Author Topic: 340 engine rebuild (Read 6745 times)

mrbill426 · « **Reply #15 on:** July 01, 2005 - 09:54:04 PM »

Quote from: Chryco Psycho on July 01, 2005 - 12:22:05 AM

the 11:1 engine with alum heads will run the same as a 10:1 iron head engine so you only need to use pump premium� fuel , it will not detonate at 11:1 seeing as the alum head absorbs the extra heat that will cause detonation�
I built a 11:1 alum head 440 last year & has minor detonation with 93 octane pump premium fuel�

I see... So I use the new pistons I have and have the E heads milled to obtain the 11:1 ratio?

Chryco Psycho · « **Reply #16 on:** July 02, 2005 - 12:25:23 AM »

you could mill the heads but the intake face or intake has to be milled down as well

mrbill426 · « **Reply #17 on:** July 02, 2005 - 08:47:33 PM »

Quote from: Chryco Psycho on July 02, 2005 - 12:25:23 AM

you could mill the heads but the intake face or intake has to be milled down as well

Okay, that part makes sense. Would it be better to cut the block down, or cut away on brand new heads, though?

And with that milling, hopefully piston to valve contact won't become an issue. I mean they built those heads with an added .060" of open chamber, I thought to allow room for the higher compression pistons of the '68-'71 340s. It just seems that milling them down would defeat the "clearance" purpose. Or perhaps I misunderstand why they opened them up? :dontknow:

Again, we are not using stock type pistons, these will sit higher in the bores and are notched. I guess there is probably more room in there than I realize. I don't intend to go much over about a .528"lift cam.

Chryco Psycho · « **Reply #18 on:** July 03, 2005 - 12:45:49 AM »

THis why the chambers need to be smaller on Eddy heads , I would mill the heads on both the deck & intake surface so they can at least be used on any block , most 340 pistons were above the deck from the factory so you need to be very careful measuring all your clearances Before you cut anything to see which way you can go

mrbill426 · « **Reply #19 on:** July 03, 2005 - 11:36:57 PM »

Okay, but these pistons are not stock mopar, they are SpeedPro forgings. This is all the info I have found so far on them:

"#LF2316F Speed Pro Power Forged pistons for Chrysler 340 1968-71. Flat-top with 2-valve relief. Coated skirt. Press fit or float pins included. Bore size 4.040". Ring dimensions 5/64 5/64 3/16. Compression ratio 10.21:1 @ 63cc. Compression distance 1.840". Deck clearance .018". Skirt clearance .0015".

Does this deck clearance spec mean above or below the deck? What is "compression distance"?

The heads I am talking about have open chambers: #60179, Performer RPM Chrysler 340 chambers are machined .060" for piston-to-head clearance with early high-compression 340 engines. Chambers: 65cc, Intake port: 171cc, 2.02" Intake valves, 1.60" Exhaust valves

By measuring "before" milling, are you suggesting that I choose a cam grind first, too? On that point, I'm just concerned about being stuck with a cam that won't "fit" (too much lift) with this combo. :newsad:

Thanks for the help.

Chryco Psycho · « **Reply #20 on:** July 03, 2005 - 11:52:28 PM »

I have the speed pro catalog at home but not here ,
the deck clearnce is generally listed as +.018 above deck or -.018 below deck
the Speed pro pistons usually have a lot of clearance for .600 lift cams - what you mill off the heads , the piston could also be fly cut for extra clearance
You set the engine up with a small cam bring it too 6* after TDC & measure actual clearance before ordering the cam

mrbill426 · « **Reply #21 on:** July 04, 2005 - 12:01:17 AM »

Ahhh, I got ya! I plum forgot about fly cutting pistons, I had to do that with a 383 some 25 years ago (also with SpeedPros)...father time is catching up with me I guess

Good info on the cam setup too :thumbs:

This 340 project just might get moving after all. :beer:

Have a great Independence Day, Chryco, and anyone else who happens to read all this!

Bill

Chryco Psycho · « **Reply #22 on:** July 04, 2005 - 12:54:35 AM »

Thanks :beer:, you too

mrbill426 · « **Reply #23 on:** July 07, 2005 - 10:10:02 AM »

Quote from: Chryco Psycho on July 03, 2005 - 11:52:28 PM

I have the speed pro catalog at home but not here ,
the deck clearnce is generally listed as +.018 above deck or -.018 below deck�
the� Speed pro pistons usually have a lot of clearance for .600 lift cams - what you mill off the heads , the piston could also be fly cut for extra clearance
You set the engine up with a small cam bring it too 6* after TDC & measure actual clearance before ordering the cam

Okay, I found the spec on the deck height for the Speed Pros, it is supposed to be -.018". I assume that means the flat of the piston should be that far below the deck in an un-milled block?
For comparison, what is the stock deck height supposed to be on a stock ('72) 340?

Chryco Psycho · « **Reply #24 on:** July 10, 2005 - 09:15:11 PM »

I`ll chek when I get home but usually a 340 piston is .018 above the block deck

mrbill426 · « **Reply #25 on:** July 12, 2005 - 10:46:49 AM »

Okay, thanks.

I know I have to check all these clearances anyway, I just want to have an idea of what I might find. I no NOT like surprises, like pistons hitting the heads (on the engine stand) from the get-go. :eekbig:

Author Topic: 340 engine rebuild (Read 6745 times)

mrbill426

Re: 340 engine rebuild

Chryco Psycho

Re: 340 engine rebuild

mrbill426

Re: 340 engine rebuild

Chryco Psycho

Re: 340 engine rebuild

mrbill426

Re: 340 engine rebuild

Chryco Psycho

Re: 340 engine rebuild

mrbill426

Re: 340 engine rebuild

Chryco Psycho

Re: 340 engine rebuild

mrbill426

Re: 340 engine rebuild

Chryco Psycho

Re: 340 engine rebuild

mrbill426

Re: 340 engine rebuild