DarrenGC

So it looks like my LNF is toast, im torn between taking a loss on my car and selling it as-is or trying to get it back to working order.

Used LNF engines are few and far between in the wreckers north of the border, but a quick search on car-part.com shows plenty of LHU engines available, how do those work swap wise with an LNF? Does the stock LNF ecu work? Are there any advantages of using a LHU as opposed to spending double the money on a ZZP LDK drop in?

Since i'm going back to school, the cheaper I can fix this car the better, i'm not super concerned about performance right now, but I dont want to buy a block thats not going to handle power should I decided to upgrade in the future.


Car as it sits

LNF with 100k km
Catless OEM Downpipe w/ defouler
GMS1 Map Sensors
Injen Hot side CP
K&N Intake
Unknown Tune


Are any of these parts NOT compatible with a LHU or LDK? What needs to be used off my LNF?

ForceFedDork

it is up to you to determine how much your car is worth broken, vs how much it'll cost you to fix it, vs how much worth fixed.

I didn't notice you saying anything about what is broken in your LNF? (i guess im just curious). also the comment "unknown tune" is kinda scary after what i've seen people do to these tunes. everyone is a freaking expert, but when you start asking questions you realize they dont understand the most basic of engine control theory or any control theory what so ever for that matter.

rant aside, read this post: LNF-LDK-LHU Compare

from what i gather it's pretty much a drop in, you just have to deal with the factory vacuum pump on the LHU, ZZP talks about that as well, they seem to have a block off plate?

from the hptuners post it sounds like the injectors are different so either use ur old injectors or tune for it.

exninja

iTrader: (1)

All are compatible. The only thing you'd need to do is fabricate a plate to block off the vacuum boost pump at the end of the exhaust cam.

Short answer is yes, totally compatible. There are a few more small things to swap from your LNF to make it easier like int & ex manifold, fuel rail, etc.

exninja

iTrader: (1)

IOW, what he said Replied at the same time

DarrenGC

Yeah the unknown tune bothers me as well, I would more than likely have a stock gms1 tune flashed with a new motor just in case. I know nothing about tuning so I think that is my best bet anyways until I eventually get it dyno tuned.

My lnf as mentioned in my other thread has an intermintant misfire issue and fuel in the oil leading me to believe piston ring failure. I will obviously do a compression check to verify before I start pulling things and spending money in don't need to spend, but I'm doing my research and preparing for the worst as time will be limited. I'm not sure how long this motor will last with lack of proper lubrication.

DarrenGC

Also worth mentioning, it could very well be a stock gms1 tune already, I'm just assuming it's not because I didn't do it and the ecu seems like it is not the original one.

Could be a canned tune, could be a gms1 ecu, I'm not sure so assuming it would need to be flashed to stock.

DarrenGC

One more stupid question. Does the LDK/LHU Have to come from a manual car or will my flywheel bolt up to one that was originally automatic? Id imagine it would but I would like to verify,

exninja

iTrader: (1)

Your flywheel will bolt up. However, you've opened up a can of warms. Since you've got it open you may as well replace the clutch. Since you're replacing the clutch you'll want to at least resurface the flywheel. It's been preached to not resurface the flywheel because GM said so. I resurfaced and have been fine. Now that the cost of an OEM flywheel is through the roof, it's a harder decision. Which is worse, removing a few thou from the flywheel, or trusting an aftermarket's tolerances with a supposedly ridiculously-tight tolerance stackup?

DarrenGC

I'd get it machined personally.

Did you specifically ask your machine shop to machine as little as possible or just a normal machine job? I cant imagine a few thou is that big of a deal. Id prefer that to OEM personally.

exninja

iTrader: (1)

The shop I took it to is a quality place and I didn't specify anything. I also didn't realize that the flywheel is stepped and both surfaces need to be ground. My place must've done it right because I have no issues, but you may want to make sure your place sees that.

exninja

iTrader: (1)

If they take off an excessive amount, a shim is a possible solution.

Devin86

I just got a fly wheel from zzp way cheaper doesn't have a GM stamp same thing tho, forget resurfacing.

Snail_SS

iTrader: (3)

That ^

63 Nova SS

iTrader: (3)

Resurfacing isn't recommended because it can cause your throw out bearing to over travel and ruin it.

Bandit2941

If it was me I'd be taking that engine apart and seeing what's wrong with it first. And getting a good tune. Depending on how much of the work you can do yourself this might be a much cheaper option. Of course the problem is always being without a vehicle.

firehawk618

iTrader: (2)

I know this is a common belief but I really REALLY have a hard time believing that a few hundredths of an inch is going to make or break the ability of the slave/TOB to do it's job.

I know the system sucks and all but if you think about it, if that tiny bit of difference really mattered wouldn't ya think the clutch pedal engagement would be a hair off the floor stock then that minuscule amount shaved off the flywheel just ruined it?

Just my .02 cents for what it's worth.

DarrenGC

Thats the biggest issue, is having the weeks of downtime on my vehicle, I dont have my own garage but my buddy owns a shop, for a couple hundred$$ we could tear it apart one weekend and put it back together the next, but for that I would need a replacement engine waiting in the wings because from what I understand the proper way to pull the motors in this car (along with most other compacts) is to drop the subframe which would render the car immobile even for pushing it around.

Ive thought about a rebuild, but I feel like the machine shop work + parts would cost me almost as much as a low KM used LHU, which is the better of the 2 motors anyways.

Its definately a thought, and come january if I think the motor is cooked i might pull the head off and see, I'll probably rebuild the engine over time to have a spare if the LNF is salvageable, or part it out if its not.

DarrenGC

I am sort of in agreement here from the theory perspective. I dont know much about these cars in particular, but I cant imagine a couple thousands of an inch making a big difference on something like this. I work in automotive manufacturing, a couple thousands of an inch is usually mass manufacturing specs, even on braking components, pulleys allow even more runout. I can imagine even GM's manufacturer for the flywheel is the same, unless its being hand made by a tool maker who can check it through the process, there is going to be slight differences in the production.