Good point on block rebuild...

[red_dog007]

I just got off the phone with my Z shop. They will do the valve job. Forgot who posted it, but thanks for the specifics that I should say! .

Though I was talking on the phone to the guy, and he was saying that if I get the larger valves put in, and the stage III cam, that I should do a rebuild on the bottom. Said that the Pistons rings might go out. I would love to rebuild the block, but don't have to if I don't NEED to. You know what I am saying? I have X amount of funds and want to dump it into the engine bay, some exterior and all my interior, while getting my motor running.

I know that it is a good idea, but is it necessary? If it is, I might as well just find a lower mileage L26 or L28 and put that in, or get that rebuilt instead.

Heck. If I do need too, I guess that is just something that I will do at home. Just pay for parts, take everything apart and put it back together. Only pay those guys to clean it for me.

What do you guys think? Engine has 100,000 miles on it, been sitting for while, and made a nice 3,000 mile trip home. Did act funny past 75mph. Was like it lost all power. Haven't figured out what the problem is. Could that problem been because of the block?

I was thinking more fuel related myself, thus new lines and an electric pump on the way, a long with rebuilt carbs.

[red_dog007]

The guy that I bought it from said that he rebuilt the engine. Should be like 8 years now since that happened. Give or take a coupe years. Sitting most of the time, with only 10,000 miles on the rebuild.

Though I don't know how worthy the sellers words are, plus I never got details of his rebuild.

So it is a little iffy.

[240ZX]

Generally speaking, an engine with 100K miles on it, is not a good candidate for higher performance mods! I would personally go through the entire engine's internals and freshen everything up!

Tom

[Arne]

Generally speaking, an engine with 100K miles on it, is not a good candidate for higher performance mods! I would personally go through the entire engine's internals and freshen everything up!

True. But if this is true...

The guy that I bought it from said that he rebuilt the engine. Should be like 8 years now since that happened. Give or take a coupe years. Sitting most of the time, with only 10,000 miles on the rebuild.

...it should be fine. Assuming that it truly WAS rebuilt at that point, not just refreshed.

[jmortensen]

I gotta disagree with you guys. A loose bottom end and a tight top end makes the best power. Obviously not if the rings are shot, but "loose" works. When I used to work for a Porsche shop we'd hone the cylinders and put new rings and bearings in the bottom end, then do a proper valve job on the top end all the time. Works great. 100K miles isn't that much for an L series engine anyway.

Unfortunately for red dog, there's that "lost power above 75 mph" thing...

[Arne]

Unfortunately for red dog, there's that "lost power above 75 mph" thing...

I'd bet on a bad fuel pump...

[red_dog007]

Yeah, that is what I was thinking. Fuel pump. It was working fine, even up to 95mph, for the first few hundred miles, then something just broke. Hoping that it is just the fuel pump. When you try to accelerate hard, even below 75mph, it wouldn't want to make full power.

I think that I will just go with what the owner said, and hope that everything is good. If I don't have compression when everything is on, I will just take it off and redo the block before the engine even runs. Will also just make sure to check my compression often as well. It won't be a daily driver, more so a weekend driver, so I will just hope for the best.

Try to keep the bad to a minimum, and give me time to get money for a rebuild or get a new block.

[conedodger]

Almost all of the possible stupidity in an L series rebuild can be made in the top end. The bottom end, particularly if it uses or reuses stock pistons is basic short of fancy reground cranks and such.

I doubt the bottom end can be too loose as your mechanic is worried about in only 10K miles. Jon is right as well. The bottom end of my 914 motor is loose enough that the rods will wobble on the crank. The stiffen up when you have oil flow. This is normal for a performance motor. I find it doubtful that the rings would have any discernible wear in 10K miles.

I understand your mechanics concern. It is a known fact that doing the top end only often unmasks weaknesses in the bottom end. If you are SURE that the engine was rebuilt 10K miles ago you have mitigated that possibility. But you wouldn't be the first guy who bought a used car from a liar.

[240ZX]

Thank you conedogger, my point exactly regarding an actual rebuild @ 10K ago! Somehow I'd have a hard time believeing a rebuild was actually done and if it was, was it done correctly. I don't know, personally I'd be pulling it apart to do at least an inspection. I quess some folks are willing to take a bit more risk than others.....relying on a stangers word.

Tom

[Diseazd]

Call me "Old Fashion", but unless it was built by Robello or someone like that, I like to see the bottom end.......besides it's like a precision puzzle....it's a blast to take apart and put together!

[red_dog007]

He isn't the lying type. He is a hardcore Christina, has many puppies of his own. Several other cars, wife forced him to get ride of something, and everyone that knows him, I know them and only have good things to say.

It is just more to the extent of "What did he do in the rebuild?", more then "Did he do the rebuild?" You know what I mean?

[ktm]

Point of reference, I am putting down around 400 wheel ft-lbs of torque on a rebuilt head and unknown mileage block.....