Truly out of the box? Edelbrock heads question?

[boydsdodge]

I did the Edelbrock swap last year because I sunk two valves in my iron heads and I had the Edelbrocks on the shelf for a stroker build in the future.
Now i was told that these would be a direct swap with the stock castings so off I went pulling the heads from my 360 and started installing the Eddys.
That's when I found that my 340 manifolds do not fit at all, the rocker geometry is of and requires shimming and custom push rods, valve job to redo the sloppy one that comes out of the box.
In the end a pair of $1500.00 heads cost $3000.00 to have running down the street.
Now you can just bolt your valve train on with out setting it up and hope for the best on the wear and tear of the valves, and you can buy cheap ass headers and hope they fit and don't leak, but I didn't and went with TTIs, Smith Bros push rods, some stainless tube for new exhaust I fabed up my self, I also bout a set of 1.6 crane roller rockers to get the geometry set up.
So I would say if you want a stock replacement head these are not and make sure you check them threw and threw.
Oh ya, would I do it again? YEP. I am ready for it this time.

[moper]

A couple notes here. The Fel Pro blue is .043 compressed, it has been since the late 80s. There is a Felpro performacne that shoudl be used with the RPMs that is .039" compressed... It's the fire ring that is different, and flat as opposed to rounded on the blue Permatorque. If you need thicker gaskets, shop around because there are a few other MLS styles that might be usable for you. Have you measured your pistons in the block? Most old school shops that used the "+.018" pistons did not set the deck height at blueprint, and many times you'll find them actually lower in the block than .018. When you design for quench, commit to blueprinting all the parts. Otherwise you may run into issues. On the RPM's, they do have soem issues. I have never had the geometry issues, but it wouldnt surprise me trying to run them out of the box. Honestly, part of the process of correcting is the valve job that properly sets that height. My question is if you found those issues, and they were obviously the heads, why run the that way? My guess is there are other things wrong that were not fixed...

[72bluNblu]

Moper-

I did actually measure the piston distance over the deck, and while I did it with the end of a caliper (not exactly a perfect method) I got EXACTLY .018". I measured all the pistons. I bought the engine from a gentleman who had a lot of 340 performance parts (all kinds of stuff I wish I had, 4 bolt main blocks etc), and this was not the first rebuild on this block, so it wouldn't surprise me completely to find that someone had set the deck height up before I got it.

As far as them being set up, the "prep" that hughes does should take care of the valve job etc. But as I mentioned earlier in the build, no stock parts are going on it. Harland Sharp roller rockers, Hooker Super Comps, etc...

[moper]

Hughes should fix them if you're getting charged for it. Just verify this is part of the services.

[femtnmax]

So combining the above info, if pistons are 0.018 above deck, and gasket is 0.043 compressed (the 0.055 was uncompressed, I measured one), then 0.043-0.018=0.025 quench...too tight.
So you could cut your combustion chambers as you mentioned.  Cut 0.010 for quench equal to 0.035 which is a good minimum quench, or cut 0.015 maximum for 0.040 quench.  Either of these would be great.  They do say the tighter the quench there is a slight increase in hp.  As moper said, the only way to do it correctly is to measure everything.   I do what Smokey recommends, I mock the engine up at least a couple times before it goes together for real.   
Pistons/rods/crank instal to verify piston deck height, crank end play, etc.  Then disassemble and off to cut the deck height.   Back from the machine shop, then mock it up again to recheck the machine shop.   Then on to mocking up the cam and long block.
I have seen real bad machine work from seasoned experts.... they were burned out, hated their work, or something.   Must recheck everything like Smokey says.

[71chally416]

So you could cut your combustion chambers as you mentioned. 

 

[femtnmax]

I know, I would NOT do it either.  He said he did not want to touch the pistons.  If this piston/gasket/cyl head were the way to go, it would be MUCH easier to trim 0.010 off the piston dome, assuming the combustion chamber cc work out correctly.

[72bluNblu]

Look guys, cutting the combustion chambers is what edelbrock says it does. The 340 head is supposedly just a 360 head cut .060" for clearance. So I'm not sure how having the 360 heads cut for a more accurate clearance is worse than what edelbrock does. My only other options are to run the 340 heads and a normal gasket, or the 360 heads with a thick gasket, reducing compression, or disassemble the engine I paid to have balanced and assembled to cut the pistons.

Obviously, hindsight is 20/20 and it's become apparent I should have sprung for forged pistons and set up a zero deck block. But I'm not an engine builder, and this isn't a race engine. Unfortunatley starting with a high compression 340 that's been rebuilt at least once before (and maybe more) may not have been the way to go, it's
a block that definitely has some quirks. But at this point I'd like to figure out a reasonable solution to keep the build on track and not cost me a fortune.

Maybe I shouldn't have taken for granted that the fact that edelbrock made a head specifically for my application meant that I was on the right path (the 340 head made for the .018" over the deck 340 piston!). I'm beginning to think just running the 340 head as planned is the way to go, even if I give up some quench. Sure, it's not perfect because of the open chamber head, but it's chamber is still at least 2-5 cc's smaller than a stock iron head this engine came with from the factory, with better ports etc. This was, after all, supposed to be a moderate rebuild, an upgrade over stock but not a $10,000 race engine! 

[71chally416]

It can be done, but only on a CNC Mill by a competent machinist. A normal auto machine shop is not equipped for that.

