well then ok but .... thats what you want.... not what you are going to need ....stock block will fail before the rods crank will.. what makes me happy is building what i need and still have money left .but that is not allways been a hard fast rule .yep things have gone off the rails but when i look back of all my engines i built for my self the 396s and 468s where the less on the $$ and the most fun as the cost to fun ratio was in line
Originally Posted by pat mccarthy
I have read this before on EFI's and cam choices.
Fuel Injection Engine Camshafts:
For a camshaft to work in a fuel injected application, it needs to make a good vacuum signal.
To create a vacuum signal, that stands a reasonable chance at working in an application without having to re-flash the ECM computer, a camshaft needs to be:
a) Short Duration : 220-222 Degrees @ .050” Maximum
b) Wide Lobe Separation/Centers: 112 to 114 degrees Minimum
Do not attempt to install a camshaft with a 108 lobe separation in a fuel injected engine, unless you are planning to re-program the ECM computer.
There are camshafts that are ground to work within the stock ECM computer parameters. Usually these camshafts have 208/208 degrees duration @.050” (intake/exhaust) and 112 degrees of lobe separation, or 208/214 duration with a 114 L/C
Both of these camshafts would be designed to function in stock CID engines/stock compression and stock computer programming.
However, if the cubic inches of the engine or compression ratio is larger than stock, the camshaft grind needs to grow accordingly and a custom camshaft would be in order.
Also, having the computer re-programmed/re-flashed is recommended with any camshaft change, even the “no hassle/safe” type grinds.
While the camshaft may work with the stock fuel/timing curve programmed into the ECM unit, it will not be working at its optimum level…..Think of it along the lines of taking a performance carburetor out of the box, bolting it onto the engine, hooking up the fuel lines and running it. It may run but without tuning/jetting the carburetor to the engine, it will not work to its full potential.
While we are on this subject, there are some engines that you need to be wary of:
Late 80’s-Early 90’s 350 Chevrolets with a K engine code and an idle speed of 500 R.P.M. (TBI)
Early Ford V-8’s with the Speed Density fuel injection.
Dodge Magnum V-8’s
Any Fuel Injected application where the customer wants a loud/radical idle.
These engines/computer combinations have very special camshaft grind requirements, so should you run into one of these combinations, it would be best to call the Erson Tech Line (775/246-4062) for a recommendation.
Now I certainly do expect to reprogram the ECM.Question is if I do use a lower L/C,then do I go for a vacuum boost or trade off some of the bottom end to get a wider L/C and given a L/C is there a formula showing the differences in rpm's where the torque band starts.
The question of using a carb on this build is not a possibility.It will be a some kind of EFI.
Pat-the PBR cam# e119847 has a 112 L/C closer to the target for a EFI engine.What you think of that cam??.
well like you just posted about the old computer set up none of the cams are not going to work ??? all past the dur of a stock cam . the map will not like it. like i said on the phone to you and i posted :) so i can not help if your sticking to your old setup now if you go mass air then them cams will work .if you can fool your old setup fuel MPG is going to hurt and it will run crappy and wash down the walls idle very rich and wear out the engine seen it done .i can not add any more. i do know what i seen in the past and the last roller engine i built with a very small hyd cam with the PBm thunder heads and a Ersons custom ground for a K code and that was last year and could use a chip was used in a burb as a car hauler. you can go up on abit more cam lift then stock and have done that to with a stock cam and 1.6 rockers and may not see much. not to be a smart a$$ but i done this build with a 355 and whats holding you back is the old setup
Pat-just posted on the other thread.Mass air for the early on.So the lobe center outline being 112 or better still applies,right??.
you can run more cam with mass air .. talk to the guys you know thats going to tune it in for you but i think you can use any cams that have been listed . it s not just one part of the cam like 112 its the dur to
OK-FYI-the crank order will go out on the 13th.Jim said this wk the bore and hot tanking will be done.Wanted me to take the block back until the rest of the parts are here.I'll post detailed pictures of the bores and block once I get it back.(close shots of it that is)
Top ring was alittle tight and we took out one thousand.The rest was dead on perfect.Still tons to go on this build................we'll update as progress is made.
Got the block back with all the machine work done,painted,new copper soft plugs,new cam bearings etc.Buying the rods are next.Jim took the crank to check it out.
This thread has been rolling along for awhile. I had my sbc 383 built with torque in mind and as low in the rpm band as I could get it. What this gave me was a sweet, streetable engine that is overkill in the torque department for moving my 1790 lb Track-T. The last dyno sheet I have was last November at 4500' elevation in Sierra Vista, Arizona, during Fred's Fun Run. This are roller numbers, not crank numbers, but I have those too. On the chassis dyno...
272.2 hp @ 4050 rpm
432.5 lb/ft @ 2800 rpm
Dyno tech asked me if I was running a "rock crawler" engine in my Track-T. On the first few pages of this thread, compression was discussed a lot. My feeling is to run as high as your local pump gas will allow. For me here in California that means 91 octane, so if iron heads, 9.25 to 1 or aluminum heads, 10.25 to 1.
Crank ratings are
320 hp @ 4050 rpm
516 lb/ft @ 2800 rpm
Deckofficer..... do you use it on weekends for pulling stumps
Yepper Bob.For one reason or another this build has gone on and refined for 5yrs.:eek:The assembly is close with the rods next and the bearings.I have to get a H/B and flexplate to do the balance.But once it started,the time to get to the finish has rapidly been coming to a end.I am still playing around with what EFI I will end up with taking all the cautions under consideration.
Charlie-the second dyno sym that Richard ran for me was close to the same numbers.I do wish it was some more HP,but that is just me wanting his cake and eating it too.
Originally Posted by cffisher
Yeah, I sure miss the high rpm zing of the previous engine. And I'm no fan of externally balanced engines in super light cars. 1st attempt at getting this engine built resulted in too much vibration that more than likely would have gone un-noticed in a 5000 lb truck. But one thing that is truly fun to do to a friend with this engine and that is when on a deserted, limited access highway, slowly creep up to around 120 mph in the 0.64 OD top gear, and when your friends realize the speed and freaks a bit, you can roll it all on without downshifting, asking him if he wants you to pull a gear to really see what it will do? At 120 in top gear, I'm at my torque peak of 2800 rpms (I'm very talled geared) so I hope he says "no" because if I did pull that gear, the jig would be up because at that speed it would pull harder in the top OD gear, but most people have never experianced an engine with the peak torque so low in rpms. This engine's hp starts falling off at just 4050 rpms.
Originally Posted by 1gary
Bob-the Howards crank is internally balanced.So that part of it shouldn't be a issue.The 700R4 is O/D of .75.Yeah I wish I had the funds for a trans like yours.But that would be a death wish going that fast in a High top Astro.:eek: