General Tips On Rebuilding Your Imperial's Engine


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Question from David:

I ventured one step further into knucklebusting by purchasing an engine stand in anticipation of building the 440 for my engineless project car. It's the kind with four adjustable plates with bolt holes running through them. Since I have no engine, I also have no bolts with which to mount the block to the stand. I'm starting with a bare block, so it doesn't come with any. Can someone please give me the specs or part number for those bolts so I can pick up a set? It's a '65 casting stock block.

Also, will I need to pick up a flex plate or can I run the bolts directly to the block? If so, can it be any old flex plate or does it have to be the one I'll have on there permanently?


From Don:

Mount the engine directly to the stand. DO NOT use the flexplate. If memory serves me I believe you use 3/8 coars thread bolts. On my stands they need to be about 3 to 3 1/2 in long to go thru the mounting ears on the stand and far enough into the block to secure it.

From Brad:

When I got my stand and bought those bolts, I bought higher grade bolts just as a margin of safety. Most bolts you get just off the shelf are grade 2 and strip or break easily. I went with grade 5 or better IIRC. There's not many engines heavier than a 440.

From Neva:

Have everything orderly laying out that will be needed to reassemble this 440 block. Leave it on the engine stand no longer than you have to as there's always a possiblility of distorting your cylinders. I didn't know this either until my uncle who was a Chrysler mechanic for 55 years informed me. I was building engines for our Dodge race car. Be sure you also get a supply of flat washers to make sure that the engine stand is attached snugly.

Question from Dan:

I think that I have finally decided to go ahead and take the engine completely out of my 83 to work on it.

Trying to get the y-pipe 'un-welded' and removing the center link and THEN working on my back on the garage floor with crap falling in my face has set my mind.

I found an engine hoist kit at a local Big Lots store. I may investigate it. I will also price out renting one.

I know that it will be FAR easier working on the engine outside of the car. Plus as I mentioned before, I can work on the engine compartment as well as painting everything.

Does anyone have info on 'special things' to look for when pulling an 80's 318? I know that there are air tubes going to the catalytic converter and other stuff that is not shown in that Rebuild Book I bought. Can the newer style A/C compressor be moved w/o dumping the R-12 (which still works)?

Reply from Dick:

Yes, you can set the compressor over to the side without having to dump the Freon out. Just be careful not to stress the hoses any more than absolutely necessary. I seem to recall I just set the power steering pump aside also, and didn't have to drain it, but I've pulled so many engines that I may have this car confused with another. I know I have always managed to avoid spilling the Freon, though, on any car I've pulled the engine on.

The only caution your book might not tell you about is the way to disconnect the engine from the torque converter. This isn't unique to your car, but just in case you are not familiar with the task, you need to do it this way:

Take the cover plate off the bottom of the converter housing (we used to call these bell housings). Mark the converter and flex plate (we used to call these flywheels) so that when you re-assemble, you get everything back in the same holes. Now reach up and unbolt the converter from the flex plate. You'll have to turn the crankshaft to get at all the bolts. Now, push the converter back into the transmission - it will move back about 1/2 inch or so. Then, with some baling wire or the like, wire the converter into place so that it cannot creep back out on you.

Before you pull the engine, remove the distributor from the back of the block, so you don't damage it. Removing the whole hood makes life easier, but you'll need a couple of helpers to do this without damage to the surrounding body work. Also, scribe marks at both hood hinges to save yourself having to fiddle with adjustments when you put the hood back on.

Rent a good engine hoist - the El-cheapo type sold at Harbor Freight and the other China made ones are dangerously inadequate, and very short lived!

