MoparFins

Techical Discussions => Tech- - Engine => Topic started by: Dan Cluley on April 29, 2008, 10:04:47 PM

Title: What heads for 318?
Post by: Dan Cluley on April 29, 2008, 10:04:47 PM
The Dart has always had some engine vibration, and I finally got around to checking the compression.

#4 is a little low, and #6 has almost none.






 
Putting compressed air into the spark plug holes indicates that the exhaust valves are leaking.
 
Talking with my mechanic friend Kenny, he should be able to fix them, but it will take a while.  He also suggested that he could probably scrounge up another set of heads pretty cheap, so I wouldn't have to have the car all torn apart till they were ready.  Problem is, he is a Ford guy, so the more info I give him, the better this will turn out.
 
A little google work has turned up the fact that I don't want the Magnum style heads.  1992 and newer, right?
 
However most of the other info I was seeing was modifications by "go-fast" guys.  I just need to know what will bolt on and work with what I've got, with minimal hassle. (http://www.moparfins.com/forum/smileys/smiley1.gif)
Title: What heads for 318?
Post by: Leaburn Patey on April 30, 2008, 02:12:33 AM
Try to find a set of 302 casting heads.
They are found in 5TH Aves and Diplomats.
They have a closed combustion chamber and are more effecient.
Still plenty hanging around and cheap.
The only mod needed is to tap and plug the smog holes under each exhaust port to fit your factory logs.
Title: What heads for 318?
Post by: Steve on April 30, 2008, 05:12:15 AM
I think you can still get rebuilts on exchange too.
 
Otherwise, what Leaburn said.  I may have a set of heads, but like your guy, it'll be a while
Title: What heads for 318?
Post by: Dan Cluley on April 30, 2008, 05:27:52 PM
Ok, so those heads should be on cars from 85-91?  
 What about truck motors, are they the same?
 
D Cluley2008-04-30 22:29:09
Title: What heads for 318?
Post by: Arlen Vander Hoff on April 30, 2008, 05:50:32 PM
As far as I know Dan the only difference in truck engines is the oil pan and the mounts on the block that bolt to the engine mounts. with the possible exception of less smog stuff on trucks because they didn't start cracking down on them till the mid to late 80's.
Title: What heads for 318?
Post by: Leaburn Patey on April 30, 2008, 06:39:44 PM
302's are 318 heads 1985 to 1991
308's are 360 1988 to 1991 and found in trucks and in telephone vans thate are 360 equipped.They have larger valves and are a direct bolt on deal.
Title: What heads for 318?
Post by: Steve on May 01, 2008, 06:35:54 AM
Doggie
 
In the LA days, the Truck 318 had larger mains.  It was a 360 main and required a different oil pan.
Title: What heads for 318?
Post by: Arlen Vander Hoff on May 01, 2008, 07:32:22 AM
Quote from: POLARACO
Doggie
 
 
Good to know!!(http://www.moparfins.com/forum/smileys/smiley20.gif) I was gonna put a 360 from a Cordoba into an 87 Dodge Pick up that was a /6 truck  and had to change the pan and the engine mounts that go between the block and the motor mounts.
Either way the heads will fit Dan's 318 right?
Title: What heads for 318?
Post by: Steve on May 01, 2008, 09:30:31 AM
If it's the same motor, it's like  a MoHome engine with extra steam ports. . .  I think.  I remember them being different in the late 70's, thinking they are the same as the late 80's.  But I could be wrong on that.
 
I thought you had a 94.
Title: What heads for 318?
Post by: Arlen Vander Hoff on May 01, 2008, 01:01:05 PM
My truck is a 98 the 87 was before that.
Title: What heads for 318?
Post by: Butch Houghton on May 07, 2008, 06:42:30 AM
302 will bolt right on, got a set here right now & used a 1/4-28 tap & set screws...took about 1/2 hour to drill & tap each & loctite the set screws in to block the AIR ports.

This is an 85 318 going in a 75 Duster,    all the other components will interchange.  The block is setup for a Roller cam but I'm running a flat-tappet ( Summit small cam ) right now so I can use the rockers & pushrods from the 75 motor.    I've got all the Roller stuff now but we'll do that later since aftermarket roller cams are pricey.

Butch


Title: What heads for 318?
Post by: Dan Cluley on July 11, 2008, 02:43:35 AM
5 hours of fun at the junkyard yesterday and I now have a set of heads.  302s from an '85 5th Avenue.
 
Now what?(http://www.moparfins.com/forum/smileys/smiley3.gif)
 
I'm assuming they should be cleaned up, and stuff checked out before I just bolt them on.  Is some or all of that stuff I can do at home, or do I need professional help (with the heads I mean.(http://www.moparfins.com/forum/smileys/smiley2.gif))
(http://www.moparfins.com/forum/attachments/22/Head_1a.JPG)
 
(http://www.moparfins.com/forum/attachments/22/Head_1b.JPG)
 
(http://www.moparfins.com/forum/attachments/22/Head_1c.JPG)
 
-----------------------------------------------------------------
 
(http://www.moparfins.com/forum/attachments/22/Head_2a.JPG)
 
(http://www.moparfins.com/forum/attachments/22/Head_2b.JPG)
 
(http://www.moparfins.com/forum/attachments/22/Head_2c.JPG)
 
Title: What heads for 318?
Post by: Arlen Vander Hoff on July 11, 2008, 10:00:56 AM
Yeah Dan,
You might want to have em "boiled" and checked for cracks at a machine shop or something. Or clean em up good yourself with some brake-kleen or some such stuff.
Being 318 heads I myself wouldn't worry too much about cracks but you never know.
 
