Fresh 6 Bolt Rebuild Want Input.

[Tanro]

This is my first 4g Rebuild. Looking for some input and opinions. My goals for now is a Reliable 6 Bolt that can push 275-350 Horsepower with no problems.

What I am starting with :

1991 Eagle Talon 4g63 6 Bolt
Brand New Head. Idiots installed a new head on a bad block.

I cracked into the bottom end today and every single bearing was spun. Crank is gonna have to be turned. Its got Head Studs that need a big fin hex key to get off so I dont know what the valves look like yet.

So piston / rod combo.

I am thinking Wiseco or JE on Eagle Rods. What compression ration is good?

I was under the impression that 8.5:1 was perfect for a turbo engine. Can I go higher in my 4G63 or would 8.5:1 be best for a daily driver.

If these studs are ARP can I reuse them? what do ARP studs look like for this engine? Can some link a pick of them installed in the engine?

Do I need to go with a Fel Pro MLS Headgasket or will Fel Pro OEM Replacement be enough for my Horsepower goals?

 

[95burgundyesi]

Stock 6 bolt will be very happy with 350whp. The weak part of a stock combo are the rod bolts. Go ARP rod bolts if you are pushing the 6 bolt to the max(500whp) for comfort.

8.5;1 is a great compression ratio, spools things up nice and will be more forgiving on a tune that is not spot on. 9.0;1 is also doable on pump. Anything higher is not so great on pump gas. But e85 is always an option. 2g pistons are 8.5;1.

You already have arps since they are studs with hex on top. They can be reused as long as the studs do no stretch. I am not sure at what psi they will stretch, but I run 30psi, and it has been over a year with a 20 dollar felt felpro head gasket.

 

[donniekak]

The stock 6-bolt headbolts take a 10mm hex to get them off. Get another crank, if all of the rod bearings are spun, the crank is junk. If you had some good rods to start with i would recomend building it to stock specs. But, i bet your rods are toast, and the pistons are scored badly. Either get a good 6-bolt shortblock and do the rings, bearings, polish crank, and resize the rods for arp's, or do a common eagle wiseco build with the block you have.

 

[FLASH1970]

Compression ratio all depends on how you tune it and how much boost you want to run. A lower compression piston will be more forgiving to tuning and boost. But anywhere between 8.0:1-9.0:1 and you should be good. Stock 1g pistons are 7.8:1 and 2g pistons are 8.5:1 as stated.

As the others said, you don't need anything crazy for 350hp. 350 is the goal I'm going for with my DD/ auto-x 6-bolt car. I'm going with ARP Head Studs, ARP Rod Bolts, forged Wossner pistons (8.0:1), stock rods, tri-metal bearings, stock crank, MLS headgasket, OEM Main Bolts. I chose the lower compression Wossner pistons becuase they were cheap and I plan to learn tuning on this engine and wanted a little more forgiving setup.

That setup is good for 500-550whp easy. People have made 600whp on 6-bolt rods. Maybe even stock pistons too... I don't remember. The thing about the 2g pistons is that you have to machine out your rods to accept the bigger wrist pin. So, if you buy new OEM 2g pistons and machine out the rods, you could have gotten a forged set of pistons for 50-75 bucks more and had an engine capable of handling another 75-100whp. The cast 2g pistons can handle about 450-500hp. Just something to htink about.

I hope this helps.

 

[Tanro]

Thanks for all the input. I have a good idea of what to get now.

Going with Turned Crank
ARP Rod and Head Bolts
Fel Pro HG
8.5:1 2g Pistons on Stronger 6 Bolt Rods.

Planning to do an E-85 Tune at some point. E-85 is only 2 cents more a gallon than Unleaded at my regular station.

 

[95burgundyesi]

You can always use evo pistons too, they are stronger than 2g pistons and also require machining. Cost me 50 bucks for all four rods to be fitted with 2g pistons. Vfaq has the print out to bring to the machine shop.

 

[Tanro]

Trying to build a Good 6 bolt for a Daily on a Budget. Not looking to go over 15 LBS of boost...

