Home | Register | Login | Contact Us

 
Auto Math
Classifieds
Forum
Gallery
Games
Garage
Tech Articles
Utilites
 
FAQFAQ    SearchSearch    RegisterRegister    Log inLog in    Log in to check your private messagesLog in to check your private messages    Forum Subscriptions1/4 Mile Table 

Oil Burning Issue

 
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Chevy - Small Block Gen 1
View previous topic :: View next topic  
Author Message
PWR_Andy
Newbie


Joined: 19 Mar 2011
Posts: 4

253.58 points



PostPosted: Sat Mar 19, 2011 9:12 pm    Post subject: Oil Burning Issue Reply with quote

I have built about 13-14 motors now with success but I am having issues with one of the last motors I built. I will start with the basics.

4.06" Bore (.0045" clearance on piston skirt)
4.05" Stroke
2618 Pistons
1.5 x 1.5 x 3.0 Total Seal Rings
.018" x .020" Ring gaps

This motor was built the exact same as the previous 13-14 motors and they are all running fine. It is burning about 1 quart of oil every 200 miles or so. Gas was in the oil after the first oil change. Cranking Compression was good across all 8 cylinders but a leak-down has not been performed. Im running out of ideas of what to check.

I did recently find out that once the engine was installed, the o2 sensors were crossed and the engines computer was adding 32% of fuel to each bank unnecessarily for the first 60 miles. Could that have caused any issues related to the fact that this engine is still burning oil and has about 1000 miles on it?
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5558
Location: grassvalley, ca
71227.76 points


1933 Willys Coupe

PostPosted: Sat Mar 19, 2011 9:49 pm    Post subject: Reply with quote

We used to call it washing the walls when having a carb with a blown PV.
I have my ways to save it but with o2 sensors I won't even go there.
Back to top
View user's profile Send private message
PWR_Andy
Newbie


Joined: 19 Mar 2011
Posts: 4

253.58 points



PostPosted: Sat Mar 19, 2011 10:05 pm    Post subject: Reply with quote

Does it sound like the rich condition caused "borewash" in those first 60 miles?
Back to top
View user's profile Send private message
clay
Moderator


Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Sat Mar 19, 2011 10:40 pm    Post subject: Reply with quote

How was it running when the O2's were switched? I'm sure not the greatest, but even with 32% added on the fuel trims, I'm betting it still wasn't rich as some carburetors idle with long duration, high overlap camshafts. How tight were the oil rings in the groove? I have seen burrs from the pin bore that slightly interfered with the oil ring support rail and caused the oil ring assembly to be very tight and not float like it should. Were different heads used? Any drainback issues there? Different valve covers used? Maybe a PCV baffling issue. I had a stock 350 my father and I rebuilt when I was in high school with similar oil burning issues and I never did find out why - hope you do though. Clay
_________________
I have done so much with so little for so long, I can now do anything with nothing.
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Sat Mar 19, 2011 11:04 pm    Post subject: Reply with quote

Was it a speed density fuel system or mas air???





[img][/img]

_________________
Back to top
View user's profile Send private message
PWR_Andy
Newbie


Joined: 19 Mar 2011
Posts: 4

253.58 points



PostPosted: Sat Mar 19, 2011 11:23 pm    Post subject: Reply with quote

Speed Density.

The heads were on the car before the new motor and ran fine. Typically a cammed car like this runs slightly rich and the ecm will pull 5-10% fuel. Since it was adding 32%, Im going to say it was probably about 35-40% too rich which would put it in the 9's for an air/fuel ratio.


Here is a picture from today during a cold start. Whatever this is, it washes away with rain which makes me think it isnt oil.

Back to top
View user's profile Send private message
higshemi
Newbie


Joined: 20 Mar 2011
Posts: 1

134.86 points



PostPosted: Sun Mar 20, 2011 1:17 am    Post subject: Reply with quote

Hey guys, this is my engine I had Andy built for me. Like him, trying to draw some conclusion to whats goiing on. Gotta say Andy's been great trying to diagnose the problem. Anyways... just wanted to add a few little things here.

The Jeep is actually burning through 1qt of oil every 60 or so miles. The pic that Andy posted was the accumulation of soot/fuel after 1 minute of start up. Does wash away like he said.

Getting a leak down test and changing the plugs out tomorrow.

Fred
Back to top
View user's profile Send private message
clay
Moderator


Joined: 24 Nov 2002
Posts: 3209
Location: South Carolina
318129.23 points


1972 Chevrolet Nova

PostPosted: Sun Mar 20, 2011 11:34 am    Post subject: Reply with quote

The picture looks like just the normal soot that builds up in the exhaust that gets blown out with all the condensation that gets blown out on the initial startup. I'm sure you are seeing more than normal since you obviously have an oil consumption issue. Wow - a quart every 60 miles is really bad. You can do a simple test for a leaking intake gasket. Pull the PCV valve and seal up the valve covers and attach a vacuum gauge to one side. Crank it up and if it pulls vacuum on the crankcase that almost has to be a leaking intake gasket. I don't remember who on here had that idea, but it sounds like a pretty slick test to me. If the compression test was good, I'm betting the leak down will be good also. Since this obviously isn't Andy's first build, I wouldn't think anything goofy was done like second ring upside down. Does one plug show signs of being wetter than the others or do they all look the same? Maybe a thin cylinder wall flexing while it's running? I know these might be weird ideas but I'm sure you already checked the obvious. When you find out what it is please let us know. Clay
_________________
I have done so much with so little for so long, I can now do anything with nothing.
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Sun Mar 20, 2011 1:16 pm    Post subject: Reply with quote

i had a speed density system with a small cam and higher compression larger cubes etc etc

that engine ran too rich , and built up sooooo much carbon above the first ring and scored the walls pretty bad in a short period of time

now my speed density was factory

is yours backfiring from the intake????ever??

_________________
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Sun Mar 20, 2011 1:22 pm    Post subject: Reply with quote

its perfectly acceptable to look for crankcase leakage via:intakemanifold, screw in rocker studs into intake runner, pcv,and valve guides

but

lets not forget there is fuel in the crankcase
and the only way that will happen is fuel going past the rings!!!!!

were all these 13to14 engines speed density????
what engine is this by the way??
whats fuel pressure????

_________________
Back to top
View user's profile Send private message
PWR_Andy
Newbie


Joined: 19 Mar 2011
Posts: 4

253.58 points



PostPosted: Sun Mar 20, 2011 7:05 pm    Post subject: Reply with quote

All 13-14 engines are Gen III 6.1 Hemi Mopar engines. All use the same 4.06" bore and the same 3mm oil rings. This particular motor has tighter top and second ring gaps than most of my motors due to the fact that it is NA and not boosted.

Leak-down showed 7-10% on all 8 cylinders
Back to top
View user's profile Send private message
squeeezer
Member


Joined: 02 Mar 2007
Posts: 2427
Location: new richmond WI
191524.76 points


1991 Chevrolet Camaro

PostPosted: Sun Mar 20, 2011 10:53 pm    Post subject: Reply with quote

all returnless fuel systems i suppose?
_________________
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Chevy - Small Block Gen 1 All times are GMT - 5 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
Home | Contact Us | Automath | Cam Files | Dyno Search | Forum | Garage | Picture Gallery | Reaction Timer

Copyright 1997-2016 SMOKEmUP.com All rights reserved.
Advertising Info     Disclaimer     Privacy Policy