Lol nothing on the people here, but i found it funny that this thread is right on top of this.

https://www.evolutionm.net/forums/ev...ml#post8131489

 

The same tuner, tuned "junction" 's car which has broken the pistons so what is your point?

I think SiC and Tephra already mentioned how piston ring wear on an older engine could increase the ring gaps, preventing this issue.

As we have noticed, our highest 500+whp Evo X stock engines are also 20k miles and older.

 

^That could be, my motor has 22k miles now and seems to be running strong at around 475whp.

 

I wasn't aware of the fuel pump relay issue until after the second engine break. Mitsu never looked or asked or anything, so I'm assuming it's the original.

 

I want you all to compression test your motors and report back.

I'm 160, 160, 160, 150 on #4. I am really seeing a trend between this thread and others involving the 4th cylinder. (I am FP Red, AMS everything, 10K miles).

Also, for the people who get their motor replaced and then it blows again... didn't AMS write an article about something with the oil cooling system housing blow-up debris that will cycle into your new motor and blow it up right away?

Lou

 

Funny when i replaced my spark plugs last week, I took out the first three plugs, they were warm but fine... on the cylinder #4... it noticeably hotter.

 

My guess is the difference is in the gap tolerance. The ones that hold together are on the loose side of the tolerance, the ones that don't are on the tight side.

I know for a fact my failure had nothing to do with the relay as I have logs of afr, boost, egt, etc etc from the failure.

 

Everyone I've seen so far that has blown a motor has had the original fuel relay in or had just swapped to the new one and boom. Also another reason I believe it to be a lean condition is due to the location they are all busting. I don't think I have seen one yet that wasn't right on top of the exhaust valve relief which in a lean condition is the hottest part.

I don't know about you guys but I'm going to just keep an eye on my fueling and run the **** out of my car like I've been doing. I suggest others do the same and invest in a wide band instead of pistons.

 

I like this idea on doing a compression test. I have a tester but no garage and its still a little too cold to be working on my car here. I intend to do this. That is interesting that you dropped 10 in #4. Very interesting. Have you ever had a spark plug ground strap get closed or hear metal bouncing around your engine?

I cant wait to see what my results are. I have had #4, twice, and #1 piston, once, chipping so far so... should see considerable drop in #4 and a slight in #1.

 

My spark plugs look fine, and the car hauls ***. But it's extremely strange to me that #4 is down 10psi where the other 3 are perfect. I run AMSoil, every 3K on the dot, etc... very conservative tune with max timing of 14 degrees BTDC.

I'm going to leakdown test on Tuesday (Harbor Freight shipping SUCKS) as soon as my testing equipment gets here.

Lou

 

If it is JUST a ring gap issue, then how do you explain the 4G not having the same issue given that the ring gap specs are nearly identical??????


Cyl 4 running lean? Weakness in the piston itself and not a ring issue?

 

i've noticed a lot of #4 piston problems in engine failures in general. could it be motor placement with heat being trapped causing it to heat up? maybe accessories near the #4 like exhaust flange too sharp of a curve causing restrictions and heat?

i'm almost glad i'm broke and can't mod and can only afford to maintain as of now.

 

I've experienced the same with other inline 4 & 6 engines. The last cylinders seem to run the hottest causing those to fail. But usually in those cases, there were signs of detonation. In this case, there are no signs of detonation so I don't think heat is the issue here.

 

Have any Ralliart owners had this "issue"?

I haven't heard of one, of course that doesn't mean it hasn't happened or I haven't seen it. Would be interesting to find out.

The Ralliart has no external engine cooler like the Evo (at least from what I could see from a quick look over) so I would imagine the oil get's a bit toastier. Of course most of the Ralliart guys aren't running the same cylinder pressure as the Evo's.

- Bryan

 

With inlines, there's definitely the potential for starving the last cylinder of air due to the intake manifold design, namely the air coming in from one end of the manifold and not 'making it' to the far end. Maybe a combination of exhaust manifold design too.

If you look at the V10 and V12 Porsche and Ferrari engines, the air enters the intake manifolds in the middle. Pretty sure Lamborghini too.