So given the lower octane Euro fuel (I am guessing its lower than the states?)...running 10:1 with a shorter duration cam and iron heads is going to be a challenge. If you are dead set on the cam, it would probably be best to buy a good set of aluminum cylinder heads. Aluminum is a better conductor of heat, so it can shed heat into the cooling system faster/better than iron (which is a relatively poor conductor of heat). This reduces latent combustion chamber temperatures and help to prevent detonation.
Well you asked for an opinion,so here goes.
You said that you wanted to learn about building engines too. I'm no pro, but I've built a few. There are a couple of things I thought I'd mention that you may or not already know.
Try to keep the squish/quench(distance between flat part of piston and flat part of combustion chamber)around .040". The turbulence created by the piston squeezing the mixture into the combustion chamber makes for a more efficient burn, and helps to suppress detonation.
Check out artice and the compression calculator at the end:
Before you order the crank, decide on what length of rod you want to use as well as piston. If you can get a rod/piston combination with the correct weight you can get an internally balanced assembly instead of having to use an externally balanced assy(harmonic dampner has an imbalance to compensate) which creates alot of extra stress on the No.1 main bearing/cap. You can probably tell Callies your rod/piston specs, and they can balance the crank before they ship it. You should talk to them before you buy anything, but have some part numbers(and weight specs) for the rods (5.7" or 6.0") and pistons you have in mind. They may already have the weights recorded from previous builds.
I had to use a 6" rod for my Scat 3.75" stroke crank to get an internally balanced assy for my 383, unless I wanted to spend alot to add heavy metal to the crank. By the way, the Scat 6.0" rods I bought/recommend (pn2-ICR6000-7/16) come with ARP capscrews instead of through bolts that stock
rods have(that usually have to be pressed in at the machine shop, and that usually have to be ground off some for clearance). The Scat rods are weight matched, and have a bushing for the piston pin. You don't have to pay/wait for the shop to press on pistons like stock rods.
Most pistons for a 3.75" stroke crank/6" rod combo have the oil rings intersecting the piston pin hole, and require an extra ring/support rail. Mahle offers a piston with a 1.125" compression height (distance of pin centerline to top of piston) needed for a 6" rod that the oil ring doesn't intersect
the the pin hole, but the one I'm refering to Flat Top(pn SBC125125F05) only has 5cc volume. They have many others, but I'll let you look them up. You can get Mahle pistons(good stuff) made the way you want to a certain degree from what I understand by contacting:
Being that the 400 piston is larger/heavier you may be able to use a 5.7" rod and get an internally balanced assy. It would also probably not have the oil ring intersect the pin hole. I wouldn't use a stock 400cid 5.565" rod if it were free. Look it up.
If you don't mind the oil support rail Sportsman Racing Products(SRP) Forged Inverted Dome Top Pistons pn 231319-1, 4.125" Bore, Dish with 2 valve Reliefs, +16.0cc Volume, 1.125" Compression Height(6.0" Rod, 3.75" Stroke), Press or Floating Pin has the volume you need to get the CR you want with the heads you have. The inverted dome design enables there to be flat portion of the crown to provide the desired squish/quench effect. The compression height plus the rod length plus 1/2 of the crank stroke(1.125 + 6.0 + 1.875 = 9.0) equals the distance the piston crown/top measures from the centerline of the main bearings, which is also the reference for the
block deck height measurement. A stock sbc, and I believe your Dart block deck height is 9.025"(better check). That would leave the piston .025" from the deck, or .025" piston to deck clearance, or .025" in the hole
(as if you didn't know). Most head gaskets that I've seen have a compressed thickness of .039". That measurement plus the .025" piston to deck clearance(.039 + .025 = .064) makes for a very poor squish number that has little benefit.
To buy a Callies crank and use cast iron heads doesn't make any sense to me. If you don't buy aluminum heads to go with it now, you'll wish you had later IMO. The weight savings off the front end is around 45lbs. They generally let you use about one more point of compression. If you wanted to try your hand at porting, they are much easier to work on. However it is easier to mess up a spark plug hole, or strip a rocker stud, but its also easier to repair. Alway use anti-seize on the threads.
Even if you stick with the heads you have, as meticulous as you were with the Vette, you would probably want to install Iskendarian Guide Plates pn ISK-200-AGP to align those roller rockers onto the valves.
