others wanting to rebuild. I want to thank you all in advance for your time and answers. I'm loving the new site and EVERYONE on it :D. You guys help me out and you'll be sure to see me at the 2011 NG with a T70 and E85. :w00t: Maybe Ill let you drive it ;). You'll atleast get a ride if requested :D. I'm hoping to run drags and possibly autocross (If I can get off work).

Ill be sure to take a bunch of pictures and post my project up either during or after its complete. :)

Thanks again and your time is GREATLY appreciated :D
10-13-2010, 01:20 PM
terrets

Day :bump: :D
10-13-2010, 03:18 PM
Austin@STM

Everyone has there own way of doing things. Heres what i can say from experience here.

Ricer our shop Evo has gone 9.2@156, We put the car together started it up made sure everything was good and it ran for a total of about an hour before we drove it from the back of the building to the dyno (we changed the oil first). On the dyno we went straight into full power tune which at this point was a little over 600whp on our dyno. This was on new clutch, new trans, new transfer case, new rear end, and all new longblock. After that the car went straight to the track in North Carolina running a 9.7 or 9.8 i believe on its first pass.

Shawna's black Evo seen here http://www.3sgto.org/showthread.php?...light=4g63girl is a similar story, In less than a week we tore it down put in all new drivetrain, clutch, and longblock. Within an hour of start up it was on the dyno pumping out 587whp, and a couple days later went to the track and ran 10.0.

As far as knowing what bearings and other parts you will need, that is up to the machine shop. Find a shop you can trust and talk to them about what you want. They will figure out how much things need to be ground or bored and tell you what size parts to use as replacement. They can also check the heads to make sure the valves are flat and straight, as well as the valve guides.

I can explain myself better later, im just in the middle of a few things but wanted to give you something to think about.

-Austin@STM
10-13-2010, 03:34 PM
terrets

Thanks Austin. I can always count on you :D. Your so awesome. haha. I wish STM was closer cause I would sure as hell have my car dynoed by you guys.
10-14-2010, 03:25 PM
billbrown72

you don't have to break a motor in but its always best to...each car is differant but if it was me and I( which i soon will be because of blown headgasket) would do atleast a 500-1000 mile break in to let rings and everything seat properly...with as much money as you are about to throw at it do you really want to beat on it as soon as you finish build....as far as headbolts I know stock ones cannot be retorqued so new ones are not an option (it all depends on which were used during recent rebuild)..
10-14-2010, 04:39 PM
mb3000

Quote:

Originally Posted by billbrown72

you don't have to break a motor in but its always best to...each car is differant but if it was me and I( which i soon will be because of blown headgasket) would do atleast a 500-1000 mile break in to let rings and everything seat properly...with as much money as you are about to throw at it do you really want to beat on it as soon as you finish build....as far as headbolts I know stock ones cannot be retorqued so new ones are not an option (it all depends on which were used during recent rebuild)..

IIRC it is actually better to "Drive it like you stole it" when dealing with a new engine.
10-14-2010, 11:21 PM
MaxClass

Some notes by your numbers.

2. Break In? Read this first. He suggests a very specific method of breaking in a new engine and most seem to agree with him. He states that you only have about 20 miles to seat the rings or else.

http://www.mototuneusa.com/break_in_secrets.htm

4. RedLine Assembly Lube

6. Stock rods are good to 700 hp from what I have been told. Why pay more?

7. Take it out the top. It’s really easy once everything is disconnected and the hood is taken off.

8. Make sure any one who does block boring uses “Torque Plates”. Stock oversize pistons should work beautifully but Wiseco pistons are highly respected in our cars. If you go with Aluminum [full floating] pistons you will need to have oiling holes added to the small rod ends. Any shop can do that. Only deck the block to square it up. Have the crank checked and reground to maybe 10 under and polished but only if it needs it. That will bring it back to just like new. You might consider have the entire crank assembly balanced. Not that big a cost for what you get back.

