D21 rattling noises.

[HRH]

So I would chalk this up as dump on Matt week what with the sickness, garage tagging, and the truck breaking. Except I'm actually pretty fortunate right now. To explain, the truck started making what I thought was lifter noise like it sometimes does on startup. A little running generally cures it though. Well last night it wouldn't stop. So I added an extra half quart of oil, still rattling. Finally just decided to drive home, and it rattled all the way home, not good sounding. Figured either the lifter was completely dead, or it might be a chain issue since it had a slightly different noise.

 

The funny part was I heard a plasticy clicking noise the other day that I couldn't find. :D Yeah. Found it now! Pulled off the valve cover this morning to confirm my suspicions. It's not the lifters. The plastic guide rail had separated from the metal guide and it was just lounging around farther down. Lucky for me, it didn't jump time and hurt anything. It is on the slack side, but still a little unsettling. This is why you double check all your parts before install. I'm guessing it was a cheap timing set. (I didn't rebuild this motor, someone else did.) I just put it in before winter so I could use the truck. Keep in mind theres only 6000 miles on this motor.

 

Anyway, I'm beginning to wonder if the original noise maybe wasn't lifters but that compromised rail starting to detach itself from the metal.

 

 

 

[HRH]

Okay, so I'm entertaining some ideas now. Another guy I know who has the same truck apparently got a double row chain from some Japanese website and it was somewhere to the tune of $400. Now, myself, I can't seem to find any KA24E double row chain sets. I also spent a crapload of time looking through all the NAPA timing gears available and didn't find one that was just right for Z24 OD and number of teeth with a smaller ID.

 

So, either I haven't found the one, or he got snookered. I don't know. It seems to me there wouldn't be enough call for a dual row timing conversion set for the KA truck motor, but perhaps there's a forklift KA that uses it or something.

 

Back to the issue. I need to replace that guide. That of course involves loosening either the head or the oil pan to weasel out the timing cover. And that's not easy because to properly reseal the oil pan, I'm going to need to remove the front differential. That is not fun on a hardbody. If I'm going to go to all this trouble, I'd like to try and install a dual row chain seeing as the KA/Z24 are same block/head heights. It may prove to be more of a pain in the ass than it's worth though.

 

The other option I have is replacing just the guide. :) Yeah. The upper allen bolt I can probably loosen. The bottom I can't reach from the top of the timing cover. HOWEVER, I have another KA timing cover and block and I can pinpoint the exact location of that bolt. With a 90 degree air drill I can probably drill a hole to insert an allen wrench and successfully remove that bolt and weasel out the guide. Seeing as the other timing components are in decent shape and new, they could remain. Doesn't look like the small amount of time the chain rattled against the metal of the guide hurt it; it still had lubrication.

 

To reseal the timing cover, I'd find a plug and RTV it in the hole. Figure it ought to work just fine.

 

And now since I don't want to be banned, more pics!!!! :D And if anyone knows of the magic easy way to a dual row chain on a KA, let me know.

 

 

 

 

 

 

 

 

 

 

 

I think if I use this guide I'm going to rough up the backing with 80 grit and seal it with the Right Stuff.

[HRH]

So we have successfully changed out the slack side shoe without removing any more than the valve cover. However, I think I have bigger issues. I'm processing pictures, it'll be a few.

[HRH]

When I first got this "rebuilt" motor, we checked it out and it looked okay. When I started it up was when the hydraulic lifters wouldn't stop making noise, or at least that's what I thought it was. I did take a long drive with it whacking around making noise, but it never stopped until I put the new lifters in. And even then it still makes noise in the mornings ocassionally. What's weird is recently in a week of cold nasty rain, it didn't rattle on start-up once.

 

There was slight surface rust on the camshaft bolt, but not enough where it was a worry as the motor had been stored outside, but had a little water near it. We checked the cylinders with a boroscope and there wasn't any rust in there. What I'm beginning to wonder now is if perhaps there is some rust on the tensioner assembly that was overlooked.

