Your thoughts.

[Perfect240Z]

might want to take a minute and rethink this. You have a motor in the car that might not need to be rebuilt. The fact that it doesn't go past 40mph tells you NOTHING! Do a compression test, look at the plugs, pull the dipstick and smell and look. Pull the valve cover off and look inside-what do you see. You might have something that has already been touched up, but right now it's not running good. Seems to be a lot of unknowns to base decisions on. You seemed to have made cost a priority, so I would work with what you have first. You might have some gold covered in grease!!!

I actually did a compression test. After I removed the transmission, I tried to put only 100psi in the cylinders(while at tdc btw). For some reason it still turned the crank from the pressure, so I could only get 40psi without it turning. All cyclinders all at least held the same psi. Plugs showed it was running super rich. My cam has this yellowing on the lobes, and looks worn, I'm sure it can still be run no problem though. What does smelling the dipstick mean? I got this car and it hadn't been running for two years, I got it running after about a week, and changing the entire ignition system. The guy i got it from eBay I think...so it's probably nothing special. I'm sure it could probably used head work to maybe run right but I'd rather rebuild it that way I have my piece of mind about it.

[Healey Z]

Not sure where to start.

You said you were on a budget, but rebuilding engines correctly is expensive. From the sounds of it, your motor could simply have had a fuel problem. To do a compression test, you don't put compressed air into the motor, you crank the motor with the starter and measure the PSI it creates. Before you start sending parts to a machine shop, I would sort out the condition of what you actually have.

Unless you really understand these motors, i would not think about doing head or piston swaps. Find an L28 that is in tact and is in known, working order. Get it and everything else working properly with the SU's. These motors are bullet proof and available and come up all the time in the bay area. Just be patient and pick a serviceable one up for $300-$600. I bought the one below in fantastic shape for $300.

Edited January 1, 2012 by Healey Z

[Perfect240Z]

Not sure where to start.

You said you were on a budget, but rebuilding engines correctly is expensive. From the sounds of it, your motor could simply have had a fuel problem. To do a compression test, you don't put compressed air into the motor, you crank the motor with the starter and measure the PSI it creates. Before you start sending parts to a machine shop, I would sort out the condition of what you actually have.

Unless you really understand these motors, i would not think about doing head or piston swaps. Find an L28 that is in tact and is in known, working order. Get it and everything else working properly with the SU's. These motors are bullet proof and available and come up all the time in the bay area. Just be patient and pick a serviceable one up for $300-$600. I bought the one below in fantastic shape for $300.

I did a leak down compression test, all of the ignition and power parts weren't on the car. So I couldn't crank the motor for a regular compression. If I see a complete one I guess I could pick it up, but my L24 block doesn't look like its ever been rebuilt, a head swap was done for sure since it also has a cam in it without an external oil bar. My Z should've had the e31 head. Maybe the person who had it in new Mexico thought it'd be a good idea? I bought the L28 block real cheap and can just get new rings and get a flex hone tool to rough it up for the ring break in and can run it. I have all the parts to make my car work, I don't need to buy anything really, just put it together. The engine may be bullet proof, but it wouldn't be my piece of mind to just use something unknown, that's just me. I have read so much about their reliability that I trust it to work, just dont trust the last owner who covered all the rust with bondo, drilled holes into the floor pan and use glue to hold things together. Hence why I think it needs a rebuilding. I'm a little bit of a newb, but I listen well and learn easily. Just having the hardest time understanding why I wouldn't have a motor rebuilt if theirs no history on it.

[steve91tt]

If it were me and the leak down test is good I would put the L28 back together, get it in the car and running. You can then decide what, if anything you need to rebuild. As you said, these engines can take a bunch of abuse/neglect before they need to be rebuilt. Once you get it running you can figure out what needs attention. Earlier this year, I bought a car with a half seized L24 that hadn't run since 1989. I replaced the gaskets/rubber bits and ran it with triples in my track car for half a dozen track days. It ran strong (for a bone stock L24) much better than I thought. I then pulled the engine and put it straight into my daily driver 240Z. It burns a tiny bit of oil but I think the oil loss is coming from the valve seals. I don't see any reason to rebuild it.

