Wildweed

Hello all,
I just joined. I have a 69 Cutlass with a Olds 455 in it. I am losing oil. I changed the heads to Mondello Promax aluminium heads. I had my cyl checked for pressure and they are running between 217-226 if I remember correctly. The engine was built for a boat but the guy decided to sell the engine, the shop that installed my engine I don't think they checked the rings. I am not burning smoke out the pipes or dripping oil I am just losing it. I had a friend say he smelled oil when he was behind me, but not since I had the heads replaced. I drove it for about 100 miles and had to add 4 qts the other day. I usually check the oil more than the last time and it is usually a qt or less low, I dropped the ball this last time. I am tired of adding oil to this car. I have to use two oil sticks one to drive with as it is shorter and one to check the oil with, I snapped a stick at the tip when left in. I believe it has an oversized crank but, the installer thanks a baffle was backwards. I won't go back to these guys for sure. Another shop in my area ruined my last engine when they installed a cam wrong and it tore up the bearing housing. I am sick and tired of being shafted by engine guys. Any ideas will be most helpful.

oldcutlass

If your running PCV, pull and cap the vacuum line and see if your oil usage goes away. It may be sucking it up through the valve covers.

MDchanic

I would say that it is impossible to burn a quart of oil every 25 miles and not leave a smokescreen worthy of the Somme offensive.

There has to be more going on here.

Welcome to ClassicOlds.

- Eric

oldcutlass

I agree it can't magically disappear, its either leaking or burning. My other concern is your dipstick situation. I'd manually mark the one that fits with a file at the 3-5 qt levels on your next oil change.

droldsmorland

Read the spark plugs...What do the spark plugs look like? Stick your finger in the tail pipes and see what your finger comes out with? Its either being burnt or leaking, it doesn't evaporate. Bad valve seals and guides can cause oil consumption as well as bad oil control rings. But you should be seeing something coming out of the tail pipes with that level of oil consumption. Is there excessive blow by through the valve covers??
Did the heads come fully assembled? Either way verify the guide seals are in place.
What kind of vacuum signal are you getting at idle? Perform a leak-down, a wet and a dry compression test. Post the results. Go this route before tearing it down for inspection.

Wildweed

Thanks guys I will do that. The plugs are clean. I had the oil consumption problem with the cast iron heads and now with the Mondello heads. I see nothing out the pipes at all. I had a dry compression test done and it was good, didn't do a wet test though. I am going to try the PVC valve and then go from there. The oil stick I will mark that for sure, thanks for the idea.

RetroRanger

What kind of valve covers and any baffles in them? I've seen a few threads where VCs w no baffles can increase oil consumption.

Wildweed

Thanks. I believe the baffles in the vavleague covers were removed to make room for the lifters on the Mondello heads. The engine looks stock except for the chrome I did, the a/c is still hooked and working. When the cast heads were on I used oil too the baffles were there, I use GTX 20/50 oil, I did use the purple oil but switched over. Thanks for the responses everything helps to figure it out.

Achcoastal

hello wildweed,i came across your post while searching for the same problem. i.m adding a quart about every 100 miles or so to my 1970 455 and i see no signs of leakage, exhaust is clean,plugs are clean and friends behind me tell me they see or smell nothing when i jump on it. i haven't done a compression check but the car runs super strong and this has me stumped... did you find the source of your consumption? thanks from Alan and btw welcome to CO

1970-W30

[QUOTE=Wildweed;932242]Thanks. I believe the baffles in the valve covers were removed to make room for the lifters on the Mondello heads.

If the covers baffles are gone, I can guarantee the pcv valve is sucking a huge amount of oil into the engine...........
.......

Rechodd Carter

I came across this post and i'm having the same issue, the oil is not leaking, or smoking. I removed the PCV and the oil stopped burning/disappearing, my question is how can it be fixed? I have already tried to replace the PCV valve and the issue came back.

(I have checked and baffles are still there)

Achcoastal

I solved my similar issue by replacing the compromised intake gaskets and replacing them with a valley pan turkey tray. I put ultra gray etc around each port both sides of the tray and did not use the rubber end seal. Used ultra gray (thick bead) in their place. Solved my oil disappearing act for good (see my photos). Good luck

matt69olds

The engine in my car has started to get a little oil thirsty over the last few years. I really wonder where the oil is going, it’s definitely not sever but isn’t normal.

I have done both compression and leak down tests, nothing out of the ordinary. The plugs are always clean, the intake has been off a few times over the years. The gasket always has a even amount of crush. I have tried a couple different part number PCV valves. I have the stock Olds valve covers. While the engine does “mark its territory”, it doesn’t leave huge puddles under the car, and it doesn’t have oil dripping off the bumper either.

I go thru about a quart every 500 miles. While the engine has always used some oil, it has gotten worse the last few years. I built the engine almost 20 years ago, it has definitely been run hard. The short block hasn’t been apart since I built it, it has had a few different camshafts and intakes on it over the years, along with some changes to the Edlebrock heads. When I installed the roller cam years ago, I installed new valve seals along with the new valve springs. The valve guide wear appeared normal.

I have talked with Mark (CutlassEFI) a couple times about this, while he has some theory’s, to find out for sure will require an autopsy. I did do the Mondello suggestion of grinding the oil reliefs on the big end of the connecting rods, his idea is the wide side clearance with the oil reliefs is saturating the cylinder walls with oil. Not enough to see in the combustion chamber or exhaust, but enough to consume oil faster than normal. This makes sense, I have built several other engines with similar internals (without the oil reliefs) and they don’t use a drop of oil.

At this point, I’m not going to worry too much about it. I drive this car 6-7 months out of the year, about 3-4k each summer. Until the engine needs major repair, or the oil consumption gets closer to the fuel economy, I’m not tearing into it.