Also head still looks good. Carbon build on the valves (very light) but they are all straight. Will try and snap a pick or two and upload them tonight.

 

[jnf63]

I had a similar situation occur to me regarding all my bearings getting spun. My initial motor was a 7-bolt, but I have chosen to rebuild with a 6-bolt, meaning my research pertains to a 6-bolt. My situation occurred during a transmission shop’s test drive (so they say). Anyway, I recently had done a lot of research, a bunch of calling (several supporting vendors), and a good amount pm sending to Wisemen. Although it is definitely your decision to make, I can offer you what I had learned. In regard to your current 6-bolt crankshaft, be careful about using a “cut” (turned) crankshaft. I had been convinced by several sources to go with a new 6-bolt crankshaft. I learned that going new is the "better" choice for reliability and durability. In contrast, a remanufactured (turned) crankshaft might be all right, yet the probability for its trustworthy reliability would be a trade off for the saved expense (according to Vendors/Shops not offering a remanufactured crankshaft). The Vendors/Shops that did not offer a remanufactured crankshaft explained that they omitted such an offer for a reason (dependability). I was informed that the choice was mine (like the choice is yours), but that saving on a remanufactured crankshaft was not the "best" place to save my money during a small block rebuild. For a 2.0L 6-Bolt, I learned the options included Eagle, Manley, and OEM (listed as a few "lower costing" [yet dependable] new crankshafts; for example; "JNZ Tuning Online- OEM Mitsubishi Parts"). I had been told that even finding a good crankshaft from a donor vehicle (junkyard) would be all right where it did not need to be cut. Many of the DSMtuners posts that I read involved explaining the benefits of using a new crankshaft. Obviously, some posts did suggest doing what a specific budget allowed. Because this is a greatly debated decision, I hope this helps in your decision process. The other parts on your list represent pieces that were recommended to me as good alternatives.
Jim

 

[Tanro]

Sorry but turned cranks are FINE unless you are going for big Horsepower.

The coating on them is .030 I am getting mine turned .010. and then micro polished.

Total cost of my machine work is estimated 174$ plus some change and then tax.

That includes my crank, block, and head. Head and block are being resurfaced. block is getting bored .020 while head is getting port matched to gaskets. And the crank is being turned.

I can get all that done for less than the cost of a new crank. I simply don't have the money for a new crank. If it took the car (had 147,8xx on the odo) nearly 150,00 miles to #### the crank up bad enough to need to be turned then I think I am okay for at least 75,000 miles on a turned crank. 75,000 miles should last me 3 years if I exclusively drive that car.

My daily has had 23,xxx miles put on it in the last year. So If I am going to be daily driving the GST only then I can expect the same mileage. GST + Saturn = 11.5k miles a year per car.

Hmmmm I think I can go about 7 years on that crank then. I am sure that something else will #### up long before then or I will have my 2.4 Crazy Built Stroker Ready to go in before then.'

Edit:

I would sue the transmission shop for that shit you posted pics of. I have never seen a single bearing that bad. Much less all of them. One of mine has pitting, and the rest have mild scoring. No torn bent or twisted ones. I would upload pics if my camera cord wasn't in the car. Buddy took it out for the night.

 

[jnf63]

Tanro,
You definitely are more informed than I am. I am a novice, and I had been "easily" convinced over the debate of using a new, or a remanufactured crankshaft. I ended up going with an Eagle crankshaft (Scat rods, Wiseco pistons). Your '91 Talon's mileage is a huge factor as well. Being more informed, like yourself, surely allows for a better budget built.

As you mentioned, I shall be pursuing civil action towards the shop. I am in the process of gathering all the necessary information about my ruined engine's condition (all the oil related parts) prior to the shop having it, and then after they ruined it (the pictures show the result). The engine had only 2500 miles on it before the shop did this to it. I want to be properly prepared in court since it is a large sum of money for repairs (the entire motor was ruined).

Have a great time with your build, as well as using it after it is done.
Jim

 

[Tanro]

Here is what my bearings look like.