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 )

2 Pages V  1 2 >  
 Reply to this topicStart new topic
> Drop Valve Seat, How do you know?
newto914s
post Nov 24 2004, 04:21 PM
Post #1


Senior Member
***

Group: Members
Posts: 561
Joined: 16-February 04
From: Thornton, CO
Member No.: 1,663
I was headed to the folks house for Thanksgiving. Stopped to get some gas(200 miles in) and when I stared it up it sounded like something was stuck in the fan or air passagess bouncing around. I shut it down, checked the oil and the pressure was pressure was ok. So I drove it the rest of the way home(about 50 miles).
The noise only came back when I was at idle up to around 1500 rmp. Above that everything was fine.
Would the car still run with a dropped valve seat?
How can I check if I dropped one?
And is their anyway to check the air passages with out dropping the engine?
Thanks guys, I've got my fingers crossed (IMG:style_emoticons/default/unsure.gif)
Samson
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mike_the_man
post Nov 24 2004, 04:28 PM
Post #2


I like stuff!
***

Group: Members
Posts: 1,338
Joined: 11-June 03
From: Regina, Saskatchewan, Canada
Member No.: 809
I think a dropped valve seat would sound much worse. There are some pics at Pelican of a dropped valve seat. It blew out the top of the case. At the very least, your car would run like crap. More likely that something came loose and is rattling around somewhere under the tin.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Root_Werks
post Nov 24 2004, 04:31 PM
Post #3


Village Idiot
*****

Group: Members
Posts: 8,338
Joined: 25-May 04
From: About 5NM from Canada
Member No.: 2,105
Region Association: Pacific Northwest
QUOTE(mike_the_man @ Nov 24 2004, 02:28 PM)
I think a dropped valve seat would sound much worse. There are some pics at Pelican of a dropped valve seat. It blew out the top of the case. At the very least, your car would run like crap. More likely that something came loose and is rattling around somewhere under the tin.

(IMG:style_emoticons/default/agree.gif) If you haven't lost any power, you are probably okay. Did something "crawl" into the cooling fan while you were getting gas? Maybe something fell off and got sucked in? (IMG:style_emoticons/default/idea.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Joe Ricard
post Nov 24 2004, 04:31 PM
Post #4


CUMONIWANNARACEU
*****

Group: Members
Posts: 6,811
Joined: 5-January 03
From: Gautier, MS
Member No.: 92
Beginnings of an exhaust leak. When it cools down make a deal withthe devil and check the exhaust nuts.
I would also pull the valve covers and check to see if everything is correct and tight.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
joea9146
post Nov 24 2004, 04:32 PM
Post #5


Senior Member
***

Group: Members
Posts: 663
Joined: 10-February 03
From: Denver, NC
Member No.: 283
Region Association: None
Most Valve seat problems are on the 2.0 heads is that what you have.
A leakdown test should reveal if the seat has dropped.
Sure its not a rod knock you are hearing. (IMG:style_emoticons/default/ohmy.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
aircooledboy
post Nov 24 2004, 04:34 PM
Post #6


Sweet Pea's 1st ride in daddy's "vroom -vroom"
***

Group: Members
Posts: 1,672
Joined: 4-February 04
From: Rockford, IL
Member No.: 1,629
Region Association: Upper MidWest
If the valve seat is dropped, you'll know because when the valve goes to sit down, it's ass will hit the floor. (IMG:style_emoticons/default/lol2.gif)

It sounds to me like maybe you sucked something into the fan housing. You would check by reaching into the center of the fan hub (with the car OFF) and maybe even by pulling off the heater ducting part where it attaches to the fan housing and see if there is something in there, I guess. I have had my alternator cover thingy sucked into the fan a couple times, and it sounded like what you described. I've never had a dropped seat, but I'm pretty sure it would make you car run a whole bunch worse than you've described.

