Thread: 383 build-Something Caught My Eye

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Originally Posted by pat mccarthy

gary clear your pm mail so i can send you your PM

PM's cleared Pat

Originally Posted by pat mccarthy

cam i used was 224/230 480/480 lsa 110 in at 108.. TQ is what gets you rolling from the get go i take TQ over Hp any day to pull we have cams that make over 1000+ tq on a small shot of Nos hard to beat that. thats the seat of your paints feel as you get nailed in the seat with the big engine and bust weak drive train parts

The torque side of street vehicles I know about that and agree.You know it's a typical cake and eat it too question about hp.LOL.

Naw-this old boy isn't going to get hooked on the bottle.$$$ refills.

Still playin' around with this tow motor....
Custom cam 206/214, 106/113/109.5, 0.420"/0.420, (-3)(29)(40)(-6) installed straight up.
Streetmaster intake manifold (1st design).
http://cgi.ebay.com/ebaymotors/Edelb...Q5fAccessories
RPM HP TQ
1000 88 461
1500 149 521
2000 204 535
2500 247 520
3000 289 506
3500 319 478
4000 346 455
4500 357 417
5000 348 366
5500 319 305
Peak BMEP 210.8 @2000. This is some serious cylinder pressure, so a very tight squish (I would be thinkin' 0.035" to 0.040" with a D-cup piston) would be mandatory to prevent detonation on pump gas.

Wow Richard!!!.Well the Icon's pistons #9926 for this build is in the hands of the machine shop to be bored..030 over on 5.7 rods @0 deck.They are a step dish.






That is 9.4 C/R with RHS#12001 72cc heads and a intake runner of 180cc.

Originally Posted by 1gary

That is 9.4 C/R with RHS#12001 72cc heads and a intake runner of 180cc.

No, here is a copy of what I figured in post #47...
I'd use the 12410 heads. With your 18cc pistons, in the hole 0.010" and a 0.040" gasket, you'll be at 9.4:1 static compression ratio. The 12410's have bronze guides, 64cc chambers, 2.02"/1.60" valves, +0.100" long. I might order the heads bare from Competition Products along with the valves, springs (part number on the timing card linked here), etc. and have Pat put 'em together.

You can use anything you want. I was just trying to follow along. The custom cam I suggested in post #63 works real well with the 9.4, but you won't have 9.4 if you run a different chamber size. Also, I don't like those pistons. The only squish there is....is a thin ring of material above the rings. Ain't gonna be much squish there. Might work ok, but they wouldn't be my choice for a high cylinder pressure motor.

Richard that is my fault.I'm sorry for the misleading info.
We looked at 0 deck and a 72cc head.Wanted a 170 cc runner but they in RHS tq'er's are not available in a 72cc head.I am insisting in RHS's clean tech.So the compromise to the RHS 12001 Pro action was made.72cc head/180cc intake runner.

The other thing was a compromise was the pistons.For what seemed like forever I was going with Mahle#SBC42530I26.Those would have been over $700 special order.I couldn't justify that cost for my use.So the Icon's seem to be a good buy and compromise.They have a offset pin to help quiet them down and a forged top for durability with floater pins and locks for $329 + 11 and change for shipping.

So I am very sorry not to keep you up to speed on these moves.I promise to do better in the future.I needed to make these decisions to get this build going and out of limbo where it has been setting.AND I need you input and support.

Thank You.

Richard that is my fault.I'm sorry for the misleading info.
We looked at 0 deck and a 72cc head.Wanted a 170 cc runner but they in RHS tq'er's are not available in a 72cc head.I am insisting in RHS's clean tech.So the compromise to the RHS 12001 Pro action was made.72cc head/180cc intake runner.

The other thing was a compromise was the pistons.For what seemed like forever I was going with Mahle#SBC42530I26.Those would have been over $700 special order.I couldn't justify that cost for my use.So the Icon's seem to be a good buy and compromise.They have a offset pin to help quiet them down and a forged top for durability with floater pins and locks for $329 + 11 and change for shipping.

So I am very sorry not to keep you up to speed on these moves.I promise to do better in the future.I needed to make these decisions to get this build going and out of limbo where it has been setting.AND I need you input and support.

