LA 318 advice

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Baggs

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Some 25 years ago I had a 318 rebuilt. All stock but a “RV” cam. The project went away that the engine was intended for, so mounted it in my ‘32 Dodge PU.

I asked a few questions on a site I’m a member of for 10 years, many suggested coming here.

Well I pulled the intake and heads-engine will get taken apart anyways to clean a line it back up) and the deck is off, each side around .010, that and the pistons are .095-.105 in the cylinders.

So here’s my options, spend up for the KB pistons, square and mildly deck the block. My heads are open chamber, rebuilt, and will just keep them.
I figure I could save a few bucks over balancing the rotating assembly and KB pistons,plus some squaring and decking, and compare to a heavy deck cut and run the pistons I have. This would just be deck and intake milling.

No balancing required. That’s a savings I referred to.

So with that in mind, how much can you deck a LA 318, still do manifold milling to get it to line up? .040?, .060, etc.
anyone experience this, or just square up the block, run the taller KB pistons.

Not shooting for 300 HP here, but I just can’t sleep well knowing 8:1 CR ratio is turning the crankshaft. And yes, I live through the neutering of the engines in the ‘70’s. My beloved BBC LS5 was cut 75/80 HP from1970 to the 1971 year.

Thanks.
 
Find some stock '86 to '91 318 roller engine pistons, they are 9.2:1 cr stock from the factory.

Mr. Gasket. 028 ths head gaskets will help up cr too. Not only thinner, but they fill the hole better than the Felpro universal 318/360 head gasket.

Pistons, head gaskets, 340 cam and away you go. Of course a 4 bbl is what wakes it up. 1406 Edelbrock, good match for the 318s.

20200608_134533.jpg


9.2:1 cr pistons stock 318, .040 ths in the hole.


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Thanks. I did look at later model .030 5.2 pistons, but all I saw were .020 lower compression height ones.
More reading and I guess the newer blocks start with a lower deck height, coupled with the closed chambered heads gets a decent SCR?
 
Newbomb Turk said:
Deck the block.
Click to expand...
That’s a question as to how much it can be decked? As I mentioned if I could square it and be .020 above the pistons, which average .100 right now, can the intake be matched, will the block be stable? Saves near 500 in rings and pistons and balancing the newer pistons, I understand the KBs are 40-50 grams lighter.

I figure (in my mind) squaring the block vs more cutting the cost would be close. Then intake milling.

Vs 500 in pistons and rings and balancing.

I don’t need the Hyperuetic pistons, other than they come with 1.81 compression height. But deck still needs to be milled for a decent SCR with the open chambered heads I have.
Using newer style closed chambers, probably means spending additional time/cost at the machine shop to go through them, plus the heads themselves.

I’m not shooting for a “quench” as I don’t need/want a high compression engine.

So if the deck can be cut say .080, and if the intake can be adjusted to suit it, I’d be fine with that and save some dollars.
 
Baggs said:
Thanks. I did look at later model .030 5.2 pistons, but all I saw were .020 lower compression height ones.
More reading and I guess the newer blocks start with a lower deck height, coupled with the closed chambered heads gets a decent SCR?
Click to expand...

You can put good used 9.2:1 cr pistons in it if your bore is still good, with new rings > good to go.

Can even use the used stock rods that come with the used pistons, so you don't have to press the 9.2:1 pistons onto your stock rods.

No Balancing.....


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George Jets said:
You can put good used 9.2:1 cr pistons in it if your bore is still good, with new rings > good to go.

Can even use the used stock rods that come with the used pistons, so you don't have to press the 9.2:1 pistons onto your stock rods.

No Balancing.....


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Click to expand...
Well, the block is freshly (25 years back) bored .030. So a stock piston won’t help it there. Seems CH on the LA and newer engine is the same. The difference I can dig up is the LA. Use 9.6 deck height ( spec’d) and the newer are 9.50? As I recall. I think that and closed chamber heads yield the 9.2 SCR.
Unless I’m mistaken?
 
ch1ll said:
How much can you deck the block?(cause I might want to deck mine).
Click to expand...

You can take .100 off a stock block.

You can take .200 off an X block.

You can take .300 or more off an R block depending on which version of the R block you have.

You will need to machine the intake manifold when you start taking that much off.
 
Somewhere in the neighborhood of .045 will bring a 318 to zero deck with sealed power four valve relief pistons. YRMV...
 
Newbomb Turk said:
You can take .100 off a stock block.

You can take .200 off an X block.

You can take .300 or more off an R block depending on which version of the R block you have.

You will need to machine the intake manifold when you start taking that much off.
Click to expand...
Very cool for me. I’ll go .080 to 9.52 deck height. Then run a .025 or so head gasket.

Thanks.
 
George Jets said:
Find some stock '86 to '91 318 roller engine pistons, they are 9.2:1 cr stock from the factory.

Mr. Gasket. 028 ths head gaskets will help up cr too. Not only thinner, but they fill the hole better than the Felpro universal 318/360 head gasket.

Pistons, head gaskets, 340 cam and away you go. Of course a 4 bbl is what wakes it up. 1406 Edelbrock, good match for the 318s.

View attachment 1716338932

9.2:1 cr pistons stock 318, .040 ths in the hole.


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Click to expand...
Do you have a part number for those pistons? Every time I try looking those up I can only find 360 pistons in general. Sorry, I didn't mean to highjack the op thread I'm just trying to get the part number of those pistons.
 
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