 

Anyway, today was successful in replacing the slack shoe. I have two holes in my timing cover now, covered with RTV and two carriage bolt heads. Weasled the new shoe (glued between the backing) in and really wasn't too bad except for the bolts holding it in being tight as hell. Thought I was going to brake the ball end allen on the top one. The hole needed to be a little more down, could only get it with the ball end.

 

So I changed the oil after hosing the inside case with brake cleaner to wash all the aluminum bits down that hadn't been collected. Re-filled with full synthetic oil as it was all I had at the moment. The resulting startup was loud as hell, clacking all the way. While the chain on metal noise was gone, it sounded like it was still whacking the shoe, and the lifters sounded noisy also. I don't know if this is simply because of the oil change using synthetic versus regular dino oil. It shouldn't matter, but this is why I'm leaning towards a leech in the oiling system because normally synthetic oil makes noisy lifters better as it gets in more, but it also tends to run thinner and can result in less oil pressure from what I've seen. Not a problem if the system is kosher and oiling effectively. But a small leak hidden by thick oil can become a big leak made more apparent by synthetic oil.

 

The other thing is perhaps the reason my slack shoe broke was because the chain was loose enough to eat away at the plastic. It doesn't exactly look that way, but it is worn down, which if it was new, really shouldn't be an issue with only 6000 miles.

 

That's where I'm at. Something is wrong. Really wanted this to be a quick easy fix, but now I'm thinking about yanking the motor, which I don't want to do, but I want to not have to worry about the truck. And it seems every motor I find has been screwed with in some way or another. I can't figure it out. Who keeps molesting all these hardbodies!!!!?????

 

Here's the list of possibilites, feel free to add to it. I'll throw up the pictures of the job below.

 

 

1. Tensioner compromised due to rust, bleeding pressure.

2. Hole in oil system somewhere. Enough to mostly pressurize, but not fully.

3. Head clearanced and cam towers not shimmed, leading to a slack chain, maybe why the plastic broke off my shoe.

4. Oil pump compromised although it's brand new and oil light goes off.

5. Other something I haven't thought of yet.

 

 

 

 

 

 

 

 

 

 

 

[datzenmike]

Actually I think this is the tension side guide. Rotate the cam counter clockwise or the crank ahead to tension the chain and remove all slack and adjust the guide against the chain to support it. The engine rotates clockwise and the crank pulls down on the driver's side of the chain keeping it tight. Any slack collects on the pass side where the tensioner/shoe is.

 

In this picture of the KA24E timing set, the curved shoe is the slack side. You can see the tensioner that pushes it over to remove slack. The shoe pivots on a bolt that goes through the far right side of it.

 

 

Here's my junker KA and you can see the head is removed and the chain tensioner has pushed out on the slack side shoe.

 

It's just a name you could call it a potato it's still worn or broken and needs to be replaced regardless. But this is how the chain operates with the tensioner.

 

KA24Es are notorious for the guides falling apart. It always starts with 'lifter noise' but is almost always chain rattle because the teflon? guide material has fallen off... usually from some wear but in some cases it just falls off. This never happens like this on the L or Z series with the well supported double chain. Nissan cheaped out by redesigning it this way. I do like the way the tensioner works on this but the plastic guide material and how it is mounted to the guides.... SUCKS! This is likely the primary reason these motors have been fucked with in the past.

 

If you ever get a KA24E, first thing, pull the valve cover and inspect both guides for wear/damage.

 

 

.

[HRH]

Hmm, interesting. I see what you're saying about the guides. Motorwise it's that way. Shoewise one's slack and one tensions. Anyway, tomato tomahto. Seeing that junker KA picture, one of the problems on mine is definitely too slack. The oil squirter above the crank gear is well worn, much like you see old 20bs and not many of them have that anymore.

 

Think I'm going to hook an actual oil pressure guage up somewhere under hood and see what I'm getting. Any other achille's heels that might be causing the issues in regards to the KA? I'm about ready to go find an SR out of an SE-R and stick that in there. I love the KA motor, but I never had any issues with my '96 or '97 D21s, but then I had them from low miles to start.

