Why does my new motor smoke???

[84blkstang]

I was driving today and i stomped the gas around 4-5k i looked in my mirror and there was blue smoke everywhere, and it wasnt tire smoke. This really pisses me off because i just spen about 2k on this new motor and parts. It is the stuff in the sig with forged speedpro pistons, .30 over. new bearings and everything else, i am so frustrated, i hope somthing isnt f-ed up. It burns about a quart every 1500 or so i know that probaly good but i have always heard that the 5.0's are notrious for this problem.

 

[bubba-dough]

I would be getting a hold of my engine builder. Sounds like the rings to me.

 

[5spd GT]

A properly rebuilt 5.0L will go well over 100,000 miles without any problems taken care of. Your engine builider messed something up it appears...sorry man It still could be "fixable" so don't fret yet

 

[vristang]

When I originally put together the 408 in my sig I ended up with low tension rings (they came in the stroker kit). This was causing excessive blowby (20% leakdown), which was blowing tons of oil through the pcv.

Now I have rebuilt the motor using gapless Total Seal top rings. Leak down is at 6%. But now the engine vac seems to be so strong that it pulls tons of oil through the pcv.

In both cases I had large puddles of oil accumulating inside the intake. I would suggest pulling the inlet hose on the TB and taking a look inside the manifold.

If you find oil check to see if you have vac or pressure in the crankcase.

Crankcase pressure can be checked by capping off the hose that runs between the TB and Valve Cover. Then cap the pcv/upper intake line at the pcv, being sure to cap off the line to the upper, and hooking a vac gauge to the pcv outlet. When you start the car you will get tons of pressure if the rings are bad (or low tension rings). Or you can do leakdown/compression test as well. I think the vac gauge is easier as a starting point.

If you suspect that high engine vac is the culprit you can check that with a vac gauge as well. This time leave the TB/VC hose and the pcv hose hooked up. Splice the vac gauge into the pcv line (the smaller fitting on th F-type pcv's is very convenient).

This will tell you if oil is being pulled or pushed from the crankcase.
Also, check and see what the engine vac is like when all lines are hooked up correctly.

Good luck
jason

 

[84blkstang]

mine is carbed for right now, can you descrbe that again for a carbed application? thanks in advance.

 

[srothfuss]

The PCV would be the same between Carb / EFI (the parts just plug into different locations)

 

[84blkstang]

ok so the pvc could be the problem also?

 

[srothfuss]

The best thing to verify would be to take off the carb and see if you have oil in your intake. If you do, you should buy a oil seperator to install in the PCV line to help pull out any oil that is getting by.

Also, how many miles are on your new motor? You (probably already) know that you need to break the motor / rings in for the first 500 miles before getting "on it"

 

[nosmatt]

Rings should seat in the first few minutes of operation.

do a leakdown......... most carb setups do not have a proper pcv setup that i have seen, at least not ones the typical hot rodder sets up. most have breathers or something...... if your using the stock 79-85 oil baffle setup on the valve cover, it should not be pulling oil in........ one way to know for sure, pull the carb real quick, if there is oil in the plenum, you know where to start.

if there is not....... you could pull the intake, and check for oil in each intake port, chances are, you may find one or more, this would be indicitive of a poorly installed, or poorly aligned intake to head seal.......could be pulling oil from the lifter valley.

anyhoo, good luck, hope it's something easy! and be glad you have a carb, a manifold pull is maybe an hour, if you drink alot and take too many breaks

 

[vristang]

mine is carbed for right now, can you descrbe that again for a carbed application? thanks in advance.

Sorry I didn't catch the carb in your sig. All of the same principles still apply though.

Let me know what you find.

 

[txstang84]

i run a carb'd 306 and the only time mine ever pulled oil from the pcv was when i removed my baffle to install roller rockers...the poly locks interfered w/the baffle...i installed a shorter baffle in the original covers and the problem all but disappeared. since then, i've installed taller valve covers and the problem is gone.

mine burns oil, but it's cuz the engine's been rode hard and put away wet too many times in the past ten years since I rebuilt it...

 

[84blkstang]

the motor has about 20K i didnt get in it till about 5k miles because i wanted to be safe, the oil is changed every 3000 with castrol syntec 10W30 and a motorcraft Fl1a. The pvc valve is on the passenger side breather it goes to the carb, and everything is new, i just hope it isnt rings or somthing.