Unless you have had the transmission out within the last few years, now is the time to replace the front seal on the tranny. It's a $5 part, but the labor to change it when it starts leaking is hundreds of dollars. To change this seal, you need a seal puller (rent that too). You undo your baling wire and pull the converter out of the transmission, being very sure to first note how far into the bell housing it goes, because when you reinstall it is a real chore to get it to back all the way, you have to keep jiggling and trying until you find the magic spot, but it is absolutely essential that you do this and get it all the way back! Once you have the converter out, you can see the front seal, just pop that sucker out of there and put the new one in after wiping the flange clean. You can use a large socket or other clean, round strong thingy to push it back until it seats. Then reinstall the converter and wire it in place.

I must say, and check your FSM to verify this, but on some cars the transmission and engine have to be removed as a unit, then the above all applies with both units hanging on the engine hoist where you can really see what you are doing. When I rebuilt my 81 about 7 years ago, I did it this way, but I don't recall whether or not that was mandatory or just my choice (I usually pull both as a unit - strangely, it seems easier to me to do it that way).

I'll be very interested to find out how bad your crank and bearings are - I'm expecting brass showing and scoring, from your symptoms.

Question from Brian:

I am having trouble starting my recently rebuilt 413. I turned the motor over by hand, put a new battery in it,and it turns over a little slow and won't fire. I noticed 2 wires that were chewed on the fire wall.They look like they were connected to two white resistor looking things. Are these ballast resistors, and would this have an effect on the spark. The points are set perfectly.


From Matt:

The car won't start without ballast resistor working or a bypass of some sort.

From Chris:

The ballast resistor should be in the neighborhood of 2 ohms. Your current limit should be at around 4 amps. The resistance of the coil should be between 1 and 2 ohms. There may be some corrosion at either the + or ground terminals that you may want to check - not at the battery but at the starter or wherever in the chassis the ground terminal hooks to.

From Charles:

Something else to consider is the condition of the plugs themselves. I had similar trouble recently with my '60 Desoto Adventurer (383ci). After checking the entire ignition and fuel system, an old friend suggested I check the plugs for 'shorting'. I couldn't understand how at first as the plugs only had about 500 miles on them. Took each plug out and true enough, just about every plug was shorting out. Spark was present but jumping from the electrode to the side wall of the plug itself. Under compression, there would not be any spark at all. A fresh set of plugs later and she fired up almost immediately.

Question from Joe:

I have a 413 that I rebuilt and what some input as to the first start up and cam run it time. I have what RPMs the cam says it needs. Do I take out the spark plugs and turn it over to build oil pressure? And added to that my pressure gauge did not work, so can I tell if something is wrong before it locks up?


From Jeff:

Using a priming tool is a very good idea. It will save your bearings. Just remember to use the drill in the "reverse" setting and hang on to it tight, when the pump starts it will want to twist the drill in your hand. Also if you still have the engine out go ahead and set it on #1 top dead center to make the distributor installation easy.

From Dave:

There are oil pump primers that require a drill to operate. It's installed in place of the distributor and you use the drill to prime the pump and pressurize the oil system before you start the engine. They are usually pretty cheap, between $10 & $20.

From Steve:

I always just use a 1/4 inch drive socket and a speed wrench to spin the oil pump. I put a oil gauge on a short length of hose screwed into the back oil galley port where the sending unit goes to watch for oil pressure. You will certainly know when that comes up as the wrench will turn much harder. I also always pack the oil pump cavity with petroleum jelly and the oil filter with some oil to speed up the process.

From Bill:

Also, to ensure an instant startup, I align the timing marks on the damper to TDC #1 (compression), align the distributor rotor with the #1 plug tower, hook up a timing light, turn the ignition "on", and squeeze the light's trigger while rotating the distributor housing (opposite shaft rotation). When the light flashes I know it's "in time", meaning the points are just opening and #1 plug would be firing. I then tighten the distributor hold-down bolt. And, make sure the carburetor float bowl(s) are full of fuel.

