318 rebuild suggestions

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69barracudavert

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I went ahead and picked up a used 318 since I am missing numerous pieces to my original 318. It is a 74/75 year block with stock heads #3769973 1.78/1.50 I Do not know if the springs and cam have been changed, it is possible that they have. From looking at the motor it has been rebuilt, but do not know how long ago. It has an Edelbrock Streetmaster intake and needs an alternator and carburetor.

I was thinking of dropping it in and hoping for the best. But since I have some work to do on the car and drive train I may do a simple rebuild before throwing it in. If I go that route I wanted to know what would be a good intake, cam, springs, lifter, push rods, rockers,timing chain, distributor, etc.

I would most likely leave the lower half (pistons and crankshaft alone, unless that is unwise). I think I would go with a Holly 600 4brl carb unless that is no good (I do not know anything about carburetors, this is my first one, always been fuel injected). A little further down the way I would like to add headers what recommendations would you all say.

This is going into a 1969 Barracuda with the 904 and small rear end. My overall goals at this time with this motor is to have more power than stock but I do not need any crazy horse power. This car will not be raced, just cruised around.
 
If you build it, just act like it's a 340. Same cam, raise the compression, ditch that POS intake and hang some Summit headers off it. It'll haul ***.
 
If you want to run the larger port 340/360 heads, consider putting in a set of 10.5 318 pistons, with the larger combustion chamber in the 340/360m heads you will end up at 9.2 compression...

Mancini racing has great deals on refresh kits. Kit A has cast iron rings for $200, kit B has moly rings for $5 more, kit C comes with cast pistons and many other goodies...

http://www.manciniracing.com/enrebkit.html
 
I will definitely get the rebuild refresher kit, Thanks KrazyKuda.

As far as the Cam goes I have seen recommendations for nothing higher than a 268 duration. RustyRatRod, you mention a 340 cam, do you know the specs on that or should I look for something else?

I plan on trying to do most of this myself with limited machine shop use to save on some money. I may have to have the crank shaft smoothed, but I will check when I pull the pan. I will clean the heads myself and have been researching porting but that seems to be very complicated to me right now.

Any recommendations on lifters or springs? What about a timing chain; would any brand I pick up out of summit work on these?


As you all have stated and from what I have been reading, compression is very important. Any simple home mechanic ways to raise compression on this 318? For right now I want to keep the heads I have, if I find a cheap set of 360s I don't mind throwing them on. If I change out pistons (such as the mention 10.5), do I need to balance the block?

Thanks!
 
if originality is important you might want to use the orig block.To minimize down time you might (if you used the other short block for piston/bore good fit) rering it with a file fit plasma moly ring set (rings/bearings/gaskets) and a good 3 way timing chain set. any dual plane intake you can find at a good price. an eddy 1406 (elec choke/600 cfm) with a strip kit for it. dial in the dist subsystems spot on in order. a pair of the big outlet magnum ex manifolds (2&5/16" outlets) which'll run you $100 likely. 2&1/2 ex pipes with mandrel bends. high comp 318 pistons ain't cheap. hog out the heads yourself. I know summer is almost over but too much down time is a common mistake & if you get up & running ASAP you can start thinking (& saving) for that 360 or 360 stroked! and be out cruisin! EDIT the piston/ring weight difference will determine if need to balance & I'd just get a cheap Summitt stock cam
 
69barracudavert said:
I will definitely get the rebuild refresher kit, Thanks KrazyKuda.

As far as the Cam goes I have seen recommendations for nothing higher than a 268 duration. RustyRatRod, you mention a 340 cam, do you know the specs on that or should I look for something else?
Click to expand...

The stock 340 cam shaft specs can be looked up and what you will find is a very mello cam. The XE268 has an increased duration making it bigger. The "Performance" replacement 340 cam is bigger than the 268 cam by about the same amount as the 268 cam is over stock.
Read it like this;
XE268 = 1 step bigger than stock, can use a stock converter
340 performance cam = 2 steps bigger than stock, should use a 2000/2200 stall converter

I plan on trying to do most of this myself with limited machine shop use to save on some money. I may have to have the crank shaft smoothed, but I will check when I pull the pan. I will clean the heads myself and have been researching porting but that seems to be very complicated to me right now.
Click to expand...
Skip porting. Let a good shop handle it for you since a good job also includes (or should!) new valves (or at the very least regrinding the valve seats) guides and etc.... Hardware all new for the heads even before any porting is done. A bowl porting and a gasket match with pushrod clearance made larger is a lot of work and more than you need for a long time.

