Why no hybrid L61/LSJ builds?
01-26-2013, 03:40 PM
#51
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not really.
I had a thread on the LSJ/L61 hybrid I did (lsj bottom end, l61 head) but it got messy because it was when I was figuring out what I needed to do.
swapping heads is pretty easy. There's nothing that really needs to be modified.
it's only when you want to use a plastic intake manifold that the LSJ head needs to be modified slightly. and those mods are all related to the intake flange for the PCV system to work properly.
head-to-block interfaces are all extremely similar. the only thing you need to change inbetween them is the headgasket... for LE5 block based hybrids, you need to use a headgasket that is 88mm bore or larger.
I had a thread on the LSJ/L61 hybrid I did (lsj bottom end, l61 head) but it got messy because it was when I was figuring out what I needed to do.
swapping heads is pretty easy. There's nothing that really needs to be modified.
it's only when you want to use a plastic intake manifold that the LSJ head needs to be modified slightly. and those mods are all related to the intake flange for the PCV system to work properly.
head-to-block interfaces are all extremely similar. the only thing you need to change inbetween them is the headgasket... for LE5 block based hybrids, you need to use a headgasket that is 88mm bore or larger.
01-26-2013, 05:57 PM
#53
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the exhaust cam is shorter.
you can run the L61 cams in the LSJ head, but one of the cam journals in the head will be empty. It has to be filled with either a blank end-journal from a spare cam, or welded shut somehow. Not having a journal in there will cause a tremendous loss in oil pressure.
so far as cam-sensor, the cassette-style wasted spark ignition uses CSI (compression sense ignition) that fires in wasted spark (1 and 4 fire together, 2 and 3 fire together)
since only one cylinder is on the compression stroke, only one cylinder fires.
what the CSI part of the ICM circuitry does is measure the resistance across the spark plugs on the coils that are firing. The one with higher resistance is on the compression stroke, so the ICM generates a cam signal based on that.
by losing the cam sensor, you lose sequential injection. But, much higher than 3000rpm, the engine is on batch fire anyway, so sequential only really hurts MPG a tiny bit.
L61
LSJ
early model L61 showing the different length camshafts
LSJ showing camshaft length detail
again, L61 cam flange
LSJ cam flanges. the intake flange is identical to the L61, but the exhaust flange is totally different than the intake flange.
L61 exhaust cam is too short for the LSJ
L61 intake flange detail
LSJ intake flange detail (you can see the offset PCV hole)
plastic manifolds don't like the LSJ intake flange. I modified this by cutting the manifold clear of the hole, then drilling/tapping the hole for NPT thread and running an external line
L61 upper rad hose connection detail. The hole to the right is supposed to have a nipple.
on the LSJ, there are two holes.. one for the ECT sensor, and another for a banjo fitting for a water pipe that goes across the head up by the fuel rail
styrofoam look of the lost-foam cast heads (L61 here)
sand cast heads look much nicer (and no seepage problems)
also, the LSJ and L61 use different spark plugs. use the plugs that match the head (taper seat vs. crush-washer seal).
02-13-2013, 12:09 AM
#64
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maybe there is more knowledge in this thread then the VVT thread. Anyone know if you can use LE5 aftermarket cams in the LAP? a lot of LAP guys would love to have cams.
also 2.7 would be sick ****
also 2.7 would be sick ****
02-13-2013, 04:59 AM
#65
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however, again, my knowledge of the VVT setups is extremely limited at best.
02-21-2013, 04:33 PM
#67
what you are refering to is a 2.1 big bore and there are several out there the 2.4 sleeve is also .060 thick same as lsj and you can run a lsj head on a 2.4 no problem all you need is a le5 head gasket and custom pistons you can use stock length rods
