is this a bad idea?
 

Hey i got a 1967 dodge D200 crew converted into a 4x4 powerwagon. the the engine that came in the truck when i got it is a 1971 360 - mostly stock except for a edelbrock intake, 750 edelbrock carb, and some headers. since i cant really afford to rebuild my engine - and someone in my area is selling a pair of fresh J heads this is what he had to say about them:

"1972 Dodge 360 / 340 ci J Heads. Custom built by a local shop. 2.02 / 1.60 valves, new guides, seats, seals, springs. Never mounted. Kept in oiled plastic. Sold the motor they were going on, no use for them now."

now my motor isnt exactly tip-top but it’s running pretty decent and i havent had any major problems yet, and all the cylinders have decent compression except for 90% compression on cylinder number 8.

would would happen if i pulled my old heads off - cleaned the block surface up a little bit - and then put those new heads back on along with new head and intake gaskets? and then ran the truck like that?

and yeah as for putting my bottom end at risk - thats why this new head idea is more of a crazy pipedream of mine - because if i turn it into a reality i have a tendency to get a lead foot and i dont wanna do any serious damage to my engine. i know i should just do it right and wait until i get the money to afford the rebuild kit from summit or RPM machine or wherever the hell i get it and start rebuilding my engine so i can actually start smashing it around and the only think ill have to worry about is breaking simple stuff like U-joints and yokes. but then again - if i can be a cheapstake and my bottom is good enough to handle the freshened heads and the occasional pedal to the floor 0-5000 rpm shifting through the gears then i might try it out...

360s are a pretty tough motor. If you do deside to go and do it, then when the heads are off, take a look down into cylinder #8 and see what the cylinder walls look like. It could be a ring that is causing low compression or the head (gasket, valves, etc.). I say do it, but in the end, it's your vehicle and your choice.

Welcome to the forum.

welcome to the site. yes, definitly do the heads, itll wake the 360 up. like 78 says, check that cyl. if theres no ridge, and the walls arent scraped up from a bad ring, then just cap it and run with them.

Like they said, tear down the top end, inspect ALL THE CYLINDERS, put on the new heads and let 'er rip! As long as there is no lower end knocking now I don't think you'll have much of a problem. Your compression loss in #8 could be thru a valve that is not seating properly or another issue with the existing head. Have at it!

aye thanks for the welcome.

the guys on the myspace mopar forum recommended against since im putting "new" heads on a motor thats seen a lot of miles. basically because of the pressure put in the rotating mass because of the increased compression and tighter sealing caused by the new heads. and that i risk the chance of blow-by if i do anything buy baby the motor - but then again the 3 guys in that group who really know everything mopar havent posted yet, but what i got so far seems logical.

if i decide to do this - and i pull my heads off and it turns out that cylinder 8's low compression wasnt caused by a valve - but indeed the rings what would you recommend then?

and now im gonna ask a very dumb question: is it possible to re-ring a piston without taking the engine outta the truck? i assume i wouldn't be able to pull the crank out without pulling the whole engine - but would i be able to drop the oil pan, undo the connecting rod bolts, pull out the connecting rod, and then pull the piston out and re ring it and then put it all back together?

Do you have the space to pull the pan out? If so I would think you have enough room to do that.

welcome to the forums stickshifted :D as everyone says go ahead and do it and check it all out , if nothing else you can always put the old set back on with new H gaskets but ill bet that motor is still good to go with a new frech set of heads, you have to have a pretty high milage engine that wasn't taken care of to hurt a 360, ive redone heads on one of my 340s with 260,000 miles on her and it never missed a beat and them 360s are built just as strong but if you decide to go ahead and do it make sure you put some good oil in her like the valvoline vr1 or the high milage valvoline oil with alot of zinc in it and i would reccomend using some lucas HD oil stabilixer also and you will be good to go for some more extreem milage :)

yeah - ive been using greased lightning in my oil because of all the PTFE (teflon) it has in it. my dad apparently has tried every fuel additive/oil additive he could find - and claims that greased lighting works the best.

idk - what is the lucas supposed to do? i never understood "stabilizers" and what weight of oil would u guys reccomend? - ive been using castrol and vavoline 10-30 oils so far.

and yeah next time i go outside ill look at my oil pan to confirm that i have the clearance to pull my pistons out and re-ring them without having to take the engine outta the truck.

The stabilizers help prevent the fuel from breaking down which it does a lot faster with the ethanol in it today.

i would think that you might just have a sticky valve that might be giving you a problem in only one cylinder so id just change out the heads if your still wanting to and make sure you do a visual in all the cylinders like all are saying and maybe run some engine clean in the oil (oil supplement) and run before an oil change and see if there is any differance with the compression before you start tearing it apart , it could just also be a sticky ring which the cleaner will help free up, but ill let you make the call :D

p.s C means the oil from breaking down so quickly :D

Yes, thanks, I was thinking about Stabil and the fuel stabilizers, and not Lucas which he was talking about.

