Engine running rough now check my last reply please.

[Dloghead]

My last post was titled "My 1985 720". Hello everyone. I told you about my truck and plans for it when I was in Afghanistan. Since I have been back I have had a few problems, but am unwilling to part with the truck. Its just too perfect for me! I bought the truck right before I deployed and only got to drive it for a few months. It had a leaky fuel tank when I bought it. Before I left it was giving me problems sputtering occasionally. Once I got back I replaced the fuel tank and filter and stopped the sputtering with a fuel pump. My transmission started making a loud annoying noise in all gears but 4th. I drained all of the oils and everything was fine except for the what I am sure are syncros that came from the transmission. I replaced the oil and have since drove the truck. The transmission is still noisy, but the gears shift smoothly and seem to lock up solid. Now the truck has started to sputter again occasionally when the engine has a high load (going up hills in high gears). I thought maybe a vacuum problem causing the distributor to miss, so... I decided to eliminate all the crap on the vacuum system that I suspected not necessary and capped everything off. I was hoping to get it to stop missing under load. Still have the same problem. I gonna remove and clean the EGR, but had trouble getting the pipe fitting out of the exhaust manifold this evening.

What should I do? What is important on the vacuum system of the z24 motor? I have a brand new weber and kit sitting in my garage, should I put it on?

[Aven]

First off, welcome home.

Second, not sure if this will help or not, but its good info none the less.
http://hubpages.com/hub/The-Datsun-and- ... t-Tell-You

[PEZi]

it is NEVER a bad idea to throw that weber on... unless you have to pass a visual inspection by someone who knows what they're looking for

when putting the weber on... replace all your fuel lines, and the filter if you haven't

also... the only vac line you NEED is the one to the distributor vac advance... all the others are emissions related and kinda crap...

as far as the EGR.... it sucks to get off... no way around that... get a BIG wrench... or vice grips.... latch... then pound HARD with a hammer/mallet.... be careful not to strip the outside or it will become even harder to get off

[seang]

You can probably overhaul the transmission wih new bearings and synchros if you feel up to it. I have never done that myself on any transmission, but I have heard of other people doing it on similar gear boxes. For my truck, a new shaft bearing kit is about 85 dollars, and synchros are extra--not end of the world expensive. Not sure on your truck, it might even be cheaper. Also, synchros are brass, and I hear that sulfide-free GL4 is the recommended fluid because sulfides attack brass or something. I have the wrong fluid in my 97 transmission, so who knows, I might have an overhaul on my hands someday.

[Dloghead]

Today I fiddled with it again and found that the coil for the exhaust plugs was not sending any heat. I have the new one outside and am going to put it on. How necessary are the filter canisters on the front driverside corner of the engine compartment? Thanks!

[PEZi]

GL-4 fluid is key to making nissan transmissions work right... but if its already out of shape you don't want to spend the money on GL-4 until you get it working right again.... then the GL-4 will make it last forever

and the canister is pointless.... take all the hoses to it off and cap them.... except for the one that leads back to the fuel tank... but a breather filter on it.

[Dloghead]

The coil did the trick! How hard is a the transmission to remove and reinstall?

[seang]

Top bellhousong bolts will require long extensions to get at. My old 2wd was only a handful of bolts, 4wd should be kind of similar in that respect. I wouldn't recommend trying to lower the transfer case/transmission without it being STRAPPED TO A TRANSMISSION JACK. I hear that they are awkwardly heavy and dangerous to handle, so a transmission jack is paramount to the operation.

The motor will be free to tilt front and back a bit with the transmission removed, this was not a problem on my old z24 2wd which was on level ground at the time. It rested a little bit tilted back with the transmission removed.

To re-install the transmission with a new clutch, you will need to use the alignment tool and have the clutch disc aligned with the flywheel or else everything will not slide together. If this happens, don't force it, just get it right and test fit it again until it does mate up without too much fuss.

If you want you can download the FSM to get the details in the right order.

[Dloghead]

Been running great for a while and the transmission is just fine since I removed the broken syncros. However now it is running really sluggish like it needs to warm up only it continues to run like that. Today on the way to work after about 8 miles it ran fine for a few miles. Then on the way home same old stuff. I wonder if maybe the EGR is not switching and causing the problem. At idle there is no change when I unplug the vacuum line. So what do you guys think EGR? I dumped a whole can of starting fluid and searched for vacuum leaks to no avail.