These cars are so easy to work on, you could just get what you have running and if you need to rebuild it, pull the motor and rebuild it. But then again, rebuilding an engine can be a fun project and if it gives you piece of mind then go for it! Keep us posted with lots of photos.

[Perfect240Z]

Heres some quick picks, since im doing body work and repainting myself in the garage, so if the paint is new the rebuild might happen. Didn't realize a lot of people would just pull the motor and run it . I figured thats also a rule to rebuild if you get a motor since its out of the car might as well do it. Since my L24 is the original block with the car, that might have never been rebuilt, but I must say that since I wanted a bit more fun power, I have to do it to the L28 since the guy I bought it from said it needs rebuilt when he did the compression test. At least he told me. I will however keep with the dished pistons, I didn't know that the dished pistons were ok to use with with carbs. But after reading that the N42 block came with dished im ok with it now.

[Perfect240Z]

I'll take a pic of my L24, it's got a chipped piece off the cam gear missing, dont know if it fell down into the bottom of the block :/ (not me btw, came like that) I'll take a pic of cam too since it looks worn? But I would use it since the lobes all still feel smooth. The motor leaks oil, probably when the oil pan gasket was changed they tighten the bolts too tight and warped/bent that part so it leaks. Need a new oil pressure sensor since mine has all the wires ripped out of it(might be fixible with some soldering). These are all jus signs to me that Ill rebuild that one back to stock.

[madkaw]

What engine are these pics of?

[ATTACH=CONFIG]50175[/ATTACH]

[ATTACH=CONFIG]50176[/ATTACH]

[ATTACH=CONFIG]50177[/ATTACH]

[ATTACH=CONFIG]50178[/ATTACH]

[ATTACH=CONFIG]50179[/ATTACH]

[ATTACH=CONFIG]50180[/ATTACH]

[ATTACH=CONFIG]50181[/ATTACH]

Heres some quick picks, since im doing body work and repainting myself in the garage, so if the paint is new the rebuild might happen. Didn't realize a lot of people would just pull the motor and run it . I figured thats also a rule to rebuild if you get a motor since its out of the car might as well do it. Since my L24 is the original block with the car, that might have never been rebuilt, but I must say that since I wanted a bit more fun power, I have to do it to the L28 since the guy I bought it from said it needs rebuilt when he did the compression test. At least he told me. I will however keep with the dished pistons, I didn't know that the dished pistons were ok to use with with carbs. But after reading that the N42 block came with dished im ok with it now.

[Perfect240Z]

What engine are these pics of?

This is my L24

[madkaw]

Kind of hard to tell from pics, but I can't see anything that looks terrible. I would guess that those retainers are not stock and that would lead me to believe that the head has been worked to some extent.

If that engine is still on the stand you can rig a piece of steel that uses your flywheel bolts to hold the crank steady. Bolt the steel to the crank and wedge the steel between the engine stand mounts. That way you can do a leak down test.

Don't worry about the yellowing on the cam, you just want to worry about the polished finish that actually rides on the rocker. Also for any gouging of the cam surfaces. If your missing a tooth on the cam sprocket, get another one and replace it-cheap, I even have a used one that is like new.You can also mic the cam to verify that it is 'worn", not unless you see damage, it would be hard to visually tell.

I could have saved myself a lot of money and time if I had just rebuilt my head on my original, motor instead I just though with 100k miles I needed to rebuild everything. This cost me a lot more money on pistons and bottom end work that in the end probably did nothing for performance compared to the head work. Spending money on that stuff took money away from things I had to have like new shocks and brakes. When I took the engine apart the bores still had the crosshatching marks in the bores with no scoring, but I was sure that 100k was too many miles. Did I do a compression test? NO= Dumb. More work and money= less enjoyment and waiting longer to drive.

So, just some things to think about when making your decision.

Best of luck

[Perfect240Z]

Ok, yeah I'll just do head work since the block is working fine on my L24.

Strange though I took the valve cover off and I didn't have any oil on my lobes, I didn't even have a thin greasey layer to wipe, maybe my car didn't didn't want to go because the cam wouldn't move across the rocker arms from no oil? I don't have an external oil bar and the cam has the holes on the lobes for the oil to come out. Would their be something else connect to the cam for the oil? Not too sure.