Any recommendations on lifters or springs? What about a timing chain; would any brand I pick up out of summit work on these?
Click to expand...
The cam should be purchased with springs & lifters as a set. A Summit double roller chain is a nice unit. Check out the Comp a a web site as they have listings for full kits to do the job. Call them before you order anything after you talk to your machinist on what exactly is being done.
As you all have stated and from what I have been reading, compression is very important. Any simple home mechanic ways to raise compression on this 318? For right now I want to keep the heads I have, if I find a cheap set of 360s I don't mind throwing them on. If I change out pistons (such as the mention 10.5), do I need to balance the block?
Click to expand...

It is not the block that gets balanced but the rotating assembly that gets balanced and it must be done if you do anything to the crank rods pistons and rings. There is no home mechanic way to raise compression. If the engine is stock. What you will need to do is do a piston replacement (like the above mention) and/or mill the heads.

IMO, the best way to go about this is a piston replacement and 360 heads. Compression is good but not as important as you may think. For a street car, the max for a ratio I would recommend to run without problems of octane requirements or other issues is 9.5-1 iron head, +1 point for aluminum heads. And that my friend is pushing it with a small cam.
 
69barracudavert said:
RustyRatRod, you mention a 340 cam, do you know the specs on that
Click to expand...


Stock 340 "auto" cam is:

268/276 duration
.429"/.444" lift
44° overlap


The comp xe 268 is a good recommendation that is comparable...
 
krazykuda said:
Stock 340 "auto" cam is:

268/276 duration
.429"/.444" lift
44° overlap


The comp xe 268 is a good recommendation that is comparable...
Click to expand...

Karl, the OE cam has a intake duration of something like 210? (Or less) I can not remember off hand.
The 268 has a intake duration of 214 IIRC
The MP replacement 340 cam has a intake duration of 222 or 228 or so.

The advertised numbers are miss leading vs. the duration @ .050.
 
rumblefish360 said:
Karl, the OE cam has a intake duration of something like 210? (Or less) I can not remember off hand.
The 268 has a intake duration of 214 IIRC
The MP replacement 340 cam has a intake duration of 222 or 228 or so.

The advertised numbers are miss leading vs. the duration @ .050.
Click to expand...

Yes, it's hard to do a good comparison of the numbers from manufacturer to manufacturer as they also measure their cams a little different.

Mopar didn't use duration @ .050 until the 90's or so, so it's hard to find a comparable .050 number for the old stock camshafts.

that's why I'm going to degree all the cams that I have, so I can compare them apples to apples because I will measure them the same...


I was just giving him the book specs for the stock 340 cam like he asked...
 
Don't forget... Treblig
 

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OH! My bad Karl. Sorry about that.
Kudos Treblig, love that hole drilled in there. I never thought about that.
 
From looking at the comp site

I should be looking at cam:

20-223-3 Xtreme Energy, XE268H, Great for Street Machines.

Also looking at the cam kit K20-223-3
 
Before buying a cam I would pull the heads off and measure how far down in the hole the pistons are and CC the head. Then calculate your compression ratio. Mr Gasket has a SB .028 compressed head gasket that will help compression a little. What rear gear do you have? Stock converter? Low compression and to much cam equals turd.
 
The 268 is too big for a 318 of this nature.
 
^^ What he said.
..And compression would be the number one thing on my to-do list.

I've put 340 top-ends&cams on/in LC teeners a couple of times, turning them into off-the-line slugs, that had great passing-gear power at hi-way speeds. Not my idea of fun. The band-aid fixes for that are gears and hi-stalls(mo money, and less fuel-economy).
Bin there/done that,............ never again.
 
Ok so first thing I will pull the heads. Are there good youtube videos on how to check for cc. I have never compression checked before.

For measuring the gap. I just turn the crank until the piston is at its highest point correct.

I am defiantly a little confused. What cam should I be looking for. Or don't know until a cc is done.

Thanks
 
69barracudavert said:
Ok so first thing I will pull the heads. Are there good youtube videos on how to check for cc. I have never compression checked before.

For measuring the gap. I just turn the crank until the piston is at its highest point correct.

I am defiantly a little confused. What cam should I be looking for. Or don't know until a cc is done.

Thanks
Click to expand...

Gotta learn somewhere...
Article on c.c. ing cyl.heads...https://www.google.com/url?sa=t&sou...3N0D6Zwcx9PWT5cJw&sig2=v-CeqmsIxH-Mwg2jacB-Vg
I would wait on cam choice,until you figure out what you want to do ( cylinder head/and compression wise). Makes it easier,in the long run.
 