9. If you pull the heads off you might as well have the valves done. Don’t do the bottom end and ignore the top end. A valve job is not that expensive along with new valve seals, etc. Might also consider Stage 2+ heads or something like them [3SX or DR]. Many 600 hp+ cars are still running stock heads so it depends on the final numbers you are looking for.

10. You didn’t say what year the block is [2 bolt or 4 bolt]. If 2 or 4 bolt go with ARP Main Studs to beef it up. Also ARP Rod bolts. ARP Bolts are the best you can get and they cost more and you get peace of mind. Word on the street is that stock head bolts are plenty strong or you can go with ARP Head Studs for Max hold.

Hope this helps somewhat.
10-14-2010, 11:27 PM
DocWalt

Stock rods aren't good to 700 if you expect it to last. I'd say anywhere after 500 should be upgraded if you plan on beating on it. Matt M. was running 660 or whatever on a bone stock engine with the DR750s, but that's a very rare case of a good tuner and a good car working well together and not blowing up.
10-15-2010, 01:41 AM
terrets

Ya MaxClass Ive read that article :D. I believe this guy too.

Im going to go with rods just to be safe because Ive heard a lot that rods are the first thing to go in our stock motors. I also plan on new pistons. Wiseco or Ross.

I dont want to go with heads yet just because they are so expensive...Im alright with the HP goal of 600 and Im VERY postive I can reach it with my setup. Plus I can always upgrade the heads later :D. I feel the moneys better spent on the drivetrain :).

I feel I have to agree with Doc on the rods. :)

Thanks for all the answers guys :D
10-15-2010, 02:32 AM
terrets

Thanks steve....I dont want to run the turbo on this motor because it has a knock :/ I know its a rod knock too. And Im sure the crank is junk/out of round. And I dont want to spend time rebuilding it just to put stock parts in and then break them :D.
10-16-2010, 11:07 PM
mb3000

Quote:

Originally Posted by DocWalt

Stock rods aren't good to 700 if you expect it to last. I'd say anywhere after 500 should be upgraded if you plan on beating on it. Matt M. was running 660 or whatever on a bone stock engine with the DR750s, but that's a very rare case of a good tuner and a good car working well together and not blowing up.

Doc, is the car in your sig yours? I remember you trying to sell your vr4...
10-18-2010, 09:33 AM
Ondonti

Stock rods don't like torque, and I think a T70 will make torque. They also don't like a poor tune. They don't break from RPMS, they break from torque and detonation.

Follow the mototune breakin.

The clutch issue goes 2 ways in my opinion.

If you are running an organic disc, breakin is important. If you are running an aggressive non organic disc, its not important. A performance clutch that is not organic should hold the first time you slip it hard and let out.

You will be running low boost while you seat the rings so don't worry about the clutch either way! You are not doing full RPM blasts on your first hit.
10-19-2010, 02:03 PM
Austin@STM

Quote:

Originally Posted by Ondonti

Stock rods don't like torque, and I think a T70 will make torque. They also don't like a poor tune. They don't break from RPMS, they break from torque and detonation.

Follow the mototune breakin.

The clutch issue goes 2 ways in my opinion.

If you are running an organic disc, breakin is important. If you are running an aggressive non organic disc, its not important. A performance clutch that is not organic should hold the first time you slip it hard and let out.

You will be running low boost while you seat the rings so don't worry about the clutch either way! You are not doing full RPM blasts on your first hit.

True, this is why it is good to read all your directions. Usually it will say a specific break in pattern if there is one, every company is different though.
10-19-2010, 09:35 PM
Ondonti

The thing is, many performance clutch companies just claim that you need to do it so they can have a reason not to warranty their product...even if its not necessary.
10-20-2010, 10:14 AM
Austin@STM

right, but most people like being covered
10-20-2010, 10:33 AM
DocWalt

Quote:

Originally Posted by mb3000

Doc, is the car in your sig yours? I remember you trying to sell your vr4...

Yeah, it is.