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1G Help Choosing a Motor

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luisgil

Proven Member
156
2
Jan 10, 2013
Paterson, New_Jersey
Hey whats going on. I need some help choosing what kind of motor would be the best choice for me. I have a 1991 Eclipse GSX. Im trying to figure out if its best to drop a 7 Bolt in or a 6 Bolt. I want to make around 450-500 HP with all supporting mods. the 1g 7 Bolts tend to be easier and cheaper to find but is it worth it? Or should I just spend the extra money and build the 6 Bolt.
 
I'm a firm believer that 7 Bolts have far too bad a reputation for what they are. Proper blueprinting, assembly, and adjustment of your clutch all will minimize the chance of things going wrong in a 7 bolt engine. Ensuring oil pressures are correct and conducting proper maintenance all are key as well. Also, many believe that the 2G oil squirters are a root cause of the issues with the 7 bolts, which will not be the case with a 1G 7 bolt motor. I just had two 2G spin rod bearings within a couple of weeks of each other, so one is now being built with a 1G 7 bolt shortblock and upgraded internals. In all fairness, it's going into an auto, but I have confidence that it will last me another 100K plus miles.
 
6 bolt will hold your power goals with NO upgrades, but if you want to do some then it will just be even stronger. MTC
 
I'm a firm believer that 7 Bolts have far too bad a reputation for what they are. Proper blueprinting, assembly, and adjustment of your clutch all will minimize the chance of things going wrong in a 7 bolt engine. Ensuring oil pressures are correct and conducting proper maintenance all are key as well. Also, many believe that the 2G oil squirters are a root cause of the issues with the 7 bolts, which will not be the case with a 1G 7 bolt motor. I just had two 2G spin rod bearings within a couple of weeks of each other, so one is now being built with a 1G 7 bolt shortblock and upgraded internals. In all fairness, it's going into an auto, but I have confidence that it will last me another 100K plus miles.
Im thinking if anything a 1g 7 Bolt. How are the compression differences. Personally I lean more towards the 6 Bolts because the 7 Bolts have a bad reputation. But i also understand the 2g 7 Bolts and 1g 7 Bolts are slightly different as well.
 
Im thinking if anything a 1g 7 Bolt. How are the compression differences. Personally I lean more towards the 6 Bolts because the 7 Bolts have a bad reputation. But i also understand the 2g 7 Bolts and 1g 7 Bolts are slightly different as well.

Per a DSM Wiseman on this thread: http://www.dsmtuners.com/threads/1g-7-bolt-pistons.440577/
The 1g 7 bolt pistons won't effect the compression. They are the same compression ratio as the 6 bolt pistons which is 7.8:1 . 2g pistons are higher compression which is 8.5:1.

It's important to know that crankwalk means thrust bearing failure. The 1G 7 Bolts don't really have that reputation, and I'm pretty sure the thrust bearing design is a bit different on 1G 7 bolts. Maybe someone else can chime in on that. My point really is that 7 bolt doesn't = bad and the chances of premature failure to CW is minimal if you do it right.
 
Personally i would go with the 2g 7 bolt due to my experience with it and how it's never failed me as long as i kept up with my proper maintenance and not beat the piss out of it. Just my opinion though, many factors can ruin any of these engines soooo:idontknow:.
 
I'm at most thinking maybe 2g pistons 1g rods with a fully built head. I just want to make sure I wont regret the 7 Bolt later on.
If that is what you plan on building, why not just use a 6-bolt?

Either engine would be fine for your goals with some h-beam rods and forged Pistons. The 6-bolt engine with a freshen up will support that power goal, but will be a little over the 400hp I like to limit stock internal engines to.

Spending money to make 6-bolt rods work in a 7-bolt isn't really worth it.
 
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