ZZzzz

so we are rebuilding the l28 from the ground up. turns out 18 second 1/4 mile and 13 second 0-60 isnt normal for this car unless you are running on 5 cylinders due to a blown head gasket, badly installed distributor (at full retard, it is still 12 degrees advanced) mismatched fuel injectors (1 new one, and the other 5 are 30 years old) a stuck valve and a kinked fuel rail.

so rebuild time! here is our plan-

we are getting the block cleaned, tapped, bored .020 over, honed and having the expansion plugs replaced. that is currently being done at the shop right now.

we will be taking the head in and having the valves and seats replaced. we will be getting the ports opened up by 1 mm (thats as far as the machinist said is safe on a p79 head) and having the valves ground down smooth and sorta notched in right above the bell, which he says improves flow. also having the gasket surface shaved flat again.

we will be getting the engine balanced, which reminds me of a question. remind me to ask it at the end of this...

we will be replacing the timing chain, pistons, rings, and all the gaskets. the oil pump is fine, so we are just going to clean it up and re-install it.

the car already has headers and a full exhaust installed.

so now for my 2 questions:

1 is there anything on the crankshaft snout other than a woodruff key and the pulley on a normal zed? my crankshaft has already eaten up the new crankshaft pulley (it wobbles on the crankshaft) so im worried im going to have to find a new crankshaft. unless there is a piece missing that prevents this. the machinist seems to think so.

and to the carb question. we can get carbs installed and jet them to make use of all the things we are doing to the car for minimal money. we cannot afford a megasquirt. the stock ecu will not utilize the upgrades at all from what i understand. i dont really WANT to go carb, so please refrain from the inflammatory posts telling me im an idiot etc. is there any other options that might make my car able to use the upgrades?

i've heard that the main problem with the 4 barrel carb is that the runners are different lengths. with a custom setup and equal length runners, would a 4 barrel be a good option?

ThaPimpShrimp

For your ECU question, check out and read up on the z31 ecu swap and Nistune. (Be sure to utilize google and other forums like HybridZ)

NismoPick

If you haven't done so yet, download the FSM, buy a Haynes manual, or go to nissan4u.com and look at the engine rotating parts diagrams. They show all the parts for the front of the crank. I would post a pic for you, but I'm at work. The only time you'd have crank pulley wobble problems is:
-If the crank pulley was installed incorrectly.
-If the crank pulley was not tightened to correct torque specs and walks loose.
-If the crank pulley damper decides to explode / come loose (usually only happens if over-revved many times.

A good machine shop should be able to weld up the key hole, re-cut, and re-balance the crank.

As for carbs, unless you are sourcing all the parts for free, it's probably not going to be cheaper than MSnS (FricFrac can hook you up).

If you go dual SU carbs, hit up PurePontiacKid. He's currently running them on his 280zx. If you go 4barrell, good luck.

FricFrac

If you have money to rebuild the engine you must have some form of income but just not to shell out right now. If you want performance you need to be able to tune it in so you'll need an after market ECU of some sort. MS is the best bang for your buck in that department IMHO. Keep it stock and upgrade when you can afford it. Don't spend your money twice with a patch job now.

Carbs are a pain and for something half decent you're looking at around $1000+ for tripple side drafts. I have them on my 240Z and I like the old schoolism and the sound but it's ancient technology that has been appropriately replaced by EFI.

Why are you balancing your engine? Is your machinist a Chevy guy?

Do you have your pistons yet? You can get really good pistons cheap for the Datsun - the ITM come with rings and wrist pins as well as being hyperutectic.

noboosts130

I would spend a few extra dollars and replace that old worn out oil pump with a turbo one.

ZZzzz

wait wait wait. pulley damper? lol whats that? i literally have a metal pulley, a woodruff key and a bolt with a washer on the end of the crank. perhaps that is what is missing.

we have a small amount of income disposable for the z. approx. 200 bucks/mo. the problem i am having is that my buddy who is going in on this with me is going to be a nuclear engineer on a sub for the navy next year, and we want him to get some track time on the car since he is helping so much with it.

we cannot afford the megasquirt, but with craigslist a carb is 75 bucks and arizona z is selling the 4bbl for $269. i am however, interested in the z31 ecu swap, but i will have to do my homework to find out what that is.

at any rate, this car is not in a restorable state as far as im concerned. getting it to get up and scoot is my only concern for it. its rusty, dented and besides the engine (after the rebuild) it is for all intents and purposes, a parts car. when i can find one (pref. a '71-'72 240 or '77 260) that has a straight body i will probably swap the engine over.

so on with the finding out what a pulley damper is, as well as researching the z31 ecu!

FricFrac

When you rush stuff you end up with problems from not weighing all the options, etc. Someone just posted about putting his pistons in backwards. Simply caused by rushing the job. It happens all the time and rush jobs take more time in the long run. Be forewarned.

Your pully has a piece of rubber sandwiched inside with dampens vibrations that will destroy the engine by shaking everything apart.

ZZzzz

ahh. well, i am getting a new crankshaft, as our thrust was out, and the pulley i just got recently got eaten up by the snout being jacked. (i replaced this before i knew anything about engines) the snout of the crankshaft has welding marks on it as well, and the hole for the pulley's woodruff key is about twice as wide as it should be.

i do not know where the rubber part would go on this crankshaft pulley. there isnt any room on the inner diameter of the pulley for one to go. does anyone have a picture of what it looks like?

does anyone have another crankshaft pulley, perhaps with the rubber vibration dampener attached for sale?

does anyone have a GOOD crankshaft for sale for less than $185 shipped?


and lastly, the z31 ecu upgrade... what about it is good? is it tuneable? is it just already better for modified engines in some way? i have seen dozens of posts about what to get, but none that have said why you do it.

FricFrac

The Z31 is better than the S130 ECU but only marginally. I think you can run NISTUNE on it but it's very expensive for what you get - I wouldn't get NISTUNE for anything older than the Z32. If you can get the Z31 stuff for free go for it otherwise save up if you want to be able to tune your EFI.

ZZzzz

so can i use the z32 ecu on the s130?

NismoPick

^^^ I think you missed his point. He's saying the NisTune is worth while on Z32's, not Z31's / 280ZXT's.

The reason for the Z31T ecu upgrade on the 280ZXT is the ease and low cost of the swap. If you can find a Z31T in a junk yard, you can do the swap for ~$20 - $100. It's worth that much to upgrade, but if you want a tunable car, just go MSnS for $300-$500.

ZZzzz

ahh i see. is the cheapest setup of msns still a good setup? the guys are recommending megasquirt 3, but all i really want is for the car to be able to utilize the new cam, exhaust etc...

FricFrac

Then go MS2 get the kit and build it yourself if you can solder/trouble shoot/have the stimulator and want to save some $$$. Other wise I'd get the MS3 since it has a lot more options and future expandability.

I think the NISTUNE is going to start around $300 as an upgrade to the Z31 stuff you're going to have to get. That's one of the reasons I recomend MS of some flavour