408 stroker smokes and burns oil at a rate 1qt 500 miles.builder says leakdown was less than 2 %.only thing he could find was less than enough sealant on rocker studs(magnum eddys)he ran it with the pcv unhooked and smoking stopped,told me to get a catch can.i did,very little oil being being caught.couple thimbles ,not a quart.funny thing is when i let it get a qt low it seems to stop using as much,how can this be?im not overfilling with oil.i dont think he was able to use the oil baffle as the scat crank wouldnt let it fit.anyone got any ideas?
oil COnsumption until 1 qt low
- Thread starter jdsduster
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Valve seals? What do the plugs look like? Same for both heads?
Are you running gapless rings by any chance ?
diymirage
HP@idle > hondaHP@redline
If it leaks/burns/disposes oil until it reaches a certain level my first question is "how do you determine it is a quart low"?
Do you pour in a measured amount, check the dipstick and then it starts to disappear, or do you go by dipstick alone?
My second question is, your builder suggested you run it without a PCV?
Do you pour in a measured amount, check the dipstick and then it starts to disappear, or do you go by dipstick alone?
My second question is, your builder suggested you run it without a PCV?
quart mark on dipstick,he said to run pcv,not sure on the rings, as he recently closed his shop.very respected builder on here.no way of getting ahold of him now. he used a scope and seen no signs of oil on the valves.valve seals were new with the magnum eddy heads.
nm9stheham
Well-Known Member
Leakdown is not really a sure indicator of oil consumption. So I don't get that as being positive proof that it should/would not burn oil past the rings.
Are you seeing oil smoke out the pipes on hard acceleration? Or at any particular time and operating conditions?
Are you seeing oil smoke out the pipes on hard acceleration? Or at any particular time and operating conditions?
How many miles on the engine? It's probably broke in by now but...... Does it have a windage tray? Deep pan? Capacity? If it has a 7 quart pan just run 6 quarts if that's what it likes. I wonder if the crank isn't picking up oil. It burns a quart off and quits happening.
replicaracer43
Grumpy Old Man
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How about a picture of your PCV system and valve covers/valve cover baffling?
yellow rose
Overnight Sensation
A quart in 500 is a big issue.
You need to drain the oil, and add back what the oil pan calls for and then check the full mark.
You could be overfilling it.
Otherwise the ring seal is crap, or you have a seal/guide issue or its pulling oil past the intake gasket.
BTW, you need a PCV. There is no reason NOT to use one.
You need to drain the oil, and add back what the oil pan calls for and then check the full mark.
You could be overfilling it.
Otherwise the ring seal is crap, or you have a seal/guide issue or its pulling oil past the intake gasket.
BTW, you need a PCV. There is no reason NOT to use one.
was a 300 hp magnum,used 0 oil.dipstick is the same.no windage tray,wouldnt fit.even made bigger baffles under valve covers.if its rings thats going to suck,pulled it after 400 miles and took it back to builder,couldnt find any major issues.if its intake issues wouldnt he have seen it with the scope?stock oil pan.
Just 5 quarts with filter I presume?
nm9stheham
Well-Known Member
Re-read the OP's 1st post.... so the builder had it on the stand and pulled off the PCV and the engine stopped smoking? Am I reading that right? Was the smoking that stopped out of the tailpipes?
If the above is correct, then it sure seems like crankcase pressure from blowing past the rings and the PCV was pulling it all into the intake. If you put the PCV back in place and ran it like that with the catch can, that may explain why the catch can is not getting much.... and it depends on how the can is plumbed in.
Dumb question for everyone: What does insufficient sealant on the rocker studs have to do with this? Are some stud holes open into the intake runners in the Edelbrock Magnum head? (The Performer head I suppose...)
OP do you have info on the piston brand/model and the piston to bore clearance that was used? Fresh bored block, right?
If the above is correct, then it sure seems like crankcase pressure from blowing past the rings and the PCV was pulling it all into the intake. If you put the PCV back in place and ran it like that with the catch can, that may explain why the catch can is not getting much.... and it depends on how the can is plumbed in.
Dumb question for everyone: What does insufficient sealant on the rocker studs have to do with this? Are some stud holes open into the intake runners in the Edelbrock Magnum head? (The Performer head I suppose...)
OP do you have info on the piston brand/model and the piston to bore clearance that was used? Fresh bored block, right?
funny thing is Chevy at one time used this as the benchmark for warranty !
I will try to find the picture.. but my brother piped his PVC hose into the side of his airfilter and sealed it .
This on a low 11 Sec 455 Firebird. I thought it was a prank when he first sent me the picture...lol
replicaracer43
Grumpy Old Man
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OK, I'm out. Good luck with your problem
yellow rose
Overnight Sensation
I know...they still use it. My dad bought a 2001 Camero and it used a quart in 500 and they said it was perfectly normal. It didn't matter to them that 99% of the public drives about 12000 miles per year, and check their oil about once a year. With those numbers, the pan would be long dry and th rods hanging out if a quart in 500 was standard.
hold on racer43 .i have a baffled valve cover ,pcv to catch can to vac. port on carb.
nm9- thats exactly what happened,yes, fresh 30 over magnum block,i have build info out in garage,ill go get it and check back
nm9- thats exactly what happened,yes, fresh 30 over magnum block,i have build info out in garage,ill go get it and check back
OK hold the bus here. If you put 5 quarts with a filter in you will burn off a quart in 500 miles. And then the consumption stops? How many miles have you driven before it needs more? Using a quart every 500 miles is way different than using a quart in 500 and then no more after that.
nm9stheham
Well-Known Member
OK. that clearance would be right for forged pistons but some of those 408 kit variations come with hypereutectic pistons, which run a much smaller clearance. If you have a kit PN that would be good.
Probably not any issue but it always pays to double-check.
nm9stheham
Well-Known Member
Well, others may comment but if the engine was running and smoking out of the pipes, and then the PCV was pulled off and the smoking stopped, then that is a pretty obvious sign that the oil was coming from the crankcase and through the PCV. No wonder a catch can was recommended; it may be that the PCV is still drawing most of the excess oil vapor slowly through the catch can.
How many qts are being added at an oil drain and with the filter being replaced? Or with the filter not being replaced?
i have all this documented,new engine ,odometer reads19,035,at 19,252 used 2 quarts,19,352used another quart,19,392 used 1/2 quart.19,481 used 1 quart.19,537 used 1 quart.pulled engine,sent back to builder.builder said all he could find was lack of sealant on rocker arm studs.put it on the dyno smoked bad,pulled the pcv and smoking stopped.he told me to run a catch can.thats where i am at.it still uses oil and smokes,i am just trying to find out why.i dont want to pull the engine again if i dont have to. i said it uses 1 quart then stops,well i quess that is not quite accurate,it doesnt seem to use it as fast,maybe i just dont drive it as much.either way it smokes and uses oil.
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