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Since I can't get the RHS Pro Torqurer heads in a 72cc head and that moves me up to the Pro Action RHS heads that is a 72cc head with a 180cc intake runner part number 12001,how bad of a hit will that make in torque in the lower RPM ranges??.Pat,I am going to go with one of your design cams,do you think for this application a 4-7 cam would help broaden the torque band??.What kind of numbers do you think I would end up with given both items??.
Still looking for opinion of me having using a 180cc runner and how that is going to effect the torque band??.
Should be fine.
It may give you a bit more top end when you take that thing on the strip. ;)
The OEM roller lifters are really limited.My 1995 L31 came threw with the bosses threaded in the valley,but was a flat tappet cam.I am going roller(hyro roller that is)so Comp Cams has a upgrade to the spider lifter retainers and better roller lifters.This is a street towing van that I want to play when the trailer isn't on it.But I doubt it will ever see a strip.So the lower end torque is a sensitive subject.We wanted to go with the RHS 170 intake runner Torquer iron heads,but found they are not offered in a 72cc head.They if they where offered in a 72cc head would have been perfect for my use.I am totally sold on the RHS cast iron clean cast tech,so another brand is out of the question.
Still would like to have a guesstimate what I am losing on the bottom end.........using the 180cc intake runner over the 170cc's.
the stock gm roller stuff is fine built many. the marine stuff used most gm lifters and will see the same rpm you will ever see . buy new gm roller lifters they last for many miles .for the cc runner from 170 to 180 i would of liked to see the 170 heads but real dyno numbers would be the acid test
Pat, I don't mean to get in anybody's way here, I just want to help.
Gary, I just went back and re-read the entire thread. 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.
650 carb on an RPM intake, 1 3/4" long-tube headers, H-pipe right after collectors.
12 degrees spark timing at the crank, 22 degrees at the weights for a total of 34, all in by 3000. I see no need for a double-throwdown super-over-and-under distributor. A well-built HEI (shimmed at the drive gear) should do it. Use a Crane adjustable vacuum can. Coordinate the dizzy drive gear with the cam mfg.
Use CompCams 08-410-8 or equivalent, installed retarded 2 degrees.
08-410-8 - Magnum
RPM HP TQ
1000 63 331
1500 111 388
2000 160 420
2500 202 424
3000 256 448
3500 312 468
4000 360 472
4500 396 463
5000 419 440
5500 395 377
Peak volumetric efficiency 88.7% @4000
Peak BMEP 186.1 @4000
The only thing that bothers me is the full dish on the pistons. I would prefer a D-cup with a nice squish pad, but if Pat says they will work, that's good with me.
The goal here was to build a max torque motor at rpm's useable for towing.
If anyone sees anything on this post that won't work, please holler out.
no thats fine with me tech ..i think the rpm is to hi for max TQ engine were my cam will not make that HP it will make max TQ under 4000 rpm and that will work better for pulling and MPG ?????? :) the ic735 is a step dish i do not see any thing saying it is a full open dish piston ?? it has some pad
I'm liking alot the 400lbs or more of torque.
480 of tq should be in your reach i was getting that at under 3600 rpm the comp s cam s i did run them as were on the file . i just made more of TQ with a Erson /Mc grind
I think the Scat stroker profiled 4340 I-bean rods w ARP 9740 7/16" capscrews part number SCR5A7,Howards Track Smart 4340 steel crankshaft with Kings bearings should be able to handle that torque rating with room to spare.A over build for long term reliability.Likely going to need the expensive Mallory metal for balancing.What's your opinion??.
i pm you and it did not go threw some thing going on with the form . on the mallory metal No and you do not need the 4340 crank cast is more what you want . with the 4340 you will need to run the H bearings kings are ok but need to be fitted a every street driver cast steel is all you need. your friend can not sink mallory metal ? we can do that job if needed but you should be fine if you stay external bal like the 400 sbc
I got a whaling deal on the Howards.Close to the cost of cast steel.Jim has a shop that they farm out balancing.
OK, installed the 14097395 cam, retarded 4 degrees. Installed standard Performer intake manifold. No other changes.
RPM HP TQ
1000 68 358
1500 116 408
2000 172 452
2500 225 472
3000 264 462
3500 301 451
4000 334 439
4500 352 411
5000 348 366
5500 310 296
Peak BMEP 186.1 @2500
Humm.Given the wheel speed calculator here is what I got.
Engine RPM Calculator
700R4's don't like towing in O/D-so that is 1 to 1 in third.
At peek Hp this is what I got
Engine RPM Calculator
That is towing in third.............105mph pushing what is akin to a pc of plywood down the road.
Not towing in O/D:
Engine RPM Calculator
140 mph Astro van in O/D.
Now with enough courage,no one on the road,and a serious death wish..........I could get to peak hp in O/D.in a Astro that has the aerodynamics of a big box. LOL.
But all kidding aside,the ability to have enough RPM/HP for passing might be something here to look at.It is kind of dis-concerning to see 68hp at 1000 RPM.
Guess what I am asking here is we are making more torque than most if not all 4 cylinder diesel's,but my experience with them is at highway speeds,they are real dogs.Opinions??.
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 :)
gary clear your pm mail so i can send you your PM
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.:eek:
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.
http://i172.photobucket.com/albums/w...Picture329.jpg
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.
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.
Well playing with it again.Pat/Richard if I go to the RHS TQ 64cc head and go .010 down it works out to be cr of 9.47.
I plugged in the correct numbers in the formula below.It won't copy and paste that way.
Engine Compression Ratio (CR) Calculator
That would get us back to where we wanted with the added bonus of the head intake runner we wanted too.
Damm,don't know where I came up with the pistons being 12's.:confused:
Richard the heads are not purchased yet.We are spec'ing this build out.So to change out to a 64cc head .010 down is no problem at all.
Man-that's embarrassing.But better to be corrected that be cash out wrong.No wonder Pat was talking the 64cc heads all along.Still a newbie mistake on my part and I admit it on the open forum.
Thank you
we were hear some time back and i was thinking you did not want to run good gas in it or you may not find good gas ? so we went down 1/2 a point or so . may not ping and if it starts your pulling timming out its never going to run good . i can not say under a very hard load its or going to death rattle at 9.5 small dur cam and low grade gas .i would stay on the low side cr . 1/2 point may not hurt or help i can not say if you want the 64 heads i will get you any thing you want
Well I am a strong believer in RHS,but if they are not going to work than they aren't.What's your opinion of a cr of 9.21 with a world 67cc s/r t/q part number 4266K??.I do think you brought those up once before.Gas I would use is 92.
use any head you want . i do not mean this in a smart way .the pistons are fine with the 72 cc . just live with the 8.94 or just cut 2 cc off the heads and that not much .010 thats 2cc (but i cc as i cut the heads could be abit more or less) and use the 180s . the 383 will take either head and like i said on this i can not give you real numbers as all my numbers are base off stock heads with a 202iintake and 1.6 ex if tech has flow numbers on the heads let him run the two heads at 9.1 cr ? and see. with the small lift numbers it could be very close. yep i did talk about them and i did say i like the PBM thunder heads too :)