Sorry about the smart ass comment, sometimes i just can't help myself. (IMG:style_emoticons/default/happy11.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
TheCabinetmaker
post Nov 24 2004, 04:36 PM
Post #7


I drive my car everyday
*****

Group: Members
Posts: 8,304
Joined: 8-May 03
From: Tulsa, Ok.
Member No.: 666
QUOTE(Joe Ricard @ Nov 24 2004, 04:31 PM)
Beginnings of an exhaust leak. When it cools down make a deal withthe devil and check the exhaust nuts.
I would also pull the valve covers and check to see if everything is correct and tight.

(IMG:style_emoticons/default/agree.gif) Exaust leak. Dropped valve seats will cause very poor performance or even a no run. I doubt you be able to drive a car 50 miles with a dropped seat. You would destroy a piston long before that, and have engine parts all over the road.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914werke
post Nov 24 2004, 04:38 PM
Post #8


"I got blisters on me fingers"
**********

Group: Members
Posts: 10,153
Joined: 22-March 03
From: USofA
Member No.: 453
Region Association: Pacific Northwest
I actually had a EX valve "head" in my 1.7 snap off and embed itself in the piston crown once.
Made a horrible racket while driving on the freeway, so I clutched in killed coasted off the freewaythen chked everything and then started up agian. It ran rough, there was audible knocking but it ran! (IMG:style_emoticons/default/blink.gif)
When I took it all apart the valve head had broken into multiple pieces, tore the hell out of the head and piston then largest part emmbeded itself into the piston and was contacting the head on the upstroke. The rest of the valve head I found in the exhaust. (IMG:style_emoticons/default/sad.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Rhodes71/914
post Nov 24 2004, 04:40 PM
Post #9


Glacier
***

Group: Members
Posts: 1,374
Joined: 8-August 04
From: End of the Road, Alaska
Member No.: 2,482
I would agree with the above prolly not a dropped seat. I had one work it's way out but not come all the way. I knew it happened because I could here the piston hitting it. Somehow it fixed its self (good thing I was in the middle of the Alcan. Eventually happened again in downtown Seattle. When I took the head off there was a nice half moon indentation in the top of the piston. The engine had serious loss of power.

Sounds like something may have gotten in the fan housing. Did ya leave any tool in there when you were getting ready for your trip?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
newto914s
post Nov 24 2004, 04:44 PM
Post #10


Senior Member
***

Group: Members
Posts: 561
Joined: 16-February 04
From: Thornton, CO
Member No.: 1,663
That's what I would have figured. I checked that pelican artical before posting (IMG:style_emoticons/default/icon8.gif) and those pictures are scary. I'll check the exhaust nuts and under the valve cover right now. Is there anyway to get into to the air ducts too?

About power it does drive fine, but when it's in that idle range when the noise starts the car bogs(like it's pulling something through the fan) and will stall if I don't give it gas.

Oh, also according to some peckerhead at the gas station it was making the noise before I shut it down( I had the radio turned up)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mattillac
post Nov 24 2004, 04:49 PM
Post #11


robots!
***

Group: Members
Posts: 536
Joined: 27-October 04
From: vallejo,ca
Member No.: 3,020
QUOTE(joea9146 @ Nov 24 2004, 02:32 PM)

Sure its not a rod knock you are hearing. (IMG:style_emoticons/default/ohmy.gif)

speaking of rod knocks, is it possible to have an "occasional" rod knock? i hear it usually when idling and at part throttle, but it goes away sometimes?! (IMG:style_emoticons/default/blink.gif) any ideas?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
TheCabinetmaker
post Nov 24 2004, 05:01 PM
Post #12


I drive my car everyday
*****

Group: Members
Posts: 8,304
Joined: 8-May 03
From: Tulsa, Ok.
Member No.: 666
Matt, a knocking sound that goes away, especially after warm up, is an indication of a "loose" valve seat. The seat has not came out, but is a little loose when cold, and could tighten up when warm. Could also be an exhaust leak. I could be wrong, but I don't think a rod knock will go away.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mattillac
post Nov 24 2004, 05:12 PM
Post #13


robots!
***

Group: Members
Posts: 536
Joined: 27-October 04
From: vallejo,ca
Member No.: 3,020
i didn't think a rod knock would go away, but thats what it sounds like. a loose valve seat doesn't sound good. am i looking at some major repairs, new heads? or is this something that a competent machinist could take care of? my pop is an excellent machinist, and he could probably do any headwork i need for free.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SLITS
post Nov 24 2004, 05:23 PM
Post #14


