1 failed rod bearing

[SLOWESTN54]

I recently noticed a high quantity of metal shavings in my oil filter during a regular oil change, and decided to replace the filter and check again in 500km's. Sure enough same amount of material in the filter again. Which lead to me dropping the oil pan and checking my rod bearings today. 1,3,4,5,6 look like they have equal wear but 2 is worn significantly more. # 2 also happens to be 15 psi lower in compression then the rest. Is it possible I might have a slightly bent rod causing premature wear?

 

[martymil]

most likely if down on comp, lucky you caught it early as it becomes a much cheaper rebuild.

 

[RuskiRacer]

Not necessarily a bent rod , sometimes the rings will start siezing and micro welding themselves into the ring grooves and that is another way of compression being down. How much torque were you making? I never even bent any rods revving to 8k on a 6875 and never bent any with some wierd overboost situations on my 6266 hitting 36psi

 

[SLOWESTN54]

most likely if down on comp, lucky you caught it early as it becomes a much cheaper rebuild.

Luckily i still had my compression test pictures from back in may. These compression numbers were taken on a cold engine.

1. 160
2. 143
3. 160
4. 160
5. 160
6. 160

Luckily i have a low Km's spare engine ready to go in just need a turbo install kit. Also, on my current engine Cylinder walls and crank look good, i'll eventually rebuild this engine with rods and pistons.

 

[SLOWESTN54]

Not necessarily a bent rod , sometimes the rings will start siezing and micro welding themselves into the ring grooves and that is another way of compression being down. How much torque were you making? I never even bent any rods revving to 8k on a 6875 and never bent any with some wierd overboost situations on my 6266 hitting 36psi

Early on my car was tuned by not the most reputable tuner, at that time car was running 22psi of boost through DAW stage 2+ on e50. Although boost was not being tapered in, which i think was the nail in the coffin for this N54. I think that might have been enough to kill it. Car has since been tuned by V8bait running 26psi with e50 for fuel.

 

[martymil]

If you didn't taper in your boost, you most likely bent a rod, leak down test will tell you if its a bent rod or rings or not a properly seated valve, if nothing is leaking its most likely a rod

 

[martymil]

Not necessarily a bent rod , sometimes the rings will start siezing and micro welding themselves into the ring grooves and that is another way of compression being down. How much torque were you making? I never even bent any rods revving to 8k on a 6875 and never bent any with some wierd overboost situations on my 6266 hitting 36psi

Single turbos will never bend a rod unless you running huge boost, they just don't produce enough down low torque like twins

 

[SLOWESTN54]

If you didn't taper in your boost, you most likely bent a rod, leak down test will tell you if its a bent rod or rings or not a properly seated valve, if nothing is leaking its most likely a rod

I wish i knew better at that time. You live and you learn. Ill leak down test it today and get ready to pull it out.

 

[martymil]

Leak down test is pointless at this stage as motor has to be pulled anyway.

 

[RuskiRacer]

Single turbos will never bend a rod unless you running huge boost, they just don't produce enough down low torque like twins

Yeah but I was running insane boost actually would spike to 36psi insanely fast and would smash rev limiter everytime for about 5 pulls until I changed the mac solenoid

 

[SLOWESTN54]

Yeah but I was running insane boost actually would spike to 36psi insanely fast and would smash rev limiter everytime for about 5 pulls until I changed the mac solenoid

Curious what rpm did it hit 36psi @

 

[RuskiRacer]

Probably around 4k-4500 its been awhile since I resolved that issue

 

[martymil]

36psi will bend a rod, you shouldn't really run anything over 28 on stock rods its a ticking time bomb as we found out on the single kit I worked on.

The bore ovalised and grabbed the piston and the rod pulled right out and lightsabered the block in half.

 

[RuskiRacer]

36psi will bend a rod, you shouldn't really run anything over 28 on stock rods its a ticking time bomb as we found out on the single kit I worked on.

The bore ovalised and grabbed the piston and the rod pulled right out and lightsabered the block in half.

Was the boost brought in aggressive or tapered in gently ? Also if the timing is aggressive thats gonna be harder on the rods

 

[martymil]

just made to much power and ovalized the bore, about 9 deg of timing.

It was making crazy power and more than anyone has seen here before and close to 1k hp

 

[Torgus]

I wish i knew better at that time. You live and you learn. Ill leak down test it today and get ready to pull it out.

The joys of twins. Must limit your low rpm boost ;( IIRC you can bend the stock rods on stock turbos will a full E85 kill map and no boost tapering.

Vendors usually show a 'max effort tune' on a built block with no boost tapering to sell twins and brag about how much better they are than singles etc. 95% of customers will never have a dyno pull that looks like that.

@SLOWESTN54 Sorry to hear about your misfortune. Best of luck with the spare engine and the build.

 

[SLOWESTN54]

Vendors usually show a 'max effort tune' on a built block with no boost tapering to sell twins and brag about how much better they are than singles etc. 95% of customers will never have a dyno pull that looks like that.

This couldn't be any more true. Whatever helps sell, is what Vendors do. I'd still blame this on my lack of experience when i first put this car together, and the good ole copy facebook tuner. 22psi before 3500rpm made for a fun time

 

[Torgus]

This couldn't be any more true. Whatever helps sell, is what Vendors do. I'd still blame this on my lack of experience when i first put this car together, and the good ole copy facebook tuner. 22psi before 3500rpm made for a fun time

I bet it was tons of fun to hoon around town with

I blame the tunah. It's just not responsible to not taper in the boost unless someone specifically asks for it. What sucks is there is zero accountability or liability in most cases.

 

[SLOWESTN54]

I bet it was tons of fun to hoon around town with

I blame the tunah. It's just not responsible to not taper in the boost unless someone specifically asks for it. What sucks is there is zero accountability or liability in most cases.

Haha you know your extooner is the best in the game when there's a massive post in the Octagon about him.

 

[martymil]

Even with a built motor I get @V8bait to taper in my tunes otherwise it's just wheel spin when you hit boost.