Gas in oil, causing rod bearings to go out?

[DJ Robu5t]

Just recently had a spun rod bearing, had the shop I go to replace the bearings and they polished the crank and rod that had the spun bearing. The crank was cut once before showing that this motor has spun a rod bearing before. Long story short, everything was good measured down to spec, used undersized bearings. I've had the car for about 2 days, and I'm either crazy or I'm hearing the knocking again, I haven't gotten over 2700 rpms since the rebuild, and now it's almost jumpy and hesitates under light throttle (could be something else) I can hear the knocking at idle, we determined right after the rebuild that one of my lifters is most likely collapsed so now it's hard for me to pick between sounds of a collapsed lifter and rod knock.

On to the real problem, this motor is chewing at the bearings, and I want to find out why so I can put it to an end. First thing's first, the oil being 2 days old smells strongly of gas, and is pretty runny, 10w-30 full synthetic. There was also gas in the oil when the shop got the car to put the new bearings in. So I'm pretty sure that the oil is being watered down by raw gas, causing a lack of lubrication hence bearing failures. Now on to why it's getting gas in the oil. I have a few scenarios and this is where I need everyone's help.

1) Piston rings, I find this highly unlikely as we saw the inside of the motor from the bottom and it's beautiful. JE forged pistons, honed/bored cylinder walls, absolutely no carbon, I bought it with about 5,000 miles on the rebuilt motor (looks like 2,000). Also 165 compression in all 4 cylinders (4g63 6 bolt)

2) Crankcase ventilation system, I got the car with this vented to atmosphere, and just recently had it put into the intake after the maf where it goes stock (I will be getting a catch can soon). Could there have been a huge build up of gases causing blow by from this being vented all this time? And now it's pushing gas into the turbo etc, because it's finally venting it? (temporary problem)

3) Tune, I find this unlikely as my afr is always between 14.5-15.5 at idle and same with crusing. This car hasn't seen boost since the new bearings so boost is irrelevant (also had all boost leaks and vacuum leaks fixed 2 weeks ago). Fuel trims are always near 1 or -1 percent..

4) This I find the most likely and could be the source of all of my problems (I hope). Walbro 255 fuel pump is overrunning or completely toasted the stock fuel pump regulator, causing it to overrun straight into the crankcase (this would explain the gassy oil in just 2 days), I plan on getting an AFPR anyways, but would like some opinions on if this could be it first. Is there anyway I could check if the stock one is bad? Pull injectors to see if it's leaking etc, anything that could help in the meantime.

Any help would be greatly appreciated! I'm at my wits end with this car, it has so much into it and so much potential but I can't afford a full rebuild or anything major, and if it keeps spinning or tearing at the rod bearings without me fixing the cause, I will be stuck with a dead car and no funds! All advice and input is needed, thank you!

 

[Sharpie1983]

Whats your spark look like? nice and blue?

 

[koryto2012]

Hows the pcv valve

 

[dfootedsm]

1. Wally 255 will overrun our stock FPR pretty easily however is the wiring done properly? how are you measuring your Air /fuels.The machine shop that did the work how reputable are they ? What hardware are you using on your main girdle was the main line honed?Was the block bored with a torque plate?These are things that can distort mains and cylinders spin bearings and cause poor ring sealing and get gas in the oil. However if you are having major wash in the cylinders thats causing the bearing failure. not to mention your oil squirters are spraying gasoline contaminated oil on your pistons skirts to "cool them down" and eliminate friction. ... but the gas is creating more friction in theory check your pistons were assembled properly I hope its the cheap solution

 

[boost97gst]

It just doesnt seem like it would run that good and STILL have one or more cylinders flooding and /or running super rich. Its 14.7 during cruise, right?

How would over running the fpr cause fuel to go in to the crank case? Wouldnt it just cause MORE fuel to be sprayed by each injector every pulse width? No sarcasm intended.

Well, there is one way but that would throw your afr's off soi doubt it: The diaphragm is blown in the stock fpr and sucking fuel. Then again, it would have to make it through the fpr solenoid too..... this is sounding very very unlikely even as i type it.

