86 nissan 720 z24 no power!

[Maddog0311]

Helpful forum Guys... Need help! Have similar problem, then began sputtering badly today. Working down the list of most obvious but rotor seems fixed to dist shaft when I went to replace. Replacement rotor button has hole for set screw but can't see one on the old button. Don't want to force or pry if I'm not seeing something. Please advise if there is a set screw I should be aware of, else I'll just apply more force. Thanks!!

[loyalone]

My rotor has a set srew to. but could be a updated rotor?

[Maddog0311]

Thanks Loyalone. Turned over far enought to see the set side. Couldn't feel it before. Finished tune up. Now just back to low top speed. Mine feels tired and winds out ok, just low cruising speed at fairly high RPM. She's well used and one cylinder is throwing oil the looks of the plug so understandable. Appreciate your input.

[acey9]

Hey all what kind of cruising speed should loyalone be expecting from this truck?

[seang]

Hey all what kind of cruising speed should loyalone be expecting from this truck?

70mph pretty easy

[loyalone]

i used to be able to do 70mph if i was drafting off a semi, but if i came to a hill i would go down to 60

[loyalone]

i drove a 90 Nissan 2wd 4spd and it had plenty of power it did 80mph no problem. only thing is it was running at a very high rpm

[Mississippi1976]

OK.. compression check done.. you were right. Cyl #1 185Cyl #2 45 Cyl #3 40Cyl #4 175

The truck still does not smoke.. What do you Nissan guru's think this could be..?

I think head gasket..(but have been wrong so many times)) No smoke..No bubbles in the radiator. No water in my oil..

Could the gasket be leaking between the 2 cylinders?

[loyalone]

I think it's a head gasket but I could be wrong. Could be burnt valves to

[Maddog0311]

You guys are way ahead of me on mechanicing but I know enough to follow the conversation.   I've got an 86 4x4 720 kingcab and have changed fuel filter, plugs, wires, cap, rotor, and found oil residue on the intake and exhaust plugs for cylinder closest to the firewall.   From everything said here  and since I have no oil film or bubbles in the radiator I'd expect my compression and probably my rings for that cylinder are bad.   If so I'd think that might effect this secondary being activated and explain my weak top speed of perhaps 60mph.   Would that make since to you?    

[loyalone]

You are correct. Get a compesion gauge on it and find out for sure. Then if you don't have the right compression then you can make a geuss on what's wrong, or get someone who has a cylinder leakdown tester and knows how to use it, to test it for you.

[Maddog0311]

You are correct. Get a compesion gauge on it and find out for sure. Then if you don't have the right compression then you can make a geuss on what's wrong, or get someone who has a cylinder leakdown tester and knows how to use it, to test it for you.

thanks Loyalone... Will do. And good luck with yours.

[loyalone]

Someday whenever it warms up outside I'll tear the head apart and let you all know what I find. It's just really hard to get the motivation to do something like that when your cold.It looks like this might be a common problem. I just hope it's not a warped head.

[RT22]

trick to figure out if it is rings or valves, learned from motorcycle mechanic. Pour some 30 weight in the cylinder through plug hole put compression tester on it and if compression goes up it is rings(oil will seal it some for a moment) if not it is valve as oil will have zero effect on valves. That is back yard way to find out if it is rings or valves. if valves it is cheaper to get head redone than to re do the pistons and rings. may even be able to just get a junkyard head and pop on and get some more miles from it.

[Maddog0311]

I'm with you on the cold.  But I'd probably never tackle A head job let alone the rings, least not without help.  I drive this old gal about 3-5 thou miles a year and it usually serves as my standby during the winter to get down a 1/2 mile dirt road when snow is deep.  If I can keep changing plugs and keep her between the bar ditches, that will have to do.   I AM interested in the conversation though and your progress, (and appreciate RT22's hint about diagnosing rings vs valves) just in case I decide I love her too much to neglect her.  She's been a good rig, needing little work for nine years now. If she were a horse I'd turn her out to pasture and let her chew grass till the end.    You guys take care and do post your progress Loyalone, once the weather and inclination steer you in that direction.      

[Mississippi1976]

Update:

I had poor compression between 2 and 3 cylinder. (established)

I have removed the head and let me start by saying I hate overhead cam engines with a new pasion.

If someone would have told me that it would take 3 days to change(4 to 5 hours a day) to change a head gasket i would have cried little girl tears, BUT - wow.. what a pain it is to remove the timing chain cover...WOW...

But for the good news.. the gasket was blown between the 2nd and 3rd cylinder. Perfectly blown in the narrowest part between the cylinders. A picture perfect blow out and i still marvel at how it continued to run.

Currently I have head sitting back in place and the timing chain is on correctly. I hope to finish this up next weekend and take it to the race track...(haha)..

Little advice.. (1)the wedge trick to keep the tensioner from coming out of it's bore was a waste on my engine, hence be prepared to pull the timing cover off. (2)harmonic balancer nut is 27mm.. and the puller kits do not come with the necessary bolts to pull the pulley.. Buy 3 6mm-1.0 thread at least 50mm long bolts to use with the ducks foot.

(3) BUY the whole $46 dollar gasket kit..I did not and made 3 extra trips to town to get it..

I will let you guys know if after i'm done it will hit 90mph...hahahhaha...

thanks for the help all...

[Mississippi1976]

I found some excellent info on this after the fact. I am still having a hard time finding information of how to set my distributor back in place.. If i find this I will post..

For now though http://tinyurl.com/y934mw4 is an excellent source of info.

[Mississippi1976]

It lives again.!!!!...plenty of power!!!!..Got timing right on first try.....Engine TDC(cam shaft position 2 pointing straight up or crank key point straight up) rotor pointing(was a 1 beside the rotor contact, but is the inside one) at number 1 plug on (number 1 is on right side/front of engine)..

I have no timing light, but the engine backfired a little when shifting.. any ideas...advance or retard?

[Maddog0311]

Congratulations Mississippi... don't have any suggestions regarding the backfire (you probably got that figured out by now anyway) but glad to see you got yours together and running, with power to boot.

I've been South so not driving mine or logging on. Just visited the site again and saw your latest. Thanks for posting your progress.

Hope Loyalone does too when he dives back in.

[loyalone]

k just thought i would let you guys know that yes i had a blown head gasket in the exact same spot that Mississippi1976 was blown, between cyl. 2 and 3. it took me 4 weeks to do the replacement cause i only worked on it when i felt like it. it runs better then it ever has for me, but still i think it should be able to go faster then 75-80mph with the wind, 65-70 against the wind. however i need to set timing yet so that may be it.

[loyalone]

oh yeah and that egr line was a PAIN IN THE A$$, as was scraping off those old brittle gaskets, i also had to take off the front timing cover cause i dropped a socket down there. still hate myself for that one.

[seang]

My 86.5 TBI Z24i 2wd 5sp would do 80mph without the wind helping it. It was only rated at 103hp just like the carbed version.

[edited, sorry loyalone ]
Modified by seang at 12:56 AM 4/12/2010

[loyalone]

ha ha sweet