1986 Nissan 720 engine rebuild

[builte]

Does anyone know where to get and engine rebuild kit for a 1986 Nissan 720 I'm new to all this so when I looked it up and seen all the different measurements for pistons and stuff I was highly confused.

[datzenmike]

All Z24 engine gaskets, bearings, seals are the same. You have to measure your old block and determine if it is excessively worn, (oval or tapered) or damaged and needs to be bored to an oversize. In that case matching oversize pistons and rings are needed. Pistons come in 0.5mm and 1.0mm oversize (roughly 0.020" and 0.040" over.

[builte]

Ok awesome Is it possible to only change replace all the gaskets? Without a rebuild

[datzenmike]

What would be the point? Doesn't make a new engine after all the work. Valve cover gaskets are the most likely source of oil leaks then maybe the oil pan gasket. Usually light tightening (not over tightening) will help.

[builte]

I've already replaced the valve cover gaskets (your right they were leaking) and I have another leak coming from somewhere I can't find the previous owners really neglected it and I would love to rebuild it but I've done some heavy research today and piston rings and all the measurements that come with that along with timing and others seems like something I would like to have some there to show me so I don't screw up and completely wreck the engine 

[datzenmike]

Poor performance may not be a worn out engine. Do a complete tune up first and evaluate your engine's performance. Should start easily, warm up quickly, idle well and restart swiftly when hot. Acceleration should be smooth and highway speeds attainable.

 

Does it use oil? You should be capable of a couple of thousand miles per quart. This could be leaks? (place cardboard under the front end and check in the morning) that are cheaper to fix than rebuilding. Does it smoke out the exhaust?

 

Is there excessive blow by out the oil fill hole in the valve cover?

[Stoffregen Motorsports]

I don't trust any online resources for these parts. Unless you know what you're looking for, chances are the parts you're buying are sub-par.

 

I always suggest a local machine shop for buying those parts, and I wonder how many times people actually take that advice. It seems like now days guys want to do everything online and via text, while person to person communication is the better method for something you're just now learining.

 

The main reason buying from a machine shop is better is because machine shops know what to expect from the various brands and grades of the parts they use, from actual experience. Buying from one of the major parts houses online - if a part is unavailable, the algorithm will substitute another similar part to complete the order.

Edited August 11, 2023 by Stoffregen Motorsports

[builte]

It is leaking oil somewhere between transmission and the oil pan I can't seem to track it down

[builte]

It runs fine starts fine reaches high speeds affectively just leaks oil like no other fro some reason and it so dirty I can't pinpoint where it coming from.

[datzenmike]

9 hours ago, builte said:

It is leaking oil somewhere between transmission and the oil pan I can't seem to track it down

 

Make sure it's not the valve cover gasket. Gravity will pull it down there.

 

Power wash all the crap off the top front of the transmission and block below the head and all the way around the bell housing and rear of the oil pan. Get it clean. Then spray down with a de-greaser like carburetor or brake cleaner and let dry. Drive it and check for fresh oil leaks.

 

If it's not the valve cover gasket the top will remain clean and dry. If it's at the rear of the oil pan and the engine plate that hides the flywheel then three possible causes...

 

1/ Oil pan gasket.... Pain in ass to replace but easier than the next two. Most likely cause for heavy leaking.

 

2/ Rear engine seal... Engine should come out to remove the flywheel to get at and replace. Less likely.

 

3/ Transmission front seal.... unlikely as the transmission would have run dry by now.

[Stoffregen Motorsports]

11 hours ago, builte said:

 it so dirty I can't pinpoint where it coming from.

Well, you know where to start then.

 

I use Purple Power which will eat grease and oil, and also brings color back to dingy paint (by cleaning the pores in the paint). Nothing works great on hard grime though, except scrapers and wire brushes. I use brass brushes because they are gentler on the finished surfaces.

 

I did try E-Z Off last year, after hearing about it for a long time, and it worked on that hard grime, but it discolored the aluminum to a dark grey, and apparently is very corrosive and dangerous to handle. You don't want to breathe it either.

 

This pic shows how dark it turned the aluminum.

[builte]

Both of these were super helpful I'll get to an update as soon as I can will power washing mess with anything electrical as you both know I just got the alternator and everything working correctly 

[Stoffregen Motorsports]

I wouldn't worry too much about the electrical components during washing. Only twice in my long career have I hurt something electrical. Once was an alternator, which I apparently pushed grit into something important (my rebuild shop had it fixed in a day) and the other time was a throttle position sensor which had a bad seal anyway. Other than that, you might have to remove the distributor cap and dry it out, but that's it.

[builte]

Thank you stoff