Is Your 2.7 Engine Burning Oil?

[Yamsi]

Thanks to User Dave for the Info!

For those of you with a 2.7 that is puffing blue smoke after idling, here's some information.

Commonly blue smoke on idle/coast down is due to bad intake valve oil seals. Have you ever been behind an early-mid 90's Crown Victoria in stop and go traffic? Those had intake valve seal problems and always smoked on coast down and idling.

Blue smoke on acceleration is due to stuck or worn rings.

In the case where you don't have blue smoke on coast down or after a short idle time (such as at a stop sign for a few seconds), but when taking off after idling at a stop light for 1 or more minutes: Exhaust valve oil seals.

I've rebuilt my 2.7 engine a while ago (now at 1500 miles). One thing I noticed was that the intake valve seals were soft and pliable while the exhaust seals were very dark and stiff. There was evidence of coked oil on top of the exhaust valve guides. Of course exhaust valves run hotter.

Chrysler used Viton in their valve guide seals. Viton is resistant to heat and is a good choice for a valve stem seal (the next higher up is teflon which has advantages and disadvantages).

Some friends of mine have a 98 Concorde with the 2.7. 115,000 miles on it and using about 1 quart of oil per 1000 miles (new water pump and timing chain on my recommendation at 100,000 miles). They have blue smoke on takeoff only after idling for a few minutes. I followed them one day last week. No smoke on coast down, just after idling for a while.

Since replacing all the stem seals requires removal of both cams and the associated work of removing the front cover..etc. I suggested that the exhaust stem oil seals be replaced. This job can be done without disturbing the intake cam and the primary timing chain.

I did this job Saturday morning. Took about 4 hours start to finish. Replaced the seals with Fel Pro Viton seals. Checked the guides for slop, no major wear found. I drove the car 70 miles on Saturday, in downtown traffic to see if the smoking was fixed. No visible smoke anymore where there used to be smoke every time.

The exhaust valves are at the bottom of the heads, right were the oil collects for drainback through the passages around the head bolts. There is considerable oil puddling around the guides in this location and I believe that increases oil travel down the exhaust guides. Afer priming my rebuilt 2.7, I can tell you there is a lot of oil slinging around in those valve covers!

Now I know some folks don't even use stem seals on exhaust valves in many applications since there is no vacuum in the exhaust to suck oil down the guides (I didn't on some small block Chevy's years ago). But in the case of many newer multi valve engines, exhaust port design incorporates scavenging and this causes a low pressure zone near the exhaust guide, just like an atomizer works. The engine isn't buring the oil, the catalytic converters are. My theory is that the oil collects on the valve stem and gets blown into the catalyst on accelleration. The smoke only lasts a couple of seconds at most.

So to make a long story short. You may just need new exhaust stem seals.

Before you start this, you MUST have a repair manual for reference. There is a specific sequence to removal and reinstallation of the cam bearing bolts as well as timing chain alignment. Remember that you will not touch the primary timing chain or the intake cam.

1. Remove intake Plenum.
2. Remove both valve covers.
3. Loosen all spark plugs (but leave them in the spark plug holes to keep stuff from falling into the cylinders)
4. Stuff rags/towels into the intake manifold openings, around the oil drainback holes at the head bolts near the exhaust valves, around the primary timing chain openings at the front of the head. You don't want to have to pull the oil pan or timing cover because you dropped something.
5. Remove all EXHAUST cam bearing caps according to the service manual. Place them on a clean towel.
6. Remove the Secondary timing chain tensioner bolts.
7. Lift the exhaust cam up, removing the tensioner, pull the cam rearward while removing the chain. Remove the cam and place it on a clean towel.
8. Remove the rocker arms, in order and place them near the camshaft lobe they run on. KEEP THESE IN ORDER!!!
9. Thread rope (1/4" to 3/8" diameter) into cylinder through the spark plug opening. Make sure before you start that the piston is at least 1/2 way down. Thread as much rope as you can. Turn the crankshaft to compress the rope against the valves.
10. Using appropriate valve spring compressor, remove the retainer locks and the spring. The valve seal is integral with the spring seat.
11. Remove the old valve stem seal. I used a screwdriver under the edge of the seat and "rocked" the seal up off the vavle stem.
12. Clean off all carbonized oil from the top of the valve guide using a good carburetor cleaner spray. Make sure there is no carbonized oil as that will tear up your new seals.
13. Liberally oil the valve stem and top of the guide, as well as the seal.
14. Install the seal, seating it on the head with a 1/2" deep well socket.
15. Reinstall the spring, retainer and locks.
16. Repeat for each valve/cylinder.
17. Replace all rockers in order.
18. Take apart the secondary tensioner and remove all the oil (don't loose the spring) and clean out any gunk you find in it using carb cleaner.
19. Reassemble the tensioner and lock it in the compressed position using paper clips.
20. Rotate the engine so that the bright links on the secondary timing chains are at the top position.
21. Install the exhaust cam, lining up the links, install the tensioner in between the camshafts (this can be a bit tricky).
22. Install the exhaust cam bearing caps loosely, drop a few drops of oil on the bearing journals to provide startup lube.
23. Install and torque the secondary tensioner bolts.
24. Torque the cam bearing caps according to the manual.
25. Release the secondary tensioner paper clips.
26. Put some oil on each cam lobe.
27. Before installing both valve covers, make sure the rockers are all in place, double check the timing chain alignments.
28. Reinstall spark plugs, timing covers, upper plenum.