[PEZi]

it could be EGR... it could be a vac leak you just can't find yet... could be carb related even

[Dloghead]

Bad plug on the intake side. Running like a sewing machine again!

[flinterman2000]

Man you need to take a step back and review the whole situation. Don't run around like a headless chicken. Do a tune up. Start with the ignition system. Check and change as necessary. If you have the webber and doesn't need to pass smog, change it out. Check and adjust the valves also. Man take you time, its worth the time. I love my truck and its been down for 15 months. You sound as though you love yours too so keep at it.

[synack7350]

I don't remember coming across any threads about valve adjustments or tolerances, do you mind elaborating a little for us less mechanically inclined finterman?

[breadbox]

pretty sure there arent any on here yet. but, screwdriver, box wrench, feeler gauges.

Look up the specs and have fun adjusting. I like my KAe for auto adjusting itself.

[captainzeros]

Well damn, I just did my valve lash last week and didn't even think to take pictures.

Runs one heck of a lot quieter now. That in combination with tightening down my air cleaner for a change and putting a muffler back on the car you can actually hold a conversation inside of it

[synack7350]

yeah I got the haynes out, lots of parts in there, and springs and stuff lol. Don't know if I'm ready to start adjusting valves till I see some pictures of the process.

[flinterman2000]

Pictures of valve adjustment, hmmm. Well I could do it but I'd need help. With the oily stuff and the camera, it would be a little tedious but do able. We'll see.

[Dloghead]

I did a tune up 25k ago and so I was a little suspicious of the fouled plug on only one cylinder. Today on the way to Raleigh I believe I blew straight through the piston rings in that cylinder. I will do a compression test tomorrow. Now I am trying to decide what to do about the truck if the motor is in need of overhaul. Do it, get rid of it, swap it with a different motor or build a turbo motor. I still have the brand new weber and turbo set up in boxes.

[Dloghead]

I couldn't wait. Yup 15lbs in the second cylinder, she's done... To further complicate my decision there is a 87 yota 4x4 with a 22r for 1700 on craigslist.

[flinterman2000]

I couldn't wait. Yup 15lbs in the second cylinder, she's done... To further complicate my decision there is a 87 yota 4x4 with a 22r for 1700 on craigslist.

Yotas are nice but there isn't much you can do with a 22r. Its reliable but not adept to mods.

[synack7350]

I just love my little truck so much, I have an account set aside for if and or when the motor fails, buy a new motor then I'll rebuild the other and make it like super clean with lots of shiny objects.

[MetalFab]

Hard to find any yota around here for less than 2500-3k, but plenty of hardbodies to be found. Wish I had picked up the pair a year or so ago both running yet with smog issues for under a grand. Bet I could have talked him down. This was before I ever thought of how nice efi would be in my 720. I've always wanted a 4.3l vortec. Only issues I see is getting the oil pan to clear. Could even use the motor/trans out of a 2wd s-10 since the xfer case is divorced on these trucks. Perhaps a body lift and setting the motor as high as possible in the engine compartment would make this work. Either that or SAS it. But that's just me, thinking only in 4x4 terms. And I'm not a purist by any means. I just want a truck thats a good mix of power, economy, and fun.

Good luck on your decision, I hope you end up sticking with keeping the 720 alive. A $400 motor at a wrecking yard (or cheaper at a pick-n-pull) is a lot cheaper than dropping 1700 bux on what may be yet another basket case.

I'd rather invest in fixing my own truck than paying premium for someone elses headache.

[captainzeros]

I've been standing by the idea that if you drop $1000 into a broken vehicle then you know what's GOOD on it, but if you drop $1000 on a new beater then it's gonna have all kinds of unresolved nonsense you're gonna have to find out about at the least convenient time.

[synack7350]

agreed captain zeros you hit it right on the head. I just work down the checklist till I know everything is good. By the time I get to the bottom of the list I have a new truck, well worth putting a new motor in if the head goes.

[flinterman2000]

Its always better knowing you made something good than hoping to get a good one. Chose the better investment, keep it.