If it only costs $1000 to fix the problem, that’s a very good deal. I’d go w/that. If you had low oil at some point prior, that is likely the cause of the timing chain problem. That’s be my antiquarian guess anyway. Let us know what needed to be done; i.e. were any valves bent? One poster above suggests it is 100% certain major damage to the valves occurred. But in my antiquated experience w/antique cars anyway it is quite possible only minimal damage occurred if it happens at start up.
If it were me I guess, I’d like to know for sure and slap a new chain on if it actually broke, and especially at start up. Wouldn’t be the first thousand bucks I ever lost. My 86 Riviera sheared the timing gear sitting at a stop light. The place I towed it to said it was shot but offered to buy the car to put his engine in. I decided to tow it the 40 miles home and paid $125 for a timing chain kit. After a Saturday’s work it ran great for another 100,000 miles.
I’d confirm whether there was valve damage before making any decisions. It’s very possible that there was no damage, and IMHO it’s worth checking.
If I knew more about the new information, the oil problems in the car’s past, that just might change my feelings however. Chronic low pressure problems, or chronic low oil problems, might indicate wear (possibly damage) that would cause me to “call it a day” with this engine. This is a major unknown at this point that just might change my mind.
Are you saying this is going to be a 1000 dollar hope and pray chain job without considering cylinder head and/or piston damage?
Yep…it’s a 1000 hope and pray job if I decide to do it. Starting to feel like with their knowledge of my car’s history that the shop is leading me astray by recommending to fix it…
If I remember the Mariner only came with the Duratec V-6. Is that what your car has?
If so you’ve got 4 overhead camshafts and merely inspecting the valvetrain for damage will require removing the upper intake and valve covers in addition to the timing chain cover.
Just inspecting it for damage will cost hundreds of dollars. Sometimes there’s no way to be sure about something without digging into it.
Checking for bent valves is not a quick and easy process as some have suggested but it does not cost $1000 to test for bent valves. Are these guys are going to charge you for a complete timing chain replacement to tell you if the valves are bent? Or give you the option to abort after inspection?
A valve cover could be removed and the valve train could be inspected for excessive valve lash.
Lash increases when a valve bends because the valve never fully seats.
Sorry, I’m not in favor of hope and pray repairs; especially when they hit 4 digits.
Tester the compression test might have been skewed but it worked well enough for me to realize that the valves were OK. Like I said…try thinking out of the box for a change. Enough air will be pulled around the rings to accomplish a cursory compression test. Try it yourself.
There was no mention of checking if the valves are bent or not…just fixing the timing chain. I do believe it is a Duratec V-6 engine. All I was told is that they would have to disassemble the front end of the engine to do the repair, which is why labor would be so much.
“Try it yourself.”
Sorry @missileman .
When it comes to vehicle repair, I’m one that uses tried and true procedures, instead of wasting time.
Tester
I’m afraid that I’m not getting missleman’s line of thinking; from the compression test on an engine with a snapped timing chain to the bicycle pump not having valves bit.
What will you do next if the valves are bent? I believe that is an interference engine, this is a note in the timing chain replacement section;
NOTICE: Failure to verify correct timing drive component alignment will result in severe engine damage.
Valves not only bend, the heads can break off and damage the pistons. I would want a closer look before going forward with the chain replacement. Pressurize the cylinders, a look inside with a borescope etc.
My bicycle pump has valves in it I think, both on the inlet side and the outlet side. Not super-high-tech valves, but valves nonetheless.
I think I get missleman’s line of thinking if it means:
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Manually rotating the crank and four camshafts together to get each cylinder to a position where both valves are closed.
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Then proceed with a normal leak down test.
Thanks JoeMario. I’ve lost some respect for some members of this board. It’s an easy procedure that saved both time and money. I can’t see why they don’t understand it. It reminds me of that group of pseudoscientists that developed the theory that bumblebees couldn’t fly. We all know that bumblebees can fly…so the theory was mute right from the start. I’m done with this since it’s time to move on.
I’m trying to understand this. A leakdown test I can understand. No problem at all with that.
Missleman, what you said originally was that you bought a Jeep with a snapped chain.
You stated that you then pulled the plugs and ran a compression test.
The compression was good so you replaced the chain and the engine ran good.
My question is: How do you run a compression test with a broken chain or snapped belt?
Bicycle pumps are another matter but they have one-way valves just like compression testers, cooling system testers, hand vacuum pumps, many cars with their in-dash vacuum systems, and so on.
It is really not as simple as removing the spark plugs and performing a compression test. If you set the cams on an interference engine so the valves are closed on one cylinder, then crank the engine for a compression test you will bend the valves in the other cylinders.
The crankshaft should be set at 30 degrees after TDC so that no pistons are near the valves when turning the cams to prepare for a leak down test. Care must be taken to set the cylinder to be pressurized at TDC or BDC so as not to cause damage to the valves in other cylinders.
I don’t know how difficult it is on this Ford engine but on a Toyota 2GR engine once the cam gears are exposed so they can be turned it only takes 15 minutes to remove all 4 cams. With the cams removed all the valves are closed. The cylinders can then be pressurized without having to time anything or risk of further damage.
“Enough air will be pulled around the rings to accomplish a cursory compression test.”
How does that same air not get pushed right back out (the same way) around the rings during the compression part of the test, giving you zero compression?
While I have never intentionally tried to check compression on an engine with a non functioning timing chain/gear I once checked compression when testing for a no start condition and when the gauge went to 100+ I assumed timing and compression wasn’t the problem. After much wasted time and hearing the sound of low compression I checked other cylinders and found no compression.
I go for @Nevada_545’s recomendation. Removing the cams or possibly just loosening the cam bearing caps and running a leak down test does seem like a good idea at this point. Throwing $1,000 into a dark hole doesn’t sound like a good investment.