basic rebuild ... possible?

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MoparFan

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Hi,

I have a 360 that I was planning a complete rebuild, but now family plans have change and I won't be able to afford it for now.
So I was wondering if I could do like a basic basic rebuild of the 360. I was thinking maybe I can change the pistons rings, new sets of gaskets, new water pump.
I am asking that because the 318 that is in my Dart rigth now does not even have 100 psi (warm engine) on any cylinders :sad:
I was able to check the 360 before I got it out of the car, and the compression (cold engine) was between 105 and 130 on 7 cylinders and 70 or 80 on one cylinder. The compression was stable on the gage, so no leaks by the valves I guess.

So is it possible that the rings are tired and that I could change them without having the cylinder honed and bored. I want to cleaned the heads, the valves and maybe a little porting (gasket match). Keep the same cam if possible. I want to use the Holley 1850 (that I already have), and try to exchange my Holley Street Dominator intake for a good dual plane intake (thinking about the Performer), and a set of cheap headers.

Tell me if I am thinking of something absolutely ridiculus, or will it be at least a not so bad running engine until I get the money to really rebuild it. Because rigth now the 318, is one of the main reason why I don't use the car.

Thanks
 
You never know what an engine is like until you get it torn apart and see how it is inside. I had a 74 360 that ran decent and the compression was a little highr than what you said yours checks at and was hoping to do what you want. When I took the heads off I was astounded to see the massive ring ridge. It needed bored .040 to clean it up. The pistons were completely worn out. New rings would have been a waste. You'll just have to tear into it and see what it looks like. Hopefully you get luckier than I did.

BTW: If you do eventually use that 360 in your car don't forget to either change the torque converter to a 360 weighted converter or weld on the 360 weight package onto your converter or you'll throw it off balance.
 
Any time you change out rings, you must hone the cylinders! The cross hatching from honing helps keep oil on the cylinder walls to lube the skirts and rings. If all you want is a super cheap rebuild and have no racing in mind, you can buy a ball hone from NAPA and hone it yourself on the engine stand, using copiuos amounts of WD40 to lube the hone. If you go this route, be sure to strive for a 40 to 45 degree cross hatch.

All this assumes that the piston skirts are not trashed, and you don't have a nasty ridge in the top of the cylinder. The only way to know if you can go this route is to tear the engine down and inspect for bore taper and skirt to cylinder clearance.

You should replace all bearings too and check the clearances with plastigauge. Replace the oil pump with a NAPA standard volume pump and don't forget to clean out the pump pickup! You'll be amazed at the crap stuck in the screen.

As far as what the heads might need is a shot in the dark without inspecting it. If the guides aren't bad and the heads aren't cracked, you can de-carbon the head and valves and lap the valves in. Don't forget new stem seals.

Inspect your cam. You will most defintely need a new timing chain. If your original cam looks good (which I seriously doubt), you can get a cheap double roller from Summit.

You should be able to pull this kind of rebuild off for well under $600 (I didn't check prices on everything so don't shoot the messenger!) Assuming you don't need valve guides and valve job (which you probably do), won't need a bore and hone (which you might), and that your crank and rods are re-useable without machining. You might get 20,000+ miles with this kind of rebuild and I've seen them go longer with quality oil and maintenance, but there is no substitute for doing it right the first time. Fishy is right about the torque converter. The 318 is internally balanced and the 360 is externally balanced. The 360 will require a 360 style harmonic balancer and torque converter.

Good luck! :)
 
ok, thanks guys , so next step I will remove the pistons and looks at the cylinders walls ... btw, it is a 1978 360.
One question (newbie question), what/where is the skirt?
cylinder.jpg

piston.jpg

emgine.jpg


Is there a way I can see if the camshaft is good or not?
camshaft.jpg


About the converter, I have the transmission that was attached to the engine but it is a 727 (the 727 is no good rigth now, she is slipping). Will the converter fit my 904?

