XJ6 & XJ12 Series I, II & III 1968-1992

Gear noise from bottom of distributor

 
  #1  
Old 10-28-2014, 12:40 AM
Senior Member
Thread Starter
Join Date: Jun 2009
Location: California
Posts: 192
Likes: 0
Received 2 Likes on 2 Posts
Default Gear noise from bottom of distributor

I installed a Pertronix II distributor and new water pump at the same time in my series III. Seems to run just fine but now I hear a distinctive gear whine at the bottom front of the engine that seems to go up in pitch with engine rpm.

Not sure what is making the noise but it is loudest when standing a little away from the right front fender.

Wondering if anyone has had a similar noise and what it turned out to be?
 
  #2  
Old 10-28-2014, 04:52 AM
Join Date: Feb 2010
Location: Adelaide Stralia
Posts: 19,690
Received 5,846 Likes on 4,187 Posts
Default

I understand the noise you are talking about.

There is a Bronze gear in there that drives the oil pump, and has the slots in it to take the tangs of the distributor drive.

I would be firstly removing the distributor and checking IT for a dry bearing.

To get at the rest is not so simple, and failure and/or nosie from that Bronze drive is countable on one hand.
 
  #3  
Old 10-29-2014, 03:30 AM
Senior Member
Thread Starter
Join Date: Jun 2009
Location: California
Posts: 192
Likes: 0
Received 2 Likes on 2 Posts
Default

What is involved to get to that bronze gear and the failed bearing?

What would cause it to fail all of a sudden? Never heard that sound till I changed the distributor.
 
  #4  
Old 10-29-2014, 05:33 AM
Join Date: Feb 2010
Location: Adelaide Stralia
Posts: 19,690
Received 5,846 Likes on 4,187 Posts
Default

Sump OFF I am afraid. My reasons for saying that are in the following scribbles.

Going outside the square, my usual haunt.

Since all this started with the distributor installation, I am thinking the distributor is TOO long, and that may be less than 1mm, so when tightened down it pushing down on that drive assembly and hence the noise. Loosen the clamp mounting bolt, not the sideways bolt and nut, the distributor "may" rise up a tad, and see if the noise alters, goes away, or stays the same?.

I have attached a drawing of the drive arrangement, and item #9 is the shaft that actually drives the distributor. Item #15 is the nut on the other end, and #16 is the drive coupling for the oil pump.

If it is lifted out via the top, the only way it comes out when rebuilding an engine, it will rotate as the spiral gear comes out of mesh with the crank gear, and the likelyhood of sliding it back in so the oil pump drive #16 actually slides into the "square peg in a square hole" is more a&^e than class.

Its been a very long time since I did one of these engines, so someone that is currently doing one may be able to clarify my thoughts.

I still reckon its the distributor at fault here.

Gear noise from bottom of distributor-xk-oil-pump-distributor-drive.jpg
 

Last edited by Grant Francis; 10-29-2014 at 05:37 AM.
  #5  
Old 10-31-2014, 11:03 AM
Veteran Member
Join Date: Jul 2012
Location: Walnut Creek, California
Posts: 5,737
Received 1,947 Likes on 1,570 Posts
Default

Yeah, I think Grant is on to it.




Production tolerances can stack. Perhaps, exacerbated by using two makers. In this case, Jaguar and Pertronix.


I would consult with Tech support at Pertronix.


Carl
 
  #6  
Old 11-06-2014, 02:44 AM
Senior Member
Thread Starter
Join Date: Jun 2009
Location: California
Posts: 192
Likes: 0
Received 2 Likes on 2 Posts
Default

Spent some time trouble-shooting the noise. After pulling all the belts off, I can safely say the noise is not related to any of the belt driven accessories. Instead, it appears to be coming from the lower timing chain.

It almost seems like the lower chain is hitting something as idle and thus making the noise. When first started, there is no noise and slowly builds up in volume after 10 seconds or so of running the engine. If the engine if reved up, the noise goes away. It only seems to happen under stead idle conditions.