 

The main thing is I need the truck back up and running as it's my only truck.

[datzenmike]

The driver's side will remain tight when running but if you have ever raised a motor on a hoist you can easily push sideways on the chain. Same with the KA. Even though 'tight' the chain can move side to side slightly and needs the guide to support and prevent it from oscillating. The other side is a different story. All the slack collects there and needs to be 'supported' or canceled out. The variable tensioner does this with the aid of a spring and oil pressure. Wear on the plastic or the chain and sprockets and chain stretch can exceed the tensioner's abiliy to cope. All you can do is replace.

 

I think replacing the bad guide will solve your problems. If you ever pull the motor maybe replace the rest but not really worth the effort right now. This is an interesting ratsun approach to fixing this problem. Don't sweat the metal flakes. You did good removing them. Any left won't float and will go to the lowest part of the pan and will either stay there or flush out with the oil. They are too large for the pick up screen.

 

The KA had a high volume oil pump so I would expect the pressure is fine. Idle will be the lowest and I wouldn't be surprised if it isn't around 30 or more. When revved it will be 45-55 range. Shimming the regulator won't change the idle pressure only the high speed, which does not help. Thicker oil will raise the idle pressure. A new pump might if the old one is worn. Try thicker oil if there is any idle rattle or hydraulic lifter noise.

 

 

BTW nice pictures and info!

[HRH]

Yeah, the problem is the rattle is way more present than before. Even with the guide fixed, there is a lot more rattle, and it sounds like it may be rattling excessively on the shoe, since it's more of a plasticy rattle, and not quite the lifter rattle. Perhaps I'll try some 15-40 regular oil and see if that doesn't raise the pressure to sufficient levels. Sucks that I just wasted some good Castrol Syntec and a quart or Royal Purple.

 

If I can get the rattles out and it seems to be running fine, then I'll be okay. I'm still trying to decide what to do because eventually I need to yank the motor anyway to address the rear main, which has been leaking since the install. That one is probably my fault, must have cocked it sideways or something when I put it in. Or the back plate wasn't sealed correctly since I didn't remove that, just drove the new seal in.

 

The thing that irritates me is I run 10w30 Royal Purple in the race L motor, and no issues at all! No hydraulic lifters of course.

[HRH]

What I'm trying to do is have a second motor ready to go. Debating whether a Z24 or KA bottom end since I don't want to use the KA I have. It's welded up where the cracks were but I just don't trust it. (This is the original grenaded motor) I'd like to find a 120k miles 240sx KA single cam or double cam for that matter. I think that would be better anyway, since it's the Japanese block. Or maybe I should rebuild a hi-po L motor for it and go carbed!

[datzenmike]

Yeah, the problem is the rattle is way more present than before. Even with the guide fixed, there is a lot more rattle, and it sounds like it may be rattling excessively on the shoe, since it's more of a plasticy rattle, and not quite the lifter rattle.

 

Is this at start up or idle?

[HRH]

Is this at start up or idle?

 

All speeds. Idle is a little less, higher rpm, more it rattles, although at above 3k I can't hear it because the motor noise cancels it out. But it's not lifter noise, it sounds like the chain is rattling on that guide. That's why I'm wondering if someone screwed the pooch when the put that together, like clearancing the head too much and not adding shims to the cam towers.

[HRH]

Well I switched out the full synthetic oil this morning for regular 10w40 NAPA dino oil. Quieted it down a little, still lots of rattling. I'm fairly sure there's an issue with the chain tightness. Haven't hooked an oil pressure guage to it. I'm debating trying to remove the tensioner and replace just that. Almost wonder if someone installed it without the spring or something. Either way, it just isn't right. I'm thinking it was that way from day 1 and it might not have been the lifters after all, just sounded like them. Figure maybe after the guide wore in it alleviated a lot of the noise and then I ignored it until it broke the guide rail.