Thanks ... btw, I am aware that this is far from the best way of doing things, but I want to look at all the options I have before leaving, for a while, the 318 in the car, and the 360 on the stand.
 
You won't be able to see the skirts until you pull the pistons out. They are 90 from the piston pins. To make a long story short, the skirt is the side of the piston that rides on the cylinder wall. Take a fine piece of sandpaper and remove the carbon at the top of the cylinder. See if you can catch a fingernail on the ridge. If you can't or just barely can, you can get away with a hone job. Don't expect a lot from this engine when your done though.

Your cam looks OK from what I can see. Check the top of every lobe and see if there is pitting or galling.

Is that rust in the intake ports? You should replace your pushrods, they are truly nasty looking. Stock ones are pretty cheap.
 
Can you do a cheapie rebuild - well it depends on the condition of the pistons, and the block.

For the coverter issue use a counter weighted flex plate - I think B&M or one of the other trans outfits sells them, then you can use the 904 as is.

To check the cam, pull the lifters out one at time and look at the bottom surface that rides on the cam itself. If you see a circular wear pattern then its good. If you see a straight line running across the wear surface its going bad. This tells you whether the lifters are spinning as they are intended. Keep the lifters in order as you remove them, if you intend to reuse the cam and lifter as a set. The lifters can be dis-assembled and cleaned.

The critical thing to check on your pistons are the bore sizes, if they are less than .010" greater than the specified bore size, in this case 4.000 or 4.010" max. Then you'll be okay rebuilding the motor with those pistons. Another item to check are the ring lands, the fit of the rings in the piston grooves, check this with a feeler guage, they are supposed to be about .003" or less clearance, check them with the old rings before removing the rings themselves.

Obviously the less wiggle you have in the bores and the tighter the ring lands are the better off you'll be. Be sure to put new cam main and rod bearings in the block along with new freeze plugs, timing chain, and oil pump. Ive also honed a block myself using a three arm hone with a variable speed cordless drill succesfully. You can save a little money that way if you are willing to try it. be sure to use the correct grit stones for the type ring you end up using.

While disassembling the engine check the bearing clearances with plastic guage. This will give you an indication of the wear on the crank. Once apart you can polish the journals yourself using a very long leather shoe string and 600 emery paper, wrap a piece of paper around the journal and then wrap one full revolution of the leather shoe string around the paper, pull the loose ends back and forth thereby moving the paper back and forth around the journals. If the journals are gouged up badly all bets are off.

On the heads you'll have to check them out. You can do a backyard mechanic test by putting the spark plugs back in and flipping them over with the combustion chambers facing up. One at a time fill the combustion chambers with gasoline and watch to see how long it takes for the gas to leak past the valve seats. If it takes more than 1-2 minutes and very little leakage then the seats are okay. If it leaks then you can tell which valve because it will leak back either on the intake or exh port. personally I'd have a low buck valve job done, knurl the guides and have the valves reground. Its really hard to do a valve job without a hot tank and the proper equipment.

Have at it and let us know what you end up with.
 
I think somedepends on what you call a rebuild. If you have a running engine, but a hole with low compression, take it apart and see why. If you cant see a score or scratch on the cylinder wall, and the valves look ok, then it's more than likely the rings. So what do you do next? Well, if you're me, my cheapest "rebuild" would include haveing the block boiled, all the oil passages cleaned out, and new hardware and cam bearings. I would pay a shop to properly hone the bores and plateau hone it. I would buy a crank kit for it. It's a cheap way to get good journals and bearings. The last 360 i looked into was $175. It costs me $250 to have a crank turned and polished, and I still have to get the bearings..So it makes sense. I dont install new bearings on used journals. I have had too many problems trying, so I dont bother anymore. clean the pistons and rods, and use a soft wire wheel on a bench grinder to clean the pistons, being very careful to not go "against the grain" or against the machinine directions on the sides of the pistons. Clean out the ring grooves with a broken off 1/2 of a used ring. You want to clean out all the carbon..not scrape off piston material. Clean them well, and then consider them done. I would use file-to-fit rings, but I hanve a ring filer. SO just use regular replacement pregapped rings and pay attention to how you install them. Those notches on the tops of the pistons face the front of the enigne block..It's important to keep them facing the right way. Carefully reassemble is making sure to check and record the oil clearances for each main journal and rod journal. I would replace the cam and lifters, the timing set,and the oil pump and pickup screen. For the heads, have them hot tanked, and replces the valve seal and springs to match the new cam. The pushrods will look brand new after being hit with some degreaser. Put the heads back on, and carefully break in the new cam using the right procedure and oil plus additives. You should be able to get out of the whole deal under $1200 with the new parts, andit will be a safe running strong engine for a while. Not as good as brand new. But very stable to beat on for a while.
 
