foxfan1992

Fastest I've done in my little truck is 90mph on level-ground. Downhill I've taken it to 95mph before I decided I was going too fast and slowed down. (It was a high-mountain freeway, only reason I did that speed is because there was little traffic and had to catch up to my travel-mates in a Honda Fit). Truck is equipped with original Z24 engine and automatic transmission - and stock carb.

Thanks all, much appreciated :-)

Hey all. Most of you probably know me as the guy with the red 1984 Nissan 720 that blew a headgasket. After the 'misfortune' of having to take the whole timing assembly apart, I replaced the timing chain and sprockets while I was down there. Now however I just have a couple of things I'd like to clear up. The gaskets for the timing cover, water pump and oil pan have to be replaced since they did not come off in one piece. I'll be going to pick them up shortly, but another question I'd like to ask is about the RTV sealant? Is it necessary to use this sealant, or will the gasket be enough to stop oil or water leaking? Thanks Harry

Yes he did, I made sure to tell him this when he posted on another forum. I wasn't about to let a fellow 720 owner make the same mistake as me ;-) As for the headgasket job, all I can recommend is cleaning the surfaces so they're free of old gasket debris and honing the cylinders. Also clean the pistons of any burned-on oil or carbon. I must admit it does look pretty rough at the moment, but it'll be a good idea to get it all done while you've got it all off. This is why I decided to take the opportunity to replace the whole timing chain and sprockets while it was all off. Anyway I hope you have the answers you're looking for, Ben.

Well the truck put up a really good fight against us repairing it today. First we removed the oil pump and filter - not a big deal, but then we had to remove the starter motor and jam a screwdriver in the teeth to stop the flywheel from turning when we undid the crankshaft bolt and pulley. Fortunately this went without too many problems - the real problem was dropping the sump, we removed every screw from it but it wouldn't budge. In the end we had to use a couple of small wooden wedges and a hammer to pry it off the bottom. No damage to the oil pan gasket as a result, fortunately. The only thing that didn't put up a fight was the crankshaft sprocket, which should have according to the manual, but it slid right off. So now we're at the point where it's no longer dis-assembly, but reassembly. Thank goodness! As you can see, the wedge we made was insufficient to stop the tensioner from popping out slightly - though it was to the exact dimensions stated in the Haynes' Manual.

Okay so we have a friend coming over to give us a hand with the 26mm socket and possibly the broken bolts too. Also for the crank pulley bolt, is it a reverse-thread or standard? We just don't want to have a go at it only to tighten it up to the point we break it by mistake.

So we've gone ahead and removed the splash guard, fan and water pump behind it (antifreeze everywhere as a result D:) Unfortunately two of the water pump bolts broke off inside the block. We're also running into special tools problems - where we don't have a 26mm socket - though we do have a breaker bar of sufficient length. Is it a big problem removing broken bolts from the block? Does the engine need to be removed or can it be done in situ? Has anybody else had this problem and overcome it without totally stripping it all down?

Does anybody know where I can download a decent online manual for the Z24 engine? I'm not so sure about going by the Haynes book again, just in case there's something else it isn't telling me - this was one prime example. It didn't mention anything about the tensioner, just keeping the chain from falling into the sump and off the bottom sprocket. Harry

Welp we'll give all of that a go tomorrow. In the meantime, let me introduce myself a little more. The truck's name is "Red Thunder". I've driven her for three years, failed my 'N' test three times and passed the fourth time with it. XD I've driven her to Seattle and Portland twice, and also went to Kelowna in high-summer with some friends. I've primarily found her very useful for taking a family member or two out to Victoria or Nanaimo. I have a very-highly attuned interest in mass transit, so this shot should come as no surprise: (Full size here) Since this shot was taken I have scrubbed off most of the rust off the chrome bumper and had the radiator replaced. Sadly that radiator replacement was obviously too late to save the head gasket.

Aye, we made a wedge out of a piece of wood we had and used that to hold the chain up while we took the cylinder head off. Unfortunately we couldn't get the wedge in before taking the sprocket off because the repair job by the high school obviously wasn't done correctly. Looking at the guide it is far too tight, so as you've mentioned this coupled with the tensioning spring coming out now means we have to take that all apart. Oh well, might be a mixed blessing really, since I do have a new timing chain we can also put on while all of that is off. In fairness - the manual doesn't state ANYTHING about the wedge actually serving to keep the tensioner in place, just to keep the chain from falling into the sump.

Right, so just to clarify it's me and my dad working on this truck. We tightened all the bolts on the head cylinder and the valve rocker assembly to the specs listed in the haynes manual - but now we've hit a big roadblock. When we went to put the camshaft sprocket back on we noticed that we could not align the camshaft and the sprocket to TDC. We tried multiple things to get it on but the timing chain will not allow the sprocket to go any higher. As you can see in the attached pics, the camshaft is 1/4" to 1/2" too high. It looks like we might have to take the whole front assembly apart. We took a peek with an oversized screwdriver and found that the chain guide is too tight, which means taking it apart to slacken it off. I had a local high school do repairs (ball joints and timing chain tensioner) which they don't seem to have done correctly now. So now I have to look for the box with a whole new timing chain assembly to see if the tensioner is still in the box - the bolts to the timing cover look as if they've never been removed. Harry

Okay... I obviously read your post wrong - I'm a total newbie at this stuff. How I deciphered it was 1. 8-7 2. 4-3 3. 2-1 4. 6-5 5. 10-9 (these numbers from the loosening sequence, not the tightening one) Heck my mind is confusing sometimes :confused:

No, but the new gasket did have the copper ring inside that oil hole, this is just a mystery piece that we don't know where it is supposed to go. Now if I've interpreted your post correctly, the tightening sequence is: 8, 7, 4, 3, 2, 1, 6, 5, 10, 9 (These numbers from the loosening sequence provided here) Though I'm a bit confused because in the manual it has a tightening sequence 1-10, beginning from the center and then working out to the back and front like this...

Poor thing :( It makes me shudder to think what could have been going that fast to do that much damage...

The gasket has an opening for the oil pressure hole, the copper washer wouldn't fit in that aperture in the gasket though... It's a mystery... Looking at the old head gasket it has the hole for the copper gasket you describe, but this copper ring is nothing like that. (Dixon pencil added in for size comparison)