Thank You.

all cam on list make 550to525 of TQ with 9.1 cr Erson E119811. 214/214 480/480 110....E119813.219/219.480/480..110 and some Elgins e136. 210/215 462/470 110 but work better at 112. this looks good abit broader e1135..230/230..480/480. thing is with the custom cam .you have to fined the master s for the lobe or on file and a core so there is some times a trade offs so a custom would be fine but after spending more time on this there is many shelf cams that will get the job done

I thought the 383's liked a longer duration/ bigger lift on the exhaust side of it.But given a towing situation/street van,it might not be significant.

The vacuum shouldn't be a issue here.TBI's systems need to keep the vac up.

Heading out to the shop to get work done.I'll look up those number cams maybe later today.

I just want to add that I am suggesting we keep mindful of the parts in this engine while building the numbers for it.Just a two cents thought I have.

Thanks guys.

Gary

As I said in post #65, you had 9.4 with 64cc heads, but you won't have 9.4 if you change chamber size. I have everything except gasket volume, which I will estimate at 9cc's.
cylinder 783.84
chamber 72
piston 18
piston deck height 0
gasket 9
Total is 882.84
Dropping out cylinder is 99
Divide 882.84 by 99 and get 8.91:1 static compression ratio. Everything is different, so be careful with your cam choice.

Richard those pistons are not 18's.They are 9.71 c/r with 64 cc heads.

Originally Posted by 1gary

The KB's I looked at on their site with a -12 dish that they call a 383 is for a 4" bore.Actually pretty common term to call that a 383 too.The part number they used is KB193.With that the c.i. given borex10746666666666667x3.75x8=376.991.Mine is going to be a 030 over which =382.667.So I took that volume for a static compression ratio and plugged that in at 0 deck with a .040 head gasket.It worked out to be 9.4867.

Engine Compression Ratio (CR) Calculator

That is getting closer to the 9.5 C/R.Should I be concerned about that??.Pat would that be acceptable??.Should I drop the 0 deck cut and just have the machine shop square the deck for a good ref point??.

Thanks guys.

Hope you feel better soon Pat.

Richard-here is how we came up with that C/R.

Originally Posted by 1gary

Richard those pistons are not 18's.They are 9.71 c/r with 64 cc heads.

We are not concerned with what they make with 64cc heads, you don't have 64cc heads.
Gary, let us start from ground zero.

1.You are building a 383. The bore is 4.030" and the stroke is 3.75". If we multiply that out, we find: (.7854 x 4.03 x 4.03 x 3.75 x 16.387 = 783.84 cc's).

2.The heads you are currently planning to use have 72cc chambers.

3.According to the KB site, the pistons you have chosen to use have 18cc crowns....
Icon Forged Racing Pistons
This piston is an open dish design with no squish pad. Look at the illustration I linked.

4.Piston deck height is 0cc's.

5. Not knowing the head gasket you plan to use, but estimating the compressed thickness at 0.040" and the I.D. at 4.100", we can compute the cc's thusly....
(.7854 x 4.1 x 4.1 x .04 x 16.387 = 8.65cc's)

Now, we add up all the values. (783.84 + 72 + 18 + 0 + 8.65 = 882.49cc's). This is the total volume pushed into the cylinder by atmospheric pressure with the intake valve open.

Now, we add up all the values with the piston at TDC, eliminating the cylinder volume. (72 + 18 + 0 +8.65 = 98.65cc's)

Now, we divide the larger by the smaller (882.49 / 98.65) and find 8.94:1 static compression ratio.

Math is black and white Gary, there are no gray areas.

ok 8.94 ? so this will not run at that ? what is the big deal just cut the heads to 70 cc that gets it to around 9.027 . dish piston? the deal is the stroke you can not run a flat tops so your going to used a piston that need a dish to get the CR down now if you want custom pistons i can have diamond make them they make nice pistons and would be my cost $1000. but still need to be dish and 18.6 to 17.6 to get the cc down and still going to end up like what you have now. other then that there s going to be traded off s from paper to the real world .i work in the real world milling the heads is still cheaper then $1000.set of piston ?

That is a decent catch Richard.Thanks.Pat how about going back to the RHS tq'er 170 cc intake runner 64cc head and running the deck 10 down??.Deck isn't cut yet.