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Oil usage

paul_laflamme

New member
"just rebuilt 1987 454 Crusade

"just rebuilt 1987 454 Crusader , reverse rotation, and it suffers from ridiculous oil consumption.(lost 2 qt. on a 20 mile ride @ 2000 RPM's)
machine work was done by a reputable shop, bored 030 over new crank, and heads were done i was assurede the deck had minimal material removed and that the heads were "just touched to clean them up. the heads have all new parts, guides ,valves and springs and seals.
we can not find any immediate faults, the engine starts fine, temp and oil pressure is good compression is about 150# but it uses way too much oil.
theres no oil in the bilge or on the water and the oil cooler pressure tests ok, the motor does not have any PVC valves on the valve cover just two hoses up to the stock flame arester the same way it was before it was rebuilt and I had no oil issues then, the port side motor was rebuilt by the same shop and has no issues and is set up the same way, we replaced the intake gaskets thinking it had a vacuum leak with no luck
any ideas?"
 
"The oil isn't evaporating

"The oil isn't evaporating - you need to figure out where it went. If it isn't in the bilge, it has to be going out the exhaust. whether its burnt or unburnt will help in finding its path.

How did you pressure test the oil cooler?

did the machine work do the assembly work?"
 
"Yep, what Mark said; also, i

"Yep, what Mark said; also, is there a LOT of blowby? Is there a bit of a sheen behind the boat?"
 
"Looking at the plugs it looks

"Looking at the plugs it looks like it's burning the oil, they were not wet but all looked about the same blackness I could also see a build up on the intake valve when we took the intake manafold off to replace the gaskets, we tested the oil cooler by taken it out and draining all the fluid we put a pressure gage on the oil inlet and put a shut off valve and a air fitting on the other side then we put 50 psi into it and shut the valve and dissconnect the air line let it sit for 5 hours it only droped 1 pound, we also checked the blowby on both motors it looked the same on all four valve covers, the machine shop put both short blocks and the heads together we needed to put the short blocks in first it was done on the dock so we had to do it by hand the heads and intake were installed after words by a former GM mecahnic he also set all the rocker ajustments, the motor sounds great and is very responsive."
 
I think I would have tested th

I think I would have tested the cooler @ 100psi.

Buildup on the intake valves with a few hours isn't a good sign....and they put new valve guides in....have you put a vacuum gauge on yet?

What weight oil are you using?

how many hours are on it now?

Do you see any residue on the flame arrestors?
 
"You saw a "build-up";

"You saw a "build-up"; of carbon or is it oily? Verify that these are 7 quart sumps, you added 7 quarts initially, the dipstick read full (or slightly over), and if you actually ran it to 5 quarts, the oil pressure headed down from 40 to maybe 30 psi? are you running straight 40?"
 
"Build up on valves looks like

"Build up on valves looks like oil, the motor has 50-100 hours on it, the motor has been using oil ever since it was rebuilt I thought it just needed to be broken in at first I followed the shops break in proceedure 2000 RPM's for 20 min. using 15-40 rotella oil with GM break in lube and I used the break in lube when I changed the oil as well, the heads have all new valve guides, valves and seals, the flame arrestors on both motors look a little dirty after a couple times out but they look about the same they don't look like they are wet from oil, I would say it is burning it all all cyl. how it's getting there I not sure, My next step is to dissconnect the hoses going to the flame arrestor and run them throught a filter, still thinking it is do to the heads being shaved a little not sure how much they taken off, going to look for thicker head gaskets, any ideas how to test if the intake gasket is pulling oil from the valley, did not do any vacuum test there is no place to test on the carb. would have to pull a plug on the intake or add a base plate to the carb."
 
"Paul,

We used to do that h


"Paul,

We used to do that head shaving trick on American v-twin motorcycles to increase compression a hair. It never increased oil consumption and you state you have good compression but is there still a chance you are getting oil past the rings?"
 
"The OEM manifolds have a pipe

"The OEM manifolds have a pipe plug between the carb and the distributor. The OEM carbs also have a capped manifold port, on the throttle plate, at the front.

If the intake is pulling oil out of the valley, the engine wouldn't run well, at all.

I'd say the "leak" is thru the intake side. the question is the 'source'. The buildup on the valves makes me think the guide seals are leaking. If all 8 valves have the about the same buildup, I'd suspect the wrong seals/guides were installed or weren't finished correctly. The other candidate is the breather hoses.

the build up on the flame arrestor is normal but seems to be occuring a bit fast in your case. If you are loosing over a quart in an hour thru the breather tubes, the oil trail from the flame arrestors to the bilge would be obvious....I'd be inclined to remove a rocker cover and inspect the valve stem seals....if you have an itemized bill from the shop, get the part numbers for the guides, valves, and seals and see if they "match" the application guides.

Are the baffles still in the rocker covers?"
 
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