[urq] Head gasket/block question
koenigj at comcast.net
Fri Dec 28 09:39:02 PST 2012
My inclination would be to forego the wire, as it doesn't seem to quite match your application/intended use, but I don't think you want to leave the grooves open. Maybe braze them up and file them flat?
My two cents' worth (or is that pence?)...
From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com]On
Behalf Of Keith
Sent: Friday, December 28, 2012 10:16 AM
To: urq at audifans.com
Subject: [urq] Head gasket/block question
I hope Christmas has been good for you all. I finally had the time to get my WR engine stripped down to reveal a properly blown head gasket on the front edge of No1 cylinder. This I know is unusual and I think this may have been is caused by the wire rings in the block. It’s long story but I’ll put it all down because I want to canvass views from you but you’ll need all the facts first.
When I bought my quattro 12 years ago it was very tired in the extreme. It had a cracked head, cracked manifold and cracked block. I purchased a brand new factory head, brand new manifold and was fortunate to be given a block by Aelred – former partner in Dialynx tuning. This block too had issues. It had suffered a melted piston and one cylinder was gouged badly so I had all 5 cylinders re-sleeved and machined to fit my pistons. The block face however had been machined to have wire rings around the cylinders which I gather is done to improve the seal around the cylinders of high boost motors – usually race motors. I re-fitted the wire rings when I rebuilt the motor and all was fine for 10/11 years when I started to notice I was losing a bit of coolant somewhere. Investigation revealed a well-washed No1 piston. The car ran fine, normal temps and no other signs until I noticed the coolant hoses pressurising. Then having spotted the washed piston I started to strip it down.
The damage to the gasket does look as though it might have been caused by the extra pressure on the gasket from the wire ring. I’ve no doubt that it gives a better seal but as I don’t run high boosts (1bar/14 psi) I wonder if the wire rings are really necessary. I guess they are fine on competition engines which are regularly stripped and rebuilt and don’t do many miles but for a road car that’s done 35000 in ten years I guess it’s done rather well to last that long. The question is: should I refit the wire rings when I rebuild it this time or leave them out? If I leave them out do I fill in their grooves and if so with what? And if I leave the grooves empty, what harm could/will that cause? Am I better to just replace the wire and anticipate another potential rebuild in 10 years time?
I’ll be interested in your thoughts. What do you think?
I’ll try and post some pictures on shutterfly.com when I get the chance and post an invite to view so you can see what’s what.
‘87 WR in a very very wet (flooded) Worcestershire.
Audifans urq mailing list
Manage your list connection: http://www.audifans.com/mailman/listinfo/urq
Pictures/Polls/Database at: http://autos.groups.yahoo.com/group/urquattro/
More information about the urq