Get yourself a valve spring tool and one of those sticks with a suction cup on the end and some of that paste with abrasives in it and go to town on the valves!!!
Title: What heads for 318?
Post by: Leaburn Patey on July 11, 2008, 12:32:42 PM
Yep...Get them hot tanked,magnafluxed and planed.
As R said,you can get the valvespring tool to do the tear-down and rebuild yourself.
 
Title: What heads for 318?
Post by: Arlen Vander Hoff on July 11, 2008, 04:54:06 PM
Yeah thats it!! Magnafluxed and hot tanked........I had a brain fart!!! Thanks Lea!!!!
Title: What heads for 318?
Post by: Dan Cluley on July 11, 2008, 05:54:18 PM
I assume the rockers and valves and stuff get dissasembled before the heads go to the shop.  Does the small stuff get tanked as well?

The odometer in the 5th ave read 37K.  The motor seemed awfully sludgy for that, but the rest of the car seemed awfully nice for it to be 137K.  The "Big Band" cassette case on the floor would seem to indicate the former owners were older folks (or Mobby has a twin here in Michigan)(http://www.moparfins.com/forum/smileys/smiley36.gif) D Cluley2008-07-11 22:55:46
Title: What heads for 318?
Post by: Leaburn Patey on July 11, 2008, 06:40:55 PM
Yes,the rocker shafts,and valvetrain gets disassembled prior to hot tanking.
You can ask the machine shop if they can,or clean them yourself to keep costs down.
Title: What heads for 318?
Post by: Stitcherbob on July 11, 2008, 07:30:31 PM
The rockers may have to be changed (a different ratio for roller cam engines I think), but they are good heads.

Title: What heads for 318?
Post by: Dan Cluley on July 12, 2008, 01:46:34 AM
Based on the part numbers I found on RockAuto, the rockers are the same for both 74 and 85.
 
However the push rods are different lengths and the exhaust manifold gaskets are different. (everything else looks to be the same)
 
Will the old pushrods work with the 302 heads?
 
Which exhaust gasket?
Title: What heads for 318?
Post by: Snotty on July 14, 2008, 10:22:07 AM
I'm jumping in here a litel late, but...
 
If you swap on a set of 360 heads, you can use a better intake like the Edelbrock Performer and use a 4bbl.  (The intake holes are too large on those to use with stock 318 heads.)  You will also have better exhaust flow.
 
However, I don't know what those would do to your compression.
Title: What heads for 318?
Post by: James Brown Jr, on July 14, 2008, 01:03:44 PM
geez dan your doing Exactally what i'll eventually do to Susan. good stuff to know.
Title: What heads for 318?
Post by: Butch Houghton on July 16, 2008, 07:40:47 AM
Dan,  the pushrods from your motor will work.   Rockers are the same for the flat-tappet & roller 318's too.   Roller motors have the roller lifters, dogbones to keep them in alignment, a "Spider" plate that keeps the dogbones in place & shorter pushrods.    Some roller blocks came with regular Hydraulic cams & it's the same valvetrain as any 318 non-Magnum.

I just built Nephews new 85 318 roller 318 & used the 302's that came with it with new Hydraulic lifters & a Summit cam & used the old 75 motors pushrods & rocker assy's.  Also used the timing cover/balancer & oil pan from the 75 motor. 

The only extra thing to do to those heads as said is to plug the A.I.R ports under the exhaust ports with allen set screws & locktite.   I used 1/4-20 set screws & just had to drill & tap.

If they're every 318 head Ive' seen with miles on it  the guides will be worn & the valve seals shot ( biggest  oil use culpirt ) .   You can get by cheap by cleaning yourself & if you can borrow/rent/buy a valvespring tool you could hand-lap the valves yourself & put on new valveseals ( I'll send ya a set if ya want ..I think I have about 3 sets of Umbrella-type seals ) .  Been there done that for a cheap fix that lasted quite a few miles.

Or...since they're a better head anyway....do like Lea said &have them cleaned & magged & have the guides checked & or replaced, new seals & a valvejob done professionally & they'll last another 100K.

Just depends on what you wanna spend.

Butch


Title: What heads for 318?
Post by: Dan Cluley on July 18, 2008, 09:46:58 PM
I appreciate the info and the offer Butch. (http://www.moparfins.com/forum/smileys/smiley1.gif)

I still haven't had a chance to call around and see what kind of money shops want for this stuff.  We actually had a couple of nice days in a row, so I've been painting.
Title: What heads for 318?
Post by: Arlen Vander Hoff on July 19, 2008, 02:06:46 PM
Yeah "hand lap" thats the other thing I couldn't think of Thats what you do with the suction cup on a stick and the abrasive paste. I know what I mean if anyone understands me then that would be scary!!!