Plastic timing chain pieces in oil pan?

3C's & a D?

Senior Member
Joined
Oct 27, 2015
Messages
2,039
Reaction score
1,740
Location
By the tree in Edmonton
I finally got around to pulling the engine out of my '71 Newport, a 383 which failed last year. It was just a touch low on oil (my fault) and was running at about 80 MPH for 120 miles when I brought it up to 110 MPH for a couple of minutes. I then heard one of the worst sounds I have ever heard and coasted to the ditch. The car came to rest with a vacuum/pump motion. It was towed home. Using a breaker bar on the crank I could rotate it 3/4's one way and 3/4's the other. I assumed a connecting rod had broken. I should have done this sooner as I am now having trouble rotating it at all, so while it's on the hoist and I'm soaking it again, I was curious to see where the rod broke/if the block is still good? After dropping the pan I am suprized and happy to see all of the rods are intact, yet confused, what went wrong? Then I see some rather large chunks in the pan. I'm guessing these are from the original timing chain? Anyone care to shed some light on what exactly happened? Also, if the engine is ok? (relatively) it was time for a rebuild anyway.
WP_20170907_17_04_33_Pro.jpg
WP_20170907_17_04_49_Pro.jpg
 
You need to pull the valve covers & rockers. Check for bent push rods. Also check oil pump screen for smaller pieces. Replace if necessary. I've cleaned them & reused. On the push rod if any are bent you can lay them on a flat surface & tap them back flat with a hammer. Done this many times on a low rpm stock engine. It will be fine. If all is good then put a new chain set on it & do a compression test. Check to make sure rotor is turning & it didn't shear off distributor shaft. If that's good I'd attempt to refire. If it starts make sure it has good oil PSI quickly. Listen for any unusual internal noises. Go from there. As for the plastic gears I didn't think those where used till 75 or later. They where suppose to run quieter. That was the benefit.
 
As for the plastic gears I didn't think those where used till 75 or later.
I don't know what year they started using them, but a 71 would have had plastic gears in the non HP versions.

As Bob said, you may have some bent pushrods but since you are rebuilding the engine, you'll want to check the valvetrain anyway.

Be sure to use steel gears and roller chain for a replacement.
 
Unfortunately Chrysler engines have what they call crash clearance. When the timing chain slips more than three teeth, the piston will slap the valves. Do everything Bob and John suggested, I would also do a compresion test to rule out any bent valves.
 
You need to pull the valve covers & rockers. Check for bent push rods. Also check oil pump screen for smaller pieces. Replace if necessary. I've cleaned them & reused. On the push rod if any are bent you can lay them on a flat surface & tap them back flat with a hammer. Done this many times on a low rpm stock engine. It will be fine. If all is good then put a new chain set on it & do a compression test. Check to make sure rotor is turning & it didn't shear off distributor shaft. If that's good I'd attempt to refire. If it starts make sure it has good oil PSI quickly. Listen for any unusual internal noises. Go from there. As for the plastic gears I didn't think those where used till 75 or later. They where suppose to run quieter. That was the benefit.

For starters, you will need to do all of the above to potentially get it running again. Be sure to replace the oil filter before any attempt to re-start. I would recommend that you put on a good timing chain as the first order of business, note the position of the alignment marks on the timing gears as they are probably two or more teeth off if the engine quit. Now remove the valve covers and the rocker shafts. This will close all of the valves so you can try to turn the engine over by hand and realign the crankshaft and camshaft for the new gear install. As you were running at speed whatever damage was going to be done has already happened. While you are doing the hand rotation, you can see if the distributor shaft is still attached as you move the camshaft.. If the engine turns freely, that is a good sign that none of the valves have broken off. Next check for bent or broken push rods, replace or repair as indicated above and reinstall the push rods and rocker shafts. If you do not find any that are damaged, that would be another very good sign. Next run the compression check, if the compression is normal, you have gotten very lucky and no valves are bent and you can attempt a restart. The 383 is not a zero tolerance engine so usually so long as the timing chain did not break in two, serious damage will not be done to the engine. The plastic timing gears were used on some mopar engines as early as 1965, do not replace your timing chain with another plastic gear, use an all metal one. I personally use Duralast gears, they are all metal and they are still made in the USA and are available thru Auto Zone and other major suppliers. Cloyes and Mel Gear also make good quality replacement gears. Your engine probably has 100k on it if the plastic gear failed so you probably do not need to worry about a roller type chain. The stock replacement all metal gears are good for at least 125k and if your engine runs that much longer, you will be due for a rebuild. A side note on replacement gear sets, many now come with multiple key-ways which can cause some confusion, that is why it is important to align the marks on your existing gears before you remove them. This avoids potential screw ups.

