This looks bad! Tell me the ugly truth. White smoke + oil . . .

[AussieinNC]

If the dumbell (barbell) is leaking the capillary reading at the factory location will be low...

Changing the oil filter for a new one removes the possibility of a clogged oil filter causing a large pressure drop...

If its still low at the factory port after changing the filter then the barbell is either missing or installed backwards or lacks the O ring...

[Lugnutz65]

Aha! Eureka!
I understand the dumbbell and how it works!
Thanks for the education.

[AussieinNC]

If you need to remove the rear cover, here is the link to the rear seal guide...you will need this to replace the cover without tearing up the seal....

https://www.summitracing.com/parts/s...iABEgIOPPD_BwE

Here is a youtube on the repair process. In the video, you can see the end of the barbell on drivers side back lower face between lowest bolt and second lowest bolt...you can also see how any leak from the barbell goes direct to the sump of the engine.

https://www.youtube.com/watch?v=bAksGbJ11Kw

and finally, here is the cover and seal set from Dorman

https://www.summitracing.com/parts/r...SABEgI5CvD_BwE

Here is the barbell unit if its missing

https://www.summitracing.com/parts/icb-551284

[Lugnutz65]

Wow! Great video. Thanks.
I wish all videos were that clear and concise. Watching it was painless. Too many YouTube DIY vids are poorly produced and painful to watch.

That might take me 1.5 hours to complete. Not sure why they listed 5 hours.

[AussieinNC]

I would assume the 5 hours includes the removal and replacement time of the engine from the vehicle...

Enjoy your day...

[Lugnutz65]

Some may wonder how I got started with this swap.
My son is a mechanic and has always encouraged me to get rid of my great running 230ci. I resisted for years.

I finally gave in when I saw a FB marketplace ad for this engine.
The seller had a garage full of rebuilt 5.3 engines listed at $2199. He rebuilt maybe 15 engines. They were selling well.
I bought his last one at a discounted price of $1200. It needed accessories and brackets and a throttle body but was otherwise a complete engine.

The seller said he had worked for Toyota building engines, then later had a shop of his own and had built many more and also helped customers complete LS swaps. He was polite, knowledgeable, helpful and lived in a local rural neighborhood where he had already poured a concrete slab for a new shop. Not someone trying to unload an engine stored under a tarp.

I pulled the trigger.

Many I’ve talked to have purchased running LM7s for half of what I paid. I know I didn’t get the “best deal in town”, but the price seemed fair for all the time and work already in the engine. My area of the country seems to have a shortage of these engines. The local salvage yard gets one every other week at best and they are usually a total mess.

Six months later I have the engine on a run stand, and here we are. I was hoping (planning actually) to fire this thing up and have it in my truck by September. Not looking too good right now.

[mongocanfly]

Know knowing this, I'd be calling him up and asking questions...maybe he'll stand behind his work..

[clay68c10]

Don’t worry too much about those compression numbers. You have some oil in there from the PCV situation combined with (probably) new rings that haven’t seated yet. Really, the low end of those numbers are close to the factory spec. I recall it being around 150-175psi
Get it running with a reliable oil pressure gauge first.

[87chevy.com]

Oil burning is a blueish color ... white could be fuel or coolant

[Lugnutz65]

Originally Posted by 87chevy.com

Oil burning is a blueish color ... white could be fuel or coolant

My first post was BEFORE I realized that oil was accumulating inside my intake. The smoke clears quickly after startup. If I sop up the oil inside the intake, there’s essentially no smoke.

My next step is to figure out where the oil is coming from. Votes favor the PCV system due to blow by and high crankcase pressure from rings that aren’t seated properly. The blow by would also explain why my fresh oil is black with carbon with less than 20 minutes of run time.

Votes are less in favor for oil coming back up through the cathedral ports. That would mean bad valve stem seals and possibly bad rings too.

I’m no expert. I drained the oil right after I saw the smoke and there is zero coolant in the oil and no oil in the coolant.