Also make sure the springs specs are up to the roller cams requirements.
Being that you mentioned the Morel stock type roller lifters you may want to look at the Comp Cams GM style spider/lifter retainer kit pn 08-1000 or 08-1001 depending on which cam retainer you need (slight difference between bolt center spacing). Measure the distance between the mounting holes for
the cam retainer that mounts between the cam timing gear and the block(at least I think it does on a dart block)to determine whether you need Comp pn 8105 CR, or 8104 CR cam retainer. Lot easier, and more reliable than a cam button IMO.
FWIW, after looking around for a combination that would give you the compression numbers you mentioned along with the cam(XR264), I used Pat Kelley's calculator and entered the SRP piston specs(16cc), a Cometic C5248-027 Head gasket(4.165 bore, .027" thickness)(6.03cc), a 72cc combustion chamber, 3.75" stroke, 6.0" rods, and shaved .015" off the block decks to get a piston to deck clearance(squish) of .037". I know you don't want to deck the block, but it was the only way I could get the squish/compression numbers. Maybe you can with some more combinations.
It gives a static compression of 9.54:1, and a dynamic compression of 8.02:1. Since you want the electronic quadrajet those numbers should be safe IMO for the heads you have and todays gas.
That along with the 180cc ports you mentioned would be large enough for a great torque engine that will rev to around 5500rpm with your intake, and have plenty of vacuum for your needs.
I also believe that it would likely break the tires loose any time you floor it below 60MPH(I forget the relative kph numbers I used to see on the Autoban in the early eighties).
The Cam Quest simulator shows over 450ftlbs from 2-5K rpm with a peak of 496ftlbs@3500 and 430HP @ 5krpm(with a non-electronic carb). I believe it would be a blast to drive and pass emisions too. It doesn't make your 450HP figure, but at first you said you wanted torque.
Excuse me if I mentioned to many things that are rudimentary, but you did mention that you wanted to learn about engines, and I didn't know where to start.
Good luck whatever you decide!
PS Use the link provided in the article to download a copy of the calculator and double check my entries!
|The Following User Says Thank You to ssmonty For This Useful Post:|
Thank you for the big writeup. I always appriciate it when people take the time to write an answer I understand compleetly.
As for the quench, yes I wanted to stay between 0.038 and 0.040.. (some). If the decks have to be milled then that is the way it is. Right now I think it's still stock, still have to check. But with 0.025 down the hole can't I find a gasket that is around 0.014 compressed (like the OEM copper one?) I see everybody working with the 0.039 gaskets but is that because they are best or is everybody zero decking for easy calculations?
If I've read it correctly then the rod/piston relation on a stock 400 is best (compared to larger 400's). Will cause less drag of the piston against cylinderwall is what I've read. So no piston pine hole crape ring problems. It will not be a pressed in pine but with floating pins.
I see in Richards sims he uses alot of alu 190 / 195 heads. When I go with alu heads SCR can go up from 9.5:1 to 10.5:1 but DCR. I think you are absolutely right what with the Callies crank I should also go with good heads.
When I have some more time I write down a calculation for the total price I (or we) pay for a expansive and cheap crank so you'll see I'm not totally crazy )
You're right I still need to buy the guide plates! I didn't know about the cam retainer, does that mean I can use a cheaper stock timing cover or still need like a compcams two piece cover?
I'll look at everyting in more detail tonight, have some more work to do today
Here's a hard-core dyno pull by Air Flow Research.....
Engine: 413 cid small block chevy
Heads: AFR 195 aluminum cylinder heads
Ignition/Timing 36 degrees
Cam: solid flat tappet
Exhaust:1 3/4" primaries, long-tube headers
Fuel: 92 octane pump gas
Manifold: Holley 300-25 extended runner
Here's another hard dyno pull on a 400 small block from AFR.....
Heads: AFR210 Competition package
Ignition: MSD distributor, 36 degrees
Cam: Lunati hydraulic roller, 242/252, 0.560"/0.572", 112 LSA
Exhaust: 1 7/8" long-tube Hedman headers
Fuel: 93 octane pump gas
It's interesting to note that the smaller heads will whip the larger heads up to
6000 rpm's, where 99.9% of your driving will be done. A bigger head will not always do a better job of making power, due to the slower velocity of the air fuel kernel not packing into the cylinder like the faster kernel in the smaller ports of the 195 heads. Bigger is not always better.