 

[txstang84]

when did you start putting in synthetic? I've read a few places that if you don't let it break in with regular oil that the rings won't seat correctly...

do you have a baffle in your valve cover where your pcv plugs into? if you don't have some kind of baffle, oil gets slung into the pcv from the rockers, and it's go nowhere else to go except into the carb...

 

[ExplodingGopher]

when did you start putting in synthetic? I've read a few places that if you don't let it break in with regular oil that the rings won't seat correctly...

This is very true, synthetic oil is simply too slippery for proper ring break-in. I used Valvoline Racing SAE 40 for my breakin and am still using it until a few more thousand miles. After that, then i will switch to synthetic. Basically, the crosshatch pattern on the cylinder walls on a new engine act as sort of a "file" to wear the rings to seat to the walls better, if you or the dumbass engine builder used synthetic oil for breakin, you will have one nice oil blower there. Sounds too me like the rings aren't properly sealing to the cylinder walls. You could always tear down and re-ring/hone but who has the time to do that.

 

[vristang]

the motor has about 20K i didnt get in it till about 5k miles because i wanted to be safe, the oil is changed every 3000 with castrol syntec 10W30 and a motorcraft Fl1a. The pvc valve is on the passenger side breather it goes to the carb, and everything is new, i just hope it isnt rings or somthing.

I jumped all over my motor at about 150 miles. You have alot more patience than me!

As mentioned by others synthetic oil will make ring seating less likely if used for break in.

The only way to know anything for sure though, is to do a leakdown &/or compression check, and look at the vac readings, as I described. Once you can eliminate the rings as the source of the problem, you can move on to modifying the pcv system, or making other changes.

Good Luck
jason

 

[84blkstang]

OK for the breaking i used regular 10w30 for the first 1000 miles, than i continued to use it till 3000 miles than i switched to syntec i will do all the leakdown when iget time. The baffles are on the valve covers also,

 

[txstang84]

hmmm, ok, if you broke it in with 10-30 for 3000 miles, you should be good on the ring seating...i guess go ahead and do the lkdown ck.

have you already pulled your pcv to see if there's oil puddling in the tube going to the carb?

and like Jason mentioned; you didn't get stuck with low tension rings did you?

 

[Grn92LX]

How did you break it in? Did you put a load on the engine to put cylinder pressure into the engine? Did you take it up to a higher rpm like 4-5k and let it decel in gear?

Sounds like a poor break in, bad hone job or bad install

Heres how to properly break in an engine. Read Barry R's response http://bbs.hardcore50.com/vbulletin/showthread.php?t=12510&highlight=engine+break Though its to late now, you know for next time if/when you repair it.

I broke mine in very similar to the link I posted, changed the oil/filter asap and changed it about 4 times by the time I hit just over 500 miles. I then switched to synthetic after I talked to Mark O'neal from probe/chp. He said 500 miles is fine. I have about 1000 miles now, doesn't use a drop of oil and has seen 6500 rpm quite a few times. I use mobil 1 10w30 and a mobil 1 filter. You should have used 10w30 or 10w40.

 

[ninety15.0]

I have about 800 miles on my new motor and have changed the oil twice so far with castrol gtx in 10-40 with an FL1A. When i broke the car in we got the thing running, timed, and adjusted then spent about 250 miles under 3500 rpm, and i would only get on it about 1/2 throttle. Changed oil with conv. again and would bring it up to about 4 grand with 3/4 throttle every once in a while. changed oil at 750 mi. with conv. and now its sees 4500 a little more frequently but i still havent floored it for any extended period and it hasnt been past 5k yet. Im thinkin about the synthetic switch at about 1500 or 2000 miles...probly 5-40 No burning oil/blowby/drips and car runs real strong through all RPMs. Ive heard its real important to really vary the rpms...and never stay at one rpm too long.

 

[84blkstang]

the rings are the standard speed pro rings in the summit rebuild kit, after we fired it up my dad revved it to about 3k and held it there for a little bit than revved it to about 4k, after a few minutes of running between 3 and 4k he let it idle, down and we adjusted the carb and timing.