Thread: Ford 302 DynoSim, street motor

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I haven't run a DynoSim for a while, particularly a Ford motor, so here we go on an early non-roller 302 block. This motor will be built as a retro-fit roller cam street motor and if built with the tight squish I suggest here and using common sense igniton timing, it should run great on pump gas. The BMEP is fairly high on this build, because I kept tweaking it until there was nothing left on the table.

We'll be using the stock crank and rods, with the big end re-sized and ARP rod bolts installed. Personally, I wouldn't use any vintage OEM parts such as the block, crank and rods until I had them magnafluxed, but that will add cost to the build that you may not want to absorb. Your call.
http://www.competitionproducts.com/A...info/154-6002/
This might be a good alternative for those of you who would rather begin with a new rod....
http://www.summitracing.com/parts/SCA-25090P/
We will be zero-decking this block and running a 0.038" compressed gasket, so we will need to do some measuring on the block to see how much to remove from the decks. It's a good idea to align hone or align bore the main bearing saddle as a first operation, but there are millions of rebuilt motors out there operating daily that have never been trued since they were machined at the factory. Your call.
The stock 3.000" stroke crank has a radius of ~1.500". The stock rods are ~5.090". The piston I have suggested here has a compression height of 1.605". Total these values and find a "stack" height of 8.195". Nominal block deck height is ~8.206", so removal of 0.011" would be required in this case to achieve zero deck. Measure your components carefully.

Run any flat-top piston you want to, as long as it is a true flat-top with no reduced area on the crown, except for valve reliefs of course. You want to pay attention to the compression height to figure how much to cut the decks of the block to achieve zero deck. Here's a budget hypereutectic from Summit that will work. You can see that the piston has a generous flat area on the crown adjacent to the bore. This flat area will mate up with the underside of the cylinder head to produce an excellent squish, blowing mixture across the chamber and creating turbulence to equalize rich and lean pockets of mixture and reducing the possibility of detonation. With a zero deck block, the thickness of the head gasket will be the squish figure (0.038" in this case) and the safety margin to prevent piston to head interference. Always use piston to wall clearances and ring end gaps recommended by the piston manufacturer.
http://www.summitracing.com/parts/SUM-17302-30/

We'll use the Edelbrock 5023 heads, 1.900"/1.600" valves....
http://www.edelbrock.com/automotive_..._estreet.shtml
Static compression ratio will be 9.80:1 with these 60cc heads, about as high as we would want to go on pump gas, even with aluminum heads, in my opinion. Consult with the cam grinder about the springs before you order the heads. The springs that come on them may not be enough spring with hydraulic roller tappets to 5500 rpm's (heavier than hydraulic flat tappets, so may require more spring). A rev kit installed in the lifter valley may be the answer. Consult with the cam grinder. I'm pretty sure these are the Edelbrock spring specs on the springs installed in the 5023 heads at the factory....seat pressure 125, installed height 1.750", open pressure 325 @ 0.550", O.D. 1.250", I.D. 0.880". Coil bind 1.150". Maybe Pat McCarthy or Jerry Clayton or one of the other engine gurus can chime in here and tell us whether or not we would experience valve float up to 5500 with these springs. If they don't answer, lean on the cam grinder for advice on this. Install the heads with Edelbrock #7313 head gasket (4.100" X 0.038").

The cam will be a custom grind retrofit hydraulic roller. I don't do flat tappet cams any more. Howards might be a good choice to grind it for you, they seem to be more reasonable than most of the other grinders. Here are the specs I used....
Duration @ 0.050" tappet lift- 216/224
Intake centerline 109
Exhaust centerline 115
Lobe Separation Angle 112
Intake lift 0.520"
Exhaust lift 0.542"
Cam timing events -1/37/47/-3
Overlap -4

I used an Edelbrock #7121 RPM intake manifold with a 650 carb. The motor wanted 1 3/4" headers rather than 1 5/8" and I noticed that when Edelbrock dynoed their power package, they used 1 3/4" headers. Seems rather odd for such a small displacement motor, but hey, I just do what I'm told.

I wouldn't think you'd need more than about 34 degrees total ignition timing with these heads. I might start with 14 at the crank and 20 at the weights. I might be tempted to install this Summit HEI Ford distributor....it should work fine to our rev limit of 5500....
http://www.summitracing.com/parts/SUM-850021/

RPM HP TQ
2000 129 337
2500 164 345
3000 211 370
3500 262 393
4000 308 405
4500 347 405
5000 376 395
5500 385 368
6000 367 322

You may find street builds that make more hp, but check where they make it on the rpm scale. This motor signs off at 5600. You can make an additional 10 hp and 5 ft/lbs by using an off-the-shelf CompCams 31-422-8 hydraulic roller, but bottom end torque (@2000 rpm's) suffers by about 12 ft/lbs. I factored the Edelbrock cylinder head flow figures down by a factor of 0.95 in an effort to eliminate any "overexuberance" on their part.

What tranny and rear gears for a 66 Mustang?

just finshing a 289..040 over O deck recon stock rods with ARP bolts 302 ford flat top .engine came with a set of winsor heads 9to1 use a Erson hyd roller E21832 grind RH-288-2 0.512/0.512@050 219/219 lc 110 weiand dual plane springs were 135 and 320 open trend push rod lifters have to go in before heads push rods are very short 6.050

G-Force synchronized Street 5-speed, 2.95/1.94/1.34/1.00/0.75, 8.8 rear with 3.70 gears/Detroit Locker/Traction Lok. First gear final drive- 10.92:1, Fifth gear final drive- 2.78:1
http://www.gforcetransmissions.com/tran_gt-5.asp

For an auto car, I would do a Hughes-built C4 and 2500 stall converter and maybe drop back to 3.31 cogs in the rear to keep r's down a little.

not ever again on a detroit locker for me that was the only way at the time to use 35 spline axles. with out a spool

i hate to ask but what does bmep is high on this build mean? what bmep mean?

Originally Posted by slepper63

i hate to ask but what does bmep is high on this build mean? what bmep mean?

It's an indication of cylinder pressure and stands for "brake mean effective pressure". The figure is determined by several factors, but the main players are the efficiency of the intake manifold and cylinder heads, static compression ratio and the closing point of the intake valve in relation to crankshaft and piston position. If cylinder pressure exceeds the detonation resistance of the fuel being used and there are no mechanical interventions such as squish, then the motor could detonate and disassemble itself. You may have heard an engine "ping", also called "spark knock" or "dieseling". That is detonation and is like someone swinging a sledgehammer down onto the piston crowns for each ping you hear. Broken rings and broken pistons or worse won't be far down the road if you allow detonation to continue unchecked.

You'll see that I specified a very tight "squish" dimension of 0.038", so that by the time the piston gets a little taller from combustion heat, the crankshaft bends a little and the rods stretch a little, there will be a near collision of the piston crown with the underside of the cylinder head. This "jets" the mixture from this area and across the chamber, homogenizing the mix so that the possibility of detonation is reduced. David Vizard has done extensive testing of the squish dimension. He said that the tighter he ran the squish, the more power the motor made, down to a squish of 0.026" on a SBC, where he encountered interference between the piston crown and the cylinder head. He is a no-nonsense writer and you may gain some insight from reading his material.