How would you rebuild this 318?

-

69cudaownr

FABO Gold Member
FABO Gold Member
Joined
Aug 21, 2008
Messages
394
Reaction score
308
Location
Waterloo, Ontario, Canada
I have a knock in my 318. Its definitely a lower end knock. My guess is a connecting rod. This is what I have;
Bored .020 over
stock pistons, rods, crank
Compression ranged from 138 - 143 when I last checked it
Comp cam XE262 262/270 duration, 462/470 lift
302 casting heads milled to 58 cc with 1.88 intake
Edelbrock Performer intake
Edelbrock carburator 1406 (600)
Headers
833 4 speed
3:23 sure grip
275/40R17 tires

This is in a street car with no intensions of racing but, like most people, I enjoy the feel of a car taking off when you hit the gas. I would describe myself as "good" with engine understanding but far from excellent. My questions;

Would I bore it to .030 and change the pistons?
Is the cam good or should I reconsider?
Should I change the heads to a 2.02 intake?
Does the knock mean I need a new crank and rods if I'm right on my assessment?
If yes to a new crank, do I consider a stroker kit and would my existing top end work with a stroker? Or is that just a whole new bag of bolts.

Thanks for your input.
 
I have a knock in my 318. Its definitely a lower end knock. My guess is a connecting rod. This is what I have;
Bored .020 over
stock pistons, rods, crank
Compression ranged from 138 - 143 when I last checked it
Comp cam XE262 262/270 duration, 462/470 lift
302 casting heads milled to 58 cc with 1.88 intake
Edelbrock Performer intake
Edelbrock carburator 1406 (600)
Headers
833 4 speed
3:23 sure grip
275/40R17 tires

This is in a street car with no intensions of racing but, like most people, I enjoy the feel of a car taking off when you hit the gas. I would describe myself as "good" with engine understanding but far from excellent. My questions;

Would I bore it to .030 and change the pistons?
Let the machinist decide if it needs it or not. The conditions of the cylinder will be determined then. The machinist will probably opt for a .030.
Is the cam good or should I reconsider?
I like the cam. Increasing duration moves the power band upwards. If you like how it performs now, keep the cam.
Should I change the heads to a 2.02 intake?
No. You can if you want but it’s not IMO, a situation of the juice is not worth the squeeze.
Does the knock mean I need a new crank and rods if I'm right on my assessment?
The crank may just need to be turned. Let the machinist guide you on that one.
If yes to a new crank, do I consider a stroker kit and would my existing top end work with a stroker? Or is that just a whole new bag of bolts.
New bag of bolts. With the stroker, it’ll be at 390 cubic inches with a .030 over bore. At this size vs the 318, mileage will tank by compare by torque will soar.

The heads, intake and carb are super restrictive on a 390. The cam becomes super tiny for a 390. Currently it’s a very good cam for general street performance for a 318. The stroker will also hit peak rpm power and thousand rpm sooner.
Thanks for your input.

Happy to help
 
Are you sure it's not:
A loose converter bolt?
Cracked flex plate?
Loose balancer bolt?
Loose lower pulley bolts?

How many miles are on it? if it has a bad rod or main bearing why would it need bored out again.

Must take apart and know what's wrong first.
 
Are you sure it's not:
A loose converter bolt?
Cracked flex plate?
Loose balancer bolt?
Loose lower pulley bolts?

How many miles are on it? if it has a bad rod or main bearing why would it need bored out again.

Must take apart and know what's wrong first.
Exactly. Kill one cylinder at a time to diagnose a rod knock.
 
You have a good collection of parts already for a healthy 318. If it turns out to be a bad rod I would just eagle sir or summit rod it along with some kb167 and a. 028 head gasket to get the compression up a bit for the healthier cam you are running.
If it needs to be bored, and the crankshaft is damaged, well at that point you are halfway to a 390 financially and not a bad thought. Then the heads, cam and intake would probably be substandard at that point
 
Where do yo want more power ?
Where is it lacking most now, low mid high ?

