Anyone ever do this? Since rods are the main failure point, im thinking of throwing in a set of eagle rods or maybe something a little better quality in the near future to handle some more tq. I am not shooting for 800 whp or anything crazy, just would like the peace of mind knowin the rods wont snap at 450 wtq. Thoughts? I dont want to pull the motor to do machine work, so dont bother suggesting aftermarket pistons. Car has 72k on it right now and gets driven about 100 miles a month in the spring-early fall.

 

Just a question. Since you have to pull the head anyway to remove rods,why not get drop in pistons?

 

Not sure they would work with 72k miles of wear and i dont really want to do new piston rings an a hone if i dont have to

 

I see the value in using stock pistons due to the wear and clearances being great for longetivity. You cant use most aftermarket rods because they are a floating pin and the stock pistons are a floating style with no retainers. The stock rods use a press fit at the pin to hold it in.

You could have the stock pistons machined with a ring groove to hold the pin in place and use an aftermarket rod. Other option is a press fit rod like a stock rod out of a 1G 6Bolt 4g63.

I have done a rebuild using stock evo9 pistons and 6bolt DSM rods machined to fit the 7 bolt evo motor. The rods are much stronger and will not be an issue. I got the rods from DSM Graveyard. I do not recommend not honing the block and replacing the rings with 72K on it. I have heard of people popping out pistons to check them and reinstalling them no issues but I have little faith in that. I redid a low 30K engine and I pulled it and had the block honed and replaced the rings. Then let the 9 turbo eat on e85 with no worries.

 

Do you feel drop in pistons are reliable?

 

If you hone the bore and use the proper ptw along with ring gap, yes.

 

So to set up the proper ptw clearance would i just hone the bores and measure and call the piston mfg to get the correct pistons or do i need to hone the bores to the pistons? This will be done in my garage with the engine in the car...

 

I'm glad you started this thread b/c I'm in the same boat. My intake manifold and TB are sent off to STM/Buschur right now and it will be a few weeks before I get them back. So I've been contemplating about leaving the block stock, replacing the connecting rods/pistons, or building a 2.3 stroker. Ideally I'd like to just replace the conrods/pistons right now and build a 2.3 when funds become available. However, I'm also at 75k and am skittish about the results.

I've read through all the posts about this topic and it seems we'll be taking a chance on drop in pistons. Although it seems like a lot of people have success with them. From what I've read, 75k is the most miles on an engine that Buschur has dropped in pistons. I've been running a gt3076r for a couple years at 28psi; so I'm unsure how this may affect the cylinder walls.

What turbo/setup are you running? Whatever you end up doing, please let us know how it turns out.

 

I would never replace pistons and rings without removing block and having it honed.

 

Food for thought Evo8john...

If BadEvo can run well over 650hp+/500ft lbs+ torque on a stock block, it might be worth just getting a good tune and sit on the stock block until you have the $$ to pull your engine and get your block bored... etc.

https://www.evolutionm.net/forums/ev...-evo8-9-a.html

 

That's poor advice, at least anything past 500WHP on a stock block. The stock rods begin to bend like a banana and then go through the block.

Build it once and right.

 

BadEv0 is the exception. He did have a good tune as well as a lot of weight reduction. He also said in a recent thread that one of the rods was slightly bent. I say he rebuilt it at the right time

 

To the OP. I've tuned several cars at 450 TQ on a stock block, but I dropped them down to 420ish TQ for a safety margin. Have you been in an Evo with those numbers? You may be happy at 420 TQ.

I too have thought of using aftermarket rods with stock pistons for several reasons.

1. To handle more torque.
2. Less wear. Forged pistons can cause piston slap until warmed up.

It seems built engines last 50K miles or less. I'm sure it has a lot to do with high HP/TQ (why would you build a block for low HP/TQ) and cause the bearings to take a pounding.

GL!

 

It's better advice than what you're offering. You didn't even address his issue. The 4g63 has proven itself to be a strong block. If tuned right, it can withstand a lot. This topic has been discussed several times over. You have your options. Evo8john obviously doesn't want to pull his engine. So rebuild is not an option. That leaves you with two options: drop in rods/pistons or leave it stock. You take a risk in either case and I suggest to leave it stock and get a safe tune. So how is that bad advice?

 

According to one post, his car's weight was 3050lbs and he wasn't interested in further cuts ie removing his rear seats. Hardly extreme since curb weight is what... 3400 ish?