Pulling down a 13bpp with low compression. What is actually wrong with it??

Added: 2026-06-01

[00:00:00]Okay, so here we go. In this video, we're pulling down this PDB with low compression in the front rotor housing.

[00:00:06]So hopefully we find out what's wrong with it. Easy enough. So we'll get in into that and never mind all this dirty face. It was one of those days at work.

[00:00:16]So just to let you know, we find the problem with this engine, but you have to wait till the end to find out.

[00:00:40]Okay, I'm not expecting this to take too long. Maybe an hour or so. But problem with this engine is low compression on the front. I believe the numbers on the rear were like 115 on average across all faces. The front one was considerably lower. I think it was 80 or even might have even been 76 or something like that across all three faces. So, that's got me a little bit stumped. Um, in my last video, I checked apex cells and they've all got plenty of spring in them. So, side seals, oil control rings, I'm not sure. But what I will do is before I pull this apart, we'll get the front cover off. I'm actually going to put uh the dial gauge on there and we're going to test the end play on it before it comes apart. Uh if I remember rightly when I did this engine, we did check in play. Must have. But um we'll do it again and just work through it. So basic tools should be good. Energy drinks. So I'm going to get into it now. Okay. So as I said, first things first, let's get the sump off. Hopefully there's not too much oil in there. Otherwise, I'm going to end up [ __ ] all over my floor. But should have some rags around here somewhere. So all 10 ms pretty easy. And then we'll take the pickup the pickup thing that's in there. Pickup tube. Something like that. We'll take that off. And then we are going to crack the engine. So I get the front pulley off. We get the front cover off.

[00:02:10]And then as I said, we'll reassemble the whole front stack. Test the end play.

[00:02:15]And then if that's okay, we'll carry on through.

[00:02:29]Hey, hey, hey.

[00:02:57]All right. Um, sump came off easy enough. There was no metal or anything like that in the sump, so that's all good. Now, I'm just looking in here at the timing chain and all the rest of it.

[00:03:08]Everything seems to be okay so far. Um, I don't think it's run a bearing or anything like that. Otherwise, you'd see metal filings everywhere. So, we're just going to keep on getting on.

[00:03:19]So, I'll get this pickup tube off. Uh, and then we'll crack we'll crack the front nut and do all of that.

[00:03:27]Okay. So, I've managed to get the front nut free. So, we'll go ahead and get these bolts out of the front cover.

[00:03:38]Drop them all over the floor.

[00:03:52]Where else are we? Is that all of them?

[00:03:55]No, surely not.

[00:03:59]Well, yes, it is. Okay, get this bolt out.

[00:04:07]And then we should be able to get the front pulley off.

[00:04:18]Oh man, why are you so tight?

[00:04:24]Rubber hammer, where are you?

[00:04:54]Why are you like that?

[00:04:58]That keyway seems rather tight.

[00:05:04]Okay.

[00:05:06]I might spend a bit of time. I'll get this off. Okay, so got the front pulley off. It wasn't too bad.

[00:05:13]Looks all right. Looks like there's a little bur on the edge of this keyway.

[00:05:17]Um I can sort that out a little bit later anyway, but we'll go get the thermal pellet out. And I want to say I want to get the spring out, but will I?

[00:05:30]Yeah, there we go.

[00:05:32]So, thermal pellet springs out and we should be able to take the front cover off now. Um, one thing I am concerned about is what is Oh, that's all loctite.

[00:05:45]That's all good. Um, one thing I'm concerned about is when I do test for end player, I need to put that front pulley back on. Need to tighten this back up. So, I'll have a think about that one. It would be good to know it's numbers. Oh, it's numbers. How much how much uh inplay float float there actually is on it at the moment.

[00:06:13]But everything in there seems good. The oil seems good.

[00:06:19]Timing chain's nice and taunt.

[00:06:23]Everything's pretty good. Gasket's still all good. So, this this car hasn't run many KS.

[00:06:30]I think we're okay. Anyway, so I'm going to go ahead get this oil pump off now.

[00:06:35]It's just those four M10 head bolts underneath. And we'll pull that off in one unit.

[00:06:42]And then I can actually put the dial gauge here. And then we will test this in play.

