Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 Engine Rebuilding Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Work in Progress
 
Rich76_911s's Avatar
 
Join Date: Jun 2004
Location: Ardmore, PA
Posts: 3,077
Garage
Ticking noise when warm

Hey everyone,

I rebuild my 930 engine about 500 miles ago and it has had a ticking noise that I haven’t been comfortable with. I’ll add some links to videos of said noise at the end of the post.

The ticking is fairly quite when the engine is cold but becomes more pronounced as the engine warms up. To my ear it sounds as though it’s coming from the #6 cylinder. I’ve tried using a stethoscope on it to attempt to pinpoint the location specifically but I haven’t had much luck narrowing it down. I think my slow motion video below confirms the cylinder though. The ticking does increase in frequency with rpms.

Initially I thought it was due to a shifting rocker shaft that I had on the #6 exhaust side, but I replaced that over the winter, did a valve adjustment and checked the headstuds for proper torque. But much to my disappointment the ticking noise persisted. I checked the #6 and #5 cylinders for compression as well and got 120 psi in each cylinder. (Nickie Cylinders with JE pistons at 7.5:1 compression)

So now I’m seriously considering tearing the engine down to diagnose what is wrong. Do any of you have any suggestions of what else I ought to do?

Here are some videos of the noise.

First one is of a cold engine without the ticking noise:
https://m.youtube.com/watch?v=DqTrqV_HkkY

Second is warm with ticking noise at full speed.
https://m.youtube.com/watch?v=509dKGP6hOs

Third is a longer video in slow motion of the engine warm, in slow motion, with a timing light on the #6 cylinder. Note that I have electromotive ignition that fires on compression and exhaust stroke. I mention this only because as you’ll see the timing of the ticking is in sync with the light.
https://m.youtube.com/watch?v=3sNqPo0O_Dw

The slow motion video makes it sound really bad.

Anyway I’d really appreciate the community’s insight and guidance on fixing this and getting myself some seat time instead of wrenching time. ����

Thanks so much in advance
Rich
__________________
"The reason most people give up is because they look at how far they have to go, not how far they have come." -Bruce Anderson via FB
-Marine Blue '87 930

Last edited by Rich76_911s; 04-16-2019 at 08:01 PM..
Old 04-16-2019, 07:58 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Registered User
 
Join Date: Mar 2019
Posts: 49
A couple of tips to help pinpoint it.

If you can't narrow it down with a stethoscope, try using a section of garden hose or heater hose, with one end up to your ear.

Armed with a 12v test light and a couple paperclips, ground out each cylinder individually and see which one reduces the ticking. (Of course the engine will misfire when you ground each cylinder.) Carefully straighten out one leg of the paperclip, then sneak that part between the spark plug wire and the boot at the distributor/coil pack. With the engine running, verify that your 12v test light is grounded on the alligator clip side, then touch the pointy end to paper clip on the suspect cylinder.

Be careful not to poke a hole in the boot, otherwise the spark could jump through the hole to something else. And be careful to make sure the test light is properly grounded and the bulb works, otherwise you could get shocked. And for gawds sake, don't touch the paperclips with your flesh, otherwise it's gonna hurt.

It could be something as simple as a loose spark plug, or something like piston slap, although most piston slap noises improve with heat. In any case, killing the spark to the affected cylinder should change the tick, since you seem confident that it's not valve noise.
Old 04-17-2019, 07:47 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Work in Progress
 
Rich76_911s's Avatar
 
Join Date: Jun 2004
Location: Ardmore, PA
Posts: 3,077
Garage
Quote:
Originally Posted by dannobee View Post
A couple of tips to help pinpoint it.

If you can't narrow it down with a stethoscope, try using a section of garden hose or heater hose, with one end up to your ear.

Armed with a 12v test light and a couple paperclips, ground out each cylinder individually and see which one reduces the ticking. (Of course the engine will misfire when you ground each cylinder.) Carefully straighten out one leg of the paperclip, then sneak that part between the spark plug wire and the boot at the distributor/coil pack. With the engine running, verify that your 12v test light is grounded on the alligator clip side, then touch the pointy end to paper clip on the suspect cylinder.

Be careful not to poke a hole in the boot, otherwise the spark could jump through the hole to something else. And be careful to make sure the test light is properly grounded and the bulb works, otherwise you could get shocked. And for gawds sake, don't touch the paperclips with your flesh, otherwise it's gonna hurt.

It could be something as simple as a loose spark plug, or something like piston slap, although most piston slap noises improve with heat. In any case, killing the spark to the affected cylinder should change the tick, since you seem confident that it's not valve noise.
THanks for the suggestions. Man i'd love it to be a loose spark plug.

Just a quick question on your grounding out. Essentially we're just not creating spark in the cylinder and determining if the noise is reduced when the spark isn't generated, right? Which hopefully will help determine the guilty cylinder.

Cheers
Rich
__________________
"The reason most people give up is because they look at how far they have to go, not how far they have come." -Bruce Anderson via FB
-Marine Blue '87 930
Old 04-18-2019, 11:20 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Mar 2019
Posts: 49
Exactly. We want to determine which cylinder is causing the noise. If itís excessive piston to wall clearance, killing that cylinder will eliminate the noise.
Old 04-18-2019, 11:29 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
pors1968's Avatar
 
Join Date: Aug 2013
Location: montreal quebec canada
Posts: 2,363
Garage
Could be exaust leak
Old 05-04-2019, 02:57 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 09:22 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.