From Ted:

The tool used to prime the engine via the oil pump is the best method. An old screwdriver blade removed from the handle and inserted in your drill motor chuck works too. Years ago before these excellent tools I simply packed the bearings with grease before torquing them down, and mixed a little 2-cycle engine oil in the gas for start up. I've heard of race engines that run with no oil-just grease packed bearings. Of course, this makes a rebuild necessary after every run. But the grease method for just startup works well-it will lube the bearings long enough for the engine to start.

Question from Roger:

Well I have always wanted to overhaul a engine myself so I have pulled a good running 440 engine from my 74 parts car so I can learn how to work on a engine are there any good books or CDs on how to do this and do any of you guys have recommendation on cam etc.


From Larry:

All of the Motors, Chilton's, Haynes , etc., have a section on engine rebuilding. I found a book by Don Taylor called "How To Rebuild Big-Block Mopar Engines" to be very helpful when I did my 67 440 last fall. It is available from Summit and probably elsewhere.

From Bill:

For books, before you "buy" try your local library (including the reference section), and used book stores.

Question from Dan:

Is it cheaper to just have someone professional do the job for you (not withstanding the satisfaction you get from saying "I did it myself") or to rebuild the motor yourself?  Second, if doing the rebuild or having it done is it better to just have it done to 'factory specs' or to have it rebuilt the best way present technology (within a price range) will allow, meaning maybe upgrading the cam, pistons, etc. to get more HP/Torque out of the rebuilt engine??


From William:

The machine shop I use has flat prices for the various machining/reconditioning operation on parts, then charges an hourly rate for assembling the engine, so it wouldn't be cheaper than doing it myself. However, if you are only going to assemble the one engine and need to buy tools to do so, and wouldn't be using them again, you might be spending just as much.

I think it depends on your desired result and what you are starting with. There's been a trend for a while by the manufacturers to return to closed chamber heads and running higher compression, using the "squish" between the top of the piston and the flat part of the head to improve burning and stave off detonation. I was reading about the new motor for the "2005" Mustang in Hot Rod magazine this morning, it makes over 300 HP from 281 cubic inches, with I believe it was 10.5:1 static compression, with recommended 87 octane fuel, not even 93 octane. I think the more precise mixture management of electronic fuel injection also helps them be able to do this.

I've found that having static compression ratio in the 10.5:1 range with a somewhat warmer than stock cam makes for a sharp throttle response and quick revving engine without detonation, and try to build with that in mind. I'm not sure if I would do so for my Imperial though, as I need the low end grunt to get underway smartly. I think one principle is, the hotter the cam, the more static compression ratio the engine can tolerate without detonation. For a heavy car with a highway rear ratio and a tight stock torque converter, the cam needs to be mild, and with a mild cam, I'd say the static compression ratio needs to be no more than 10:1 to use regular gas. I'm not an engineer or a pro engine builder, this is just what I've been reading combined with some experience.

From Bob:

I rebuilt my '68 440 for my Imperial convertible. I had the machine work done at a locale engine shop were they bored it out 30 thousands and align bored it and redone the heads and put in the hardened valve seats all for $1500.00 Total money in engine is $2000.00. I saved a lot by doing the tear down and reassembly my self.

Question from David (331):

I need advice from the engine folks. My '54 Custom Imperial (331 Hemi) is running just fine...but bad symptoms are just starting to occur (original miles 90k). There is black, wet (as in water) soot coming from the exhaust pipes. And, there is oil in the radiator. My assumption: bad head gasket. Also, the car burns a bit too much oil for my taste.

So, here is the question: What is the most and least I can do in my garage on my own (without pulling the engine, and without getting a machine shop involved or a costly mechanic)?

For example: Pulling the heads should not be a problem. And therefore redoing the head gasket should not be a problem either, right? Should I have any work done on the heads with them off?

Okay, what about the engine burning too much oil? Sounds like the rings, right? What type of piston/ring work can be done on a car without pulling the engine?

What other advice do you have for me? I am being too cheap...and should pull the engine and have the thing re-bored, honed, new pistons, rings etc.?


