318 poly wide block crankshaft in a 326?
 

Hi again. I finally got my 318 poly crank the other day and although it will fit and I could run it, I overlooked that I will lose compression in my 326 poly.

My 326 has a compression of 9.2 to 1 and a stroke of 3.31". I believe that the 318 has a stroke of 3.21"... can anyone verify this info?

I am wondering if anyone has any idea of how poorly my motor would run if I use the 318 crank. Any thoughts on this are helpful.

Also, I have discovered that the whole mess started because of a problem in my oiling system.... I've been working on getting my oil passages clean, and figure I may as well just get a new oil pump too. Does anyone know what other oil pumps will interchange with a 326 poly?

Thanks for your time and info!
~Melissa

Re: 318 poly wide block crankshaft in a 326?
 

Mel,
My "Ultimate American V8 Engine Data Book" by Peter Sessler says that the 318 has a bore and stroke of 3.9062 x 3.312 and that the 326 has a bore and stroke of 3.9531 x 3.312 so according to this book, the crank might be the same. It also says that the 318 had a compression ratio of 9.0:1 to the 326's 9.2:1. I got this info on page 152, if you have access to the book.

That chapter covers alot of stuff, pretty much every engine that Chrysler, Dodge, Desoto used in the 50's, so there wasn't any in-depth info on the oil pumps in this case.

Re: 318 poly wide block crankshaft in a 326?
 

Hey how's it goin !I'm also a poly fan!here's a link to a good book you can get about poly's.It looks like it has lots of good info in it http://victorylibrary.com/mopar/poly-book.htm Good luck!

Re: 318 poly wide block crankshaft in a 326?
 

Thanks! I wasn't sure about that 318 info I had since it was off someone's personal website and I couldn't find any more info of the sort anywhere else on the net.

I don't have access to that book, so thank you for the info!

It is my theory that I could use just a small block mopar oil pump, since I can make some small block parts fit with a little convincing.... but I can't find anything to back that up.

~Melissa

Re: 318 poly wide block crankshaft in a 326?
 

I think your questions are likely answered in Ceridono's book on the Hemis--it has a short chapter on poly engines. Probably you can find and read this at a Borders or Barnes and Noble.
Both the hemis and polys are closely related to the the later A motors, and I'm pretty sure the oil pump interchange is in here.

Re: 318 poly wide block crankshaft in a 326?
 

Mel, according to the Mopar bible, the poly 318 has a stroke of 3.31. There's a ton of onfo in those books, but I see nothing on 326s and only two pages that are poly specific.

Re: 318 poly wide block crankshaft in a 326?
 

I'll have to keep my eye open for that book.

The 326 is a one year, one model engine... that would be why you can't find any info on it. But I have a shop manual that gives me all the info on that motor.

Thanks http://www.jalopyjournal.com/ubbthre...lins/smile.gif

Re: 318 poly wide block crankshaft in a 326?
 

there is a mopar bible?

Re: 318 poly wide block crankshaft in a 326?
 

Mel - Have you seen this book? It sounds like it might have the info you are looking for..

http://victorylibrary.com/mopar/poly-book.htm

Re: 318 poly wide block crankshaft in a 326?
 

It's an old Direct Connection book, Chrysler P/N P4349340. It may have benn superseded as this one is an engine only book. The chassis manual is P/N 4349341. These books replaced the old single book and inclouded updated imfo and expanded model coverage. They are oreinted towards A/B/E/L body cars. Drag racing and street performance are the bulk of subject modifications.
413, you don't have a set of these?! I would have never thuoght! http://www.jalopyjournal.com/ubbthre...mlins/grin.gif

Re: 318 poly wide block crankshaft in a 326?
 

Mel, I went through my Mopar Performance HEMI book with no info showing for the little "A" engine...I know I had another publication here showing a little "A" and "LA" interchangeability but I'm damned if I can find it....Ggggggrrrrrrrrrr! and I thought I was sooooooo organized too...shit!
It sounds like you have enough info to spring on that 318 crank like a duck on a junebug anyway...I say go for it.

Re: 318 poly wide block crankshaft in a 326?
 

I'm gonna have to look at that book... sounds like it's got everything I've always wanted to know in it.

It's alright Rocky. All I gotta do is clean out those oil passages, get a new oil pump, and wait for my bearings... meanwhile I'm getting ideas for fun projects. "as long as the motor is out it'd be so easy to get to...." mwahahaha

~Melissa

Re: 318 poly wide block crankshaft in a 326?
 

compare the casting numbers on the crank, if the same theres your answer, if different you have to do a little more investigating, is you old engine still together, measure the actual stroke of your engine, then measure the stroke of the crank(dont know how to do that w/ the crank alone) but theres a way, that will tell you exactly what stroke you have! unless you measure wrong!

also though i may have sourced an engine for you but it turned out to be a 56 dodge instead of a 59 like i thought it was, owe well.
TITUS

Re: 318 poly wide block crankshaft in a 326?
 

Here are a couple of Poly links I have found that may help ...

http://www.dodgepolara.com/318hotrod.html
http://www.1962to1965mopar.ornocar.com/poly318.html

Re: 318 poly wide block crankshaft in a 326?
 

Hey Mel,

I found some info on the polys and 318s. Not so much on the polys, but quite a bit on the 318s.

http://www.allpar.com/mopar/318.html

look around this site there's more and somethimes it's hard to find.

Oh yeah and I found this on a site too:
bore stroke
326 3.950 3.31 1959
318 3.910 3.31 1957-1967

Re: 318 poly wide block crankshaft in a 326?
 

Thanks for looking out for me Titus. I appreciate that.

I know the crank will work... that's not an issue since I got one from an A series 318 with an 8 bolt flange. The LA 318 cranks have a 6 bolt flange and are a wee bit shorter.

I was just concerned about how much shorter the stoke was in the 318 compared to my 326... the info I had was wrong and the answer is they're the same. So I'm waiting on my new main bearings and life is good.

Just working on finding an oil pump that will fit right now...

Thanks again guys http://www.jalopyjournal.com/ubbthre...lins/smile.gif

Re: 318 poly wide block crankshaft in a 326?
 

Mel, If the 326 is just a bored out 318 then according to this guy a LA oil pump will work.

http://www.1962to1965mopar.ornocar.com/poly318_1.html

Re: 318 poly wide block crankshaft in a 326?
 

the problem is that some guys say the LA oil pump is a direct bolt on, some guys say the early Hemi pump is a direct bolt on. Nobody seems to agree.

-Bugman Jeff

Re: 318 poly wide block crankshaft in a 326?
 

You don't have to loose compression, you use pistons with an adjusted deck height, or longer rods.
You do have to loose cubic inches, but that might be a good thing. Destroked engines can wind better, it depends on the rest of the rebuild.
Note: I haven't read all the other posts, I just wanted to add my .02. So if I have repeated any or everything that someone else already said please disreguard. http://www.jalopyjournal.com/ubbthre...mlins/grin.gif

Re: 318 poly wide block crankshaft in a 326?
 

Mel, you might want to check ebay for a Motors Manual. I have one from '62 which has all the info you need back to '55. They're normally reasonably priced, especially if you don't object to a few dirtied pages. The stroke and bearing sizes check out the same between the Dodge 326 motor and the Plymouth 318 for the same year (1959)
Mart.