"This Utah shit is HARSH!"
**********

Group: Benefactors
Posts: 13,602
Joined: 22-February 04
From: SoCal Mountains ...
Member No.: 1,696
Region Association: None
I dropped seats in two engines. First one, no sound of impending doom - just wound it up and bam, the engine siezed. Second one sounded like a BB in a tin can. Came and went. Then one day it went. Drove another 150 miles home missing on one cylinder - trashed the head badly.

Your guess is as good as the others!
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Allan
post Nov 24 2004, 05:37 PM
Post #15


Teenerless Weenie
*****

Group: Members
Posts: 8,373
Joined: 5-July 04
From: Western Mesopotamia
Member No.: 2,304
Region Association: Southern California
QUOTE(SLITS @ Nov 24 2004, 03:23 PM)
I dropped seats in two engines. (Mine was a Datsun) First one, no sound of impending doom - just wound it up and bam, the engine siezed. Second one sounded like a BB in a tin can. Came and went. Then one day it went. Drove another 150 miles home missing on one cylinder - trashed the head badly.

Your guess is as good as the others!

What he said. I think.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Allan
post Nov 24 2004, 05:38 PM
Post #16


Teenerless Weenie
*****

Group: Members
Posts: 8,373
Joined: 5-July 04
From: Western Mesopotamia
Member No.: 2,304
Region Association: Southern California
OOps! Hey Slits, the Datsun thing was mine. Just didn't know how to edit. Sorry. (IMG:style_emoticons/default/biggrin.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mattillac
post Nov 24 2004, 05:39 PM
Post #17


robots!
***

Group: Members
Posts: 536
Joined: 27-October 04
From: vallejo,ca
Member No.: 3,020
what's the best way to take care of the valve seat before i drop it and completely
ruin my motor, assuming that the valve seat is the problem.

(IMG:style_emoticons/default/idea.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
d7n7master
post Nov 24 2004, 06:17 PM
Post #18


Gary#
***

Group: Members
Posts: 663
Joined: 13-March 03
From: The O.C, Ca.
Member No.: 421
That pretty much nails how my engine sounded over about two weeks or so of daily driving. During this time, never did it knock on cold start. Drove to work/came home.
A slight knock at idle @ operating temp. No knock at cruise speeds. Then I stopped one day on the way home & when I started it up again (about 10mins later) it started right up & KNOCKED HARD (read SCARY!!!) knock on startup.
Teardown:#3 is smoked. (IMG:style_emoticons/default/barf.gif) I'll post pics comin' up.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mattillac
post Nov 24 2004, 06:25 PM
Post #19


robots!
***

Group: Members
Posts: 536
Joined: 27-October 04
From: vallejo,ca
Member No.: 3,020
now i'm starting to worry. i really dont want to have to do any major repairs when
i'm just now getting ready to get my 914 back on the road. i'd rather take care of this problem before i drop a seat. recommendations for repairs? should i plant on just rebuilding both of the heads to prevent this? what parts can i reuse if any? or should i just stick with all new parts as long as i'm doing a head rebuild?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SLITS
post Nov 24 2004, 06:28 PM
Post #20


"This Utah shit is HARSH!"
**********

Group: Benefactors
Posts: 13,602
Joined: 22-February 04
From: SoCal Mountains ...
Member No.: 1,696
Region Association: None
Take the valve cover off and see if any of the valves have tightened up or see if one is really loose.

Other than that 1.) a leakdown test and 2.) Pull the suspect head
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

2 Pages V  1 2 >
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: 15th June 2024 - 11:39 AM
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 ...