Hey guys:

I'm in the same boat as 69barracuda, in that I have a 318 and looking for a cam. I'm reading all this and I wondering is there a way to tell what your compression ratio is by doing a compression test? I'm really not planing to take the heads off mine unless absolutely nessasary.

Jon
 
prostreeter9 said:
Hey guys:

I'm in the same boat as 69barracuda, in that I have a 318 and looking for a cam. I'm reading all this and I wondering is there a way to tell what your compression ratio is by doing a compression test? I'm really not planing to take the heads off mine unless absolutely nessasary.

Jon
Click to expand...


Not with any accuracy.

Too many factors influence compression pressure. Pistons, heads, head gaskets, cam grind, cam timing, engine wear.

A factory stock 318 with wear should test 100 to 120 if in good shape, but I've seen worn cylinders and valves bring it down under 100.

Who's to say that it doesn't have high compression and very worn cylinders...


The best way to accurately tell will require taking off the head, but we can get you very close to your actual compression for your engine if you follow this thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=278215


And definitely replace the stock 318 timing chain with a good double roller one...
 
I recommended a cam already. Use the 340 cam......OR you can use a more modern grind that's close.
 
69barracudavert said:
Ok so first thing I will pull the heads. Are there good youtube videos on how to check for cc. I have never compression checked before.

For measuring the gap. I just turn the crank until the piston is at its highest point correct.

I am defiantly a little confused. What cam should I be looking for. Or don't know until a cc is done.

Thanks
Click to expand...


This isn't a video, but I think it will show you how to do it yourself cheaply and accurately.

http://www.forabodiesonly.com/mopar/showthread.php?t=278215
 
Ok

I have been looking at the service shop manual and it is referencing tools needed to change out the main bearings. Is this tool needed or is there an equivalent?

It also talks about changing the camshaft bearings is this nessessary? Again will need a tool for that.

On the bearing kit it asks for size, where will I be looking on the original parts to find that information one I have the engine opened up.

So I guess I need to know what tools I will need to rebuild the engine other than the standard tools. So that I can change bearings and rings.

Thanks
 
69barracudavert said:
From looking at the comp site

I should be looking at cam:

20-223-3 Xtreme Energy, XE268H, Great for Street Machines.

Also looking at the cam kit K20-223-3
Click to expand...

You said "just a cruiser", I'm with RRR on the cam is too much for what you want. With that cam, in order to get any enjoyment at all out of it, you will have to change out the gearing in the diff. at a minimum. I run the 268 and I had to go to 3.55's just to make it run better.

I did use it, with an intake, a 600 Summit street/strip carb and headers, and it runs real good for what it is. I never touched the bottom end, as I'm in the process of building a new engine, and knew I would be when I did this.
 
If the engine is on the stand, you can get a pretty good idea of the Static C/R by pouring and measuring oil into a cylinder. The piston has to be at TDC compression-stroke and the engine has to be rolled onto its side to put the plug-hole to be at the high point of the chamber.
I use a 100cc medical syringe. I inject oil in until its flush with the bottom of the hole.Then I move the piston back and forth a little to prove its was at TDC. Then simple math tells me how much oil went in.
With that number and the swept volume, its easy to calculate the Static C/R.
The catch is if its been overbored. That can throw a monkey wrench into the calculation.
But on a teener its a minor error amounting to about .12point;going from 3.91 to 3.95bore.
Also if the valves are leaking there will be another error. So I do a leakdown first and pick the best cylinder.

Heres an example;
The swept volume on a stock-bore teener is about 39.74cid x 2.54 cubed = about 651cc.If you are able to pour 95cc into that chamber, this is what it looks like;

(651 + 95) / 95 = 7.85 Sc/r........................This is typical with pistons .150 down; But if you can only fit 70cc in there, then;

(651 + 70) / 70 = 10.3 Sc/r........................This is possible with Zero decks and closed chambers

I highly recommend that you not put a performance cam in an engine with a c/r in the basement at 7.85 . A cam with a 60* intake closing angle( the Xe268), will net you a Dcr of 6.4. This engine even with a good leakdown, will be really soft off the line. Reeeeeeeeally soft.
With a 40* angle, the Dcr comes up to 7.2. This is about stock. So you can see that the hi-perf. cam is nearly a full point lower, and therefore at lower rpms (I'd guess below 3600)may actually have quite a bit less performance than the 2bbl cam.
And where is most of your driving done? You guessed it...........
On the otherhand, the 10.3 engine and the 60* ICA will be around a Dcr of 8.44. With iron heads,this will probably need premium gas under full load, but will be very peppy, right off idle. You can keep your 3.23s(maybe 2.94s even), and stock TC.
With 2.76s you might wish to loosen the TC some. Time will tell.
 
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