S/C vs. N/A differences (series 1)
 

I know there are a few internal differences. Since I am going all out on the rebuild of the S/C motor, and replacing many internal parts along the way, I am in need of this information. I can find many S1 N/A's around here, and 1 in particular since it only has 80k on the clock. So far, I only know that the pistons and connecting rods are different. The crankshaft is the same. In particular, I want to know if the camshaft is the same, but any other parts that are different please post. Maybe once a complete list is done, maybe post it in tech info.

As far I know other then the block n/a is bascilly compelte different

Not *completley* different, but the major components were upgraded internally due to the higher stress levels. It's obvious that the intake manifolds are different, and the accessory drive, but I am looking for the not-so-obvious. The FSM gives different directions for connecting rod-piston separation between the 2 engines, which tells me those are different in design. From my research, the crankshafts are identical (which doesn't make sense, other than GM overbuilt the crankshaft). The heads are the same between the 2 models too, though the springs and valves may or may not be (again, more research is needed for that). For now I am going to assume the cams are different, but I am hoping to have a definitive answer while at work today. EDIT: Autozone lists the same camshaft for both applications.

Here's the list as I know it:

Pistons (pistons and rods use a sleeved/bushing wrist pin, rather than floating like the L27)
Rods
drive axles (much beefier)
harmonic balancer (don't re-use your original 93 balancer. Get a new one)
fuel pump (new also. This and the HB are long past due)
LIM (duh)
accessory brackets
wiring harness
PCM

This is off the top of my head. I've probably overlooked one or two little things.

Moving to General Chat.

Ooops...I guess I should have stated "long block" differences :? Basically, the rotating mass (w/exception of the crank and cam) is the only difference between the L27 and L67. Remember, only discussing internals, no accessories.

My balancer looked good from what I could tell, but will replace it when this Frankenmotor is running. Same with the fuel pump...will prob go with a Walbro unit.

Thanks for the input guys...I will have pics of the teardown up soon, already have the radiator-side head off, should have more comming off tonight or tomorrow.

I posted the other 'non rotating' stuff simply because someone else in the distant future may dig this topic up for a different purpose than you are needing it for.

eventually im gona put and SC'd drivetrain in mine...after this one runs it's course...but that would just mean swaping them out...so....but i did have a question...would you/should you stiffen the body or something...or are there any other mods needed to go from N/A to SC'd?

Ya need any help? I also have an engine hoist if you want to pull the entire motor out

The frame and subframe are identical. But the L67 powered cars USUALLY have FE2 suspension.

I already have a full-fledged SSEi, but my problem, as clm2112 found, pickings are extremely slim on l67's here, and when one is located, it's either been pillaged beyond salvage, burned, or already taken. Same with those transmissions. Another option is to buy a remanned motor, but those aren't cheap. So, the only logical thing to do is rebuild what ya got. Since my son will be here this week, funds are now pretty limited, but I still want to get this car going. I won't give up on her...already gone pretty far with her as it is. Since the L67 and L27 share alot of the same parts, it only makes sense from a budget standpoint to seek out a low-mileage L27 to source parts from, or better yet, transfer L67-spec parts to it. I found one here at the u-pull-it w/ less than 90k on it that had been t-boned, and everything inside the motor looks near-new. Just transfer my L67 pistons and rods and it should be good to go!

I may very well need that hoist when I go get that motor. A local shop is doing me a huge favor by letting me do half the work for this buildup, and the other half of the work has been done via trade on some car audio equipment I am not using, so parts is all I need to come up with.

I'm sure that you could use you internal parts with the L27 Block and crank.... But, understand that taking pistons from another motor that already have wear on them and installing them into another block will only create more wear... As well those rods that had spun bearings will have to be resized..

Have any of the pistons punched the head or left a mark on the head / piston? This could be bad news for the wrist pins and the pistons...

As well if you do use the L27 block you will want to remove that crank and have it turned to ensure that its perfectly smooth and within specs.. If the crank is in good shape than say have it cut .005 under and go with .005 oversized bearings...

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The plan is to take out the pistons of the L27 and have the bores gone over to knock the glaze out. Re-ring the L67 pistons as I am sure they have seen better days, plus get me back to original compression specs. At 90k, I doubt the L27 heads need attention but I will know more when they come off. I do know the L67 heads I have had seen MUCH better days, and would say they are good for nothing more than core-outs. (EDIT: No, the pistons didn't strike anything on the head that I pulled, I think I am all good there). The crankshaft I will have spec'd before I have any machine work done on it, and same with the connecting rods (though 2 bearings spun, I am only concerned about one of them needing attention, and if it is out of spec, I know where I can go get a few pistions in Orlando that are w/in spec). I also discovered a HUGE crack in the radiator-side exhaust manifold, but I can have that welded right up here at work.

I have, at the most, 3 months at the shop that the car can stay, as the owner will be away for 4 months, and the techs there are more than willing to work on my car for a few bucks straight to their pockets, plus I can go up there on my days off of work and check on progress. So I have alot of control on what goes into this motor and time can be taken to make sure I won't have to do this again for a long time to come.