Dave
 
I finally got around to pulling the engine out of my '71 Newport, a 383 which failed last year. It was just a touch low on oil (my fault) and was running at about 80 MPH for 120 miles when I brought it up to 110 MPH for a couple of minutes. I then heard one of the worst sounds I have ever heard and coasted to the ditch. The car came to rest with a vacuum/pump motion. It was towed home. Using a breaker bar on the crank I could rotate it 3/4's one way and 3/4's the other. I assumed a connecting rod had broken. I should have done this sooner as I am now having trouble rotating it at all, so while it's on the hoist and I'm soaking it again, I was curious to see where the rod broke/if the block is still good? After dropping the pan I am suprized and happy to see all of the rods are intact, yet confused, what went wrong? Then I see some rather large chunks in the pan. I'm guessing these are from the original timing chain? Anyone care to shed some light on what exactly happened? Also, if the engine is ok? (relatively) it was time for a rebuild anyway.View attachment 141956 View attachment 141957

In answer to what happened. The plastic parts in the photo are from the OEM upper timing gear. This type of failure is common. The older the vehicle gets, the more brittle the plastic gets. Eventually, any where from 80k on the plastic starts to crack and the gear starts throwing teeth. When enough of them are lost, the gear fails and the chain will start jumping teeth.

Dave
 
These guy's have you covered, I think you will be really lucky if it didn't hit the valves. A friend of mine had a early 80's 302 in his Ford truck and they are not interference engines and when he was at highway speed and it skipped a couple of teeth it hit some valves. He finished the job when he got it restarted and ran it more trying to get it home. It skipped a couple more teeth quit running and got more valves. Best of luck to you
 
I had this happen to my 72 Monaco with a 360..all stock. Car kinda died coming off the cross bronx expesway...bad place, would not restart, starter spining over crazy fast...clued me in on what happenened. Towed it back to Brooklyn, did the timing chain...started right up with no problems and ran great.
Personally any 70s Mopar with one of those timing chains, should have it changed upon purchase. If it didn't go yet, it will at the worst time.
 
I had this happen to my 72 Monaco with a 360..all stock. Car kinda died coming off the cross bronx expesway...bad place, would not restart, starter spining over crazy fast...clued me in on what happenened. Towed it back to Brooklyn, did the timing chain...started right up with no problems and ran great.
Personally any 70s Mopar with one of those timing chains, should have it changed upon purchase. If it didn't go yet, it will at the worst time.
Yes they will always fail at the worst time, the worst for me was in a 1975 "B" body Fury with a 318. I had the wife use it and one day she is out with the kids, car dies, she tries to restart it and it cranked real slow, (timing to advanced because of the slipped chain). Guy comes along and gives the car a jump, engine starts and hammers 7 of the 16 valves before it gave up the ghost, (you gotta love the 318). Man what an expensive repair that was.
 
Rule of thumb........ change the timing set and add a new water pump at 75K. It's not a tough job.
About 20yrs ago a friend picked up a 88 Lincoln Town Car and that was the first thing we told him to do was bring it in and change the timing set and water pump. Ford used the aluminum/nylon gears well into the 90's
 
I know my 67 Mercury has a plastic gear. When I opened the 72 engine in my truck the plastic gear has nothing broken off but there were a lot of nubs. Those nubs were found gathered around the oil screen in the pan.
 
