 new top end, intermittently runs poor, Does I need dizzy bearings? |
|
|
|
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. |
|
|
| Flat VW |
 Dec 11 2004, 12:07 AM
Post
#1
|
|
Illegal Soapbox Derby Racecar  Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105  |
Got my 72', 1.7FI out of the shop after having the top end done. (IMG:style_emoticons/default/MDB2.gif)
The car ran well for a day or so, then started to miss at higher revs. (IMG:style_emoticons/default/headbang.gif) It ran rather poorly and lacked torque and was'nt "revvy" now at any rpm. I took the car in for 500 mile valve lashing, got the car back and the "power" was good again. BLAH,Blah,blah......... It seems when the car is hot, perhaps, the "spark" diminishes.... (IMG:style_emoticons/default/confused24.gif) I once needed new dizzy bearings for my 75' 914, is that perhaps what my problem with this car is? (IMG:style_emoticons/default/chairfall.gif) The Az Toy Run would be allot "funner" with full power! (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/MDB2.gif) (IMG:style_emoticons/default/MDB2.gif) |
   |
 
|
  |
Replies(1 - 19)
| Mueller |
Dec 11 2004, 12:19 AM
Post
#2
|
|
914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None 
|
sounds like muffler bearings instead (IMG:style_emoticons/default/smile.gif)
what kind of ignition setup do you have? (coil, points or electronic??) |
|
|
|
| Flat VW |
Dec 11 2004, 12:23 AM
Post
#3
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
Stock FI, D-jet sound right?
TIA |
|
|
|
| Mueller |
Dec 11 2004, 12:27 AM
Post
#4
|
|
914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None
|
yes, that sounds correct...but inside your distributor you will either have mechanical points (contact breaker) or an electrical device, (magnetic or optical)
check out this site: Brad Anders most excellent D-Jet information web site he has some tables and troubleshooting info... |
|
|
|
| Flat VW |
Dec 11 2004, 12:28 AM
Post
#5
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
I have breaker type- points-
|
|
|
|
| Flat VW |
Dec 11 2004, 01:16 AM
Post
#6
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
|
|
|
|
| SpecialK |
Dec 11 2004, 01:30 AM
Post
#7
|
|
aircraft surgeon Group: Benefactors Posts: 3,211 Joined: 15-March 04 From: Pacific, MO Member No.: 1,797  |
I'd ditch the points and go with an electronic setup (pertronix, crane, etc...). If it starts out okay cold, and then loses power after warm-up they might have the valve/rocker gap too tight.....just a thought.
|
|
|
|
| DJsRepS |
Dec 11 2004, 05:22 AM
Post
#8
|
|
Member Group: Members Posts: 431 Joined: 4-November 04 From: Sarasota Florida Member No.: 3,060 |
Hi check your trigger points smooth movement (lube) clean points and lube cam lobe. Then the FI harness for grounds and mine had a couple terminals ready to rot off the end of the green copper wire. I removed every plastic plug from the harness to inspect the crimp connection where I found the green copper wire corrosion. One terminal fell off when I opened the insulator clamp of the terminal. Every terminal has 2 clamps one for the insulation and other for the copper connection. I cut the casing off the harness to inspect the insulation for cracks or stiffness. Then used spiral wrap from raido shack and heat shrink tubing from another eletronics supply.........Oh yea I found alot of loose connections on the ECU connection. The ECU plug has terminals you can slide a feeler gauge into to feel the difference of each terminals grip on the ECU then pinch the terminal tighther as nessary. Mine had loose ECU terminals on both 12v supply's and the ground and on trigger points all thoes C clamp looking terminals. My intermintent miss took awhile to find sometimes ran 3 days fine and other days it would come and go in one ride. It got so bad I would park it a week out of anger and thats hard to do with a street legal 914. Good luck mine drove me crazy. I agree with the pointless ign. I cant feel any play in the distrubitor but my timing light jumps all over the mark. I think the perlux ? pointless ign will help that. Good luck my miss about drove me crazy. Did alot of reading on this board and alot of procedures like soldering the rivets in the relay board. That one didnt help but it was a process of elemination. Sorry bout the long post hope it helps.
|
|
|
|
| Flat VW |
Dec 11 2004, 09:55 AM
Post
#9
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
Thanks, DJsRepS (IMG:style_emoticons/default/chatsmiley.gif)
|
|
|
|
| Bleyseng |
Dec 11 2004, 10:02 AM
Post
#10
|
|
Aircooled Baby! Group: Members Posts: 13,035 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
Slap a timing light on the engine and warm it up. Check the timing marks for jumping, blurring more than 1/2" etc....thats what bad dizzy bearing looks like. You can also pop off the cap and see how much slop side to side the dizzy has. Should be fairly tight.
