Captain Obvious

Complete Misfire on Three Cylinders

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LOL. No, they're not all out. I haven't done anything with them yet. They're all still in there.

So, basically the answer seems to be... "No, there is no logical reason for the lengths of those studs." and the follow-up info of " However... Mess with them only if I'm willing to accept the possible consequences." Roger that.

I guess I'll try gently to pull one and see what happens. If it comes out easy, maybe I'll try two. And so on. If the first one seems like it doesn't want to come out, I'll just cut down the extra longs with a hacksaw and call it a day.

Yes, they are all-thread, and cut to custom length by hand. I don't think it was part of a kit.

And no, they didn't really cause any functional problem. Other than having to screw the nuts on forever, they worked OK. In fact, the only location that was a problem was the front exhaust nut from cylinder #5. Because of the way the header turns forward so close to the head, getting a wrench on that one was a PITA. Haven't figured out what to do about that one yet, but I need to come up with something better than the way it was done before. Anyway... Small problems compared to the big picture.

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So while I'm logged in and asking stupid questions... Anyone understand the point of doing this? Here's number three:
P1150279.JPG

 

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Clearly it is so the PO knew which chamber was #3 rather than #4. I am just hoping he/she counted right.😉

Edited by jonathanrussell

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8 hours ago, Captain Obvious said:

asking stupid questions.

As a teacher ones sayd: there are only stupid students that don't ask..

Maybe the 3 is a marking from a head restorer so he knows it was one of him..  is it 123456 in all of them or just a 3 (in the 3th cylinder?)

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Sorry for not being clear... All of the cylinder are punched with their respective numbers.

I didn't take pics of all of them, but here's #4:
P1150280.JPG

My issue about "what's the point" is... What possible reason would there be for punching the chambers like that? What's the value add?

It's not like they can possibly move around! I can understand it on things like the cam towers where it's possible to get them into the wrong positions, but the cylinders themselves aren't going anywhere!!! Even if you're trying to do something like get the same valves back to where they came from* or something, you don't need numbers. Just look at the head and hope you can count to six?     :facepalm:

* Side-note BTW - Based on the non-matching wear patterns on my valves and the seats from whence they came, I don't think he did. I believe I've spent the last couple thousand miles re-wearing valves to the wrong cylinders. Working on some of that is the next project on the agenda.

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I wouldn't spend too much time trying to make sense of the PO's thought processes. They might start to make sense. That said, have you searched the top and the bottom of the block for the reference stamps that show the block's orientation in the car?

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Haha!! I didn't see stamps on the block for that, but I did see a stamp in the head "F".

Here, you can see it to the left of the plug I put in up by the thermostat housing. I'm trying and trying to convince myself that it does not mean "Front":
P1150310.JPG

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So my valves were indeed AFU. Based on the wear patterns, they were all mixed up, and most of them were not sealing properly.

One of the exhausts (4E) was even bent a little and not sealing for squat!. And I can tell by looking at the wear patterns and carbon traces that it's been like that for quite some time. Probably since my PO messed with it. It definitely did NOT just happened when the cam snapped.

Today's progress was I got all the exhaust valves sorted out. As best I could, I matched the correct valves to the correct cylinder and lapped them into place. Thankfully I have a set of set of valves at my disposal that I stripped out of an N47 years ago. I saved them, because that's what we do. They were sitting on the shelf, and thankfully I've got 24 valves from which to pull the best 12.

So exhausts are done and (barring surprises) I think the intakes will be much easier since they are in way better shape.

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how are the guides? I was messing with my N47 and noticed I had NO play on the intake, some on the exhaust. Just wondering if exhaust typically show more wear.

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7 hours ago, Captain Obvious said:

One of the exhausts (4E) was even bent a little and not sealing for squat!. And I can tell by looking at the wear patterns and carbon traces that it's been like that for quite some time. Probably since my PO messed with it. It definitely did NOT just happened when the cam snapped.

Once you sort out 12 good valves are you going to get the valve seats re cut?

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No. That's exactly what they would they expect me to do. 

