If a 4g63 engine has close to over 100,000 miles on it and you replaces pistons, rods and cams with forged ones so basically building the bottom end would it be considered almost a new motor? would it be safe to get hp gains from a built motor with high milage? If not what would need to be done IF anything to reproduce reliable hp gains from a high milage motor?

 

Rebuilding the bottom end with forged components would basically make it a new motor if your head is in good condition.

 

Im curious as well, bump

 

+1

Also, the 4g63 can manage high mileage. There are now dozens of 100k+ mileage Evos out there. Many with high horsepower.

 

im in the stages of considering building a higher hp evo VIII but it has over 100k miles, tranny is solid and body is clean, i found one for $13k so ive been pondering selling my gts and doing a built motor with an fp red or 35r.

 

then why the hell am I worried about hitting the 30k mark?

god I'm a *****.

 

Yea I wouldn't do drop ins at that point but a full engine overhaul with machining and such and yes your bottom end will be like new and ready to push big power.

After tanking, machining, painting, etc.... There is no difference between a 100k block and a 30k block

 

I hit 100k while on the dyno! It is at 103k now, and running like a champ everyday! Our winter autox season schedule just got finalized, so I'm readying her for it! Mileage isn't as important if the car has been well cared for!

 

when you say drop ins, you mean upgraded turbo, injectors etc? Id do all mods after doing an engine overhaul, that would be my main priority is build the engine and make it strong and reliable before an fp red or any other high boost mods.

edit: My goal essentially would be in the 450whp range reliably. what about e85 after rebuild, should be fine to run right?

 

just do stock compresion, aftermarket pistons,rods, do springs/retainers. Make sure to machine the block.. and replace all the drive train belts...

rods will be stronger and pistons, plus springs and retainers to the head i dont see why it woulnt last longer,

 

When you do a rebuild like that, you are replacing all the parts that are suspectible to wear over that kind of mileage. The major things like the head, block and crank should be checked for any faults or damage. The block gets bored a bit to make sure the cylinder walls are smooth. IF they pass the test, then yeah, its almost like a new engine.

 

"drop ins" are standard bore pistons. I wouldnt use those on a block with more than 35K
When a block is built correctly, it is blueprinted. At that mileage, overbore is necessary to ensure straight and even cylinder walls with proper hone and piston/wall clearance.

Cylinder head may need valve seats depending on the pitting, or valve springs previously used (ie high pressure). Valves also take a beating. Hope this is helpful

Blueprinting will tell you if the block is usable, as it will be brought to spec and checked for warpage and such.

 

+!

I'm such a ##### too!

 

when you machine ,balence, and replace a bottom end you no longer have a high mileage motor. Just make sure you go to a reputable machine shop or engine builder if your not assembling your self.

 

you will probabaly also want to keep an eye on the drivetrain with that kind of mileage on the car....and if you are going to replace that and build the engine, then why not just buy a newer evo?