[moper]

72, Edelbrock does this yes.. It can be done with an end mill on a Bridgeport by almost any machinist. But, it's not easy because of the shape. That just translates to labor time. The up side is the decks are thick, so you can cut as far as you need to. I'd think in terms of cost, it would cost me about $80 to have the pistons milled, and I'd say double that at least to have the chambers enlarged. It's aluminum. Anything can be done to it. You just need to get an idea of cost to do it first.

[femtnmax]

Take alook at your volumes to see if the combo will work so you don't waste your money.  Here is a handy calculator.    http://kb-silvolite.com/calc.php?action=comp

Need to fill in all the boxes, so here it is.
Cylinder head volume         63cc    Edel performer rpm #60779
piston head volume             6cc    KB243, dome 0.018 above deck of block
    According to KB the 6cc takes into account the dome and valve notches
Gasket thickness             0.039     Felpro #1008
Gasket bore                    4.18      Felpro  1008
Cylinder bore                   4.07      0.030 overbore
Deck clearance               0           piston flat (not the 0.018 dome) to top of block
Stroke                           3.31       stock stroke
rod length                       6.123    stock rod length
Intake closing                 61 abdc   for Lunati voodoo cam, need to enter yours.  This is intake closing angle seat to seat, not 0.05 closing suggested by calculator.
Results are  10.1 static and 8.2 dynamic.  Both of these are real good.

The above assumed no piston dome cutting.  Now cut 0.015 off the dome for 0.039-.0003=0.036 quench clearance.  For a full circle 4.04 diameter and 0.015 tall volume=0.192 cubic inches, but dome is only about 1/2 of full circle, so have 0.096 cubic inches.  Using handy calculator to find cc's.

http://www.metric-conversions.org/volume/cubic-inches-to-cubic-centimeters.htm

Answer is 0.064 cubic inches = 1.6 cc.   So account for top ring land and add total of 2 cc to piston volume because combustion chamber volume is increasing if we cut down the piston dome.  I know I fudged on the ring land volume.
KB result is then   9.85:1 static compression and 8.0:1 dynamic compression.  Again both of these are real good.
Typical compression ratio adjustment for aluminum heads is drop 1 point off ratio for heat disappation of aluminum.   So you would have about 9.0:1 static ratio, the engine should run great on regular grade pump gas, and with the quench clearance at 0.036 you would have no problems with detonation.
So this combo would work excellent.
If you unshroud the valves in the combustion chamber it will quickly add more cc's to the chamber volume.  I did a set of Edel magnum heads and unshrouding added almost 6 cc.   Unshrouding helps port flow, but if you do this to your combo the result is 69cc combustion chamber volume which gives you only 9.2 static and 7.5 dynamic.  Both of these are getting low for an aluminum head, so I would not do it with those pistons.  Sorry to talk so much, but this is what it takes to match the parts correctly.

[femtnmax]

I thought about the numbers I posted, the dynamic compression ratio seems kinda low considering the almost 10:1 static ratio.   I did another check, and it looks like your intake closing point should be NO LATER than 61 degrees after bottom dead center, in fact 58 degrees or earlier is much better.
The way I was told to check when building with aluminum heads is to calculate with your actual aluminum numbers, then assume you have cast iron heads, and add to the combustion chamber volume until the compression ratio drops to about 9:1 static so you could "use" regular grade pump gas.  At this static ratio the dynamic ratio should be about 7.7:1 to 8.0:1 maximum.
When I do this check on this combination, I used 71cc combustion chamber, all other numbers the same as before including 61 degree intake closing, I get 7.4:1 dynamic ratio which is low.   
So then start advancing the cam, which moves the intake closing point toward bottom dead center.  I tried several steps, and 55 degrees intake closing gave a dynamic ratio of almost 7.7:1 which shoud work well at sea level.
So it looks like if you put in a "hot" cam with late intake closing, the engine will sound tough, but not make much torque or hp.
Someone check my numbers, I think its correct.

[moper]

I use 8.25:1 dynamic as a max with open chamber iron heads and no quench. This ends up in most cases around 175psi cylinder pressure. For aluminum, about 8.75:1 with a tight quench is fine, about 185-190psi.

[femtnmax]

I use 8.25:1 dynamic as a max with open chamber iron heads and no quench. This ends up in most cases around 175psi cylinder pressure. For aluminum, about 8.75:1 with a tight quench is fine, about 185-190psi.

Using moper's aluminum dynamic ratio and the KB calculator, the piston valve recess volume needs to be reduced.  Here's the results:
cyl head volume   63cc
piston volume        2cc  Sealed power valve relief volume
head gasket         0.039
gasket bore          4.18
cyl bore               4.07
deck clearance       0
stroke                  3.31
rod length             6.123
intake closing         59 degrees abdc
RESULTS:   10.57:1 static compression and 8.73:1 dynamic
These are good sounding numbers.
Now apply my test by increasing the combustion chamber volume to a iron head type lower compression.  I used 73cc head volume, all else the same.  Gives static ratio of 9.4:1 for "regular" grade pump gas at 4000 foot elevation, and 7.8:1 dynamic compression, which is in the 7.7-8:1 that I suggested.  So it checks out.
So the kB pistons for the 340 have too large of valve reliefs to properly set up a strong running engine with aluminum heads and good quench.  Sealed Power pistons have smaller valve reliefs.

These results are worth posting on it's own post so I'm going to .

[moparmaniac59]

denniskauf,
I hardly doubt you're a Mopar enthusiast if your first post is an ad for a payday loan. I have some swamp land in Florida I'd love to sell you. 

                                                     Matt B.