It's almost like the lower timing chain tensioner is going and is allowing the chain to rattle at idle. The engine has 170K on it and the chains are original.

I tried putting in some of that thick Lucas oil and it seems to make a small difference in the sound.

What are the symptoms of a worn lower timing chain tensioner?

btw -- we did loosen the new distributor and raise it slightly. However this made no difference in the sound.

We did recently replace the water pump and alternator. Wondering if this work could have somehow affected the operation of the lower timing chain?
 
  #7  
Old 11-06-2014, 03:04 AM
Join Date: Feb 2010
Location: Adelaide Stralia
Posts: 19,690
Received 5,846 Likes on 4,187 Posts
Default

The lower chain arrangement on the XK engine is really bullet proof.

Rotating the engine "backwards" CAN, on SOME high mileage engines, cause the hydraulic tensioner piston to "drop out" of its housing. This is RARE, but I have seen it a couple of times.

Following your mention of the water pump replacement, I thought the impellor MAY be rubbing on the timing cover, BUT, you removed the belts and NO difference in the noise, so thats not it.

Behind the tensioner housing, up inside the oil gallery of the cylinder block, is a conical fine mesh filter. Now, this may be blocked, and the tensioner is NOT seeing the correct oil flow/pressure to do its job???. This I have seen many times.

Sadly, it looks like timing cover off, no matter what we type.
 
  #8  
Old 11-13-2014, 04:55 AM
Senior Member
Thread Starter
Join Date: Jun 2009
Location: California
Posts: 192
Likes: 0
Received 2 Likes on 2 Posts
Default

Not much to update on this except I tried some thicker oil with Lucas additives, tried the car parked on hill both nose and nose down, also tried running some powerful engine cleaners through the oil to see if that would clear some oil passages but there is really no difference in the noise after all this. It seems to peak around 1200 rpm and drop off after that.

Still the problem seems to pop up after all that work on the front of the engine. Any way some bolt or something could be sticking to far in the timing cover and making close contact with the lower timing chain? Seems like the tensioner wouldn't have gone out just like that.
 
  #9  
Old 11-13-2014, 05:45 AM
Join Date: Feb 2010
Location: Adelaide Stralia
Posts: 19,690
Received 5,846 Likes on 4,187 Posts
Default

Not sure what you did to the front area, but I am thinking the top chain might be adjusted too tight, which is "usually" a whirring noise of sorts, or too loose, which is "usually" a rattling type of noise.

The words are hard to put for the sound, but each is a sound the engine does not normally make.

Misaligned damper blade on the LH side of the lower chain, is a COMMON misfit, as the bolts are easy to get at, NOT, and a lot of wrenchers end up with near enough, and chain "slap" is the result.

The huge front pulley bolt may be loose, clutching at straws here, as that is uaually a knocking noise.

Incorrectly assembled "rabbits ears" is also a cause of noise. There are a few specific spacers in that assembly, and if put together wrong things are simply misaligned.

Some XK engines have a tin plate oil slinger behind the timing cover front seal, over the snout of the crankshaft, and that will rattle, hence most remove them if they find one, BUT, I doubt a S3 engine had, or has, one.

The lower chain catching a bolt head is more than probable, especially on that LH lower chain blade.

Sadly, timing cover off again is needed.

A LARGE bottle of JD will help sooth all sorts of things, but wont fix the noise.
 

Last edited by Grant Francis; 11-13-2014 at 05:48 AM.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Jandreu
XK8 / XKR ( X100 )
9
12-08-2016 02:42 AM
Poet
XK8 / XKR ( X100 )
14
10-06-2015 09:40 PM
abonano
S-Type / S type R Supercharged V8 ( X200 )
25
09-25-2015 10:43 AM
tsimms7
X-Type ( X400 )
1
09-15-2015 12:43 PM
hen555
XF and XFR ( X250 )
2
09-07-2015 11:13 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Quick Reply: Gear noise from bottom of distributor


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: