[mbardeen]

I found this in my oil pan as I was cleaning it. It's obviously broke as the two bits fit together, and looks like it has bent before breaking.



   



   

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[Lear35A]

What's the prize, 'cause I know what it is and it sure shouldn't be in your pan.



There are two of these in the head. They block the oil holes that are in the cam bore that aren't used. They are at the back of the head. They are held in place quite well. Only way one could get in the pan would be if a mechanic dropped one while assembling it. Very easy for it to then fall down one of the oil drain passages. Say "oops", button it up, and give it back to the customer.



Better check to see if one is missing. It would be bad for oil pressure in the head to have one missing.

If you take off the piece that holds in the two black plugs, you'll see these two pins. Or at least you should see the two pins.

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[mbardeen]

I love this forum! I must budget a big sponsorship payment soon.





Now... what to do?



The fact that it's been obviously bent doesn't make me pleased. That means it got stuck somewhere prior -- I wonder where and what damage was caused? If one was missing, which I assume is the case, bad oil pressure in the head would explain the excessive lifter noise. But what's worse, that means someone probably had the head off at some point. And given the quality of the repairs on the rest of the car, that scares the bejesus outta me.



First things first -- I'm looking at the parts diagrams now, but I don't see the part listed. Where should I be looking?

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[Cloud9...68]

That's what I thought those pieces were, but I had no idea what their purpose was. They look funny sitting in the cam bores all by their lonesome, with no apparent function. Thanks for explaining what these are and what they do, because it was one of several little things in the back on my mind that "just seem funny". One by one, I'm checking these off, so hopefully I'll have a successful start. We'll see soon...

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[Lear35A]

It's done that way for machining purposes. Line boring the cam journals and drilling the oil galleries are easier done when its an all the way through operation. Then you plug off what you don't need. Our blocks and heads are full of such things. This is the only place it's done with this kind of plug though.

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[MB968]

Unusual interdrilling plug, they are usually a single diameter. I can only assume it had to be that long so as to be able to get a tool on it to drive it into the hole they wanted to plug. So, anyone know why it has two diameters.



Could it be that it was broken when it was being driven into the interdrilling?



I'd assume that if instead it was broken being hit by something in the crankcase, then you should see some impact damage on the crank or one of the rods. If you don't see any damage on these, then I'm thinking it was already broken when it got to the crankcase.

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[mbardeen]

There's a slight indent on the larger diameter piece, near where the diameter changes. Looks like a strike of some sort. This same piece is bent as well. The strike is on the inner bend of the entire rod when the two pieces are reassembled. Bend is aprox. 30 degrees off axis.



I'll take a good look at the cranks and rods now. My gut feel is that this got hit by the crank.

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[Lear35A]

The smaller diameter is a slip fit into the hole. It slides in and out with two fingers. The larger diameter end just keeps the small end from going in too far. The length of the larger diameter takes it into contact with the bridge piece holding the pin plug in place.



In the crankcase it probably got caught in the spinning crankshaft. The pin is aluminum so it probably didn't do any serious damage.

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[mbardeen]

Lear got it exactly right. The plug is missing from the intake cam side. Now to see if I can find a replacement plug.

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[mbardeen]

For future reference, part number is 92810526200.

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[Lear35A]

Wow. Somebody had to have known that happened. No way for the pin to fall out of there. I am sure this situation would hurt the oil supply to the intake side lifters. Good thing you found it when you did and asked.

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[mbardeen]

There's RTV around those plugs in the back, so evidently someone tried to fix an oil leak and dropped it then. The end results of the fix are probably worse than the original problem!



I also suspect someone has taken the head off the engine at some point. Given this, and everything else I've seen on the car, I'm going to pull the head in February and re-do it correctly.



And good thing we've got people like you in the forum that can help in situations like these. I would have been lost trying to find where the part originated and would still be scratching my head as to why I have excessive lifter noise. Once again, thank you!

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[MB968]

[quote name='mbardeen' timestamp='1356887518' post='136847']

Lear got it exactly right. The plug is missing from the intake cam side. Now to see if I can find a replacement plug.



[/quote]



Wow, that's even more unexpected. If I'm reading this picture correctly, looks like the pin fits into the cam. Wonder why they just didn't plug the end of the cam. Did they want some oil to seep out of the end for some reason??

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[mbardeen]

Sorry, the perspective on the picture is a bit deceiving.





The red dot indicates the unplugged hole in the last cam bore. The camshaft ends just after the last lobe, so that last cam bore is completely unused. The green dot is the good plug. The missing plug should run from the red dot to the cap, which is the piece indicated by the yellow blob. The cap holds the plug firm in the hole.





I created a stop-gap plug by milling down a screw using your drill & file method, MB. I've got the correct part on order for when I return to redo the head later-on.

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[Lear35A]

Better perspective. One in, one out, just like mbardeen

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[MB968]

Lear, thanks for the pics. I understand now how they fit in the head.



Still not sure why the design has these as removable. Suppose it could be for later service/rework of the head. Or was there some design where this head was used on the other bank of a v-8, or used longer cams with bearings in the back for extra support??

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[Fox944]

I had one of these missing in my head after it was rebuilt. Pete @ RS Barn picked up on it and replaced the missing part for me. A lot of techs wont know what its for or even notice it is missing unless they have worked on one of these engines before.

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[tamathumper]

If that's the same galley hole from my 944S, it was not only missing but blocked off with a NAIL!

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[Grandpa#3]

Can someone please turn this into a PDF?? I would but don't know how.



Cheers,

Larry

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[Lear35A]

Turn what into a PDF?

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