Timing chain....do I need to worry about it? If so how?

Pclancy

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I am planning a massive trip in my '77 Newport....to Montana and back to DC with the wife. The car has the 400 engine. I have about 61,000 miles on the clock. I belive the chain on the engine is original.

I maintain the car and engine well. But I have never thought about the timing chain, and I wonder if this should be looked at before I leave. If it broke on the road I would be screwed, no?

Can anyone give me guidance? Can my trusty mechanic look at the chain and see visually if it looks worn? How you you tell? How much of the engine needs to be disassembled to do that?

What's involved cost wise to replace the chain on a preventive basis, and what's the best chain to use?

Thanks for you help per ususal guys.

Peter Clancy
 
Pretty easy to tell. Have to pull the timing cover off and see if any of the nylon teeth are missing or the chain is stretched.

That's the main reason I replaced my engine in my 78 NYB . 400 with 65,000 miles. I never even pulled the timing cover. 40 year old nylon teeth on the gears....time to change it.

I would say you would be pretty brave to take a major trip without replacing the the timing set and water pump.
 
Can anyone give me guidance? Can my trusty mechanic look at the chain and see visually if it looks worn? How you you tell? How much of the engine needs to be disassembled to do that?

What's involved cost wise to replace the chain on a preventive basis, and what's the best chain to use?

Thanks for you help per ususal guys.

Peter Clancy
I would like to know the same, please and thank you.
 
Best way to look for a worn timing chain is to turn the engine clockwise until the timing mark is on 0 degrees, (Top dead center). Remove the distributor cap and mark the rotor, Then turn the engine in the reverse direction, (counter clockwise) until the rotor just starts to turn, If it is less than 10 degrees you are OK, 11 TO 15 degrees, it is on the way out, over 16 degrees, and you should replace it.
 
As far as what type of gear to replace it with, go with an after market metal gears rather than the stock plastic faced unit for the upper gear. Cloyes makes a good replacement. Avoid any of the crap gears and chains made in China, most of them are worse that the plastic originals. Timing gears can go anytime after 70K, but your plastic gear is now more than 40 years old and the repeated heating and cooling of the plastic tends to make it more brittle over time, so this would probably be as good a time as any to replace it. If it jumps on the road, you will indeed be screwed and this can break off valves and scatter your low mileage engine. I would get a price quote from a respected shop as prices can vary a lot by location and from shop to shop. The parts are relatively inexpensive, the main cost is the labor.

Dave
 
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Bump the above.. my 2 cents! If there’s plenty of time before your trip! Have it changed.. y’all NEED to at some point. Better now then while on the road... you know your mechanic at home!! While away “Jimbob and Billy” could take you for a financial ride.. just say’en..
 
As far as what type of gear to replace it with, go with an after market metal gears rather than the stock plastic faced unit for the upper gear. Cloyes makes a good replacement. Avoid any of the crap gears and chains made in China, most of them are worse that the plastic originals. Timing gears can go anytime after 70K, but your plastic gear is now more than 40 years old and the repeated heating and cooling of the plastic tends to make it more brittle over time, so this would probably be as good a time as any to replace it. If it jumps on the road, you will indeed be screwed and this can break off valves and scatter your low mileage engine. I would get a price quote from a respected shop as prices can vary a lot by location and from shop to shop. The parts are relatively inexpensive, the main cost is the labor.

Dave

Dave,

With much respect and humility, are you certain that a broken or slipped chain will cause the valves to come in concantact with the pistons on a 400?

I had mine slip on a 440 and it ran like **** until I figured it out.

I always thought and recall hearing that 400 and 440 engines were non conflict engines, ie the valves would never come in contact with the pistons even with the timing chain broken or severely slipped.

Never tried it out myself. Nor, can I think of why I would.

But you peaked my curiosity and upset my paradigm so I need to ask. Anyone else I would have blown off but a word from you and I will modify my paradigm.

