Contour Enthusiasts Group Archives Forums General Troubleshooting V-6 Cylinder Head/Valve Damage - Repair or Replace

My mechanic informs me that the rear timing chain on the V6 jumped and there is damage to the valves, likely due to contact with pistons (contact during engine cranking only, not during engine running). What are some options for repair: machine shop to repair heads/valves, replacement heads with new valves (where to find), etc.

What are the chances of addtional damage to the pistons.

tcj

Chances are high for damage to the pistons, even just during cranking. Damage to the heads will also be certain as bent valves tend to mess up valve seats and combustion chambers. I think your best bet is a used head from http://www.car-part.com and three new replacement pistons for that bank.

Cost to repair depends on your shops labor rate, guessing at around 12 hours or so. Parts should be around $300-$400 for mostly used parts, more for new.

What was vehicle's symptoms prior to mechanic's diagnosis.

Has he actually determined valve damage or is he just assuming?

I've had a timing chain jump in a v8 with no collateral damage, not sure what happens in a Duratec v6.

a timing chain jumping depending on how long it jumped will tell you the damage it can do if it jumped one tooth then it should be alright but if it jumped say 5 or 6 teeth then it could/would damage things

In all my years and all my miles driven, all my motors and all my motor head friends and all their motors I have heard stories of jumping timing chains. I have however never seen one or found a way to make it happen. Now the chains on the V6 are long, but if you look at a chain of any kind you will see that it just can�??t �??slip�?�. In order for this to happen the cams would have to turn faster the crank and overcome the tensioner causing slack on the inbound side of the crank sprocket. This just would not happen since the cams have no way of going faster then the crank. Now, if the engine was rotated backwards a few times with no pressure on the tensioner I could see how you would get slack on the wrong side of the chain and possibly get it out of sync. This is why OHC engines should not be rotated opposite of normal rotation.

Ask your mechanic for a better explanation and do some more troubleshooting before you tare the heads off.

jeff

May I ask you what year your Contour is? And how many miles do you have on it? Because '95 Contours have the chain tensioners that bleed off oil when they sit overnight. Did yours fail on first cold start of the day? Another forum member with a '95 had his chain cover off to update his chain tensioners to the newer style (as per Ford TSB) at around maybe 115,000 mi and he said all his chain guides were worn out as well.

I had a "crank - no start" problem after I replaced a clutch. Ford dealer fixed what they could under emission and underhood wiring harness warranty, but couldn't get it to start (and I couldn't afford to fix for a while).

Anyway, I sent the car to to local mechanic. Initial compression test showed no compression on the rear cylinder bank. Valve covers were removed, and rear timing chain is loose. Air compression tests with cams loosened failed indicating damage to valves.

That's where I am now, oh, it's a 95 LX V6 MT with less than 70K miles.

Here's what I'm think my options are:

1. New heads with valves and cams -- big bucks
2. Reman heads with valves, reuse cams -- less money
3. Take heads to machine shop for valve job and damage repair -- costs are variable.

I am leaning towards no. 2, hoping pistons survived. Much more of this and I'm going to part it out on ebay!!!