I had this happen to my 72 Monaco with a 360..all stock. Car kinda died coming off the cross bronx expesway...bad place, would not restart, starter spining over crazy fast...clued me in on what happenened. Towed it back to Brooklyn, did the timing chain...started right up with no problems and ran great.
Personally any 70s Mopar with one of those timing chains, should have it changed upon purchase. If it didn't go yet, it will at the worst time.

Yep, it happened at 1:00 A:M: 60 miles from home. Not a fun night. The starter on mine was hitting a brick wall, I knew I was in trouble. I pulled the rockers and push rods, as recommended. Thank you all! None were bent, there is one wear mark on the number one cylinder intake side. I cut the timing chain next, the cam moves freely and the distributor gear is good. Crank still will not budge. Heads coming off soon.
WP_20170908_18_54_51_Pro.jpg
WP_20170911_16_18_57_Pro.jpg
 
Well, apparently I got lucky the heads are off and no damage to the valves or pistons is evident. Should have mentioned earlier that the car has 120,000 miles on it. The one cylinder all the way down the bore had some rust in it, the valve must have been open and condensation must have crept in and added up over time, again I should have done this sooner. Lots of built up oil deposits and some cereally, almost completely clogged water ports. Never had over heating issues though. She's still seized, I'll get her though.
WP_20170913_17_38_28_Pro.jpg
 
Well, apparently I got lucky the heads are off and no damage to the valves or pistons is evident. Should have mentioned earlier that the car has 120,000 miles on it. The one cylinder all the way down the bore had some rust in it, the valve must have been open and condensation must have crept in and added up over time, again I should have done this sooner. Lots of built up oil deposits and some cereally, almost completely clogged water ports. Never had over heating issues though. She's still seized, I'll get her though.View attachment 143170


Well thats good news then??
 
Well with 3C's and a D, you now know about the importance of checking your timing chain before something bad happens. Check the rest of them. You will sleep better and save a lot of expense getting rid of the OEM plastic gears.

Dave
 
Well with 3C's and a D, you now know about the importance of checking your timing chain before something bad happens. Check the rest of them. You will sleep better and save a lot of expense getting rid of the OEM plastic gears.

Dave

At 120k the engine is marginal as far as things go, the 383 was usually good for about 150k. Usually the valve guides go first. You will see smoke on start up and fairly high oil consumption. At the very least, you are going to need a valve job. Usually on an engine at 120k you are looking at bronze valve guides, hard seats and new valves. This will typically run $800 to $1000. You can buy the assembled after-market performance heads for around $1200 to $1400 depending on which ones you decide to go with. If you are going to keep the car stock, go with the first option. The lower end will go for about $1000 for a commercial rebuild. I would probably opt to do it all at once and know I would have an engine that if it is properly cared for will last for at least 150k if not more.

Dave
 
Well thats good news then??

Yep, great news! I was thinking only the transmission would be worth saving. Unfortunately/fortunately this was the straw that broke the camels back. The car was purchased as a parts car due to alot of rust. It made it through two Edmonton winters everyday (almost), and then some. I regret getting attached to a "parts car" however we had some great times and I learnt alot.
 
Well with 3C's and a D, you now know about the importance of checking your timing chain before something bad happens. Check the rest of them. You will sleep better and save a lot of expense getting rid of the OEM plastic gears.

Dave

You had better believe I have learnt that! I'll be checking the rest of the stable over winter. Regarding the next post, yes it was experiencing the occasional smoke show on start up and oil consumption was moderate. There was chunks of the original valve guides found too. Thanks for all of your advice Dave.
 
refurbish the eninge and put it back in.
Your Newport wants to do a couple of more Edmonton winters
 
Back
Top