Gas powered deisel maxima? who had it?

[Mack]

someone had a deisel maxima they had converted to run on gas, I was just wondering how it was running, as I am planning a long rod deisel block motor for my Z. I know they had to re drill the head bolt holes out to 12mm instead of 10mm. other than that , any other modifications to the block or head? thanks in advance!

 

McAdam

[DAW]

That would be me. The engine runs great. Very smooth, great low-end power, reliable, and starts easier than any car I've ever had in any kind of weather (the LD28 starter probably has more power than an L28).

It's in a daily driver for now. I used an N42 head to make about 10:1 c.r.

 

I may omit something since I built it about five years ago...whatever L6 head you use you'll drill the headbolt holes from 10mm to 12mm, preferably using a drill press. In some places you'll use the LD28 headbolts with an extra washer, in others you'll use early (70s-80s) BMW headbolts (from either an I4 or I6). Torque to LD28 specs. I may have drilled some water passage holes in the block deck to match coolant passages in the head (I can't remember if it was this engine or an LZ4 block with L4 head that I did this on). Drill block at dipstick boss in block for rear sump pan use if motor is going into a Zcar.

 

I used an LD28 head gasket (which come in different thicknesses). In fact, it's a sturdy gasket and I reused the same one. You'll need to remove the timing cover section of the head gasket and replace it with an L4 or L6 section.

 

Use a timing cover and chain from an L20B. I wanted to use the LD28 water pump as it obviously had more capacity than an L4 or L6 pump. In order to do this, I had to grind some clearance between the impeller and L-series timing cover. You could use a stock L6 pump without any grinding. I think I also had some minor pulley alignment problems when I retained the LD28 water pump onto the L20B timing cover, but this was partially due to power steering pulley. I used the hefty LD28 alternator. It has a big vacuum pump integral to it. (Might be useful in a turbo car) I removed the impeller to disable it and blocked oil flow to it. I believe doing this also increased the capacity of the oil pump because the oil system to the vacuum pump appears to be of significant volume. Given the larger volume of the complete oil system of the LD28 I used the LD28 oil pump as I figured it was closer to an L28ET pump than an L28E pump.

 

You can use the entire f.i. intake and EFI system from an L28E for starters.

I lightened the AFM door spring pressure slightly and placed some added resistance into the water temp sensor circuit to enrichen and I think I set initial timing to 12 degrees. Timing is read off the flywheel and it only shows TDC (because it's a diesel block) so you'll need to figure out 12 degrees.

 

I think that's about it...I'm using a 3LN71B trans behind it using the lower stall speed torque convertor and have no problems, it jumps forward when you apply power off idle. This trans has a hydraulically locking convertor which is nice because it drives like a 4spd a/t. There is a significant difference between the tooth profile of the LD28 ring gear and starter gear than that of the L6s. For a m/t car, you'd probably be happier with L6 driveline than LD28 pieces.

 

Well, you asked so there it is. Good luck. BTW, the oil inside the LD28 is pitch black...you're going to be a mess.

DAW