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-Chris

Wow. Looks like someone has something to be proud of.

What type of pistons do you intend to use? (I'm interested in the compression ratio, so I can figure if you're gonna Turbo the daylights out of it).

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1970 240Z

Purrrdy

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Isaac - Groton, CT

Stock L28ET profile ITM cast pistons .50mm over with swaintech coatings. I just have a stock Nissan L28ET head gasket now so compression ratio shouldn't change much from stock. I have considered getting an aftermarket MLS head gasket that's thicker, but they're expensive and I'm not sure I'll need it. If anything I'd rather the gasket be the most likely thing to blow in an "oops" situation.

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-Chris

.50 over ~ so did you find a diesel crank so you'll have a full 3 liters this year?

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1970 240Z

Nope, standard fare L28 crank. Used the one out of my old stock L28 NA motor and had it cleaned up and rebalanced. The crank that came in this motor was destroyed.

I'd LIKE to have a VO7 crank, but its just not in the budget.

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-Chris

NICE!

sweet!!

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Mike Tubiak
1978 Datsun 280Z - HLS30-438694

I see big power in your future!

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-Dave
76Z Turbo'd
72 In Progress---DONE!

I was hoping for longevity and durability too, lol.

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-Chris

Is this for a daily driver, good days of course? ...and going to be turbo? Doesn't the over bore put it at 3.0 or was it 3.1 I forget. I just know you can get a 3.0, 3.1, or a 3.2 out of the 2.8 using a combo of oversized pistons, repositioned pistons, and crank shaft, L28D. How about the 1mm steel headgasket?

Well, maybe not a DD anymore. It used to be before I got the Mazda. Now maybe a summer DD. The overbore was only half a millimeter, so its not a drastic change in size(86.5mm as opposed to stock 86mm), certainly no where near enough to bump it up to 3.0L. I'm pretty sure you have to bore it close to if not 90mm to get to that point. At that bore on an F54 block the walls get a bit too thin for comfort. I wouldn't mind running an LD28 crank in the car and keep stock sized pistons for a small displacement bump, but at this point its just not available or cost effective for me.

The car is staying turboed, but since I was pretty much forced to rebuild it last summer I'm OVERBUILDING it to a degree. ARP studs on the head, rods and mains should help a bit with rigidity. No 1mm MLS head gasket yet though, I'm still debating this. On the one hand I'd really like to have a more durable head gasket (as well as thicker to lower compression ratio), but on the other hand the stock head gasket is almost a "failsafe" in that it SHOULD be the first thing to blow out should I do something dumb and detonate. The ceramic on the piston domes should be design help prevent hotspots.

There's some other things I plan to do in the build to keep it as reliable as possible. Essentially I'm trying to build a 600hp motor that will never see above 400hp. I'm probably going to get some guff from people about overdoing things, but if I can give myself some overhead and end up with a well running machine I'm fine with it.

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-Chris

So when you picking me up?

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Mike Tubiak
1978 Datsun 280Z - HLS30-438694

You sure ain't gonna get any guff from me with that logic. It makes perfect sense. It also leaves you a margin to build on if you want more hp later.

Ford did that same thing when they made the Cobra. First it was a 221ci V8 engine which didn't provide enough power. So they replaced it with a 260ci V8 which produced 271hp. That gave an excellent power-to-weight ratio but it strained the engine. So they replaced it with a 289ci V8 which produced the exact same hp with far less strain. In other cars they later replaced the 289 with 302s, but kept the same hp. Less strain on the engine for the same output, increasing reliability and endurance.

Jaguar did the same. The first XKE had a 265hp 3.8L engine. The next series had a 265hp 4.2L engine, all for the same reasons.

Many of those increases were gained by replacing the crank, giving a longer stroke. That increased torque (longer throws) and lowered rpm, increasing engine longevity.

Have you already bought new rods?

Frank

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1970 240Z

Actually Frank, I ALMOST did. The one place I found a nice looking set of H beam rods was ebay, for a little less than $400. The reason I didn't was because I wasn't entirely sure I could trust them. They're the only aftermarket rods I've ever found for the engine and didn't have a name, so I held off. The other problem would be that I believe they would have been meant a full floating piston pin design, which would have meant I would have to get a set of forged pistons. More expenditure than I can manage at the moment I'm afraid. Plus, I'm not sure I would have felt comfortable listening to the kalacka -kalacka-kalacka of cold pistons in their bores as the car warmed up. It just seemed a bit much for my street motor.

Maybe someday, but I had my current rods checked, balanced and trued, and they seem up to the task.

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-Chris