[00:06:48]Yeah, I think we should.

[00:07:05]Okay. So, just going and set the doll gauge up now. You can see there I've pretty much got it to zero. Just a little bit under. But oh wow, this engine is tight.

[00:07:20]Why is it tight?

[00:07:23]So that's 0.02, which strange H. Okay, we're going to carry on. But yeah, that's that's not cricket. Okay, so I've just gone ahead and pulled the counterwe off now. It was very, very tight. So the keyway in there, I'm going to replace it. I'm not happy with that.

[00:07:48]uh torrent bearings.

[00:07:50]That one's all good. Uh spacer. Now, when I reassemble this, I'm going to need to keep an eye eye on that spacer because yeah, as I said, it was very, very tight.

[00:08:02]But what I'll do is we'll get this stack cover off here. Um we'll pull the other bearing out. We'll pull the in place spacer out. And then, um then we'll just keep on pushing through, I guess. But yeah, that keyway wasn't right.

[00:08:17]And there I was thinking I was doing so well. We just had a massive spill. Oil and water. So, I mean, I'll clean that up and then we'll go ahead. We'll get the flywheel off and then we'll undo the through bolts and we'll start pulling those um in plates and the housings apart. We'll check the rotors. But, um I'm leaning towards I want to check that E shaft, see how straight it is. I do have the tools here to do that. I'll probably do it tomorrow, but we'll get the engine torn down tonight. And yeah, but now got bit of clean stuff. Okay, back.

[00:08:51]Floor is a little bit nah, I'm not going to lie. It's still [ __ ] but this there isn't fresh oil on the ground. So, we should be all right. So, I'm just going to go ahead get this clutch off and then we'll undo the flywheel. And then we need to get the little keyway that's in the back of the E-shaft. We need to get that out. and and then we're ready to start pulling the engine apart. So, we're getting there. Why are these different size?

[00:09:27]I suppose while we're here, we can actually check out check out the clutch and see how well it's doing or not doing, whichever's easiest.

[00:09:37]But so far by other engine being tight now, could that have been because the keyway was holding everything tight? I I don't know. I struggled a little bit to get the counterwe off. So I don't know if that was tight down. We couldn't We didn't have the slop in the E shaft.

[00:10:05]I don't know. Probably tomorrow when this engine's apart, I will need to run everything on the front of this E shaft.

[00:10:13]See if it runs smooth um without the keyway in. And then I will get a new keyway and we'll do it again. And as as long as everything's running nice and smooth, I believe we'll be okay. But I do I will I will check to see if this E shaft's straight as well. Um I guess it is.

[00:10:36]ish. Don't know. Anyway, fresh plate got a little bit hot.

[00:10:45]Clutch is in store right condition and firewall's not bad at all. So, mint. So, get rid of those.

[00:10:54]And now we'll go ahead rattle off the flywheel with the 54 mil socket.

[00:11:04]So sick.

[00:11:11]Okay, now rubber mallet time.

[00:11:28]Come on. Come up.

[00:11:31]I'll get this off. I'll come back. Okay, flow was off. Uh, we'll go ahead and get this little keyway out here and then we're into it, I guess.

[00:11:46]Mint. So, that keyway is in good shape.

[00:11:50]Yep, that's mint. So, I'll go ahead now. We'll get it more.

[00:11:55]Which way does this need to go?

[00:12:02]I really need to drill some more holes in this to get it dead vertical. But we'll leave the rest stack gear um cover plate in. We'll undo these screw bolts here. We'll pull them all out and we'll crack this rear um plate off. Oh no, not more oil.

[00:12:20]What have I got? What have I got?

[00:12:25]Rags. Rags. Rags.

[00:12:28]No, I don't know.

[00:12:37]That might have to do.

[00:12:46]Bloody hell. Okay, I'll go ahead get these out now. So these are all 17s. So bit of a rattle gun won't take us long at all.

[00:13:00]Now I don't think we need to be too careful of anything. I'm going to replace all these little washers underneath them.

[00:13:19]Oh man, why is my night tunes the rubbish?

[00:13:34]I still undo these bolts in like a zigzag pattern. Um, don't know why. I just in my head it makes sense to do it that way.

[00:13:54]Yeah.

