And another one bites the dust (engine that is)

[superdave]

It looks like the L31 in my truck is giving up the ghost. Oil consumption has suddenly taken a turn for the worst. 187k on the engine, so I shouldn't complain. Was using a quart about every 2500 miles, that got down to 1500 miles, and now I have thrown in 4 quarts since my last oil change, 2500 miles ago.

I'm thinking it's hard to beat the deal on a new L31 crate engine with a 395 cam stabbed in for sport while it's convenient. I have rebuilt quite a few engines in the past, but an all new one for $2000ish seems hard to beat. It will also allow me to git-r-dun over a weekend rather than putting me down for a rebuild.

Anybody stumble across any better deals on something similar.

edit: I am going to poke around under the hood this weekend and see what's up. I'll check the compression and probably do a leakdown test. The other thought is maybe an internal intake gasket leak, drawing oil into the intake. If the compression looks good, maybe that is a possibility.

 

[SAATR]

Intake valve stem seals are another possibility, if compression is good. I couldn't see ring seal having gone down the tubes that quickly, though testing will bear that out. A stuck PCV can also cause excessive oil consumption. An internal intake gasket leak is certainly possible, though I would expect symptoms other than just oil consumption.

 

[Supercharged111]

Do a compression test and see. Mine was thirsty a couple years ago and a simple long road trip took car of it. I think the rings were sticking, that's the only explanation I could come up with. Back when I had the 289 in my Crown Vic, it would drink a quart per tank of fuel. The valve spring retainers were smashing the umbrella seals so most cylinders literally had no valve seals at all. I don't think a worn Vortec type seal would drink that hard though.

 

[superdave]

Okay, I checked compression. I have a three at 170, three at 180, and two at 185. Nothing jumps out there as a dead player. All the plugs looked good. I just put another quart of oil in after 250 miles. I am getting enough part throttle spark knock that I really feel I'm burning it somehow and not leaking it.

I also question the possibility of an internal intake manifold gasket leak and the valve stems. I'm not getting any visible smoking or any leak other than the typical, greasy underside. No visible drips. I hate to spend $2500 on a new engine without checking those out first. Of course, those are items you have to do and hope it was the issue. No way to check (that I know of) without some exploratory surgery.

 

[Supercharged111]

Try Seafoaming it. The fuel system and the oil, you may also have some massive carbon buildup causing spark knock and ring stickage.

 

[superdave]

Just Seafoamed thru the vac line to the brake booster about 2 weeks ago

 

[Supercharged111]

You'd think the detonation would be gone. you put any in the tank?

 

[superdave]

You'd think the detonation would be gone. you put any in the tank?

Nope

 

[superdave]

I guess I'll replace the intake manifold gasket and put in umbrella valve seals. I still have the poppets, so an spider upgrade will happen too. If it doesn't fix the issue, I still need the injector upgrade on a new motor.

Now since I'm the king of "while I'm at it", the temptation to do so much more is what always gets me. I mean, a few more bolts and I can have the heads off and gone through. Good time to replace the water pump, and while that's off, should probably replace the 20 year old timing chain. Hey, the cam's right there and the rockers are off for valve seals...new cam time. If I am going to do all that, might as well just pull the engine and do it right. Should I throw in some new rings and bearings now? Let's get that crank turned if I'm that far in.

 

[Cokeman95]

I guess I'll replace the intake manifold gasket and put in umbrella valve seals. I still have the poppets, so an spider upgrade will happen too. If it doesn't fix the issue, I still need the injector upgrade on a new motor.

Now since I'm the king of "while I'm at it", the temptation to do so much more is what always gets me. I mean, a few more bolts and I can have the heads off and gone through. Good time to replace the water pump, and while that's off, should probably replace the 20 year old timing chain. Hey, the cam's right there and the rockers are off for valve seals...new cam time. If I am going to do all that, might as well just pull the engine and do it right. Should I throw in some new rings and bearings now? Let's get that crank turned if I'm that far in.

I like the way you think lol. I'm the same way.

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