Went to start the car and seemed like something let go? Engine cranks but sounds like no compression, just spins? Thought the timing chain let go, but took off a valve cover, and all appears normal. Cranked it again, and noted the cam sprocket is rotating? Any ideas?

 

Can't figure that, how could all 6 cylinders lose compression at the same time ?
Are you sure that the cams are also turning along with the cam sprockets ?
All I can think of offhand is a slipped cam drive gear on the crankshaft .....
This is an INTERFERENCE engine, be careful !
If the cam/crankshaft timing is too far off, you could be seeing bent valves and banged up pistons.
( This could have already happened, but you should have noticed that, it is not a quiet event ! )

 

Thanks for that input. As you said, I would have expected to hear pistons hitting valves. Maybe the chain jumped on the drive sprocket. Cam shaft is turning, rocker arms are pushing valves.

 

I started a thread a couple years ago....

Crossfires - Interference or Non-Interfernce engines ?

I never had heard the term but a friend had asked me.
I came here looking for answers..not much discussion.
My best to you that it is something inexpensive to fix.

Gary

 

A flooded engine can give you the same symptoms.

 

Went through timing chain installation alignment procedure. Looks like timing chain jumped a tooth on the drive sprocket. both cam shaft alignment marks line up with crank at 60 degrees ATDC (should be 40). Maybe the tensioner is bad? Guess I'll need to inspect all sprockets, guides, tensioner, chain and go from there. Any advice is appreciated! Service manual says step one for replacing the timing chain is to "remove engine". Would rather not do that.

 

How many miles on this engine ?
Has the oil level ever been real low ?

Probably a new chain and tensioner(s) ?

I'm not sure, but I think you can do it without removing the engine, unless you have to drop the upper oil pan, then you could probably just use a cherry picker and raise the front after unbolting the motor mounts.

 

I am not sure what you mean when you say they line up. Do the camshaft timing marks line up with the copper timing chain links?

CamTIMING001_zps9b03590e.jpg

 

Since the engine has a 10:1 compression, I suspect it is an interference engine (if the chainbreaks the pistons will hit any valves that are open. In general a non-interference engine will have less than 8:1 compression.)

A chain will generally provide audible sounds, particularly at idle, that it is unhappy. Timing chains rarely break. They do stretch which retards the cams and reduces power. People replacing stretched chains often report the engine feels more responsive.

I usually replace the sprockets, tensioners, and guides when replacinga timing chain.

Once had a small OHC turbo diesel that had a timing belt. These had to be replaced every 40-60k miles. Not a great idea. If the belt broke while running at least a new head was needed.

 

Thanks to all responding. Cam shaft timing marks line up horizontally with cam bolt and with copper links, but the crank should be at 40 degrees after TDC; its at 60 (onehundred80). I haven't take off the timing chain cover yet, to confirm, but that's why I think it jumped a tooth at the crank sprocket. There's 120K mile on the engine (ala_xfire). I have never run low on oil, in the 4 years I've owned the car. It was running OK.

 

The cam marks are not horizontal at the 40 degree point. In the drawing above you can se that if the crankshaft was turned so that they were horizontal then the 40 degree mark would have gone by the pointer.
The crankshaft key is at the top when the 40 degree mark lines up. You should be able to see the slot in the pulley at the top.

 

I know about how much it will cost to repair you engine, so I have some good news for you. I have a Limited engine with 35000 miles on it ,, get the car to my shop and I will sell it to you and install it for $2650.00,,, hell make it $2500, call it Christmas time,, then you can drive it home or ship it. back to yourself in otherwords you pay shipping both ways.


in fact if I can help anyone that has a engine they need replaced . At either shop, South Florida ,, or Illinois . right mow we only have a aspirated engine out of a limited Crossfire ,,with 35000 miles on it.

 

Can you post a video of sounds when cranking? Are you certain it isn't something simpler, no fuel, no spark... Or if you really suspect something mechanical, first think I would do is drain oil and look for debris.

 

I think you are not correct in assuming the timing is out by 20 degrees, all the timing marks should align at 40 degrees and you only mention two of them. The two you mention will always align with the copper links at some point because they are directly connected by a fixed set of links in a chain. All the copper links, timing marks, with the pointer at the 40 degree line up at some point and seemingly only after four engine turns each time.
One turn of the engine will turn each gear by the exact number of teeth on the crank shaft sprocket, so the maths has to be done to calculate how many turns of the crankshaft equals one complete engine firing cycle. Seemingly the magic number is four. Your engine is at one of these four turns, which one is the question.
So I would gather from the four turns we can assume that the cam shaft pulleys have four times the teeth than the crankshaft and balance shaft pulleys.

 

Here is what my system shows of the timing marks on my timing chain replacement guide:

34863.png_zpskeze9obc.jpeg

 

That is a better picture of what I show in post #8.

 

The diagrams provided are correct, and are similar to the service manual. However, by design of a 4 stroke engine, the marks must align every other revolution!!! Drive gear has 180 teeth (20 degrees apart). Cam gear has 36 teeth. Cylinders fire every other revolution.
For anyone that needs to change the timing chain, this is what the manual says (supported by the drawings posted):
1. Invert the engine on the engine stand.
2. Install the crankshaft sprocket (2).
3. Ensure the crankshaft has maintained 40 degrees ATDC. If not, rotate until aligned with 40 degree marking.
4. Align the balance shaft sprocket with the timing mark (3) and the copper teeth (1) of the timing chain.
5. Insert the camshaft sprockets (6) into the timing chain and align the camshaft sprocket timing marks (4) and (5) with the copper teeth (1) of the timing chain.
6. Install the timing chain with the sprockets and route within in the timing chain guides (1).
7. Using Special Tools 9104 (1) and 9105 Camshaft Locating Plates, lock the camshaft sprockets.
8. Install the oil pump, the oil pump drive chain (2) and the oil pump drive chain tensioner (1). Refer to Page 9-676.
9. Rotate the engine to the upright position.
10. Install the timing chain cover. Tighten the bolts to 20 N·m (15 ft. lbs.). Refer to Page 9-688.
11. Remove Special Tools 9104 and 9105 Camshaft Locating Plates from the camshaft sprockets.

 

Typo in the above it would be 18 teeth on the crankshaft pulley.
You are correct though, firing is every 120 degrees. I baffled this old brain with maths.
I still doubt the engine has slipped a few links. I have had it happen on a Ford 302 engine and it slipped a tooth at a time more or less and the performance went down reasonably slowly, quick blips of the throttle made it jump a tooth or two.
The chain was like a limp noodle when held out on edge. Finally the pistons hit the inlet valves if I remember correctly, not a pretty sight.

 

Use the "KISS" technique. Do a compression test. No compression + valve train still turning = bent intake valves due to loss of valve train timing

 

Finally warm enough to get working. Checked compression; nothing registers on any cyclinder. I hear a 'puff' through the exhaust, which may support jump of timing chain (exhaust valve opens late when cylinder has compressed air). Anybody know how to view the crankshaft/ balance shaft alignment with the chain without removing the engine?