misery motorsports

I have a ls2 404 stroker with
ls3 cnc ported heads
decked 11:1
.650 lift cam
custom headers
victor jr intake
1" carb spacer
Quickfuel 850 carb
3500 stall torque converter
5:14 gears
37" tires
vehicle weighs 5200 lbs

this is in a desert off road race truck so im driving it hard for 50-250 miles at a time during races and occasional fun desert trips just cruising

ive had some issues since I got the motor built with PCV pressure ive lost a few rear main seals. I put -10 hose from both valve covers and from valley cover to a oil catch can with a filter on top of it and still has not fixed the problem. im getting sick of the oil blowing out all under the truck and sick of having to pull trans and torque converter and flywheel to change a seal and gasket.

do you think the moroso crankcase evacuation system will fix this? it has 2 bungs that weld onto exhaust and connects a hose to breathers and helps suck the extra pressure out?

WE TODD DID

iTrader: (2)

It shouldn't have that much pressure. Sounds like you have something going on with the rings/ pistons. Is it oiling the plugs? Something else to look at is the plug in the back of the crank. Make sure it's not leaking oil.

LS6427

iTrader: (2)

Fix the problem.....do a leakdown check. Thats crazy pressure.

.

Doug G

Been there.... I did the 2 3/8" hoses off the valve covers.... but also added a 3/4" NPT barbed fitting to the oil cap (drilled and screwed in) with a filter. Issue over.
Hope it helps/fixes.
I would try the cap/filter first (cheap, easy, and can return to stock if needed)

dogsballs

As above, shouldnt be doing that, adding extra breathers is just a bandaid. Heck most ls motors hardly breath.

Could be rings, glazed bores.

Does it pop the dipstick as thats thr first that goes? Otherwise could be something weird on rear main

Doug G

Mine was a fresh build with maybe 100-200 miles on it.

misery motorsports

the plug in the back of the crank is fine and not leaking. the dipstick stays in just fine and not leaking. plugs look great !!

do all 3 of my hoses coming from both valve covers and valley breather have to have there own breather/filter? cause right now they all go to -10 fittings on a oil catch can I made and share 1 filter.

the motor is built by a very reputable ls engine builder and its only a year old !! probably has 2k miles on it
its been dyno tuned by danzio performance
the rear main doesn't just blow out right away it normally takes a race or 2 until I notice oil underneath and then it gets worse and worse

WE TODD DID

iTrader: (2)

I don't think you have a crankcase pressure problem. Are you getting oil in the catch can? What type of seals are you using? Is the rear cover correctly aligned to the crankshaft? Are you positive that it's the rear main seal and not the cam sensor (if it has a rear sensor) or something else leaking down?

LS6427

iTrader: (2)

How was it broke-in...?

Was it warmed up and then within the first 2-3 miles and first 4-5 dyno pulls.....did it see WOT pulls...? If not....rings may not have seated properly.

Also...take the oil fill cap off...and temporarily plug all breather openings.........with the engine running do you get little puffs of air puffing out of it...? If so....you have a lot of blow-by going on.

Happened to my friends 427ci. He even blew valve cover gaskets it was so bad........but it was a really bad case. He pulled it and had it honed and rebuilt. 700 mile engine that was not broken in right. The tuner just idled it for 30 minutes....then treated it like a grocery getter all day on the dyno. ruined the engine........rings never seated.

.

WE TODD DID

iTrader: (2)

There is not really a "break-in" for the rings. Rings either seal or they don't. With a couple revolutions of the engine, they settle in and they're good to go. Happens before the engine is even started. Now if you have a shitty hone job (too coarse), it'll burn the rings up. The slicker the hone job, the better.... But you have to take in consideration in keeping oil on the cylinders. Really, the only engine break-in is for flat tappet camshafts.

MIGHTYMOUSE

iTrader: (59)

post some pics of the set up so i can get my head around it

no oil on any plugs i assume.

speedtigger

iTrader: (16)

I would not state the above as a rule. There are all kinds or rings out there from ductile iron to stainless steel. Each has different characteristics and needs. The ideal bore finish depends on the type of piston ring used. Some rings require a more coarse finish, while others a more fine finish hone. The recommended break-in also varies. While some piston ring manufacturers have some models that they say no break-in is required, most recommend that the engine is warmed up and and checked for any leaks or problems then run at moderate load increasing to full load through the mid-RPMs for several cycles.

misery motorsports

no oil in the catch can maybe just a film of residue at most.

the engine was broke in what I would of thought was the right way I obviously started it a few times at home no crazy revving or anything and let it cool then took it too the desert and did like
10 min drive at low rpm let it cool
15 min drive at 4k rpm let it cool
20 min drive at 5k rpm let it cool
then on the last cruise I opened it up good and drove it for 20 min and loaded it up and headed home

I have personally replaced the rear main 3 times total on this engine once when it was a stock ls2 and twice since its been built. and the first 1 I did not use a alignment tool or really align it but for the 2nd and 3rd one I watched a you tube video but did not have the tool so I just took my time and measured my gaps all the way around with calipers and got it as almost perfect as I can

1 time it was the gasket on the back up top leaking out and 2 times it looked to be rear main seal.

I will try and get some pics after work today and really really look at I. I just pulled the trans on sat and have not gotten a chance to get in there and check it out since

thank you for all your help

WE TODD DID

iTrader: (2)

Of all of the engines that I have built, I've never based the hone job on the type of rings that I use. I understand what ring manufactures recommend, but my personal findings say otherwise. I have a particular way that I have blocks finish honed, depending on the intended use of the engine, and I don't have ring sealing issues, ever. The rings don't care what finish is on the bore to seal, just as long as the bore isn't acting like sand paper and wearing them out. Again, you have to find a happy medium of a hone that will hold oil VS being slick. If you have a super slick hone job, it'll make good power and seal good, but the rings won't last because there's no oil on the bores. Let's say that you have a steel top ring, and ductile second... Going off ring manufactures recommendation, how would you hone that?

When I dyno an engine, I put it through a heat cycle, adjust valves, and start pulling on it. My emc engine last year had over 200, 4000 rpm sweep pulls on the same rings and hone job.

WE TODD DID

iTrader: (2)

With no oil in the catch can, I'm pretty confident that you don't have a ring sealing issue. Here's what I would do. Take the rear cover off, install a new seal and make sure it's not backwards. It's easy to get these mixed up. If you look at the seal, there will be very very small writing on it saying "this side out". After the new seal is installed in the cover, reinstall the cover letting the seal center the cover on the crank. Of course, replace the rear cover gasket too. I would also use GM gaskets, but I'm pretty sure that national seal makes their seals.

ATwelveSec02Z28

iTrader: (17)

When BES built my shortblock I was surprised how light the cross hatching was....

Although it was very apparent when the rings fully sealed, I datalogged the initial start up and could see the pan vacuum slowly increase then hold flat.

If you think you've got crank case pressure issues just do a leak down... That will tell you all you'll need to know

WE TODD DID

iTrader: (2)

There is a lot of power in a hone job. Friction and ring seal. Less friction, and better ring seal = more powa

Crossrider

Us header crankcase evacuation. Also go to And oil it help seal those rings.

G Atsma

Misery hasn't been here in 6 years

speedfreak440

iTrader: (9)

Oh there are some miserable people here, just look around LOL.