Last point: First hand experience: Never count out the rings. My motor is BEAUTIFUL. No excess play anywhere, all pistons look the same. You couldnt visually tell by the bore or the piston which one was bad. However, huge difference, my bad cylinder was leaking down 35% and had compression ~half of the other 3. You dont seem to have that either.

Im just walking through these with ya. Its really tough to get gas in the oil basically unless you are running a lot of boost and have bad rings. Thats pretty much the long n short of it. Given all the info about your afr's you have given and the nature of the beast.

Ok, you used a cut crank. Most, myself included, have had bad experiences with this. If the bearing TRULY spun, the crank is more than likely shot and your going to throw more good money down the drain the longer you mess with that crank. You may end up wrecking a rod or more in the process. Also, during break in after reassembly, you will get gas in the oil from blow by. Things havent seated yet so i wouldnt be TOO alarmed about the gassy odor.
My "verdict"(): bad crank. Cut cranks are bad cranks in my opinion unless the machinist is good or whomever cut the crank is damn good.
I also dont believe the crank ever spun a bearing. It was out of spec and caused the knock which you wisely caught before more damage was done. I was in a very very similar predicament so i speak from knowledge of cut cranks. Made it 300 miles on mine before the SAME rod started knocking. Luckily i shut her down and saved the rod

 

[craig4g63]

What brand of oil? Please don't say Mobil 1.

 

[DJ Robu5t]

Whats your spark look like? nice and blue?

Spark is good, new spark plugs and new wires

Hows the pcv valve

Not sure how to check the pcv valve.. heard you shake it and see if it rattles?

1. Wally 255 will overrun our stock FPR pretty easily however is the wiring done properly? how are you measuring your Air /fuels.The machine shop that did the work how reputable are they ? What hardware are you using on your main girdle was the main line honed?Was the block bored with a torque plate?These are things that can distort mains and cylinders spin bearings and cause poor ring sealing and get gas in the oil. However if you are having major wash in the cylinders thats causing the bearing failure. not to mention your oil squirters are spraying gasoline contaminated oil on your pistons skirts to "cool them down" and eliminate friction. ... but the gas is creating more friction in theory check your pistons were assembled properly I hope its the cheap solution

The motor was built by a shop in New Jersey Bison engine and machine shop. I figured at this point the bearings are going either because of gas getting into the oil or the crank itself. Can you have bad rings even with near perfect compression? Guess I need a leak down test, also on that note, boost is at 15, but I haven't seen boost since the new bearings.

It just doesnt seem like it would run that good and STILL have one or more cylinders flooding and /or running super rich. Its 14.7 during cruise, right?

How would over running the fpr cause fuel to go in to the crank case? Wouldnt it just cause MORE fuel to be sprayed by each injector every pulse width? No sarcasm intended.

Well, there is one way but that would throw your afr's off soi doubt it: The diaphragm is blown in the stock fpr and sucking fuel. Then again, it would have to make it through the fpr solenoid too..... this is sounding very very unlikely even as i type it.

Last point: First hand experience: Never count out the rings. My motor is BEAUTIFUL. No excess play anywhere, all pistons look the same. You couldnt visually tell by the bore or the piston which one was bad. However, huge difference, my bad cylinder was leaking down 35% and had compression ~half of the other 3. You dont seem to have that either.

Im just walking through these with ya. Its really tough to get gas in the oil basically unless you are running a lot of boost and have bad rings. Thats pretty much the long n short of it. Given all the info about your afr's you have given and the nature of the beast.