[00:13:59]And this should be the last one.

[00:14:02]Okay, so I go ahead pull all these out.

[00:14:10]I just need to clear some room for these irons and whatnot.

[00:14:39]Okay, get those down over the way.

[00:14:44]Make some room here somewhere.

[00:14:48]Oh, can't forget those. Just got to put those bolts back in the flywheel.

[00:14:53]I'll do that later. Uh, move this.

[00:15:02]Okay, so hopefully this isn't too hard to pull apart.

[00:15:12]There we go.

[00:15:26]That's right. I forgot these have been these rotors have been lightened.

[00:15:33]Still looks good. So, inspection of the rear iron. No step wear or anything like that.

[00:15:44]Everything seems mint on that one. So, we'll get that out of the way now.

[00:15:59]Uh, water seal seems um good.

[00:16:03]Both of them. Yep. No, they're fine.

[00:16:06]Once again, replacing those also. So, they're no longer needed. I'll just slide that.

[00:16:15]I'll need to check all the tolerances on these side seals again later on. I just want to keep them all roughly in their homes.

[00:16:25]Uh go on, get in there.

[00:16:29]Okay, I need a container for these.

[00:16:33]Okay, I'll be back in a second. Okay, so time to pull this rear rotor out now.

[00:16:44]Let's get these corner cells before I lose them somewhere.

[00:16:50]One, two, three of them.

[00:16:57]This corner still need all right now.

[00:17:09]Damn it.

[00:17:12]We'll just get that in there.

[00:17:18]Okay. What do we drop? Apex seal springs.

[00:17:24]Already got the corner seal. Corner seal spring.

[00:17:30]Okay. Just make sure I fish all of this out.

[00:17:37]Okay. Looking pretty good on that one.

[00:17:39]So now, oh, I thought I thought I forgot that seal there. No, it's on the It's on the iron. That's good. Okay, so these here are the plates that we got done last time I had this engine uh through greens. Now, they're just the water jacket cover plates. There is Devcon underneath these as well. So So that's actually pretty cool. But now, why is that silicon not breaking? There we go.

[00:18:20]Road housings are still in good shape.

[00:18:22]No chrome pearl. And as you can see, it's got a big PP. It's a real nice one, actually. Um, okay. So, that's the rear rotor done.

[00:18:37]water seal. Uh, still mint as the other one.

[00:18:46]Still all good.

[00:18:49]Come on. Come out of there.

[00:18:57]Okay. Where's that other D? Okay. It's in the It's in the um road housing. Uh, dipstick.

[00:19:09]Okay. So, almost there. What I need to do now is we need to get the E-shaft out. No, we don't. We need to lift the E shaft so we can pick this plate up off its dowels and turn it. Now, this part isn't that much fun.

[00:19:27]So, what you got to do is get in a funny position, get your knee underneath it.

[00:19:35]Okay.

[00:19:41]Why you not Okay, I just need to break the seal first.

[00:20:10]Oh, come on.

[00:20:26]Yeah, it's broken there.

[00:20:36]Okay, that's moved. This is tied on the dells for some reason.

[00:20:45]Didn't feel like I had that much play on this.

[00:20:50]Come on.

[00:21:00]Why are you doing this to me?

[00:21:06]Really tight on those dowels.

[00:21:15]same time trying to hold this E shaft up with my knee.

[00:21:20]Ah, there we go. There's one.

[00:21:26]Okay. Water getting going all over me.

[00:21:47]Okay, as for the front, water seals are still good.

[00:21:57]So, we'll have a quick look. I'll just get this out of my hands and then we'll have check this this spring on the side seals, uh the oil control rings, all of that. Let's get those apex sills, the corner seals.

[00:22:22]That was okay. So side have that one's not even in there.

[00:22:42]Let's bring in those are. Okay. And all control rings feel all right, too.

[00:22:52]Okay, we'll get this E shaft out.

[00:23:04]There's some weird marks on the end of it there by the stack here. I'll find out what that's about. But besides that, the rest of it looks pretty good. Um, put that somewhere safe.

[00:23:24]Okay. So, what's going to come forth flying out of view?

[00:23:37]Everything you watch.

[00:23:52]Okay, I'll just put that there.

[00:23:56]It doesn't look too bad.

[00:24:06]There's no signs of um of any issues in this front rotor. So, come on.

[00:24:21]Front row housing mint as no chrome pull. No, there's nothing.

[00:24:26]There's not even any marks in there.

[00:24:29]Looks nice. Okay, so uh we'll check this front plate.

[00:24:37]Oh, spilling everywhere. Bearing bearing's okay.

[00:24:46]Um stack gear looks all good. Sills are all good.

[00:24:53]No step.

[00:24:59]I was hoping, well, I wasn't hoping, but I was expecting to find something that was like that's the problem. But I'm actually do my homework. I'll have um I'll actually ask around about about that in play and like the counterwe being tight on the on the front stack there. Um I don't know if it was the keyway holding it. I can't even get get those out. The keyway holding it or was it the E-shaft itself, but I dare say it was the keyway. But no, this Okay, so having a quick look at this front rotor now everything so far looks looks pretty good. Uh plenty of spring in the oil control rings. There's plenty of spring in the side seals.

[00:26:05]Must have been in the front stack. Has to be. These corner seals, plenty of spring, everything is nice.

[00:26:11]The bearings are nice. Um, everything in it really, really good.

[00:26:18]Um, yeah. Uh, it's not what I expected to see to be honest, but it's good in a sense. Um, must have been something to do with the front stack. Had to be cuz that was just that was just silly tight and well it just shouldn't have been like that at all. So yeah, I'll come back to you. So I've just been thinking about this for the last hour now.

[00:26:51]Uh, the low compression in the front, everything inside the engine is fine. So now I'm looking back at the front stack.

[00:26:59]Now that counterwe and all that and lack of end play shouldn't have caused the compression to be lower on the front rotor. What could be is an issue with the front stack gear bearing possibly. Maybe something's just not right. So tomorrow I'll take stack gear out of that front iron there and we'll check the E shaft.

[00:27:24]Rotors are mint. All the seals are mint.

[00:27:26]So, we're going to check that front stack. Uh, I dare say we're going to look at reassembling the engine and then we just we'll muck around with the M play. We'll get the M play dialed in. Now, it was at 0.02.

[00:27:41]Now, at tightest it can be 0.04. So, it's too tight. So, we'll figure it out anyway. But first off, as I said, tomorrow we'll check a few things and then we'll go from there. Right. So, it's the next day and I have been racking my brain all day today about what has caused this low compression.

[00:28:05]Now, I spoke to a few people last night and the front stack being so tight shouldn't really have affected the compression in the front rotor housing, but I don't know. So, what we're going to do now is going to do a few important tests. Now, first one is going to be we're going to check how straight the E shaft is. We are going to measure the rotor housing, see if there's any shrinkage in the housing. Uh we're also going to check the apex seals to see if they're bent. Um the fact that it's low on all three faces is just bugged me. So, we'll check all these things to the specs and kind of hoping there is a problem there, but then I'm hoping there's not because to replace that rotor housing.

[00:28:53]Not too keen to go down that road. So, first off, I got the eh shaft set up in this little jig. We will we'll see if there's any um throw out in the shaft.

[00:29:03]Okay. So, as you can see, pretty basic setup. Just got it sitting here and here. So when I turn it, if it is bent, it's going to throw this point up or down. Both actually. And we'll be able to see it on the dial gauge. Now at the moment is set to zero. And I'll try and do this onehanded.

[00:29:25]Okay.

[00:29:35]It's not moving very much.

[00:29:40]Oh, there we go. A little bit there.

[00:29:52]All right. It's just clicked into that groove. Okay. So, it's pretty good to be honest. So, I'm happy with that. So, Eshaft is mint.

[00:30:05]Okay. So next up we're going we are going to check shrinkage on the road housing. But just having a look at that E shaft um replace if run out is more than 0.06 which we weren't. So Esha is definitely okay. Now for um shrinkage on the rotor housing we measure point A which is the top and we measure the three points around the spark plug holes. Now, so that's this point and three points down there.

[00:30:38]Now, if the same again, if it's more than 0.06, the housing's no good. So, what I will do, take this dimension here as base.

[00:31:05]Okay, that's pretty tight.

[00:31:09]Is that tight?