From Kerry:

Interesting problem that leads to some questions and comments.

1- Is there visible smoke from the car? If the oil consumption is not really visible, I'd not worry about it. A quart every 500 miles is not usually visible from the tailpipe and is much cheaper than an engine rebuild.

2- Water and soot from the tailpipe is normal to an extent, i.e. condensation will form in the exhaust system and drip when the car is first run. If it's continuous while running you have a definite problem.

3- Regarding the radiator, can you see bubbles in the water? That is an indication of blown head gasket. If no bubbles and the water level is not going down, I'd not jump to the conclusion of a bad head gasket.

General comments. It is quite possible to pull the intake manifolds, heads and replace the head gaskets at home. It will take some help to lift the heads and do yourself a favor and pull the hood first. It is also possible to do a hone and re-ring job with the block in the car. Somewhat painful but I and lots of others have done it. Pull the heads, drop the pan, disconnect the rod caps and push the pistons out the top. Hone the cylinders, clean the bores well, reinsert the pistons and put in new bearings and seals. No big deal. How much you can do is dependent on what needs doing. If the ridge at the top of the bore is minor, a rering might do the trick.

If you have visible smoke at startup only, it is valve seals and guides. The seals can be replaced without pulling the heads. Another email can explain if you decide to go that route.

Ok, now for the controversial part. I do not like visible smoke even at startup, also don't like low oil pressure. My solution? 50W Valvoline non-detergent oil. In MY EXPERIENCE, multi-grade, detergent oils will cause visible smoke while single higher weight non-detergent oils will not. I've done this for 35 years. The ONLY problem I've seen is in VERY cold temperatures it is a little slower cranking.

If you determine you don't have air in the radiator, I'd put the heavier oil in it and see how it does.

From Arran:

The first thing that you need to do is perform a compression test on each cylinder. If you find a cylinder that is way bellow spec., squirt some oil down them and check the compression again. If it improves then you will have a ring job coming up, if it doesn't then you have a valve, or a gasket, problem. Of course the result is the same in any case, you still have to pull the heads. If you have oil in the radiator I would make sure that the transmission cooler isn't leaking by taking the cooler to a radiator shop and having it checked out. More then likely you just have a bad head, or intake, gasket but it's better to be safe then sorry. With regards to a ring job, you can pull the pistons out with the engine in the car but it is a pain. However if it needs reboring, and not just a honing, you will have to pull the engine anyhow. The only way to determine whether it needs a rebore and new pistons is by measuring, something that I need to do myself. I have found with my own '54 Imperial that to get at the pistons, or valves, with the engine in the car involves as much work as pulling the complete engine but without the convenience of being able to get at everything with ordinary wrenches and socket drivers. Plus if you pull the engine you can actually paint the engine block and the engine room while it is out. If you can find an old D.I.Y mechanics book like, "How To Fix Your Plymouth", or an old Motor Manual it will explain how to measure everything of interest.

From Dick:

The black, wet (as in water) soot coming from the exhaust pipe is probably entirely normal, assuming you are looking at it within a short time after startup. Water is a normal product of an internal combustion engine, and when the exhaust system is cold, it appears as a liquid dripping from the pipe, typically carrying with it some soot from the extra rich mixture used during warm-up. When the exhaust system is thoroughly hot, the water is evaporated before it reaches the outside world.

The appearance of oil in the radiator is worrisome, though. What you need to do is to have your radiator tested by a combustion gas detector. I have one and will do this for you if you want to drive down here to Temecula, or you can take it to a local radiator shop and have them test it for you. Another alternative is to buy the test kit to do this yourself. It is sold by Balkamp, amongst others, and can be bought at any NAPA store. The instruction are included, and one kit will last for years and many uses. The cost is about $50. The result will tell you if you have a blown head gasket, in which case the oil is probably from the engine. If you don't have a blown head gasket, it is probably from the transmission.