In these two pulls, it should be evident to you that you will be making more cumulative torque and horsepower with the smaller heads, from about 2000 rpm's to redline. They don't show the figures under 4000, but trust me, the smaller heads are kickin' butt from 2000 to 6000.
Last edited by techinspector1; 05-10-2013 at 01:58 PM.
|The Following User Says Thank You to techinspector1 For This Useful Post:|
excellent post Richard!
so many people recommend 200 cc intake runners on a 350 and the tell the builder to use a 600 cfm carb?
Should be the other way around,use 180 cc heads and a 750 cfm carb
I'd disagree with those who say the stock Chevy 400 rod/piston relationship is the best. If you mean
rod to stroke ratio(I don't think so), I'm with the crowd that believe the longer R/S ratio benefits out
weigh those of the shorter R/S ratio mainly for the reduced side load/friction on the piston.
Another benefit of the longer rod in a 400 is to be able to balance the rotating assembly internally
with out heavy metal in the crank. I just figured to get two for one. I just wanted to make you aware
of the facts before you buy anything.
I don't remember which side of the flexplate has the welded on weight, but I couldn't see it in the pic
you posted. If its for an externally balanced 400 there should be an offset weight on one side. Also I
couldn't see anything to indicate the balancer in the pic was for an external balanced assy., but if I'm
not mistaken you can buy a bolt on weight from ATI to bolt onto the dampner if you want, but you
better double check.
An article you might want to read;
406ci Small-Block Chevy - Car Craft Magazine
They made a mention of a standard 5.7" rod assy, but I'm sure your aware the stock rod is 5.565".
Like I said, you can get pistons for the longer strokes/rods that don't have the oil ring groove getting
into the piston pin hole. See the attached pic of my 3.75" stroke/6.0" rod piston and see for yourself.
It has a compression height of 1.125" where most have a comp height of 1.130" or more. True it has
to use the thinner rings(1.5mm) vrs the more common(1/16"or 5.64") to get them all squeezed in
between the crown and the pin hole, but if Mahle thinks there good enough, then thats good enough
Check out: http://www.summitracing.com/parts/mle-sbc125125f05
The only problem is that it has only 5cc of volume and with 72cc heads it comes to over 10.3:1 CR.
I think you can get them more to your needs if you try.
Another article you might want to read:
How To Build A Kick-***, Pump-Gas, NPAA 680HP Small-Block Chevy - Car Craft Magazine
You can use the stock timing cover with the stock cam retainer as far as I know, but it does require
a stock type timing set, or at least an aftermarket type specifically made for a stock applications.
The stock roller cams as well as aftermarket cams specifically designed for roller cam blocks, have
a nose that has turned down steps that fits through the retainer, and into a bore on the back side of the
cam sprocket. The back of the retainer keeps the cam from moving forward. The back of the sprocket
pressing against the front of the retainer keeps the cam from moving back into the block.
As far as the stock cover its a different matter if you get a double roller timing set as they are wider
or thicker(depending on your point of view). They generally protude farther forward from the front of the
block, and contact the inside of the cover, or too far rearward and contact the block around the
uppermost oil galley. I don't know if thats an issue with a Dart block. You can see where I made
clearance for a double roller on the front of the block in the pic.
They(GM) made two different retainer plates for the roller cam equiped V8s. PN 10168501 has
3.294" bolt hole centers, and PN 10088128 has 3.620" bolt hole centers. They don't come with the
bolts they use at the factory pn 14093637(have to buy two). You might find a hex head bolt, but it
needs to have a bolt head that is not as thick as standard bolts or it may contact the sprocket.
Depends on the sproket as well. A button head is an option if you don't mind an allen socket, but
not known for torque. Either definitely needs locktite IMO.
This article has a list of part numbers you may want to check out as well as some I just mentioned:
Chevy Small Block - Car Craft Magazine
Vinnie, you caught a mistake I made on the Cam Quest simulation as I had used a
"Dual Plane High Flow" intake instead of a standard flow which I'm guessing would approximate
the Vette intake? Nice catch, and I appologize to Peter for posting bad info. I ran it again and come
up with 403HP, and 479ftlbs at the same rpms, but even then their just estimates that are probably
inflated a bit. Sorry for the error. Won't be the last.
Hope some of this helps.
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