Ok, you used a cut crank. Most, myself included, have had bad experiences with this. If the bearing TRULY spun, the crank is more than likely shot and your going to throw more good money down the drain the longer you mess with that crank. You may end up wrecking a rod or more in the process. Also, during break in after reassembly, you will get gas in the oil from blow by. Things havent seated yet so i wouldnt be TOO alarmed about the gassy odor.
My "verdict"(): bad crank. Cut cranks are bad cranks in my opinion unless the machinist is good or whomever cut the crank is damn good.
I also dont believe the crank ever spun a bearing. It was out of spec and caused the knock which you wisely caught before more damage was done. I was in a very very similar predicament so i speak from knowledge of cut cranks. Made it 300 miles on mine before the SAME rod started knocking. Luckily i shut her down and saved the rod

Wow what an answer! I thought I read somewhere that a wablro 255 could overrun the fpr and cause gas to leak down especially when the motor is off, something about it not being able to return, or too much pressure for the return line etc, injector o rings and such. I may be wrong and read wrong. On a side note, this may help everyone narrow it down. When we changed the bearings, all were good except cylinder 3. Does that rule out the gas in oil since it's isolated to only one cylinder? Perhaps that points to it being the crank, and you were right sorry it didn't fully spin, far out of spec and I caught it before it spun all the way, very light rod knock which is why it's hard for me to pick out now if I'm having it again.

It was running shop brand synthetic to flush out after the initial flush, I'm changing the oil again today, so this will be the 3rd batch of oil in the motor within 100 miles. Mobile 1 that bad? Also does full synthetic become runny quickly?

 

[craig4g63]

Spark is good, new spark plugs and new wires


Not sure how to check the pcv valve.. heard you shake it and see if it rattles?



The motor was built by a shop in New Jersey Bison engine and machine shop. I figured at this point the bearings are going either because of gas getting into the oil or the crank itself. Can you have bad rings even with near perfect compression? Guess I need a leak down test, also on that note, boost is at 15, but I haven't seen boost since the new bearings.



Wow what an answer! I thought I read somewhere that a wablro 255 could overrun the fpr and cause gas to leak down especially when the motor is off, something about it not being able to return, or too much pressure for the return line etc, injector o rings and such. I may be wrong and read wrong. On a side note, this may help everyone narrow it down. When we changed the bearings, all were good except cylinder 3. Does that rule out the gas in oil since it's isolated to only one cylinder? Perhaps that points to it being the crank, and you were right sorry it didn't fully spin, far out of spec and I caught it before it spun all the way, very light rod knock which is why it's hard for me to pick out now if I'm having it again.

It was running shop brand synthetic to flush out after the initial flush, I'm changing the oil again today, so this will be the 3rd batch of oil in the motor within 100 miles. Mobile 1 that bad? Also does full synthetic become runny quickly?

Use a non-detergent high zinc oil. Any of the oils Fp recommends in this article should suffice.

http://store.forcedperformance.net/...nce%20Recommendations%20for%20Motor%20Oil.pdf

 

[92AWDHX40]

I had a issue with the walls washing out because I was way to rich all better now with a tune.

 

[DJ Robu5t]

Use a non-detergent high zinc oil. Any of the oils Fp recommends in this article should suffice.

http://store.forcedperformance.net/merchant2/graphics/news/Forced%20Performance%20Recommendations%20for%20Motor%20Oil.pdf

Bad link =/, I just put pennzoil in temporarily to get the gassy oil out, in another 200 or so we will be putting royal purple in also ran seafoam at idle before the oil change. So far the ticking/knocking type noise I hear the most has gotten a lot quiter, I'm thinking what I've been hearing was lifter tick or a collapsed lifter.

When I drained the oil it still had what looked like dark metal, it can't be the bearing because it would be new and shiny, none of the specs were shiny, perhaps it wasn't metal at all but instead carbon from the seafoam removing blockages in the oil passages.

Also was thinking it could be the tune as i did it and irs my first time tuning on this level. But both my wideband and dsmlink's afr est. Show no rich condition. Wideband shows 14.5-15.5 at idle and 14.6-14.9 cruise. Dsmlink estimate shows 14.9-15.9 at idle and 15-16 at cruise. Unless both my stock 02 sensor and wideband are bad..

 

[craig4g63]

Sorry, go to:

http://forcedperformance.net/merchant2/

And then click the last link under latest news "important information...."

 

[pacn91]

most of the time if a rod bearing is spun, and the rod gets reused, it has to be resized. You might be able to get away without it, but after resizing the rods should be rebalanced.