If you do NOT find combustion gases in the coolant, disconnect the transmission cooler lines and plug them off. Then drain and flush the cooling system and refill it. Then drive the car for a few days to see if the oil still occurs. (The transmission will not object to running without a cooler unless you abuse it). If the oil does not recur, buy a Hayden transmission cooler and install it, and forget the rest of the story, unless you want to have your radiator rebuilt and the incorporated cooler repaired. The Hayden does a much better job anyway, so I'd advise just going with that.

If you find there ARE combustion gases in the coolant, you need to do a compression test to find out which cylinder is leaking. There are other causes for low compression, though, so make sure that you pressurize each cylinder at TDC (for that cylinder), one by one, until you see (or hear) where the leak shows up (coolant, exhaust, intake, crankcase). You want to avoid barking up the wrong tree by fixing the wrong problem.

If you find one with low compression, and you see bubbles in the radiator or hear air escaping from the adjacent cylinder (plugs out) when you pressurize it, that's the place to start looking next, and you'll have to remove the head to see what is wrong there.

As far as the amount of oil your engine is consuming, without knowing the amount, I can only guess that it is normal for an engine with 90,000 Mi on it, perhaps 1 Qt in 500 miles? Or are you bothered by blue smoke from the tailpipe? Considering the age of your engine, if it has not previously been done, you certainly need to replace the valve stem seals (assuming the Hemi uses them, just like real engines), as they have long since turned to petrified plastic. This would account for blue smoke on deceleration and a puff or two at startup.

Unless your engine has been severely overheated in the past, I wouldn't expect your rings to be worn enough to cause serious oil consumption. If the car has a history of short trips, it would probably help to run a few oil changes of very high quality detergent oil through it, I prefer Chevron RPM Delo 400, available at Chevron distributors (not service stations) or at truck stops, in case lots, 4 gallon jugs per case. I'd use SAE30W in your car and environment (Southern California), not the multi-vis stuff that is all the rage these days. A few oil changes of this stuff (at say 1500 miles per oil change) should free up any stuck oil rings, and probably do your engine a world of good.

You can buy a lot of oil for the cost of an engine rebuild - and it smells good when it burns too!

Question from Remco (392):

It looks like I have to rebuild my 392 soon. It was in storage for 8 years before I got it, and from the beginning it was not in great condition.  The oil is very gray and there is a lot of gray mud in the oil pan. Bad news... I know.  

I have seen P.A.W cast and forged pistons... what is the difference in quality? Sometimes I see used pistons on ebay... is that worth a try?   Also when I rebuild the engine, I want to try to get some more power and probably go for hardened valve seats.  I am thinking of new pistons and rings and new bearings... is it important to also get new rods? I want a bit hotter cam also but the car must still be drivable.  Any advise??


From Thad:

On your 392 I would advise staying away from "PAW" brand items, not necessarily the store but their brand items. The quality is a little iffy. Every cam that I and my friends have bought there in the past has had problems. I have bought name brand stuff from them and have not had any problem (although sometimes had to educate the parts counter guys in the fact that it is not a Chevy or Ford!) I would like to suggest you check out a firm called Hot Heads I have found their site very informative and I feel they can help you a lot. I must say that I haven't ordered anything from them as of yet as I haven't figured out what car I will put that ol' 354 lying in the garage in yet!)

From Arran:

If it were me, and I wanted some new pistons, I would go with a set from PAW for your 392. If you get a set from E-Bay there are no guarantees of quality, with P.A.W there is a guarantee. I would also make a list of what you need and get a quote from Egge machine as well, sometimes one will have a better price on some parts as opposed to others. The main difference between cast and forged pistons is that the forged ones are somewhat tougher and less prone to detonation, or breaking up, at high engine speeds. Forged pistons are designed primarily for racing where your engine's r.p.m would regularly exceed 5000 r.p.m for prolonged periods of time, they also cost at least twice as much as cast ones. Cast pistons are what your Imperial's engine has in it right now because it was never expected to run over 4000 r.p.m let alone 5000. Just remember that these cast pistons have served your car very well for the past 40+ years so another set will likely serve it just as long. You could go with a forged set but I think that you would be throwing your money away since they aren't necessary. Before you go any further I would find out why the oil is turning gray. If the engine is going bad it should be consuming more oil not turning grey, if anything it would turn black quicker. The last time that I saw gray oil it happened to have water mixed in with it, so you better check for a bad gasket.

