Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 Engine Rebuilding Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Sep 2012
Location: Vacaville / Travis AFB
Posts: 14
Garage
Question 1st time rebuild 3.0

Howdy, I'm new to Porsche. Got a sweet 1980 3.0 down to the cylinder base gaskets for seepage repair, and 1 Head bolt snapped. Every thing is great inside. I'm looking for advice on replacing the rings. Pistons and cylinders are round and undamaged. Replacement was the norm for my past experience with verticle engines. Should I reinstall the used rings? Thank you for your assistance. Mark

Old 09-19-2012, 10:14 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
KTL KTL is offline
Schleprock
 
KTL's Avatar
 
Join Date: Sep 2000
Location: Frankfort IL USA
Posts: 16,639
Check the end gaps when they are installed in their respective cylinders. Also, be sure to check the clearance on the upper ring lands. Anything more than 0.004 is too much.

How do the cylinders look in terms of hatching/wear? Typically you can hit these with some red scotchbrite pads and oil to "deglaze" them a bit. I did this on my recent 3.2SS build and the new rings on the old cylinder surfaces sealed up nicely.
__________________
Kevin L
'86 Carrera "Larry"
Old 09-19-2012, 01:22 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered
 
E Sully's Avatar
 
Join Date: Nov 2008
Location: NY
Posts: 3,974
Garage
Mileage on the engine? Take a magnet to the cylinder wall. If there is attraction? Pictures help.
__________________
Ed
1973.5 T
Old 09-19-2012, 02:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered
 
Join Date: Mar 2002
Location: Philadelphia, PA
Posts: 12,620
Garage
Top end rebuild.......

Mark,

You did not mention the location of the broken head stud. I would guess it is the lower (exhaust) cylinder head stud. Was it made steel or not? Check for the presence of dilavar head studs on your engine. They are prone to breaking than steel studs. If they are dilavar, time to replace them.

Inspect the mating surfaces between the cylinder head and the cylinder for defect or imperfection that could cause leak. Depending on the mileage and condition of your valves, valve seats, valve guides, and springs, you could clean the heads and lap valve grind each one. Test for leak and sealing.

Tony
Old 09-19-2012, 06:59 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Sep 2012
Location: Vacaville / Travis AFB
Posts: 14
Garage
Thanks for the help.
Story time: This motor was transplanted with low miles
(40K), but it shows an overhaul with mismatched heads, Cam Chain Tensioner mod,etc. It sat for 15 years. My son brought it home. The fuel pump and alternator were dead. The oil had backfilled the case and flowed to the wrong side of the pistons. In The Great State of California I need to pass Smog with the EGR and Air Pump functional. So a clean and inspect was due.
#5 wouldn't hold pressure for a rotten exhaust valve seat. Looks like carbonic acid etching, and may be beyond grinding.

Tony, The broke stud is the aft exhaust on #4. There is less than an inch of shaft remaining at the case. Are visegrips the best tool? All the studs look the same; Only the exhaust were Dilivar, yes?

Mr. Sully, I don't know the milage, but the cylinders still show machining patterns.
The magnet does not respond.

KTl, The .004 checks good. The cylinders are not even dirty from previous tear down. I read that some folks did not recommend new rings in old jugs.



Bad seat



Broke stud



Nice jug

Old 09-20-2012, 08:52 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered
 
Join Date: Oct 2008
Location: Malmö, Sweden
Posts: 27
Looks like nikasil liners to me?
Old 09-20-2012, 10:51 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered
 
E Sully's Avatar
 
Join Date: Nov 2008
Location: NY
Posts: 3,974
Garage
Non magnetic is Alusil.

__________________
Ed
1973.5 T
Old 09-21-2012, 05:25 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Reply


 

Tags
advice , rings


All times are GMT -8. The time now is 04:47 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.