hi moparfan,
i have used this company many times- good service,
price and parts

northern auto parts- 1-800-831-0884

www.northernautoparts.com

order thier catalog

all thier rebuild kit are upgradable
they also have hp kits

for a cheap rebuild if the engine was running fine ie:
no knoxs, cylinder scrathes, cracks, crank is ok
ridge ream if nessasary
deglaze the cylinder bores
clean the block well
rering with cast iron rings
new bearings
new oil pump
i always use a new cam & lifters
new timing set
regrind valve seats
guides if nessassary
replace springs- a must
these motors usually cost less than $400.00
to refresh and run very well
carburation, distributor, exhaust still must be addressed
i've refreshed many engines like this

good luck
longarm
 
Well thanks a lot for all the infos again. Four pistons are now out of the block, and I have check the most thing I could until now. One of the four cylinder as little notch at top that you can feel the the finger nail. The 3 others seems much better. I also started with cylinder #3, this one was reading 70-80 psi, turns out that the 2 rings are stuck close tight. Not the 3 other cylinder.

So I took some info at a good reputation machine shop in my area, and will start with having the block acid wash (migth be something else!!!), and having them check the whole block (if it need machining for the cylinder, crank and cam).

66dartgt said:
To check the cam, pull the lifters out one at time and look at the bottom surface that rides on the cam itself. If you see a circular wear pattern then its good. If you see a straight line running across the wear surface its going bad. This tells you whether the lifters are spinning as they are intended. Keep the lifters in order as you remove them, if you intend to reuse the cam and lifter as a set. The lifters can be dis-assembled and cleaned.
Click to expand...
When you talk circular wear ... my guess it is what it should look like. The lifter in my 360 are all like this one.
lifter.jpg


Last question .... any idea of what could create that red color on the rod...I scratched it with a knife, it is no paint ... and the magnet really stick to the rod.
engine1.jpg


lifter.jpg


engine1.jpg
 
The lifter looks fine - make sure all of them have a similar circular wear pattern. The red stuff is called varnish, nothing to be concerned with, just clean them up. If you found the bad cylinder had two stuck rings then thats probably all that was wrong with that cylinder, but go ahead and tear the thing down measuring everything you can as you go, record all the measurements for reference later.
 
Moparfan! I forgot to mention that if you plan on keeping the original cam, the original lifters must be put back in the same lifter bore they were removed from! Did you keep the lifters in order? If not, you can use new lifters with an old cam, but not old lifters with a new cam.
 
I've had a couple 318s with those rods. What they did was when a rod checked out as "too big" on the end(or ends), the factory would copper plate them. It's a very thin layer that built the surfaces back up, then the rod was re-machined and put into service. It's not a big deal at all. But it's copper plating.
 
66dartgt said:
The lifter looks fine - make sure all of them have a similar circular wear pattern.
Click to expand...

That lifter is NOT OK! It is completely worn out. You can tell the cam is worn, too because of the shiny wear stripe that goes all the way to the edge.

Trust me, I was an ASE certified machinist for over 10 years. That cam & lifters belongs in the scrap barrel.

Lee
1966 Barrcuda, 340 4 speed
 
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