Question from Steve (440):

My '68 seems to have developed an appetite for pushrods... I straightened, then replaced a few, then started replacing lifters one-at-a time where pushrods kept getting bent, thinking the lifters may be sticking. This is a 44,000 mile car that sat in a barn from 1979 until almost 2000 when it came to live here.

Has anyone else been through this with a 440 that's sat a long time? I should probably just replace all the lifters, by the sound of it, but wonder if anyone else has some input?


From Dick:

It may not be the lifters; another good possibility is that the valves are sticking in the guides. To check this out, you'll need to pull the rocker shafts, then take the keepers off the valve stem to see how easily they slide in the guides. It is very common for engines that are left undriven, or driven on short trips only, for a sort of varnish to build up on the valve stems, making the valves seize up when the engine gets hot. The cure for this is to clean the stems and guides, but if you don't want to remove the heads, try soaking the valve stems with carburetor spray cleaner, then working the valves up and down a few times until the stems seem to be clean and slide easily in the guides.

If this doesn't seem likely to you, you can try running a detergent booster additive to your oil for a while to see if you can free up whatever is sticking in the lifters to make them pump up too high. The problem with bent pushrods is that this is a symptom which also tells you the valves have been driven into the piston tops, if the cause was pumped up lifters. At least in the case of the sticky guides, there is probably no damage to the valves or pistons - so hope for that!

From Joe:

Had a 383 that had ring seized last year.Add a quart of Marvel Mystery Oil to the oil and just let it idle for half an hour. I changed the oil and it's been running great ever since.The stuff is amazing!!!

From Chris:

The '70 Imperial Lebaron that I just purchased (and safely transported it 6 hours to its new home) had a similar problem from the last owner. A pushrod bent and a lifter popped out of it's bore causing oil pressure to cease in the engine. The engine was rebuilt; but, I think only the heads needed done. What I feel that cause the initial problem was the valve sticking in the valve guide causing the valve train to bind up resulting in a bent pushrod and lifter poping out. Now might be the best time in having the heads redone including hardend valve seats installed. This might be your best bet.

From Bill:

Several have mentioned the probability of a sticking valve stem causing the bent pushrods. I wanted to mention that it may be more cost effective when rebuilding heads to simply buy a reconditioned set from Aerohead in Indy. They advertise in some of the Mopar magazines a price of $499 for a pair, outright, of either big block or 360 heads, with an additional charge of $80 for adding hardened exhaust seats. Last summer I decided to rebuild the heads on my 340 Cuda and took them to the local machine shop. These are the '72 and up style 340/360 heads, not X or J. They skimmed the surfaces, installed new .500 lift valve springs, hardened exhaust seats, ground the valves (I needed 1 exhaust valve and 2 intakes), new exhaust guides, and added new umbrella seals, the total cost was nearly $800. The Aerohead deal also includes new valve springs capable of over .500 lift, and the other things named. I wouldn't have to consider shipping since I live about 50 miles from their shop, but shipping should be around $150 to the furthest reaches of
the lower 48 I would suspect, making a grand total of $730 or less. If one of your original heads has a crack anywhere, add $100 per crack for fixing them, that's what they charge in this area anyway. So it ends up looking pretty good. I haven't tried them myself yet, but I'm condering getting a set for my '65 Imperial, which really needs a valve job pretty soon. I might add the extra $100 to obtain 915 heads to retain the full compression ratio.

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