Vanagon EuroVan
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (February 2005, week 1)Back to main VANAGON pageJoin or leave VANAGON (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Thu, 3 Feb 2005 08:14:57 +1100
Reply-To:     Ray Hunnam <rayjen@PNC.COM.AU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ray Hunnam <rayjen@PNC.COM.AU>
Subject:      Re: wrist pins/boston bob
Comments: To: ROBERT DONALDS <donalds1@VERIZON.NET>
In-Reply-To:  <2ada01c507fd$910bd800$6601a8c0@yoursz6x6sefxo>
Content-Type: text/plain; charset="iso-8859-1"

Greetings all

I have been following this tread and would like to give you the benefit of my experience. Firstly you all call them wrist pins we use the old term gudgeon pin and yes they do come loose.

My 2.1 was suffering from a strange noise sounding like a hand full of small stones (pebbles ) being rattled around in a tin can. Only happened on deceloration. Took it to my local VW Dealer who stated I needed a rebuild.

When I got the old parts back they showed me where the gudgeon pin had " Walked " and started to score the side of the liner barrel. Reason given is because the gudgeon circlip had broken ??? allowing the pin to move. Gradually the hole elongated resulting in the bottom of the piston skirt smashing , hence the small pieces of metal in the bottom of the crank case sound like pebbles in the tin.

The Dealer said he had never seen a circlip go before.

Anyone interested I have some happy snaps of the damaged to the piston and gudgeon taken on my digital. Unfortunately the shot of the liner with the score marks did not turn out.

Regards Ray Hunnam Penrith Australia.

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf Of ROBERT DONALDS Sent: Tuesday, 1 February 2005 12:28 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: wrist pins/boston bob

Mike, Jimt and fellow vanagon types

The wrist pin noise is not what it sounds like pun intended The term wrist pin noise is a piston slap unless the bushing comes loose in the rod and the piston rattles around then its just called engine failure Wrist pin noise or piston slap is heard when the piston does not transition from one side (skirt) to the other just before the piston reaches TDC..Pistons are made with an offset wrist pin hole the offset is in the WBX piston is 1MM with this offset the piston gently transitions the piston unless of course you install the piston backwards. Other things that can cause a piston to not transaction are damaged pistons or tight fitting rod bushings . Most con rods also have an offset top to bottom the top sits a little to the left or right depending on what side of the engine we are talking about. When the rod is installed backwards it can touch the wrist pin boss of the piston and hold a little side pressure on the piston and this prevents the piston from transitioning and you can hear that for sure. I had one fellow bring in an WBX engine that he had taking apart more than once tiring to find the rapping noise with no luck I was brought in for the autopsy it was the rods on backwards The air cooled bug engines can have a wrist pin noise if the rod bushing is worn but its minor AND WOULD LAST FOR EVER most water cooled engine may have as much noises but the water jacket is a great noise damper One other thought about wrist pins is that if the bushing is damaged when the piston pin is installed then the bushing can come loose over time the signs of bushing damage is that the piston does not float on the con rod after it installed this is hard to check when the cylinder and piston go onto the rod at the same time with little room to wiggle the piston on the pin. I think that the chances are that its not a wrist pin noise but more likely a lifter, rocker or crank rattling around in the case. Loose main bearings are common in the 1.9 enignes at about 20 to 30Kwhen the block is not align bored at the time of the rebuilding or reassembling. If you suspect the main bearings are loose in the case check for exsessive crankshaft endplay its a dead giveaway for loose mains

yes I ramble what's your point

going faster miles an hour with the heat on I remain Bob Donalds Boston Engine http://www.bostonengine.com

----- Original Message ----- From: "Mike Miller" <mwmiller@CWNET.COM> To: <vanagon@GERRY.VANAGON.COM> Sent: Saturday, January 29, 2005 2:58 PM Subject: Wrist pins

> Volks, especially engine volks, > > A friend has a 85 van with less than 30k on a rebuilt engine. Mechanic > says > that the new noise in it is wrist pins, dump it. > > What are the chances it is wrist pins with that many miles? > > Is that an engine killer with van engines, or like piston slap in the > early > Audi 5 cylinders, let them slap? > > TIA > > > Mike >


Back to: Top of message | Previous page | Main VANAGON page

Please note - During the past 17 years of operation, several gigabytes of Vanagon mail messages have been archived. Searching the entire collection will take up to five minutes to complete. Please be patient!


Return to the archives @ gerry.vanagon.com


The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.

Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.