What I'm doing instead kinda goes like this. Under magnification and with the use of some sharpie marks on the sealing surfaces, I've tried to match up the correct valve with the correct cylinder. And then after that, I'm lapping them to match the seats.

For example... Here's one of the seats before I've done much of anything to it. The valve that WAS in this location wasn't even close to making contact on most of the seat. I managed to find one of the other exhaust valves that was pretty close. Here's what I'm starting with:
P1150357a.jpg

Here's my handy-dandy valve lapping "tool". I use double back sticky tape to hold the valve to the "tool":
P1150361a.jpg

Some 800 grit lapping compound:
P1150362a.jpg

And I work the pair:
P1150364a.jpg

until I have something like this. Smeared contact markings over the entire seal:
P1150372.JPG

P1150373.JPG

Yes, there are still a few pits on the valve seat, but I'm not looking for perfection here. I'm just looking to be able to drive a little bit more on this engine until I finish the F54/P79.

What I'm ending up with is 1000 times better than what I started with!!

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11 hours ago, Dave WM said:

how are the guides? I was messing with my N47 and noticed I had NO play on the intake, some on the exhaust. Just wondering if exhaust typically show more wear.

All of the valves wiggle a little bit, but yes, I've found that the exhausts wiggle more than the intakes. I'm not going to measure them, because then I'd know.

I did measure the lengths of all the exhaust valves though, and found one that was twenty thousandths shorter than the rest. No idea why it's like that, but that one did not make my set of the six best exhausts.

  • Haha 1

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I can't imagine you letting the wiggle go un measured....

:)

snorkle

 

need a procedure. If you come up with something I will try as well. I suppose a way to measure the bore would be best a series of go no/go round gauges would be best for the bore.

Edited by Dave WM

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21 hours ago, Dave WM said:

I can't imagine you letting the wiggle go un measured....

Well you're going to have to accept it because I'm not going to measure it.  LOL 

I like the small bore gauge in that video. I don't have one of those, but I should.

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So I've got those Sealed Power valve seals on order, but Rockauto's inventory quantities were screwed up and the order was delayed. Won't be here until next week sometime. No biggie.

So todays questions:

I need to get a new head gasket on order. I won't use Fel-Pro. Anyone have other suggestions they think is the best way to go?

And I think I've already got an intake/exhaust manifold gasket around here somewhere... Have we definitively determined does the metal faced side go against the head, or against the exhaust manifold? I know it's been discussed, but I don't remember if it has been 100% confirmed. Looking for guidance there.

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23 minutes ago, Captain Obvious said:

Well you're going to have to accept it because I'm not going to measure it.  LOL 

I like the small bore gauge in that video. I don't have one of those, but I should.

I think I am going to get one, looks like fun tool to use.

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I got a couple from this guy. I did local pickup, only concern is how they would survive shipping. They look very OE like.

https://www.ebay.com/itm/McCord-7114M-Head-Gasket-Fits-1970-84-Nissan-2-4L-2-6L-2-8L-6-cyl-engine-280Z/142521324095?fits=Model%3A280Z&hash=item212eeed23f:g:IE4AAOSw4A5Ym8kz:sc:USPSFirstClass!32819!US!-1

McCord gasket seems out of production, so old stock.

What's the problem with Felpro?

 

Edited by Dave WM

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Not wanting to start a religious war over gasket brands, I've had two high annoyance gasket failures with Fel-Pro. First was a head gasket on an Acura Integra, and the second was an oil pan gasket failure on a Honda Civic.

I'll use simple paper gaskets from them, but the complicated stuff doesn't seem to work for me. I'm just cutting my losses.

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An update to the project...

I've got all the valves sorted out and cleaned up waiting to be reinstalled.

I cleaned up all the burrs and distorted metal in the holes on the head and cam towers where the alignment dowel rings go. This allowed me to test fit the cam towers and my "new" cam. So far so good!!! Spins easy with two fingers! And that was even without a whole bunch of fiddling with the towers and the bolts.   @jonathanrussell

This. Just. Might. Work!!!!     :ph34r:

Some of the alignment rings for the towers were bent and mangled beyond use, so I need to get some of them on order. That and a head gasket.

Edited by Captain Obvious
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