If it's down low, there's probably not much to be gained besides CR and gears if you want more than that in the low and mids, cid is the best way, mids and high cylinder heads is probably gonna give the best return something like SpeedMaster.
 
I have a knock in my 318. Its definitely a lower end knock. My guess is a connecting rod. This is what I have;
Bored .020 over
stock pistons, rods, crank
Compression ranged from 138 - 143 when I last checked it
Comp cam XE262 262/270 duration, 462/470 lift
302 casting heads milled to 58 cc with 1.88 intake
Edelbrock Performer intake
Edelbrock carburator 1406 (600)
Headers
833 4 speed
3:23 sure grip
275/40R17 tires

This is in a street car with no intensions of racing but, like most people, I enjoy the feel of a car taking off when you hit the gas. I would describe myself as "good" with engine understanding but far from excellent. My questions;

Would I bore it to .030 and change the pistons?
Is the cam good or should I reconsider?
Should I change the heads to a 2.02 intake?
Does the knock mean I need a new crank and rods if I'm right on my assessment?
If yes to a new crank, do I consider a stroker kit and would my existing top end work with a stroker? Or is that just a whole new bag of bolts.

Thanks for your input.
Is the oil pressure good? Check with a gauge if You don't have one already. If it's a piston/pin it goes knocka-knocka & is a sharper/brighter sound, rods usually sound duller/heavier with a deep knock-knock. If that's Your ride in the avatar, I'd find & fix the knock, & get back to cruisin'. It'd be a shame to miss a big chunk of the season w/the car apart. If You want to step up the grunt, I'd just start from scratch with another mill, then swap.
 
Are you happy with the power output now? If so, All I would do is put a crank kit in it. You don't bore one "just cause you want to", you bore it if it needs it. Does it smoke now? Use any oil now? Those compression numbers IMO are pretty good with a non stock cam. That tells me rings and valves are sealing good. If you pull the whole thing out and go to boring and buying pistons, new cam and such, you're almost justifying finding a 360. I hate bein "that guy" cause I never am, but honestly, how much more power do you think you'll get with just an over bore and maybe a cam change? You ain't addin 100 HP. You could with a 360. I'm just saying that because I don't know what your expectations are. If all you want is something to cruise around in and have fun with, just repair what you have.
 
2 plug wires in the incorrect firing order can make your engine sound like it has a rod knock(forgot which ones). If messed with the plug wires recently and you have a mild knock, check your firing order. If you did not mess with it and it just started to happen, then oof.
 
Waterloo is at 1000 ft elevation according to Wiki.
That cam, in at 108, has an Ica of 59*.
To make an average pressure of 141psi, your compression ratio is estimated to be about 8.85 to 1.
Those are facts,
Here are my opinions, and I'm sortof thinking it out as I go.
> This makes your bottom end fairly weak.. Coupled with 3.23s, and a 2.66 low gear ( a starter gear of 8.59), I imagine taking off briskly takes a lotta clutch. The Wallace calculator estimates your V/P index to be just 110....... A peppy V/P target is ~135 minimum.
However;
Even at 10/1 compression ratio; the pressure while rising to 165psi, the V/P is still only 129. While this is a 17% improvement; a stock 5.2 Magnum@1000ft, has a V/P of ~124. That means, that even if you pumped your cylinder pressure to the max, your engine would still only have the bottom end of a stock 5.2M, from idle to about say 3300rpm.
With an automatic, this is no big deal, you just stick a 3300 stall on her and call it done.
But
with a 4-speed, and 3.23s, probably 95% of the time, you're gonna be at under 3300, so bottom end is a really big deal.
Your tires are about 25.7 tall= 80.74 roll-out, thus
3300, will get you to 29mph in first, 41 in Second, 56 in Third, and 78 in Fourth. So, until you get to those speeds yur teener is sucking wind.
Am I right so far?

