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-   -   Elusive knocking noise (http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/432704-elusive-knocking-noise.html)

sand_man 11-21-2008 02:46 AM

Quote:

Originally Posted by Alan L (Post 4315834)
Sometimes life sucks. But I still find them more consistent than women.
Regards
Alan

No truer words have been spoken...

WERK I 11-21-2008 04:54 AM

Don,
Were there any other cylinders that had bad valves/guides or was #3 the only one?

DonE 11-21-2008 04:49 PM

4 of 6 heads had trashed guides, both intake and exhaust. The valve stems were trashed as well but they sealed just fine on their seats - compression and leakdown tests were all good. The only explanation given was bad guide material.

ghnat 12-18-2008 06:07 PM

Don,
Any updates?

DonE 12-18-2008 06:20 PM

Picking up the heads in FL while on vacation next week. I should have it back together around new years day. Let's see if I can top more than 5000 miles before I take it out again.

ghnat 12-18-2008 06:25 PM

What part of FL? I'll be in Tampa and Hernando next week...
I'll need some head work as well. Maybe you can give me a contact???
Has the studying finished?

DonE 12-18-2008 06:27 PM

Bill at Xtreme Cylinder Heads in Palm City FL. One more test in early Jan (CRPC) and I hope I'm done. Waiting on results from CFP exam (takes 6 weeks).

x98boardwell 12-19-2008 07:28 AM

Yoh!
 
Don,

My buddy just went for the week long course in November to Dallas for the study session for that test which he has also now taken. He is waiting the results. CFP, here you come. Best of luck.

Bryan

AFM744 12-19-2008 08:01 AM

Quote:

Originally Posted by DonE (Post 4317970)
4 of 6 heads had trashed guides, both intake and exhaust. The valve stems were trashed as well but they sealed just fine on their seats - compression and leakdown tests were all good. The only explanation given was bad guide material.

Don, do you know which guides your previous machinist installed? Also, which stem seals did you use? Obviously these guides should be blacklisted.
I thought my exhaust guides were bad, with about 1mm clearance at 89k mi. Then at German Precision I saw some reeeeally worn guides, like you could put an extra valve or two in there!

DonE 12-22-2008 02:15 PM

I picked up my heads from Xtreme Cylinder Heads in Palm City FL this afternoon. Below are some pics of one of the heads, and a pic of the trashed valves (intake and exhaust).

The valves are custom stainless steel intake and inconel exhaust valves, both turned from blanks. The guides are manganese/bronze. The inconel valves cost $25 for the blanks and $25 to custom machine each. Stock exhaust valves are $48 each. The custom stainless intake valves cost $42 each (blanks plus machining) compared to $50 for stock.

http://forums.pelicanparts.com/uploa...1229986408.jpg

The springs had to be replaced because of the new custom valves and their retainer positions. They are Elgin springs with titanium retainers. You'll see the top of the stems are a bit higher off the retainers than stock.

http://forums.pelicanparts.com/uploa...1229986428.jpg

Here are the old intake and exhaust valves cleaned up, but clearly show severe wear. The intake valve has a ridge cut in it at the top of travel. The stems feel as if they where sanded with 50 grit sandpaper.

http://forums.pelicanparts.com/uploa...1229986548.jpg

The engine should be back together around Jan 1.

DonE 01-12-2009 06:14 PM

Here's the engine on the stand. You can see that I've packed the turbo shield with new insulation. After I took this pic, I joined the tranny and motor, so tomorrow it goes in the car.


http://forums.pelicanparts.com/uploa...1231816260.jpg

AFM744 01-12-2009 07:29 PM

Quote:

Originally Posted by done (Post 4413931)
...so tomorrow it goes in the car.

woot!!!

ghnat 01-12-2009 08:24 PM

Alright, can't wait to see the beast again...

purplehaze 01-13-2009 06:53 AM

Nice work, Don!

Looking forward to seeing it back in your car.

When I think I've had a bad day, I just think of the ***** you've been through, and it puts it all in perspective.


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