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Certified Rennwerker
Join Date: Oct 2002
Location: Kansas
Posts: 1,906
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Damage assessment....head
Oh boy is this a fun repair or should I say repairs. For starters I had an issue with the oil pump drive gear backing out and losing time. Car ran like it had 2 cylinders. Figured the worst happened...piston/valves getting up close and personal so I buy a new head and all the goodies(some mods) to rebuild a good head, send it off to the machine shop and all is good until I looked over the lifters. They were so concave on the top puck surface all needed replaced.
The HG came out in one piece but w/dozen or so holes and corroded beyond recognition(had I not known the look of the HG) I would have thought it was a colander from the kitchen cupboard coated in a baking soda and sand like substance. Major pitting on the old head mating surface. It would take 2-3mm yes MM not thousands, to clean it up. One lifter bore is severely scored with vertical scratches about 2 thousands deep and around the entire bore. Looks like RR ties. The guide pin on the front half of the tower was rounded out in the bore and the pin fell out(they are press fit ) and should not be ez to come out on it's own. The cylinders look good as do the pistons in exception for #3 which was corroded and discolored. Back to the valves/pistons....no pistons hit any valves!!! So the issue was the HG/lifters. Well I have a new head and cam now!! I guess i should try to look at the plus side.  Several inner springs were broken/cracked but all else appears ok, but no issue now as it is all new. Better stay that way too because Titanium is not cheap!  (sublimital hint here).......Well to finish I got a new torque wrench and hopefully I will have the top end back up and the car screaming down the straight away this evening, hope so it has been 10 months since I drove it and that equals 10 months of using the city BUS.  So to those reading and new to the game the moral here is anything and everything could be an issue and knowing that may help keep your spirits up!  Send me good vibes dudes and dudettes may need them and the Porsche wants to get back to the road course! Dal
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PCA " I've been everywhere, done everything......just can't remember any of it!"
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10-04-2007, 06:35 AM
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Greasy Member
Join Date: Mar 2006
Location: Indiana
Posts: 1,457
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OUCH!
Well, I definitely send "good vibes" your way! I think the only thing that could be said at this point is: at least it was all top end damage! Be glad you didn't have to pull the whole motor  Good luck getting her back on the road! After this she should treat you well! -Nick
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Owner: Bennington Motorsports www.benms.com Sponsor for Midwest Region 944-SPEC racing series -When was your timing belt changed or tensioned?? -Yes, I'm the crazy man that will loan out my 9201. Just PM me, I will add you to the list and get it out ASAP. |
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10-04-2007, 07:02 AM
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Politically Incorrect
Join Date: Aug 2005
Location: Hoover, Alabama
Posts: 1,497
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Dat's da pits...
If you have to mill that much off (2-3mm), you might want to think about how that will affect the cam timing. The cam gear will now be closer to the crank gear. Two possible solutions are: stackable copper head gaskets (search: Paeco) 0.06" thick, $190 ea X two; adjustable cam gear (Lindsey Racing) $310. Looks like the adjustable cam gear will be cheaper and you have the added benefit of moving the power band around (within limits).
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Edek '87 924S '91 535i Last edited by onZedge; 10-04-2007 at 09:58 PM.. |
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10-04-2007, 09:53 PM
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Certified Rennwerker
Join Date: Oct 2002
Location: Kansas
Posts: 1,906
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Not an issue edge. I replaced both the head and cam assembly from an 89. The old head/cam tower are lawn ornaments right now!
Thanks Dal
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PCA " I've been everywhere, done everything......just can't remember any of it!"
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10-05-2007, 04:57 AM
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