Fixing poor leakdown, Cyl 1 leaks at 50%, rest are cool. |
|
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. |
|
Fixing poor leakdown, Cyl 1 leaks at 50%, rest are cool. |
VaccaRabite |
Oct 24 2007, 07:00 AM
Post
#1
|
En Garde! Group: Admin Posts: 13,554 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
So, at the Sterling meet I did a leakdown test on my motor, and found a problem with Cylinder 1. 45% leakdown, but 120 lbs of compression. Was tempted just to let sleeping dogs lie, but pulled the head off.
What was going on was clear as soon as we did that, the head was not totaly sealed to the cylinder, off by a very small amount. Instead of having the head recut, I decided to try and lap the two of them together. So, last night I hand lapped them, using ground graphite to check for even contact. I got good contact after the third round of hand lapping (lap, clean, check). Now I need to get the jug back on the block. I have a ring compressor on the piston, but I can't ficgure out how to get the head back on. Do I have to take the piston head off the rod? If so, how do I get it off. It looks like that tis a spring keeper that needs to be removed. Is there anyhting on the rod the needs to be loosened before I can pull the pin out to remove the piston head? Obviously, if there is a trick to getting the jug back on without pulling off the piston head, I'd like to do that. Zach |
scotty b |
Oct 24 2007, 06:54 PM
Post
#2
|
rust free you say ? Group: Members Posts: 16,375 Joined: 7-January 05 From: richmond, Va. Member No.: 3,419 Region Association: None |
Cap'n he has done no damage. The blowby was VERY minimal all he did was use some valve grinding compund between the cylinder and it's mating surface in the head. I told him to use a sharpie marker to give it some color and only lap until all of the marker was gone. I'm not you but I have done this procedure MANY times myself with no ill effects.
Assumptions are the mother of all Fuchups right??? Zach the cylinder CAN be put back on like you have it with some care. First you need a flywheel lock to keep the engine from moving. Make certain your rings are sitting correctly (notches NOT lined up, preferably equally seperated) put the compressor on the rings, slip the cylinder onto the very end of the cylinder and gently tap it over each ring. Waxth CAREFULLY to make sure the ring is fully compressed and that it doesn't get cocked or slip out. A second set of hands is almost a necessity to keep the studs lined up with the holes in the cylinder. Make sure the flat part of the cylinder is on the INSIDE ( center of the case) |
Lo-Fi Version | Time is now: 27th September 2024 - 07:59 AM |
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 ... |