[Lugnutz65]

Update!
It’s the PCV alright!
Looks like I have a bad OE oil pressure sensor too. I swapped it out for a capillary tube style gauge and now it closely matches my electric style oil sensor that’s installed near the oil filter.

Here’s a video of tonight’s test. After a few minutes at idle RPMs I didn’t get any oil in the catch can. Higher RPMs (3000) for a minute or two caused obvious oil to come through the PCV. VIDEO LINK

[mongocanfly]

Good deal.!!

[Lugnutz65]

Originally Posted by mongocanfly

Good deal.!!

It’s good that I found a bad oil pressure sensor.
It’s bad that I have oil coming through the PCV!

[mongocanfly]

I didnt watch till the end....I thought you had it...
So I went back and did...
That is alot of oil in your can...did you change the pcv?

[Lugnutz65]

Originally Posted by mongocanfly

I didnt watch till the end....I thought you had it...
So I went back and did...
That is alot of oil in your can...did you change the pcv?

My VC is a later design and doesn’t use the replaceable PCV that fits in the rubber grommet. I don’t think it’s a PCV failure. Seems more like blow by. I’ll do a cylinder leak down test this weekend.

[gmc684x4]

New unseated rings my thoughts it will have some leakdown

[AussieinNC]

You will need a new rocker cover....

Your rocker cover is a later series with the fixed orifice pcv vent....thats why you dont see a typical PCV valve...just a nipple

You can try spraying carb cleaner into the orifice after you remove the cover to try and free up the ports but it is usually a temporary fix....

Here is a link to a Dorman product...

https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds

Nowadays it pays to run an aftermarket catch can system to augment the PCV system....the link is to a fully baffled catch can setup..

https://www.addw1.com/products/chevy...smart_campaign

[Lugnutz65]

Here’s a quick video of my leak down test. CYLINDER 5 VIDEO LINK
I pressurized the cylinders again tonight and HEARD AND FELT air at the OIL FILL HOLE and INTAKE THROTTLE BODY. If I also have leaking intake valves, then the cylinder leak down test numbers will be falsely lowered.
The plan for the weekend is to run the engine for a while and test it again when warm. I want accurate info before I ask the engine builder to remedy the problems.

Here are the leak down numbers I got last night.
The engine was COLD when I tested. It was too late to warm the engine up, because I already had the valve cover off. I have some serious problems.
#1 = 91
#2 = 76
#3 = 94
#4 = 96
#5 = 62
#6 = 61
#7 = 91
#8 = 71

[mongocanfly]

wow...id be calling the man and let him know whats going on

[AussieinNC]

Originally Posted by Lugnutz65

Here’s a quick video of my leak down test. CYLINDER 5 VIDEO LINK
I pressurized the cylinders again tonight and HEARD AND FELT air at the OIL FILL HOLE and INTAKE THROTTLE BODY. If I also have leaking intake valves, then the cylinder leak down test numbers will be falsely lowered.
The plan for the weekend is to run the engine for a while and test it again when warm. I want accurate info before I ask the engine builder to remedy the problems.

Here are the leak down numbers I got last night.
The engine was COLD when I tested. It was too late to warm the engine up, because I already had the valve cover off. I have some serious problems.
#1 = 91
#2 = 76
#3 = 94
#4 = 96
#5 = 62
#6 = 61
#7 = 91
#8 = 71

Now you have your reason now for so much blow by....

2,5,6,and 8 are critical failure readings....hearing air in the oil filler means ring blow by...most likely broken or missing rings.....
1 and 7 are indicative the rings have not sealed to the cylinder walls.

3 and 4 are the only two close to ok...

BTW...I believe anything less than 95 is a fail....

Hearing air in the intake manifold is most likely poorly seating or burnt valves or a bad vacuum leak at base of manifold....pulling blowby air from sump into manifold.

Suggest you do not pull the engine down without discussing this with the seller....

I remember noting the absence of Rings on the parts replaced list on the Ad post...suspect they were not replaced and old ones were installed....

[Lugnutz65]

I posted a new thread with the update. My problem may solve itself. LINK TO NEW THREAD.