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Discussion Starter #1
I'm well into a head rebuild on an N47. Have removed the s/s exhaust liners and have been working the rough casting down in the intakes and exhaust ports and have a pretty good finish in the intakes.
My question is, how important is a bright finish in the ports, intake and exhaust?
I'm also looking for more information about timing chain slack if I do as planned and mill the head .050 to boost compression. Will .050 really be a problem if I don't shim the cam towers?
About the polishing, I have already removed the valve guides so I can get to just about all of the intake surfaces if it is important. How important is it?
How about the valve guide bosses particulatly in the exhaust. They are pretty rough looking. Should these be milled to improve flow?
 

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I am close to finishing this engine I am building, put back to stock 83 L28, but I have another that my performance cam and everything else is going into. I want to port and polish the head, I have the tools, just would like to know how you removed the liners. My thoughts, use the die grinder and grind them into two pieces each half and pull with pliers. About the valve guide bosses, do you remove them or just smooth them, a book I have removes them from Chevy's and Ford, but they are iron heads, different story. I would like to know as much as you will tell me. Thanks for any help you will give me.
Joshua L.
Oh, the head is actually a P79, but basically the same thing thing as far as liners are concerned. Also, did it mess up the ports?
 

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Discussion Starter #3
> I am close to finishing this engine I am
> building, put back to stock 83 L28, but I
> have another that my performance cam and
> everything else is going into. I want to
> port and polish the head, I have the tools,
> just would like to know how you removed the
> liners. My thoughts, use the die grinder and
> grind them into two pieces each half and
> pull with pliers. About the valve guide
> bosses, do you remove them or just smooth
> them, a book I have removes them from
> Chevy's and Ford, but they are iron heads,
> different story. I would like to know as
> much as you will tell me. Thanks for any
> help you will give me.
> Joshua L.
> Oh, the head is actually a P79, but
> basically the same thing thing as far as
> liners are concerned. Also, did it mess up
> the ports?
JOSHUA, L.
You have the right idea on the liners. I did do some cutting with the die grinder first but only cut out a ring about one inch wide by reaching down into the port. Then I used a sharp chisel and split the liner down in several places and folded the metal toward the center of the opening. Did some prying with a sturdy, long screw driver.
You will have some trouble getting the liner out from under the valve seat. In order to do that you will have to drive the liner back toward the valve seat opening to distourt it enough to get something behind it so it can be pried up and over the valve guide boss.
I didn't remove the valve guides before I removed the liners. I ended up replacing the guides anyway. The liner removal would be easier with the guides removed. Suggest you do that.
I have not yet removed the valve guide bosses yet. Actually, The exhaust is where the bosses are kind of rough. I will tackle those next. On the intake side the lines are smooth and really don't need any work that I can see.

Hope this helps.
Larry in Nappanee, Indiana
 

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Discussion Starter #4
>
> Hey Larry
I have a 78280z with 130,000 on it,compression
is 140 on all 6.So I'm thinking about rebuilding
the head later this year and hope talk to you about your rebuild before I start mine.
thanks
Dave S
Joliet IL.
Ps
are you snowed in yet
It looks like I have about 2 foot
 

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Discussion Starter #5
> I have a 78280z with 130,000 on
> it,compression
> is 140 on all 6.So I'm thinking about
> rebuilding
> the head later this year and hope talk to
> you about your rebuild before I start mine.
> thanks
> Dave S
> Joliet IL.
> Ps
> are you snowed in yet
> It looks like I have about 2 foot
Hey Dave,
Happy to help when you are ready. Just give me a call. I'm right in the middle of my rebuild and having a blast. I'll be ready this Spring with the new head and the Center force 2 clutch I have waiting. Good luck
Larry in Nappanee, Indiana.
Have 4 foot drifts in the driveway.
 

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HEY DAVE!

> I have a 78280z with 130,000 on
> it,compression
> is 140 on all 6.So I'm thinking about
> rebuilding
> the head later this year and hope talk to
> you about your rebuild before I start mine.
> thanks
> Dave S
> Joliet IL.
> Ps
> are you snowed in yet
> It looks like I have about 2 foot
WHATS UP DAVE.Right now im currently
rebuilding the motor from my 77 Z,In nearby
Berwyn I'm putting a N47 head decked with some
of the sleeves removed re polished cam on the F54
turbo block w the flattop pistons new bearings
rings.I already had the center force 3 clutch,
header,mallory coil,exhaust,roll bar,strut bar
this car is moderatly loaded .Any way you are more than welcome to stop on by any time and check
out the internals on this motor its really simple,
and my car since it s the same model as yours.
I should be picking up my degreased and machined
block from the machine shop as of monday morning.
And will have it assembled by the end of the week.
I have done lots of tricks to the block and oil
system you would like to see.This is my year round car i am rebuilding due to a high rpm piston melt down!And the snow has not slowed me down one bit 24in round here.
So feel free to contact me Jim (7087882758)
 

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JOLIET and BERWYN

Hello guys, this dosent relate to this post, but i live in St. Charles IL. I was Also wondering where you guys got your roll bars, are they custom and if so who made em. I will buy one this winter and dont know of a good source besides MSA for them.

The Z is put away for the snow, so now i have time to work on it.

Take it easy guys- evan
 

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Discussion Starter #8
> Hey Dave,
> Happy to help when you are ready. Just give
> me a call. I'm right in the middle of my
> rebuild and having a blast. I'll be ready
> this Spring with the new head and the Center
> force 2 clutch I have waiting. Good luck
> Larry in Nappanee, Indiana.
> Have 4 foot drifts in the driveway.
Thanks Larry
with all that snow on the drive
I guess you are stuck in the garage
hough
I'll be talking to you
Dave
 
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