[HRH]

Going to try and switch oil pumps here in a second to see if that makes any difference. Just re-examined the old shoe from the original grenaded motor I had to replace, the one without oil pressure to the lower end due to a hole through the oil galley. Not a mark one from the chain on that shoe.

 

Here's another nasty thought I just had. Since the original '93 head had some broken studs I opted to use the '95 head that came with the "rebuilt" motor I bought. To my knowledge all the heads are the same height from 90-97 for the KA single cam truck motor, but maybe I'm wrong? Anyone have or know that? I'd call Spaldings for a hollander interchange, but they're not open today.

[datzenmike]

Try shimming the oil pump slightly. (won't do anything at idle/low speed) but will give higher cushion of oil pressure at speed.

[HRH]

Well, just tried replacing the oil pump with the original one that came with the motor. Nothing changed, noisy as hell. I'm beginning to think this whole time I was chasing noisy lifters, I was wearing in the chain on the guide. Seems to be reasonable. So that means from day one this motor was fucked, either because I put a 95 head on it, and somehow it's different, or due to some other issue. The last thing I can think of to try is changing out the tensioner. Have not done that yet as it's slightly touchy. Not sure if I want to do that one like I did the guide. I'd rather have the timing cover off completely. Just debating on building another motor then figuring out what the problem is when I yank it out. There's a guy in Spirit Lake with a block and head from a KA for $100. Might just buy that.

 

I would try shimming the pump but I don't think it's an issue of oil pressure. There were oil pools up in the head when I took the valve cover off, and considering it took 6000 miles to eat enough off the plastic to break it, that's pretty decent lubrication really.

 

Have I mentioned this is just like finding poop in your cereal? It really sucks! :(

[datzenmike]

Hail Mary: Run with valve cover off and gently pry the slack side shoe above the tensioner over with a piece of wood. If quiet its the guide/tensioner. If not maybe you can hear the lifters.

[HRH]

You know, I was thinking about that. The only problem is all the oil that's going to splash all over if I do that. Any idea on how to prevent that from happening or just put it outside with a bunch of rags all over?

[I'm BLUE]

You know, I was thinking about that. The only problem is all the oil that's going to splash all over if I do that. Any idea on how to prevent that from happening or just put it outside with a bunch of rags all over?

 

a welding blanket ? ( I picked one up from Harbor Freight :D )t I wouldn't waste money just on this project unless you weld a bit then it's worth it ;) , bu

[datzenmike]

Yeah, after I sent that I remembered the oil. My old neighbor had a chev valve cover cut lengthwise so he could run it while setting the valves. Maybe tape a piece of that plastic corrugated board over the valve area and leave the front open?

[HRH]

Found it.

 

[datzenmike]

Aha!

[I'm BLUE]

Sweet , glad you found it :D

[HRH]

Yeah, although here comes the next fun. I welded a wrench onto another wrench in hopes of getting the bolts out. Got the top one loose, but it hits the case, can't pull all the way out by like a 1/16, and you can't turn the bottom bolt with the wrench as it hits the top bolt. I suppose I could make a 90 degree angle wrench and do it, but it still wouldn't work now that I'm thinking about it since the bolt head would make the tensioner have insufficient clearance to scoot past the tensioner shoe.

 

So it looks like I'm going to cut yet another hole! In fact, maybe two small holes to facilitate the removal of the two tensioner bolts. Interestingly enough, the tensioner is slim enough to slide out in the cavity of the upper timing cover even with everything else in tact. I'm sure it wasn't planned that way, but I've already test weaseled it out on my spare block. And worst comes to worst I pull the whole mess and replace it with the spare timing cover I have.

 

Anyway, that's the next step, drilling the cover (on an angle this time, kinda poopy.) and making some more shaving messes! Most of this I should be able to catch with a paper towel stuffed in the timing cover though.

[izzo]

dont be a sissy, just yank it all apart :D

[HRH]

Meh, it's going to take a lot more time. I'm half tempted to, but I'd rather weasel it, and then yank the motor later to fix the leaking rear main. But let's be realistic. If it doesn't leak too much, it's probably going to stay in there for awhile.