I am sending a 2.3 with 5k on it back to be rebuilt. Leak down showed 7% loss and 20psi comp loss. How long should these motors last between 450-500whp? No track days or launches. If this is common I'm going back to 2.0. Should the 2.3 last like a 2.0?

 

Just some basic knowledge tells me that the answer is a no.

*Someone will provide a more technical answer, but bear with what I have to say, lol.*

The 2.3L consists of a 100mm crank in a block with a smaller deck height than what it normally comes in (4g64). Because of the smaller deck height coupled with the larger crank stroke, the rods can't be long enough to optimize the rod/stroke ratio of that of a 2.0L, or even better, a LR 2.0L.

The less than optimal rod/stroke ratio increases the side loading on the cylinder walls, and thus, that department of things wears out faster.

Another cause of the long stroke crank in stock deck height block is the angle of the rods. The angularity of the rods in a 2.3L is very much less than optimal, which I believe is harder on bearings/side loading as well. This combined with the rod/stroke ratio also tends to put more stress on nearly every area of the bottom end, thus causing it to wear out faster.

It's common on extreme stroker motors across the board. For example, a 302 based 331 stroker is much more efficient than a 347 stroker (Sorry, I used to build Mustangs lol) for what I understand to be the same reasons that I posted above.

By all means, someone correct me if that information isn't correct, but I thought I'd take a stab at it.

 

Something was wrong. 5K miles is pretty much a new engine. There's a lot of things that could have caused it, but something wasn't right. (Rings never seated, rings weren't gapped properly, bad cylinder bore, etc.)

 

Mine has 40k miles

 

30K miles still going strong

25+ track days

50+ autocrosses

power between 300 and 500 whp

 

Yeah it almost sounds like the rings didn't have a chance to seat correctly, maybe. There are people who have stroker motors on here with 500-600+awhp and they are holding up fine with plenty of track days and daily use.

 

35k miles on mine(6 years use) and 155+ compression across the board. Seen a 35R, a 40R and now a FP Black. HP ranged from 350-625. Mine was built with budget parts as well.

 

poor leakage tests and compression test could be from poor valve sealing, no necessarily the block.

I would get those checked first and go from there.

 

7% is not needing a rebuild. Cranking compression can cart a lot and I would only go by the consistency of the readings.

 

who built the motor?

 

MAP. I pulled the motor and I have a badly bent rod? How can a motor run so good and pull so hard have a rod that looks like a "S"? Can detonation bend one rod? If so the bearings, valves and everything held better than the rod..lol. The bearing on the rod and crank look great. This motor purred. I'm sending it back for a full rebuild. The guys at MAP were very nice about it and gave me a fair price to repair it, but it will still cost. I will try to get pics of the rod. I've never seen a rod bend in two places. Its a stage 2 block also. The only reason I pulled it was a dark spark plug. I'm on a stock turbo @ 23psi. Everyone who has seen the rod thinks it was bad, but anything could have happen I guess. I should have a pic Wed or Thursday. Fun stuff!!!!

 

What rods were in the motor?

 

To much timing can bend rods or to much power outside of the rods limits can do this until it will eventually break. It's a great thing that the bearing surfaces were not harmed.

 

Also if detonation was that bad I would think the ring lands would show something as well. Did you happen to notice anything in the ring lands area?

 

Have seen this in a GMC Typhoon-- "s" shaped rod. Not discovered until motor was diassembled. Likely cause was weak rod and high torque of the motor. Cant say thats the issue here--just the same as whats been seen before.