Geoff (IMG:style_emoticons/default/biggrin.gif) |
|
|
|
| Flat VW |
Dec 11 2004, 10:04 AM
Post
#11
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
Special K,
Thanks for your reply. It seem to be a spark thing,IMHO Comes and goes, when driving at revs you can feel it snap on (miss) and snap off (clean up). Me gut says spark. (IMG:style_emoticons/default/smash.gif) |
|
|
|
| Bleyseng |
Dec 11 2004, 10:09 AM
Post
#12
|
|
Aircooled Baby! Group: Members Posts: 13,035 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest |
then I would start checking and cleaning all the grounds...tranny strap, battery neg, FI grounds block on engine etc....
Geoff |
|
|
|
| TheCabinetmaker |
Dec 11 2004, 10:52 AM
Post
#13
|
|
I drive my car everyday Group: Members Posts: 8,301 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
A miss at high revs could also indicate misadjusted dwell. Check the connection to the head temp sensor also. And yes of course, the grounds
|
|
|
|
| anthony |
Dec 11 2004, 11:37 AM
Post
#14
|
|
2270 club Group: Benefactors Posts: 3,107 Joined: 1-February 03 From: SF Bay Area, CA Member No.: 218 |
QUOTE Check the timing marks for jumping, blurring more than 1/2" etc....thats what bad dizzy bearing looks like. My car behaved like that when I got it but it wasn't a worn distributor just one that needed to be cleaned. I took it apart, lubricated it, and added a Pertronix and driveability improved 100%. |
|
|
|
| Flat VW |
Dec 11 2004, 01:41 PM
Post
#15
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
The Pertronics fixed it right up, did it? (IMG:style_emoticons/default/lol2.gif)
Yes, a ground check is in order. The problem is not dizzy bearings, too repeatable after further testing ( Bad dizzy bearings are much more "excentric" ( greater swings in timing?). This problem seems to be heat related- happens when the engine is good and warm. What does the head temp sensor do? dwell adjustment? (IMG:style_emoticons/default/confused24.gif) To drive the car, the "miss" seems consistant with a "flaky" electrical connection, ie. in corners sometimes it will suddenly clean up and there is a certain "on" - "off" feel to the power going in and out. I will first check the grounds, then go thru and clean every FI electrical connection I can find. (IMG:style_emoticons/default/ar15.gif) Thanks for the feedback to all (IMG:style_emoticons/default/cool_shades.gif) |
|
|
|
| jwalters |
Dec 11 2004, 04:44 PM
Post
#16
|
|
Sooo Close....... Group: Members Posts: 1,677 Joined: 14-May 04 From: Huntsville, AL Member No.: 2,068 Region Association: Europe |
(IMG:style_emoticons/default/confused24.gif) When you had the engine worked on---do u still have the aluminum pushrods?? if not the valve clearance specs will change---that sounds far too like too close of a clearence.
|
|
|
|
| TheCabinetmaker |
Dec 11 2004, 07:47 PM
Post
#17
|
|
I drive my car everyday Group: Members Posts: 8,301 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
QUOTE(Flat VW @ Dec 11 2004, 01:41 PM) The head temp sensor is a part of the system that is a requirement for it to work. It's the wire coming out of the engine tin above and right of the # 3 spark plug. Dwell is the amount of degrees the points are open (for spark). An essential for proper tuneing. |
|
|
|
| Flat VW |
Dec 11 2004, 10:00 PM
Post
#18
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
vsg914,
Does the head temp sensor (thru the d-jet I suppose) vary dwell? (IMG:style_emoticons/default/wacko.gif) |
|
|
|
| TheCabinetmaker |
Dec 11 2004, 10:09 PM
Post
#19
|
|
I drive my car everyday Group: Members Posts: 8,301 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
No. Do you have a djet system? 2.0? 1.7?
|
|
|
|
| Flat VW |
Dec 11 2004, 10:14 PM
Post
#20
|
|
Illegal Soapbox Derby Racecar Group: Members Posts: 1,692 Joined: 13-November 04 From: Phoenix, AZ Member No.: 3,105 |
1.7 1972 d-jet, l-jet, it all the same thing. (IMG:style_emoticons/default/bootyshake.gif)
stock FI... (IMG:style_emoticons/default/biggrin.gif) |
|
|
|
|
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 1st June 2024 - 11:29 AM |
Invision Power Board
v9.1.4 © 2024 IPS, Inc.