Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
 Reply to this topicStart new topic
> To re-ring ot not re-ring?, Need some advice
krazykonrad
post Feb 23 2011, 03:50 PM
Post #1


Senior Member
***

Group: Members
Posts: 1,140
Joined: 21-February 06
From: Canton, GA
Member No.: 5,610
Long story short, the engine is out of the car. Loose head/cylinder studs are the suspected culprit. I'm planning on pulling the cylinders to lap them into the heads before I put it all back together. Will this necessitate re-ringing? The rings have about 8,000 miles on them.

Thanks for y'all's help!

Konrad
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Feb 23 2011, 04:29 PM
Post #2


Send me your transmission!
***************

Group: Members
Posts: 23,032
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
10Kmi is the recommended interval that I have read in the manuals. It is not expensive, and "while you are in there" you might as well. Hone the cylinders, though or they wont seat.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mepstein
post Feb 23 2011, 04:32 PM
Post #3


914-6 GT in waiting
***************

Group: Members
Posts: 19,578
Joined: 19-September 09
From: Landenberg, PA/Wilmington, DE
Member No.: 10,825
Region Association: MidAtlantic Region
Buy the girl a new ring/don't use the old one. Woops, wrong thread. (IMG:style_emoticons/default/confused24.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
TheCabinetmaker
post Feb 23 2011, 05:33 PM
Post #4


I drive my car everyday
*****

Group: Members
Posts: 8,318
Joined: 8-May 03
From: Tulsa, Ok.
Member No.: 666
If ya use new rings, you should at least hone the cyls
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Woody
post Feb 23 2011, 05:38 PM
Post #5


Sandbox Rabblerouser and head toilet scrubber
****

Group: Members
Posts: 3,858
Joined: 28-December 10
From: San Antonio Texas
Member No.: 12,530
Region Association: Southwest Region
QUOTE(Dr Evil @ Feb 23 2011, 04:29 PM) *

10Kmi is the recommended interval that I have read in the manuals. It is not expensive, and "while you are in there" you might as well. Hone the cylinders, though or they wont seat.



Wait did you just say that 10,000 miles is the recomended interval to replace the piston rings?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Cap'n Krusty
post Feb 23 2011, 06:29 PM
Post #6


Cap'n Krusty
**********

Group: Members
Posts: 10,794
Joined: 24-June 04
From: Santa Maria, CA
Member No.: 2,246
Region Association: Central California
Ring it if they're worn out, and hone the cylinders if you ring it. DO NOT USE A BALL HONE!!! I suspect the rings will be fine at 8K miles, unless they got really hot. Have the heads surfaced if they're the least bit "iffy". Lapping them in is a joke, and lapping them without milling the surface is downright criminal. When you cut the heads, shim the cylinders to compensate for the cut. Loose head studs are rare on a T4 unless they've gotten REALLY hot, and even then it hardly ever happens.

The Cap'n
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
VaccaRabite
post Feb 23 2011, 07:31 PM
Post #7


En Garde!
**********

Group: Admin
Posts: 13,584
Joined: 15-December 03
From: Dallastown, PA
Member No.: 1,435
Region Association: MidAtlantic Region
What is the issue that you were having?

If you are rebuilding the top end, it would be silly NOT to hone and re-ring. its so easy on these cars since you can just slip the jugs out and hone them.

Zach
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Dr Evil
post Feb 23 2011, 07:37 PM
Post #8


Send me your transmission!
***************

Group: Members
Posts: 23,032
Joined: 21-November 03
From: Loveland, OH 45140
Member No.: 1,372
Region Association: MidAtlantic Region
IF the jugs are pulled, the recommended interval is 10Kmi. I see where that could be confusing how I stated it before. You do not need to change the rings on an engine that is assembled every 10Kmi (IMG:style_emoticons/default/biggrin.gif)

John, why not use a ball hone?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Cap'n Krusty
post Feb 23 2011, 07:59 PM
Post #9


Cap'n Krusty
**********

Group: Members
Posts: 10,794
Joined: 24-June 04
From: Santa Maria, CA
Member No.: 2,246
Region Association: Central California
QUOTE(Vacca Rabite @ Feb 23 2011, 05:31 PM) *

What is the issue that you were having?

If you are rebuilding the top end, it would be silly NOT to hone and re-ring. its so easy on these cars since you can just slip the jugs out and hone them.

Zach



A good machinist will set the cylinders up in a fixture to assure the hone is centered, round, and even. Not all that easy.

The Cap'n
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
krazykonrad
post Feb 23 2011, 10:28 PM
Post #10


Senior Member
***

Group: Members
Posts: 1,140
Joined: 21-February 06
From: Canton, GA
Member No.: 5,610
Here's the background:

The driver's side lost compression on both cylinders. The head checks out ok, no dropped/burnt valves. No apparent cracks or voids. This leads me to believe that the studs have backed out a little. They are not loose by hand, but I suspect they have turned enough to break the seal between the cylinder and head.

The motor is a 2.0 Porsche case with 2.0 bus heads. My plan is to use this as a weekend driver until I can put a 6 in it, so I want to have a reliable engine, but without putting a whole lot of $$$ into it.

Konrad
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Cap'n Krusty
post Feb 23 2011, 11:34 PM
Post #11


Cap'n Krusty
**********

Group: Members
Posts: 10,794
Joined: 24-June 04
From: Santa Maria, CA
Member No.: 2,246
Region Association: Central California
How much compression? What was the leakdown, and where did it go? Are the valves seating? What do the gaskets look like (if there were any)? Was there any popping or other noise before you tore it down? Did it get hot? How hot, and for how long? If the loss was from the head/cylinder interface, you'd hear it and you could see where it was going.

The Cap'n
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
krazykonrad
post Feb 24 2011, 12:16 AM
Post #12


Senior Member
***

Group: Members
Posts: 1,140
Joined: 21-February 06
From: Canton, GA
Member No.: 5,610
The leakdown cold went to 0 almost immediately. When it was warm, it would intermittently hold compression, but no leakdown was done while it was warm, so I don't have any numbers for you. I don't remember any popping sounds, but this was about 2 years ago. It definitely didn't sound like it was running right. It never got hot. I don't have any numbers, but my melt-off warranty tag has always been in place.

Thanks for your help Capt'n!
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
krazykonrad
post Feb 24 2011, 12:18 AM
Post #13


Senior Member
***

Group: Members
Posts: 1,140
Joined: 21-February 06
From: Canton, GA
Member No.: 5,610
QUOTE(Cap'n Krusty @ Feb 23 2011, 09:34 PM) *

How much compression? What was the leakdown, and where did it go? Are the valves seating? What do the gaskets look like (if there were any)? Was there any popping or other noise before you tore it down? Did it get hot? How hot, and for how long? If the loss was from the head/cylinder interface, you'd hear it and you could see where it was going.

The Cap'n


Also, valves are seating fine. The gaskets, around the combustion chamber (if they are gaskets and not shims) have some carbon build-up but aren't scored or torn up.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
VaccaRabite
post Feb 24 2011, 09:14 AM
Post #14


En Garde!
**********

Group: Admin
Posts: 13,584
Joined: 15-December 03
From: Dallastown, PA
Member No.: 1,435
Region Association: MidAtlantic Region
If you suspect head studs, did you re-torque and try the tests again?

Zach
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Feb 24 2011, 09:26 AM
Post #15


Custom Member
***************

Group: Members
Posts: 24,638
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
to answer the original question.
re-ring it...hone the cylinders and do it.
Simpler now than later.

Rich
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 31st October 2024 - 08:24 PM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...