Start the engine and allow it to idle until warmed up. Turn it off, check for leaks.

Hope this helps someone save some O2 sensors, catalytic converters (oil poisons them) or even an engine (run out/low on oil).

[Peva]

Originally Posted by Yamsi

...(the next higher up is teflon which has advantages and disadvantages)...

So would teflon seals be a net gain? < < < Never mind that question - I see where you addressed that on "another forum".

Since the original seals are viton, and the Felpro are viton, should I expect the Felpro's to last longer than the OEM seals, or will the same problem eventually show up in 100 to 150k miles after replacing the exhaust valve seals? Is there such a thing as "super-premium this-stuff-lasts-forever" viton?

[Paratrepper]

Bump.

[kimura]

So would it be a better bet to just use road as opposed to an air compressor with a spark plug hose to keep the valve stems in place?

Debating which method I should use on the 3.5...

[Peva]

Originally Posted by kimura

So would it be a better bet to just use road as opposed to an air compressor with a spark plug hose to keep the valve stems in place?

Debating which method I should use on the 3.5...

I did my 2.7 valve stem seals a couple of years ago when I did my timing chain, etc. If I had it to do over again, I would use the rope trick. Instead, I used compressed air, and do not have any kind of moisture trap on it. The carbon in the cylinders swelled up from the water/moisture that blew into them during the valve stem seal replacement, and caused interference at TDC when I had everything together. Fortunately I discovered that problem when attempting to turn it over by hand for the timing - if I had spun it over with the starter with that condition, some damage could have been done. Problem was fixed by dissolving the carbon with Sea Foam. Had me worried for a few hours until I figured out what the problem was and what to do about it.

Plus - by using the rope instead of compressed air, you don't have to have any concerns about what to do if your compressor craps out on you right in the middle of things - potential disaster.

Hey - suggestion on your 3.5: While you have the valve covers off, consider getting the rocker pivot kit that is supposed to be the fix for valve clatter that is common in those engines (TSB no. 09-002-04). I've already decided that if I ever need to do the valve stem seals in my 3.2 and money isn't too awfully tight at the time, I would do that at the same time. The kit is $150 from mopardiscountparts.com.

[paintballdude05]

Has anybody actually purchased the rocker kit for the LH and installed it? I ask because even the newer 3.5's get the tick that we have, figured they would have fixed it by now but it doesn't sound like they did.

[kimura]

Originally Posted by Peva

I did my 2.7 valve stem seals a couple of years ago when I did my timing chain, etc. If I had it to do over again, I would use the rope trick. Instead, I used compressed air, and do not have any kind of moisture trap on it. The carbon in the cylinders swelled up from the water/moisture that blew into them during the valve stem seal replacement, and caused interference at TDC when I had everything together. Fortunately I discovered that problem when attempting to turn it over by hand for the timing - if I had spun it over with the starter with that condition, some damage could have been done. Problem was fixed by dissolving the carbon with Sea Foam. Had me worried for a few hours until I figured out what the problem was and what to do about it.

Plus - by using the rope instead of compressed air, you don't have to have any concerns about what to do if your compressor craps out on you right in the middle of things - potential disaster.

Hey - suggestion on your 3.5: While you have the valve covers off, consider getting the rocker pivot kit that is supposed to be the fix for valve clatter that is common in those engines (TSB no. 09-002-04). I've already decided that if I ever need to do the valve stem seals in my 3.2 and money isn't too awfully tight at the time, I would do that at the same time. The kit is $150 from mopardiscountparts.com.

Thanks for the the advice Peva! I think I'll go with rope then. Plus I wouldn't have to worry about something flying off at 60+ psi worth of force in my face.

As far as the rocker pivots, I actually thought about doing this and would like to, but I don't think funds can afford it right now. However it is something I would like to try down the road.

[Peva]

Originally Posted by paintballdude05

Has anybody actually purchased the rocker kit for the LH and installed it? I ask because even the newer 3.5's get the tick that we have, figured they would have fixed it by now but it doesn't sound like they did.

It's been talked about and talked about, but I don't think anyone has done it and posted about it. Let's see - put up with a little harmless noise, or spend $150 to *possibly* get rid of it (we don't know since nobody has ever tried the kit!)? Hmm . . .