84 720 rebuild

[tommy Nadon]

Hey guys and gals I am rebuilding an 84 720 and cant get a rebuilt z24 anywhere. Are there any other motors that will bolt up to factory trans? Truck is almost complete, just need motor. What I get for the cart before the horse.

[Stoffregen Motorsports]

Do you have an engine that you can rebuild? Or is there no engine at all?

 

How about a KA24E swap? Bolts to that trans and simple EFI. Do you need to pass smog in Gardnerville?

[tommy Nadon]

I have original motor pulled out and stripped down. It had 250,000 miles and was tired. The people who were going to rebuild it for me fell through.

[tommy Nadon]

Swap sounds fine but mounts and stuff have to be redone.

[tommy Nadon]

would love to have my original redone but don't know where to send it

[tommy Nadon]

[DuallyDatsun]

honestly, with 250k, As long as the cylinders aren't marred up, I would just dingle ball the cylinder, resurface the block and heads, get new gaskets and seal everything back up and keep running it. Seen plenty of these engines go well over 300k miles without issue.

Edited April 19, 2022 by DuallyDatsun

[NC85ST]

Agree^. My engine had 400,000 and I went through it, new bearings, rings, timing set, crank polished, block cleaned and honed, head surfaced with valve job done. It runs great. These engines are very easy to build, just take your time and familiarize yourself with the various parts. Getting everything cleaned up takes time. You said you stripped it down, hopefully you kept track of all the pieces and where they go.

[tommy Nadon]

I kept all pieces for sure. Ill eventually find a good machine shop to rebuild original motor.

[tommy Nadon]

[Stoffregen Motorsports]

Have you ever rebuilt an engine before? It can be quite easy with a little guidance. Many parts can be re-used. Engine bearings, head bolts, rod and main bolts, etc. Get a new timing set, KA24 oil pump,a set of Hastings sprayed chrome rings, and a good gasket set. That's about all you need. Have the cylinder head done by a pro and assemble the rest of the motor yourself. You could even have the machine shop boil the block, rods and pistons for you while they are doing the cylinder head. Have the crank magnafluxed and polished too.

[NC85ST]

I agree^, except I wouldn’t waste money magnafluxing the crank, this isn’t a race engine. I would use the money to replace the rod and crank bearings. Just my two cents. You have a great start, it’s already on an engine stand ready for tear down. Keep the major component bolts together and for, like the timing cover, you might want to take note which bolt goes where. Take lots of pictures if that helps you keep track of things better. 

[tommy Nadon]

Guys I really appreciate all your help. I am only somewhat mechanical and not confident enough for that. I want my truck to run good when put back together. Hahaha

[datzenmike]

 

 

1/ Don't measure anything just hone the cylinders, replace the rings, rod and crankshaft bearings. Buy a valve cover, head gasket, manifold set and a pan gasket. Get cheap cast iron rings, they break in faster on an old bore that may be tapered or oval. Replace valve seals. Optionally you could get some valve grinding compound and lap the valves with an electric drill. Probably under $150. Depending how worn out, tapered and/or oval the cylinders were, you could get up to 30k more miles.

 

 

2/ Carefully measure the cylinder wear and...

 

a/ If within spec do 1/ above. Better chance of maximum miles for the least amount spent.

 

b/ If out of speck buy new oversize pistons and have block bored to match. Now do 1/ above but get the best chrome rings available. These work best in a pristine cylinder. Replace rear crankshaft seal. Replace the timing chain, tensioner and guides. The kit comes with a timing chain gasket set and replace the front crankshaft seal at this time. This will result in a bottom end that is equal to the engine when it was new. Over 200-300k miles or more is possible depending how well you look after and maintain it.

 

c/ Have the head rebuilt, new seats, valves are usually fine to re-use, replace valve guides and seals. Not cheap but combined with b/ above you have a brand new engine.

 

 Oil pumps don't really wear out, replacing all the bearings will bring back the oil pressure. The high output pump from a KA engine in the D21 Hardbody truck is just insurance.

 

 

[tommy Nadon]

Had no business doing this project, but loved this truck in high school and wanted one. Of course then you have no money. lol I found this 720 on the way to the junk yard and got a wild hair to safe it. Hhahaha. All and all been super fun, and truck is coming out super sweet. This forum is awesome.Heres part of the progess. Thanks everyone.

[tommy Nadon]

Datsun Mike, I have the complete motor, tins and all. She ran when taken out. I need a pro to rebuild.

[Newbie Brian]

tommy let me know who you find to rebuild your motor i have the z22 in a 82 that needs rebuilt. im not too far behind you with bringing my 82 back to life.. where did you get the pain did? im really contemplating sanding my own down and making my own plastic paint shed or sending to maaco.

[tommy Nadon]

Newbie Brian, I found a local guy here in Nevada that did the paint and bed liner. Will let you know if I getmotor going.

[Stoffregen Motorsports]

It's sad that we live in a time where one can't find a shop to rebuild a simple four cylinder. Everyone is being told that they need to get a degree in astrophysics and that's leaving a major gap in our job lineup. Someday soon, we'll all be living in a country that resembles Hunger Game's, "the capitol", or basically London, England.

 

There has to be a shop in Reno that can build your motor. I have a good friend in Sparks who writes for automotive magazines. I'll give him a call and see if he has any recommendations for you.

Edited April 21, 2022 by Stoffregen Motorsports

[tommy Nadon]

Thanks Stoffregen, Ive actually called several shops in Reno. One shop will do it, but 8 months out and wants 5k

[tommy Nadon]

also looking at ka swap out, but would have to start from scratch as i have none of the parts to go with a reman. intake/exhaust etc.

[Stoffregen Motorsports]

Donor truck. Having a donor will give you 90% of the parts you need for a swap. If you can find a running crashed donor that isn't too badly damaged on the front, you'll likely pay only a few hundred bucks for the entire truck. On the other hand, a running and driving 2wd Hardbody can be had for a thousand bucks (more or less).

 

Here's a pretty nice one for $2500 - https://sfbay.craigslist.org/pen/cto/d/daly-city-nissan-hardbody-pickup/7463724011.html

 

Once you're done with the conversion, you can sell off the rest of the donor to make some of your money back.

 

Redeye here on Ratsun makes motor mount kits. @]2eDeYe, Goddam your handle is hard to remember...

Edited April 21, 2022 by Stoffregen Motorsports

[Stoffregen Motorsports]

Here's a 2001 with a KA24DE for only $2200 - https://sfbay.craigslist.org/nby/cto/d/santa-rosa-2001-nissan-frontier-5spd/7473606752.html

[bottomwatcher]

The KA is a fun upgrade but costs a few dollars and the wiring can be daunting. It is well documented on here. The donor is they way to go. I went the "other" route starting with a long block and spent buckets of money and time chasing down the missing parts. Don't be scared of the rebuild either. These are simple motors as the others have said.

[NC85ST]

Compared to doing a swap rebuilding that engine is nothing. Familiarize yourself with the various parts of the engine and it’s really simple. Think of the satisfaction you’ll have when you say, “I rebuilt it.” Like Stoffregen said earlier “It can be quite easy with a little guidance.” If you have questions about something, post a picture and the experts here can give you guidance. The trickiest part to me is the timing chain and even that’s not difficult.