>Your only solutions to this are
1) way more cylinder pressure, or
2) an earlier closing intake event
3) a bigger engine, or
4) supercharging.

You can bandaid the situation with a higher starter gear, or bigger rear gears, this is true, but eventually, the low-pressure 318 just runs out of steam.

So from your question sheet, I'm gonna read between the lines and answer thusly;
1) I do NOT disagree with anything that has been said in earlier posts.
2) You have already spent a lotta time and money on the current combo. Which is actually a pretty good combo, except for the lack of cylinder pressure.
3) so, since the engine has to come apart anyway, the cheapest bang for the buck, IMO, would be a new set of pistons, fitted to make about 160psi.
4) and I agree that a stroker kit is a great solution, but it requires additional monies to bring it on line.
5) the simplest solution, if hiway travel is NOT considered, then, is to leave the engine as is, and go with a lil more rear gear. The current combo would like a starter gear of at least 10/1, which, with a 2.66 low gear, means a rear gear of 3.73s.. That will increase your torque multiplication in every gear by ~15.5%, nearly equaling the 17% earlier talked about. The downsides are the higher cruise rpm, higher fuel consumption, and sooner or later the low-pressure 318 is still gonna run outta steam.
6) another other option is to get a Commando trans with it's 3.09 low gear. Thus, to get a 10/1 starter, you only need 3.23s, which you already have. Unfortunately, the other gears are the same, and 3300 now only gets you 25mph in first, and on the shift, the Rs fall down to 2050, so there you are stuck back in lo-performance mode.
---------------------------------------------
>Ok so now; what would I do?
Well, I've been driving Mopar 4-speeds all my life,(since 1970) and currently have one of every SBM box, except the 2.47 T/A which I have no use for on the street. So I am very familiar with them.
and my current combo is a 68 Barracuda, which as you probably know, is at least 150/200 pounds heavier than a similarly equipped Dart, and Ima thinking your wheels are plumping that up a bit too. My 68 is 3450/me not in it; with an all-aluminum top end, all aluminum 4-speed and a GVod, so I can't get much lighter.
So, if I was in your shoes, and
if I was looking for more performance on a budget,
The first thing I would do is pump up the pressure,
But I wouldn't stop at 160/165 psi.
Nope, I would install some alloy heads and target 190/195 psi. That would take an Scr of about 11.2, and would yield a V/P of 150(sweet)
Lest you think 11.2 is impossible, I ran 11.3 in my 367 for quite a while, the only trick is to run a tight-Quench (I ran 028).
>My opinion is;
that at a V/P of 150, you will never complain of a soft bottom end again. This is about where big-blocks of yester-year ran. At a V/P of 150, you can run the 2.66 trans and 3.23s just fine.
But this is no longer budget friendly. Yur looking at both heads and pistons, and eventually a carb.
But the bonus is that you can move up a camsize , with very little loss of pressure. Plus, if you went to a stroker, you'd need better heads than you now have, anyway.
The 3.23s are still a bit of a handicap, but that V/P of 150 will power thru it.
__________________________________
With your new found pressure, you have an ideal opportunity for transformation with one of the the A833od boxes.
Your current trans should have ratios of
2.66-1.92-1.40-1.00 with 3.23s the roadgears are
8.59-6.29-4.52-3.23
If you drive like me, then you are mostly using First and Second. and occasionally fourth. Third is mostly used just to get to Fourth. Am I right.
Your 262* cam power-peaks at about 4800, and you can shift that at say 5200 on the street.
Thus that 6.29 Roadgear will get you 60mph@4940/perfect. So you don't want to stray too far from that number.
Say you had the A833od with ratios of;
3.08-1.67-1.00-.73od, then 3.73s, will get Roadgears of
11.52-6.23-3.73-2.72. Compare that to the current
' 8.59-6.29-4.52-3.23
As you can see, from 6.29 to 6.23 is near enough to be perfect. Your starter gear is now in tire-frier/parade mode, Third gear is 17% worse but that overdrive is dropping your Rs from 65=2750 to 2320, and since Third is mostly used just to get to Fourth, that 150VP will power you thru that. IMO that is a fair trade, even if First gear is pretty low. My 367 ran that overdrive box with 3.55s pretty good. With 3.23s First was better, but Second was worse.
Ima thinking ;
Your current heads, with the right pistons and Quench, at 160psi, would do pretty good with those roadgears.

