Rebuilding the engine

[cbudvet]

I have an early model 240z that I am restoring and am planning on rebuilding the engine, clutch, and transmission. I have no knowledge that there is anything wrong but the car is 40 years old and hasn't been driven/started in the last 10 years or so. This may sound like a stupid question but what do I rebuild? I have a friend who rebuilds engines for a living that is going to help me but there are so many things/parts. I have read about the valves/guides/etc. needing to be updated because of lead free gas. I guess I was planning on buying as many replacement parts as I could afford and letting my friend go to town. Should I wait until the engine is apart and rely on my friend to tell me what to purchase? I appreciate everyones input.

carl

[snag point]

Check out these: datsunzgarage.com/rebuild/ and atlanticz.ca/zclub/techtips/enginerebuild/index.html#target6

[DeesZ]

With some TLC and patience, you may find that the engine does not need to be rebuilt. There is a lot of information in the archives about "bringing back" one of these engines that has been sitting for years. It could be well worth your time to check into that option first. These engines have the potential to last quite a long time without needing a rebuild..... heck, in a recent thread here a member was having a few problems with an engine that had 300K on it. That seems on the high end, but the point is that they were well made in the first place. Following the suggestions in the archives here I successfully brought one back to life that was sitting for 19 years, and It runs quite well (actually better than my daily driver).

[cbudvet]

Thanks. I guess I better not jump the gun and start spending money if I don't have to. Lord knows I will have plenty of costs to come. I appreciate the input and will let the guy doing the rebuilding go over it first.

carl

[m4xwellmurd3r]

I'm glad I found this thread. I was going to post asking for some tips for a first time engine rebuilder (but not a first timer at tearing apart engines)

those links posted above were exactly what I needed to find.

my engine got a rebuilt head put on and has perfect compression (165-175psi) but smokes a bit. i'm not sure if this is due to being rich or not, but a leakdown test showed nothing. idle HC is 250 load HC is 1100 but CO% is perfect, so I was thinking it's getting blow by past the rings. the shop couldn't figure out what's causing it except the possibility of blowby.

I'm going to tinker with it next week and see what happens. if I can tune out the smoke then it was rich, otherwise, I'm tearing her apart in several months

[snag point]

Sounds like your valve seals need replaced. There are some good threads on this, and how to replace them with the head on the motor. Also how to tell if they are worn. Jon

[snag point]

Ah, I reread your post. I just got up and now my poor brain has cleared a bit. Rebuilt heads should mean the seals have been replaced. What type of black do your spark plugs show, that could tell you if it's oil or fuel. Jon

[Nissanman]

.....I was thinking it's getting blow by past the rings.

Maybe blowby but perhaps the reverse!

Blowby is into the crankcase, I'm thinking sucking oil vapor from the crankcase.

I was always taught that doing up a head and not doing rings was a wee bit iffy:nervous:

The extra load of the combustion chamber being as fresh as, can strain the rings and cause an oil burner.

Anyhoo, like the man said, what do the spark plugs look like, sooty or oily?

Sooty=rich, oily=well, oily:ermm:

[m4xwellmurd3r]

I haven't taken a look at them yet. Won't be able to till probably tues/wed I was thinking it's getting blowby into the crankcase, and venting through the PCV into the intake, causing smoke, but it could be sucking it out as well. But I wont know till I pull the plugs and see if it's running rich or if it's oil burning.

it had good compression before, iirc it was in the 140-150's before the head rebuild(maybe a bit lower, don't remember off the top of my head) but even then, the sudden jump in compression imo would cause it to turn into an oil burner for sure haha. I'll just have to wait and see when I get it back. Anyways, rebuilding the engine doesn't seem too hard. I've torn down VW engines and put several short blocks together (and one or two long blocks)

[Zs-ondabrain]

So I'm actually seriously thinking about doing a simple rebuild/improvement on my numbers matching block. I'm thinking new dished pistons, rings, bearings. ballance the rods and crank, ballance and lighten the flywheel, put on the rebuilt N42 head with my stage 2 cam, then re-install the Webers, Mallory and headers.

Here's my simple question. Based on about a 30 over bore.

1) What is the best, low priced rebuild kit I should get? (gaskets, bearings, freeze plugs, etc) where and how much?

2) What are the best low priced dished (stock style) pistons and rings, that will work with my stock rods.? who, what and how much.

I just want her to run for another 173,000 miles without smoking or loosing 2 quarts of oil per tankful. Yes, I said 2 quarts per tank........ And I figure why not rebuild, bore and ballance her while I'm at it.

Any help would be great.

Dave.