And Peter...... just change the timing chain before you go please... even if the rotation test comes out good. No reason to spoil a vacation with needless worry when you can fix it easy. I think it takes about 10 hours labor and parts should be less than $200.
 
Excellent advice and help from all concerned. Thankfully, I have a couple of months before we hit the road. On the list:

Cloyes metal gears/chain/set
New water pump
And although not mentioned...rebuilding my original 500 lb AC compressor, which has been wheezing?

Thanks guys!
 
Dave,

With much respect and humility, are you certain that a broken or slipped chain will cause the valves to come in concantact with the pistons on a 400?

I had mine slip on a 440 and it ran like **** until I figured it out.

I always thought and recall hearing that 400 and 440 engines were non conflict engines, ie the valves would never come in contact with the pistons even with the timing chain broken or severely slipped.

Never tried it out myself. Nor, can I think of why I would.

But you peaked my curiosity and upset my paradigm so I need to ask. Anyone else I would have blown off but a word from you and I will modify my paradigm.

And Peter...... just change the timing chain before you go please... even if the rotation test comes out good. No reason to spoil a vacation with needless worry when you can fix it easy. I think it takes about 10 hours labor and parts should be less than $200.

You are correct that the 400/440 will not usually suffer a catastrophic failure that will break valves off. The 400/440 are non interference engines with stock valve gear, that does not mean necessarily that they are completely non-contact engines. The Mopar valve gear is a pretty robust design, it can usually absorb any contact that might occur because of a jumped, out of time timing chain that has caused the valve timing to be off. The chain can jump a tooth or two and the engine will not come apart. If the failure is bad enough to stop the camshaft from turning bad things are probably going to happen because this is outside the range for which the valve gear was designed to survive, especially if the engine is running at high RPMs when the failure occurs. Stock engines with hydraulic lifters are designed to take a lot of abuse before something breaks and most of the time push rods will go before a valve breaks but who wants to take that chance. I have seen several of these engines that had complete chain failures during high speed police pursuits and it ended badly for the engine because it was running at high RPMs and things started to break and come apart. It did not happen often, but it did happen.

Police chases are admittedly a severe situation. A more normal failure would be that the engine will start to run like crap and just quit someplace by the side of the road as the chain continues to degrade. Sometimes this can cause valve clatter sometimes it won't. In either scenario, you are stuck by the side of the road, some place you do not want to be. Regardless of whether any permanent engine damage has been done, your day has been ruined.

Dave
 
Even when the cars were newer, 80K was about when things started to unravel on many OEM timing chains. Mileage might be a little lower, but plastic ages. It's good INSURANCE for a long engine life to get it done before you have to!

The normal OHV V-8s were not usually termed "contact" or "non-contact" engines, as most OHC motors are. The saving grace on the 400 and 440s with the 8.2CR is that the piston is so "deep in the hole" that an open valve at the wrong time might be likely to make contact with the piston crown. But 9.2-10.0CR motors, with the pistons higher in the hole, a much different story!

Personally, you can do the "stretch/wear check", but it could well be inconsequential or might give false results. That's just the way I'd look at it. Others might differ, which I understand. The KEY thing is that if you even think it might need changing (at this time) and feel sure it is still the OEM chain in the engine, then just change it and be done with it. Like I said, all things considered, it's CHEAP INSURANCE and then you'll know where things are for quite some time into the future.

I personally know that the Cloyes Plus Roller chain that I put in my 305 Camaro has well past 500K miles on it, when we swapped the motor for other reasons. Just put cam assembly lube on the back surface of the cam sprocket, where it contacts the front of the cylinder block and pour the liquid cam assembly lube over the complete chain and lower sprocket (with the roller chain, both upper and lower chain sprockets will need to be changed). With a non-roller chain, you can get by with just the upper sprocket and the new chain being changed. Either way, make sure that lube gets everywhere before you put everything back together. Otherwise, oil splash is the main lube source in that part of the engine, so it would be best to pre-lube it all before the final cover is replaced.

