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 |
VaccaRabite |
Oct 24 2007, 11:31 AM
Post
#2
|
En Garde! Group: Admin Posts: 13,554 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
^^^
If I have to have the head recut, then I do. My goal here was to try and mate the cylinder to the head better, as it was off by a very small amount. I did this by getting some lapping compound, and lapping the cylinder to the head by hand. When I get it back together I'll redo compression and leakdown. It might fix it, it might have made it worse. If it made it worse, the head will need to go to the machine shop any way. I won't figure that out until I get it back together. Either way, I removed a very, very small amount of metal through lapping. All told, if I wasted time, then I suppose I'll never get these 2 hours back. Given the amount of time that I have spent working on this car in general, I'm cool with that. I'd rather be able to do it myself anyway. Zach |
Lo-Fi Version | Time is now: 27th September 2024 - 07:55 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 ... |