[00:31:22]No, that can't be.

[00:31:24]Oh, things moved on me.

[00:31:32]I need a proper um one of these.

[00:31:48]Yeah, it keeps opening up.

[00:31:51]Just get the point on.

[00:31:57]Okay, what I've got here is a uh filler gauge.

[00:32:11]Now, I've got a 0.07. So, if this is going to fit through, then road housing is no good.

[00:32:34]No, we're good. So, road housing's fine now.

[00:32:40]Next test is uh apex. Now, I'm not not worried about the rear rotor at all.

[00:32:52]cuz that had good compression. So, what we need to do with these just give them a clean up and we need to put the tops like so. And if I can fit that feeler gauge in between them, then the apex need to be replaced. Now, this could be a dead ringer for why we have low compression on the front. If they're bent, they're just letting compression pass through the guts of them. So, just get those.

[00:33:32]No. Are those clean on top?

[00:33:51]That's not great.

[00:34:14]That's going straight in there.

[00:34:21]Check that again.

[00:34:30]Apex right here. Replace the full three apexs on the rotor.

[00:34:40]D is more than 0.06 mil.

[00:34:45]As I said, I've got 0.07 mil.

[00:34:55]Yeah, that's straight in there. What I might do is we'll try some of the rear ones.

[00:35:04]Those look the same.

[00:35:27]No, they're not going in.

[00:35:31]bent apex seals.

[00:35:35]What would have caused that? Okay, I'm going to do some homework on that. But that looks like that's our problem.

[00:35:48]Oh yeah, I can see it now. You see the light passing straight through them.

[00:35:53]Okay, I'm going to do a little bit of homework. Okay. So, another thing I wanted to test whilst here is this counterwe was very very tight on the front of this E shaft. So, what I want to do is with the keyway gone, want to see.

[00:36:16]It's pretty good, but no, that's actually not too bad. I might just give it a clean up in there.

[00:36:26]But that spins nicely on there. So, me having the trouble getting that off yesterday was solely down to uh the keyway. I guess there is a bit of a bur on that edge there. I can clean all this up. But yeah, I need, as I said, I need to find out what would have caused those to bend. But interesting.

[00:36:54]Okay. And also just for googles, I've gone and put the e shaft into the front bearing and there's nothing binding that up. So that's sweet through the front stack gear. So what I'm going to do is I will talk to the owner and we'll see about replacing the apex seals in it. Um may as well do the springs as well. Uh we'll get a soft seal kit. We'll put the keg back together and then we're going to pay a bit of attention to the front stack. um make sure all of that is smooth. Um because that lack of end play yesterday had me really concerned and I went back through my old video of putting this engine together and we had plenty of end play back then. So yeah. Yep. I think we need to do this one good and proper. So we'll go down the right avenues and take our time with it, I think. Okay. So, I've spoken to some people and I asked about the Apex Sills. Now, one person in particular, the Walking Encyclopedia, told me that the front rotors run lean and he told me to check the spark plugs and there will be a difference. And I did and he's right. So, front rotors run lean, dented the apex seals. So, where does that leave us? Um, I've spoken to the owner replacing all the apex seals. Probably run power seals. So, that's good. I may I'll check over the springs, the Apex springs and stuff like that, but I'm fairly confident everything else is really, really good.

[00:38:28]So, as I said before, we will get the cake stacked. We'll spend a bit of time on the front stack.

[00:38:34]We'll make sure everything's there.

[00:38:36]We'll make sure our inplay is there and make sure everything is running smooth, nice, give it back, and then he's away laughing again. So, good news, bad news.

[00:38:47]The car was going to get tuned anyway.

[00:38:49]So, running lean. I don't know.

[00:38:53]Good news, bad news. So, sucks. Apex seals bent, but at least it's not anything like the rotor housing or anything like that. So, achievable to fix, cheap to fix, cheaper than some other options, that's for damn sure. So, look forward to getting this one back together. Anyway, long video. You asked for it this way, so sucked in. And I'm glad we found out what was wrong with it and moving forward. Anyway, if you made it this far, thanks for watching. Next video will be at Smoky Valley in the RX7 and maybe I'll bend some pixels there.

[00:39:27]Anyway, enjoy.