Water pump's a good idea too, as it will be off anyway. Then put a fresh set of OEM production quality v-belts on it to complete the job. While you're there close, a new fuel pump and filter might be considered, too.

Once done, these things might not be needed to be thought about for a long time and many miles of enjoyable driving. Usually.

As for the a/c compressor, make sure you put oil back in it that's compatible with the type of "gas" that will be in the system.

Just some thoughts,
CBODY67
 
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Excellent advice and help from all concerned. Thankfully, I have a couple of months before we hit the road. On the list:

Cloyes metal gears/chain/set
New water pump
And although not mentioned...rebuilding my original 500 lb AC compressor, which has been wheezing?

Thanks guys!

The RV2 compressor in this car will usually live longer and run better if you can leave it charged with R12. This is getting harder and harder to do as many of the current generation of techs will have no idea what you are talking about when you mention R12. If the compressor is groaning or other wise noisy, most likely it is low on oil. These compressors lose oil over time from the front shaft seal. The oil loss increases if the unit is also undercharged with refrigerant as gas pressure is used to hold the seal tight against the case and the crankshaft. You will first need to determine what your A/C system is charged with, R-12 or R-134a. If it is charged with R-134a, it will need to be topped off with the proper oil and recharged and that should get it back to where it will work quietly again.

The R-12 presents a more complicated problem. If you can find an old tech that still has R-12, the unit should be topped off with the proper oil and recharged same as above. More likely, you will probably need to have the system converted to run on R134a. This will involve flushing the system of all the old oil and replacing the hoses and O-Rings to the modern Green type which are a higher density rubber that is compatible with the smaller R-134a molecule. The filter dryer should be replaced and the rubber hose fittings on the suction side of the compressor are probably the barbed type which punch small holes in the suction hose to secure the hose to the fitting. This will not work with R-134a as the smaller gas molecule will leak at the connection points, so these fittings need to be replaced as well. Once the system has been upgraded to accept R-134a, the system can be evacuated and recharged with R134a compatible oil and refrigerant.

A work of caution about systems charged with R-134a, they are much more prone to leaking because of the smaller gas molecule. The smaller gas molecule also is not as efficient about moving oil about inside of the system. If there has bee a loss of refrigerant, the gas pressure drops and the oil stops circulating. Most of the time this results in the compressor running "dry" and burning out. You need to keep regular tabs on the system and keep it fully charged at all time so preserve the compressor.

Dave
 
You can get a little glimpse of the timing chain from the distributor hole. But I agree to replace it.

I'd put a couple hundred local miles on those new parts that you change before the trip. I had a new water pump start gushing out the weep hole after 50 miles. I ran the Prestone coolant system flush though it before hand though, could be the chemicals in that ate the seal, who knows?

I've also had a new fuel pump and lower ball joint fail within a year. Smart thing to do would be to keep some spares of cheap and easily replaced items in the trunk.
 
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The RV2 compressor in this car will usually live longer and run better if you can leave it charged with R12. This is getting harder and harder to do as many of the current generation of techs will have no idea what you are talking about when you mention R12. If the compressor is groaning or other wise noisy, most likely it is low on oil. These compressors lose oil over time from the front shaft seal. The oil loss increases if the unit is also undercharged with refrigerant as gas pressure is used to hold the seal tight against the case and the crankshaft. You will first need to determine what your A/C system is charged with, R-12 or R-134a. If it is charged with R-134a, it will need to be topped off with the proper oil and recharged and that should get it back to where it will work quietly again.