Hey C its all good :D and the lucas oil is a oil stabilizer which has no sulphur or chlorine and no teflon in it that im one that doesn't really like the teflon and it helps eliminate dry starts and it helps seal the worn cylinders and it helps stop the thermal break down of the oil

Myspace morpar guys. phst, a lot of people on there give bad advice, thats why I don't waste my time with them. What is the worse that can happen with a fresh set of rebuilt heads? Better flow? Better throttle responce? the fact that you now have some more power? Yeah, those all sound like bad reasons to me. :rolleyes:

Do the swap and you will be in love, trust us, the people that live, eat, sleep, breathe and poop mopars!

As far removing the piston in the motor...... It can be done but take a lot. You may be able to rotate the crank enough to squeeze it by. If not then you will need to pull the motor. It is just too much hard work to pull the crank in the vehicle.

AGREE 78 and for the piston i think he just wants to pull just that one but if it were mine i would just look at it then go from there but im still for using cleaner first if thats the case but im sure its not ,,, it needs the heads changed and a good OIL and run the crap out of it :D

lol yeah i know that the majority of people on the myspace groups dont know much more about mopars than i do. however there are at least 3 guys on there who answer nearly every post who truely are "the people that live, eat, sleep, breathe and poop mopars!"

however those guys didnt respond to my post that time...

and lol im considering re-ringing all 8 of my pistons that way - if and when i do that - what should i use to clean the pistons with? WD-40? brake parts cleaner? both? and after i put the new rings on them can i just coat them with 10w-30 oil and pop em back in? and then just look up the torque specs for the connecting rods?

im trying to do this as cheap and effectively as possible. if i had to take out my whole motor - i tell myself i just might as well rebuild the damn thing.

and yeah ill make sure to get a nice valvoline oil with a shit ton of zinc.

I wouldn't use WD-40. The WD stands for water diluted. Clean up the pistons with kerosine (I think I murdered the spelling on that one) and use plenty of oil when putting it all back together. If you plan on re-ringing the pistons, then you are going to want to install all new bearings. If you are going that far, then pull the motor and make it easier on yourself. Pull the cam shaft out as well and install new cam bearings and a mild purple shaft cam. You will be very happy with it then. Plenty of power, strong and realiable. You just have to make use that you break in the motor properly. If the stock cam looks good, I would even just throw it back in to same yourself some money.

I agree with 78, by building up or fixing certain things you are going to expose your weak points, and you can avoid it by looking at those bearings, cam, and crank. If you are going to do all of them I would recommend pulling the engine and putting it on a stand so you can rotate it over.

It makes it much easier to work on, take measurements and torque everything to spec. Plus you can paint it while you have it out.

yeah i still dont know what i want to do with it. the other day i fired it up and drove it around for a few hours and it was running pretty good. it does make a lot of smoke on a cold start up - but once its warmed up it runs good.

and i just replaced my spark plugs 2 days ago. what should the gap for the plugs be? kragen told me it was .035 so i made sure all the plugs i got were at that gap - but the plugs that i pulled outta the truck we're all .032 gap.

which one should it be? and whats your guy's take on NGK plugs?

I would only put in Champion plugs in a mopar motor, especially the LA SB and BB. Run the gap at .035, thats what it should be. No higher than about .045 though if you have some ignition upgrades.

What color is the smoke?

i only run champion plugs either
i have the gap at .35

well when i first fire it up - it starts idling at 1000-1100 RPM theres no smoke except a hint of black smoke comming out. then now after like a minute while its still on fast idle at like like 1500 now, the smoke is greyish-white. then when i see the temp gauge going up i hit the gas pedal to bing it back down to 700 rpm idle and the smoke is a wispy grey.

and yeah as far as ignition goes i have electronic ignition and i think its the mopar performance one. as for the plugs whats the deal with plug gaps - what do different size gaps to - for performance vs economy or spark size or what? i dont know enough about this...

and say what should my engine temp be when im driving? the needle usually stays at around 190 degrees. is this right or should i get a 180 degree theromostat?

and since these new plugs have a bigger gap should i ajust my air/fuel mix and timing again? right now my timing is at 11-12 BTDC and when i took out the plugs they were all a light brown color - but they may have been a little bit on the lean side...

so should i be worried about this grey smoke or is that just the way it is in wintertime?

Your plug gap should be at .035 gap. Having the gap open more will create a larger spark to burn more of the fuel/air. It sounds like your plugs are good.

As for the black smoke, hat could be too much fuel at the beginning or carbon build up. How many times are you pumping the gas before you fire it up? You should be doing it only aout 2-3 times.

As for the grayish-white smoke, I'd be willing to bet that you have a coolant leak somewhere. Either a head gasket or a head.

The 190* thermostat is good for that motor. I wouldn't change it unless you do some big upgrades (cam, alum heads, pistons, boring, etc).

I wouldn't change your timing just yet. Even if you have a larger size gap plug, you shouldn't have to change your timing.