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Advice: Used or Rebuilt Engine Swap (or V8?)


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If you can find a head that is functionally sound, then just bolt it to your block and fire it up. See what happens. I can't be specific as to what might happen, obviously the hope is that you either burn less or no oil at all. Whatever does end up happening to the engine will give you a better idea as to where that gremlins hiding. The caveat to this is that the head needs to be perfect for a real diagnosis. You can buy a rebuilt head from Datsun Parts llc. for... Ehem...$450 but at least you'll know it's not the head :P

 

If it is the rings (or the lower end at all), then you're staring down the barrel of an engine pull and rebuild. May as well get an F54 from a 280zx if you're gonna stay with the original engine...

 

If you want to swap a V8, I would suggest that you be aware of how much weight is going in the car. An LS engine has an aluminum block so you save weight and add power all at once, but unfortunately that's something only available to those with a lot of cash to burn (if that's you, go for it) or some very good connections. Iron block LTs (the JTR kit) are just that... Big, heavy chunks of cast iron that love to screw up your cars handling. I've never been in one personally, but a friend of mine who owns a Z shop says that anything with an iron block doesn't belong in a Z. That includes the l28. He builds cars for road racing and handling so he might be a little biased toward lightweight hardware, but to me there's no sense in having 500hp if it's all going to go into heating up your brakes because you can't make it around a corner.

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There is only one BIG problem with the L28 and that is cylinder head cooling on cylinders 5 and 6. Sounds like a casting problem, a design error and possible crud buildup on top of it. One of the most important pieces of the engine concerning performance and economy. Old technology pistons and chain drive cam are also down sides. Positive side is reliability. SBC V8 can be built up with Modern Tech Pistons, Rods, Crank, Cylinder Heads, Camshaft and Induction for about the same cost as rebuilding the L28.

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There is only one BIG problem with the L28 and that is cylinder head cooling on cylinders 5 and 6. Sounds like a casting problem, a design error and possible crud buildup on top of it. One of the most important pieces of the engine concerning performance and economy. Old technology pistons and chain drive cam are also down sides. Positive side is reliability. SBC V8 can be built up with Modern Tech Pistons, Rods, Crank, Cylinder Heads, Camshaft and Induction for about the same cost as rebuilding the L28.

 

V8's are all fine and dandy, but I totally disagree on the cost side. L28's are easily cheaper than a mild built sbc. You say they are cheap, but I have real life experience with how expensive building a high HP SBC really is. The downside to the L28 is all in he head. It is non-crossflow. As in, it doesn't flow worth a crap.

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V8's are all fine and dandy, but I totally disagree on the cost side. L28's are easily cheaper than a mild built sbc. You say they are cheap, but I have real life experience with how expensive building a high HP SBC really is. The downside to the L28 is all in he head. It is non-crossflow. As in, it doesn't flow worth a crap.

 

I was under the impression that a good port job on the head alleviates (to some degree) the "bad" flow of the head. I read BRAAPs write up on heads, and he seems convinced that the laminar airflow created by the same-side-port head can be utilized to produce more than 100hp per cylinder with the right porting and head modifications. Unshrouding the valves, getting bigger SS valves, chamber welding, port work... All kinds of magic voodoo that I can't do hahaha

 

I should probably also mention that, in the same article, BRAAP makes a point to say that the $ to hp ratio gets pretty steep when doing all this, which is why the V8 swap is so nice. For the boatload of cash you spend to get 300hp on a n/a L30 you could get a 4-500hp V8 in there. Or even a 400hp L28et.

 

The deciding factor is how much cash you have to burn. If it's not enough to get a 300+hp V8 in there, chances are you're better off with the L28. The bottom line is that going for a maximum effort L28 will be much less cost effective than putting an equal amount of money into a V8. No replacement for displacement..... And 40 years technological improvements *Cough* LSx *cough*

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I agree with many here that doing a SBC, though very cool, isn't the wisest thing for you to do right now.

 

The shop the car is at seems questionable, and they don't seem interested in working on your car. Get it home, whatever it takes, even if it's a $300 tow bill.

 

Then find a used motor and throw it in. It'll cost you less than $300 in tools MAX and then you'll have your start to having what you need to work on a car. Sure it'll be a used motor, but if you hunt around long enough you should find one in good enough shape.

 

For example my '81 burns oil, and I'm fairly certain it's the rings. Smokes pretty bad on decel. I got the car with 205k on the odometer and now it's got over 240k in less than 3 years. I have to put in a quart of oil about every 1500 miles or so, but I decel with the clutch in and watch my oil levels. It's amazing how long bad rings can last when you're taking care of the car. Oh, and this car was FREE. Not because I knew the owner or anything, he just needed it gone. FREE

 

This is why most of us own datsuns, they're CHEAP, easy to work on, and FUN!

 

So get on the cheap bandwagon and go hunting on craigslist. You'll be a better man to your car by knowing how to work on it. Find a cheap motor and see how it goes. If the new cheap motor burns just as much oil then you now have a spare motor to rebuild if you wish. Have a machine shop do all the hard work and assemble yourself.

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