The R-12 presents a more complicated problem. If you can find an old tech that still has R-12, the unit should be topped off with the proper oil and recharged same as above. More likely, you will probably need to have the system converted to run on R134a. This will involve flushing the system of all the old oil and replacing the hoses and O-Rings to the modern Green type which are a higher density rubber that is compatible with the smaller R-134a molecule. The filter dryer should be replaced and the rubber hose fittings on the suction side of the compressor are probably the barbed type which punch small holes in the suction hose to secure the hose to the fitting. This will not work with R-134a as the smaller gas molecule will leak at the connection points, so these fittings need to be replaced as well. Once the system has been upgraded to accept R-134a, the system can be evacuated and recharged with R134a compatible oil and refrigerant.

A work of caution about systems charged with R-134a, they are much more prone to leaking because of the smaller gas molecule. The smaller gas molecule also is not as efficient about moving oil about inside of the system. If there has bee a loss of refrigerant, the gas pressure drops and the oil stops circulating. Most of the time this results in the compressor running "dry" and burning out. You need to keep regular tabs on the system and keep it fully charged at all time so preserve the compressor.

Dave

One issue with R12 is that to be correctly serviced, the tech needs to have a R12 Freon recovery machine (charged and ready to go) in order to work on it. Putting R-135a into that machine contaminates the whole mess and then it has to be cleaned/purges of the incorrect gas. As R12 hasn't been used in many years, finding a shop that can use the recycling machine to evacuate and recharge an R12 system might take some doing. But doing things "the old way" with venting the gas into the atmosphere, pulling a vacuum with a separate vac pump, with a gauge set attached to the fittings, might still be doable.

Just some thoughts,
CBODY67
 
Change the timing gears and chain for the above mentioned reasons, and when the nylon falls off of the gear all of that **** ends up in the oil pan where it can clog the oil pickup and can cause all kinds of other problems.
 
I took the engine in my Imperial apart at around 140K miles to find it still had its original timing gear with all the original nylon teeth intact and the wear was not at all excessive but I’m sure that was unusual, I’d change it if I were you.
 
With much respect and humility, are you certain that a broken or slipped chain will cause the valves to come in contact with the pistons on a 400?
Just to add in my 2 cents... if the chain jumped one tooth, you'd run bad or not at all... but if it managed to jump more teeth, you'd have damage....
 
If the failure is bad enough to stop the camshaft from turning bad things are probably going to happen

That's what killed my parents 1973 Fury with a 318 in it. Mom just left the house and car died, called AAA and the gas station just down the road sent out a pump jockey in the tow truck to jump start it. Long story short crank crank crank till a piston broke off one valve head and locked up the motor. I hadn't been in touch in awhile and they couldn't reach me via my beeper because they still had rotary dial phones in the house. I finally get the call when the gas station wants $1,200+ to most likely put in a boneyard motor which I can get for $100/$150, I cheep out on the job with my boneyard letting me pull 2 heads, 2 pistons & rods plus pushrods for fifty $. Didn't even send the heads out, learned that lesson with the 440, just a light grind & lap, chain kit, swap rings & bearings over to used pistons, good to go on the cheep.

:thumbsup::thumbsup:
 
Well...….personally, I would just do the test that traintech55 mentioned. Do a full tune up & change all your fluids. Carry an extra ballast resistor, ignition box & voltage regulator....and enjoy your trip.
 
Well...….personally, I would just do the test that traintech55 mentioned. Do a full tune up & change all your fluids. Carry an extra ballast resistor, ignition box & voltage regulator....and enjoy your trip.
He is not doing the test, his mechanic is. Save the test money and put it towards having it changed, it's just good practice. You do very right by the car so this will insure you have no practical, life experience info on "if the valves hit when it breaks".
Buy a quality water pump, I have had 2 different parts store pumps fail what I would consider early.
I would convert compressor to sanden unit but that is involved. I always carry a spare clutch assembly with me. Even if the compressor locks the clutch will spin freely when not engaged allowing you to move on. Dispite what the FSM says you can pop the clutch off by loosening the bolt and a quick smack on the side of pulley it will pop right off the taper shaft (leave belts tight). You may have to loosen to put other clutch on aliging the woodruff key and tighten the bolt.
 
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