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Author Topic: Can I get away without surfacing the head?  (Read 3996 times)

February 04, 2007, 02:24:54 am

wolf_walker

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Can I get away without surfacing the head?
« on: February 04, 2007, 02:24:54 am »
Well, it's cold as heck, I'm short of time and money, and the motor will be coming out of the Caddy soon if it runs well after the head gasket and injectors.

I'm doing the head gasket for the typical oil leak on the back side.  No other leaks.  Head's never been off, has plenty of miles on it but was well cared for.

Also, as I posted here awhile back, about 20K miles ago I had an incident while on a 24 hour road trip that I think was a piece of carbon(or worse) came loose and made a hell of a racket for a span of 5 minutes or so, then quit.

It can't be too bad since as I said, that was 20K ago.  Idle's been a little off and it started a little rough, but the injectors had new nozzles and were NOT pop tested by my shortcut taking Father (he's a pilot/mechanic, if it stays on the ground, he'll tend to be lax with it).  So I think the injectors would account for most of it's oddness, and it was run with worn nozzles and smoked like heck for a long time before hand, hence lots of carbon.
In the current upper 30's F weather it still fires right up on one glow plug cycle and idles alright, just nails a lot till it's warm, and some then.
I plan to check the valves for leaking while it's off, and hope the carbon or whatever it was didn't bend one.  If so that's another story.

Anyway, since there was no overheating or such, is it imperative that I have the head shaved do you think?  I can get it done I guess, but I have no faith in pretty much anyone locally here.

Related question:  If you shave an OHC head that's warped, does it not screw up the bore centerline for the cam?  I know we used to align bore the mains on V8's years ago, never hear anyone mention it for OHC heads though?


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Reply #1February 04, 2007, 04:07:20 pm

hipifreq

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Can I get away without surfacing the head?
« Reply #1 on: February 04, 2007, 04:07:20 pm »
Taking couple of thousandths off the head surface will do two things for you. It'll get the surface clean and shiny, an otherwise tedious task to do by hand. It'll also ensure that the surface is flat, making for a better gasket seal.

If you take it in make sure that they know how to handle the prechamber inserts (it's an IDI iirc). The inserts are VERY hard compared to the aluminum head, so they'll need a special cutting head and must take it very slowly.
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Reply #2February 04, 2007, 04:28:32 pm

wolf_walker

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Can I get away without surfacing the head?
« Reply #2 on: February 04, 2007, 04:28:32 pm »
Probly the best thing.

But, with the wear in a couple of valve guides and the scoring in the bore, I think the whole works is on hold for the time being.

Bummer..  And with only 300K on it too..
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Reply #3February 04, 2007, 05:34:29 pm

jtanguay

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Can I get away without surfacing the head?
« Reply #3 on: February 04, 2007, 05:34:29 pm »
so you pulled the head and found wear on the valve guides and scoring on the cylinder bore??? man thats nasty :(


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Reply #4February 04, 2007, 06:14:43 pm

wolf_walker

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Can I get away without surfacing the head?
« Reply #4 on: February 04, 2007, 06:14:43 pm »
Pretty much, yeah.  I had the motor for probly half of it's 300K lifespan, regular oil and filters, no idea why it's so worn.  :(

If I'm going to rebuild one, I have a TD long block I'd rather do, so I dunno what I'm going to decide right this second.
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Reply #5February 04, 2007, 08:52:32 pm

craiggroombridge

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Can I get away without surfacing the head?
« Reply #5 on: February 04, 2007, 08:52:32 pm »
the way i get my heads resurfaced is by a stone wheel, not carbide cutters the stone cuts the aluminum and the pre chambers with ease

Craig
My first was an 85 gas fun
my second is an 86 gas more fun
my third is a 92 n/a diesel project

 

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