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Illustrated rebuilding of a L36 into a supercharged 3800...

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Old 02-04-2007, 01:46 PM
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Well, while I didn't have enough head bolt to do both heads, I did have enough to do one, so I'll skip ahead a little and finish the 1-3-5 cylinder bank.

With the head on, I've installed the exhaust manifold and rocker arms. Nothing much exciting to it. Things are just going back together the way they came apart. Since I only have one head on, I've got to tighten the rocker arm bolts one pair at a time, rotating the crank the correct number of degrees per the firing order.

The exhaust manifold has been painted with a hi-temp exhaust paint and cured in an oven @ 500 degree for an hour. The exhaust manifold bolts are a mix of studs and bolts (bolts go in the lower flange holes on #3 and #5 cylinders so they don't interfere with the dipstick tube.



With the manifold on and the torqued, time to finish out the cylinder head with the dipstick tube, valve cover, heat shield, plug wire loom, coil pack bracket and coil packs.



It'* starting to look like an engine again...

Next up, timing cover/oil pump/water pump/oil filter boss assembly.
Old 02-05-2007, 06:51 AM
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The timing cover was really nasty, so I spent an hour or so just scrubbing it down and removed the crank seal. Tried punching it out from the oil pump side but all the seal metal did was bend out. On the left side, front, theres a flat cast into the cover that the seal lip peeks out of. Using a mallet and a flat blade screwdriver, I managed to raise the outside edge of the seal and could then drive the seal out.

Putting the new seal in was a piece of cake. Set it in place, then drive it into the pocket with a wood board and a mallet.

Here'* the cover with the seal in place and the water pump back on.



I've been trying to figure out a way to pre-oil the engine before starting it up. Normally on the engines I've worked on, you can drive the oil pump shaft with an electric drill to pump up the oil pressure and fill all the passages. Since the oil pump on the 3800 is driven directly from the crank, this isn't possible.

While cleaning up yesterday, I got a momentary flash of brilliance....here'* what I came up with:



What I've done to the filter boss is thread a compressor fitting into the spot where the oil pressure sensor/fuel pump switch normally goes. Now, when the engine is completely assembled I can pump the oil in using compressed air. What I will do is fill the compressor hose full of oil, plug it into the fitting, and run about 10psi of air pressure behind it to force the pint or so of oil in the hose into the engine. Filling the oil filter up with oil before screwing it on will fill the pump with oil and prime it.

Anybody ever tried that before?
Old 02-05-2007, 01:20 PM
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You can pack the oil pump with assembly lube or something like that.
Old 02-05-2007, 05:00 PM
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The oil filter housings look like they have the same bolt pattern between the S1 and S2....hmm.....I wonder if you wanted to add an oil cooler, you could possibly use an L67 S1 adapter??
Old 02-05-2007, 07:06 PM
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I didn't read through the entile thread so this may have been answered already. Isn't the L36 FWD different than the L36 desighned for RWD. If so, what are the differences.
Old 02-05-2007, 08:33 PM
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I believe the only differences are in the intake and exhaust manis, and the flywheel. The blocks are the same.
Old 02-05-2007, 09:38 PM
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don't forget the oil pan the drain plug on an FWD is on the long side and on the end for an F-body (RWD)
Old 02-05-2007, 09:50 PM
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Originally Posted by fantastic88
Isn't the L36 FWD different than the L36 desighned for RWD. If so, what are the differences.
No, they are the same basic short block regardless of FWD vs RWD use. They both are based on the same block casting. Only differences are between the L67 rotating assembly and the L36 rotating assembly. I thought that the Camshaft grinds might be different, but every place I have looked up replacement cams lists the same Melling MC1292 roller cam as a replacement for both N/A FWD and RWD motors..as well as the */C L67. If someone cares to look up GM part numbers and post them, that would be great.

In a Long Block state, the differences are:

Entire intake manifold - RWD motors have a manifold with the TB on the Accessory Drive end of the motor. FWD motors have the TB on the Bellhousing end of the motor. All the FI related components are also different because of the manifolds.

Valve covers - Same design, but the RWD ones for the F-Bodies are die cast metal vs. Composite. Doesn't mean much, but is can be handy if you want to modify them.

Oil Pan - FWD motors have a rectangular pan with the drain plug on the left side of the motor (rear when it'* in the car.) RWD motors have a pan with two large notches taken out of the bottom of the pan. One allows the motor to clear the crossmember, the other allows the exhaust Y-Pipe to cross under the motor. The drain plug is also on the centerline of the motor at the bellhousing end of the pan. In a RWD installation, the motor is angled slightly towards the rear, so the drain plug is positioned at the lowest part of the oil pan. FWD motors sit level in the mounts.

Harmonic Balancer - Three different flavors: Single serpentine belt for the RWD motors, Single with enough metal for a double row for L36 FWD, Double belt row for L67.

Oil Filter Boss - RWD motors need to clear the crossmember, as well as the power steering rack. So the filter boss points straight towards the front of the car. The fitting for the oil pressure switch is also moved above it. (In an F-Body, the engine bay is ultra-tight fitting to the motor..hanging the oil pressure switch off the side would probably hit the fender well)

Here'* the two side-by-side:

Old 02-05-2007, 11:03 PM
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Originally Posted by sandrock
The oil filter housings look like they have the same bolt pattern between the S1 and S2....hmm.....I wonder if you wanted to add an oil cooler, you could possibly use an L67 S1 adapter??
You probably could. I considered using the LN3'* oil filter boss on this motor (before I found an L36 in the salvage yard) The bolt pattern looks the same to me too. Only differences I can spot are the position of the oil pressure sender/switch. The ones that mount it vertical on the boss raise a problem...it would interfere with the Power Steering Pump. If the sensor sticks straight out sideways like these do, then I don't see why not.

Getting back on track with the assembly...

Time to put the oil pump back in the timing cover. I checked the clearance between the outer rotor and the timing cover, then between the inner rotor "teeth" and the outer rotor. All was well, so they got slathered up with assembly lube and the cover put on.



With that done, the timing cover can go back on with it'* gasket. Line up the oil pump rotor with the crank (dimple is one slot counter-clockwise of the timing chain gear mark) The large timing cover bolts get 22ft-lbs and sealant on the threads. The crank position sensor goes on at this point along with the dust cover.



Next up, the harmonic balancer, power steering pump, and accessory brackets. (Hopefully, the missing head bolts will show up and I can finish the 2-4-6 cylinder bank tomorrow.)


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