Thus you are trading a set of alloy heads for an overdrive box, and 3.73s. Great deal. the budget is back! But you still gotta ditch those pistons.
With iron heads and a hydraulic cam, IMO this would be as good as it gets for the money spent.
If you ever buy another cam Consider a fast rate of lift, tight lash, Solid lifter type, if for no other reason than to preserve the pressure.
----------------------------
So to recap, what I would do is;
1) Increase the pressure to in the window of 160/165psi together with a tight Quench of less than 040. It doesn't matter how you get there.
2) install an A833 od
3) install some 3.73s or if you need a better parade gear, then 3.91s
4) leave everything else as it is. except you might have to tweak the power-timing to come in a lil later. It's a 4-speed and that is normal.
5) speaking of parade gears
Your current combo, at 550 rpm, the slowest it can drive is ~4.9mph. Since nobody can walk that fast, to parade, you gotta ride the clutch. This sucks for the clutch and sucks for your left leg, so you tend NOT to parade, am I right.
Well, with the 3.09-Overdrive and 3.73s, 550= 3.65 mph. But, if you install a High-Volume oil pump while the engine is apart, you can idle that 262-cammed engine down to 500 pretty easy, and your new slowest speed is 3.3mph, and parades are now possible. For me, that was a happy day. Idling thru the parking lot at 500 rpm at the car shows, was a rumpidy-rumpidy good time.

Ok so, those are my opinions.
 
Last edited:
No to 2.02 valves in a 318 bore. You might have to notch the block just to have it not hit and if you do get them in the shrouding would negate the value of the switch. I think you have a great set of heads for a street 318 just the way they are!
 
No to 2.02 valves in a 318 bore. You might have to notch the block just to have it not hit and if you do get them in the shrouding would negate the value of the switch. I think you have a great set of heads for a street 318 just the way they are!
1716073336466.png
 
If everything else is in good shape, just repair the short block, get a gasket set, and move on...imo.

I'm sure it's a fun ride just as it is.
 
If the OP is happy with the power he makes, then yes nothing needs to be changed combo wise, but since he asking what to change sounds like he's looking for more power. And that's mainly done through cam and or heads, better heads probably be more streetable than larger cam, especially if he's not changing cr and or gears. Something got to change if the goal is more power.
 
If the OP is happy with the power he makes, then yes nothing needs to be changed combo wise, but since he asking what to change sounds like he's looking for more power. And that's mainly done through cam and or heads, better heads probably be more streetable than larger cam, especially if he's not changing cr and or gears. Something got to change if the goal is more power.
Correct. But how far does he want to go and how much money does he want to spend on a 318? Unless he's going to add a roller cam, some exotic heads, turbo or blower, he's not going to make a huge difference from what he has now. That's why I recommended sticking with what he has.
 
No to 2.02 valves in a 318 bore. You might have to notch the block just to have it not hit and if you do get them in the shrouding would negate the value of the switch.

2.02 + 1.60 = 3.62 is a 3.91 stock sized bore. They fit and work.

Valve shrouding should be avoided however even the factory offerings across the board don’t worry about valve shrouding. It is just not that big of an issue and means near nothing in an everyday street car.

Worrying about it is BS. Suggesting to be worried about it is BS.


I think you have a great set of heads for a street 318 just the way they are!

One of the very if not thee dead last as cast heads I’d ever use.

Now if you port the F’in hell out of them…….

