Thread: Got Rod Knock at the convention? Post it here...

you blowing any smoke from breather while engine is running, if not you got lucky, but either way i think there is ring damage from it definetly. Especially if you were throwing a spark plug tip around a bit, Usually they go right out when that happens so you probably faired well in that.

Just to let you know, two of my motors that i detonated and cracked ring lands still read 160psi and 175psi compression with bad lands but it was smoking out the breather pretty good and spitting oil out everywhere from it as well. Might want to check that as well.
I think you should really consider backing the tune down a little to give you some leway cuz your pushing it. Im not saying this to be negative but you are. I had a nice talk with wnwright about this as well last night. When your making 300whp with stock cams and only 11 psi you are right on the edge, it is well up there on the super efficiency but with that comes trouble. Might want to back that tune down some or at least the timing.

Neways hopefully there is no major damage. Cuz been there done that. It sucks. But thats what happens when you push the limits. Cuz ive done that, now im much more conservative. And being conservative doesnt mean you cant make some good numbers it just means its safe. Cuz i plan on making some serious numbers with my setup but it will be safe. Id rather make safe power than make the most power i possibly can out of it.

No smoke anywhere really to speak of. Maybe a tiny bit from the exhaust but not at cruising or anything. The ghetto blow-by filter I have (catch can just didn't make it on before the track) shows minor amounts of oil after a couple months of boosting.

Thanks for the info. Good to know. I'll make sure to check that when I take the engine apart soon.


I keep bringing timing back as I find situations that bring up detonation. I will continue to until there are no problems. I think I'm close but obviously could use a bit less. My problem is there's no timing map out there even close to what I need and I was sent out into the woods at first.

If I'm detonating and I remove timing to get rid of it which I plan on doing, I will make more power. Not exactly something I'm looking for, but those are the ropes. I'd love to be able to make less boost but 11 psi is my minimum and there's not much I can do about that. I will get this thing sorted. Don't worry.

As we say every year at the convention, this is now an opportunity for you to build the motor how you wanted

bad thing is, normally we only say that once....not 5 times

haha true, yeah might as well build one up now. The cast pistons really dont like heat at all. For one they retain heat and dont dissipate it very fast. So extended boost periods or periods where your making the most power or higher boost applications on small turbos that create backrpressure only adds to the heat into the cylinders not allowing it to escape out the exhaust. All my motors that i detonated had a nice white color on the pistons right below the exhaust valves and thats usually where the detonation damage was found. There is a reason for that and the reason is the backpressure from higher boost levels on a small turbo. That and bigger cams like the s4's. But its primarily the backpressure from too much boost.

Ben your boost level is fine, You just need to richen it up a bit and back down some timing. Id say drop to about 275-280whp on 11psi and it would be strong yet safe. I had no problems at all with my s15 bb t28 setup at 9-10psi all day long and man that thing with s4 cams flew. Again with that setup in a 2100 lb sentra i was walking away from an 11.9 cobra and 12.0 zo6 vette all the way through the powerband and all gears. I didnt stop pulling. The topend was rediculous. My tune was spot on for that boost level. Id have to say by the feel of it i was around the 275-280whp mark with that setup. I was running open 3" downpipe, flywheel, pullies, s4 cams, tubular manifold and 9-10psi.

Then i got greedy and upped the boost to go for some record times and once again the cast pistons could not handle the higher heat and backpressure created by the t28 at 21psi of boost. Again, cracked a ring land. So thats when i decided to go with efficeincy for high power and not just lowend response. I had to make the sacrifices and for a car that is primarily gonna be a drag car i really dont mind loosing the quick response of the t2 series turbos because even the t3 im using still kicks in pretty dang hard by 3800 rpms, by 4200 its all over.

Neways hope the build goes well. Forged aluminum pistons are a must and you know what your tune might be good for those as the aluminum pistons are not easily prone to hot spots and they dissipate heat very well. So who knows. But to be safe i would definetly richen things up a tad and knock the timing down a bit. You should still make some very good power but be safe while doing so.

All I know is that when I pull the motor on Saturday, I'm hoping that the bearings are still okay. Low oil pressure > no oil pressure. Good time to clean up the engine bay, though! I had been planning on doing it but didn't want to pull the motor. Now I don't have a choice!

Tekkie, the eating a 5 quart jug thing sounds eerily similar to when I attempted to limp my daily back home from New York. I noticed I had lower oil pressure (I was prepping for boost, had all my gauges in) at the beginning of the trip, and it gradually got worse and worse until I was forced to pull over 10 minutes south of Rochester. Popped the hood, oil was dripping out of my intake :X

I attributed it to an overly rich tune that gassed down the oil and ended up messing up the piston rings causing excessive blowby and low to no compression. When I took the pistons out of the block there was a lot of wiggle room between the head of the pistons and the cylinder walls. Really stupid mistake...

What do you guys say about royal purple oils or Redline oils instead of Mobil 1.

Royal purple sucks, i used it one time and the one time i used it all my gaskets magicly started leaking for some reason, brand new gaskets and seals at that. Hell no, i switched to mobil 1 and never looked back.

I'm officially back now, made it back over I95 no problem, and no weird noises or problems on my DE so far. (fingers crossed)

BTW, I did an oil level check while the engine was cold, and I had just above the 'full' tick.

my motor is officially finished, the main bearings were gone , all four- didn't even bother to look at the rod bearings- aw well, time for the next motor