Nearly everyone fell for the BS that the 302 head was a magic head and used them as cast. Few admit to crying over the switch.
When you port the crazy *** crap out of the head, then! After all that effort, you’ll have a kick *** head.
 
OP, find more power and n a good 4bbl carb and intake.
For the heads & what you’re doing with them, any enhancement is going to be pricey with a low return - but just a bowl porting is a good step. Better if you use the 1.88/1.60 - 360 valves.

Also work on your exhaust.
 
What is your budget?
Exactly. Whatever you THINK the budget is.......add more for life and reality. How much more? I don't wanna say and then get bludgeoned over it but with supply chain issues- machine shop extended times and everything else in 2024 things tend to be much more $$ than planned.
 
Thank you all for your replies. To answer some of your questions;
I like what I have performance wise but have felt its a little flat and AJ has explained why.
Budget wise, I was secretly hoping that I would get some support on the combination I had and could reuse a lot of it.
Low thud knock, not a ping. Everything is tight and the oil pressure is good.


Based on all of the replies this is my take away, which is budget friendly;

The stroker kit idea is tossed.
Once the shop gets a look I can likely hone, not bore, the cylinders. I don't expect any problems.
No need to change the heads to a 2.02 intake
While repairing bottom end. Change compression and quench with new pistons.
Consider 833OD and 3:73 gears to perfect the combination.

If I've got this wrong, please tell me.
 
Sounds like a good plan. IDK if the OD trans is a good route to travel. The first gear is a blast. You’ll have to rev it up a little more for that RPM drop into second. Third is a normal shift and OD is for the Hwy.

If you really want it, then do it. It should change the 3.73’s to a 2.60 - ish rear gear feel. The car won’t like much of a camshaft duration increase.
 
Seems wise. Work with what you have. The machine shop results will determine everything. Good luck.
 
Exactly. Whatever you THINK the budget is.......add more for life and reality. How much more? I don't wanna say and then get bludgeoned over it but with supply chain issues- machine shop extended times and everything else in 2024 things tend to be much more $$ than planned.
You got that right. Kinda like when you sit down and design a size of a shop. When you get done, double it. lol
 
Thank you all for your replies. To answer some of your questions;
I like what I have performance wise but have felt its a little flat and AJ has explained why.
Budget wise, I was secretly hoping that I would get some support on the combination I had and could reuse a lot of it.
Low thud knock, not a ping. Everything is tight and the oil pressure is good.


Based on all of the replies this is my take away, which is budget friendly;

The stroker kit idea is tossed.
Once the shop gets a look I can likely hone, not bore, the cylinders. I don't expect any problems.
No need to change the heads to a 2.02 intake
While repairing bottom end. Change compression and quench with new pistons.
Consider 833OD and 3:73 gears to perfect the combination.

If I've got this wrong, please tell me.
No, AJ gave you his opinion of why. None of us has a crystal ball and can tell you exactly what will work and what won't through the internet. Remember that.
 
Thank you all for your replies. To answer some of your questions;
I like what I have performance wise but have felt its a little flat and AJ has explained why.
Budget wise, I was secretly hoping that I would get some support on the combination I had and could reuse a lot of it.
Low thud knock, not a ping. Everything is tight and the oil pressure is good.


Based on all of the replies this is my take away, which is budget friendly;

The stroker kit idea is tossed.
Once the shop gets a look I can likely hone, not bore, the cylinders. I don't expect any problems.
No need to change the heads to a 2.02 intake
While repairing bottom end. Change compression and quench with new pistons.
Consider 833OD and 3:73 gears to perfect the combination.

If I've got this wrong, please tell me.
I would refresh what you have. There are other, MUCH less costly ways to make what you have run and run really well. There's no way in heck I'd spend the dough on different pistons and or boring if it's not needed. Some of these guys are real good at spending other peoples money. You seem to have bought the bill of goods and kool aid so good luck! I hope you get what you want.
 
-
Back
Top