|
By mikeT - 3 Years Ago
|
Working on my 292 project i have a Howards cam #290862-10
How do you think it will work in my combo?
fenderless truck hot rod will weigh 2700lbs?
ford 8.8 with 4.10 posi rear
T5 trans
292 engine .040 over, zero deck flat top piston's with felpro or best head gaskets
c2ae rods with arp bolts
Main studs with windsor windage tray deep sump pan , chopped up a scruby sb deep wide sump pan .Fitted sump to y block truck pan, modified pickup for 3/8" clearance from bottom of pan, holds 8 qts.
gerotor oil pump new
Heads are CT1E will be fully ported , milled to 70cc chambers. Will have manley stainless 1.85 intake and 1.55 exhaust valves installed
comp cams springs and hardware
Static compression ratio should be 8.7:1 to 8.8:1 ?
Intake is edelbrock 257 ported per Joe Craines advice will use holley 2x4 sniper fuel injection
MSD ignition
Headers into flowmaster mufflers
camshaft is 238 @ .050" I &E
lift is .350" lobe lift, rockers are Barker ,Approx. 1.5 ratio lash is .022"
valve lift should be approx..507" at valve with .018" hot lash
will check for piston to valve clearance .
Would this run on pump gas regular or premium?
going to be a fun street rod to play with on weekends .
thanks for the info 55blacktie
It shows dynamic compression at 7.24:1
|
|
By 55blacktie - 3 Years Ago
|
|
Go to gofastmath.com to calculate dynamic compression ratio. Personally, I would want more compression with your cam. Ideally, you want your dynamic compression to be close to 8:1. With flat-tops, 70cc heads, and 238 duration @ .050, you will be considerably lower than that.
|
|
By 55blacktie - 3 Years Ago
|
|
I've read Tim McMaster's article on porting the C1TE heads. It makes sense to me, if you already have the heads, and you are capable of doing all of the work yourself. On the other hand, I got a pretty good deal on G heads, which should flow as well as the modified C1TE heads, but without all of the work. With a street port, I'm inclined to believe the G heads will outflow the ported C1TE heads. G, 113, and Mummert's aluminum heads seem to be the preferred heads, if you are looking to increase performance. 411 heads, with their larger combustion chambers, are desirable on supercharged engines.
|
|
By 55blacktie - 3 Years Ago
|
|
Sorry to be beating this into the ground, but you did ask. I looked up CS Cams description of your cam. The rpm range is 2800-5400, which seems to lack both low and high end. Clay Smith also recommends a static compression of 10:1+. You've given considerable thought to your build, but I think you can find a cam that is better suited to your combination. Something with less duration and overlap will raise your dynamic compression ratio. Another option would be to use domed pistons.
|
|
By 55blacktie - 3 Years Ago
|
|
Well, I got everything right but the brand, sorry. I did look up the right cam, but thinking Mummert, I said Clay Smith, not Howards.
|
|
By mikeT - 3 Years Ago
|
|
Yes, I have the heads and will be porting them myself. Wish Mummert still had the forged pistons with .100" dome available? Cant justify 850.00$ for custom pistons on this project. I have read the Ted Eaton engine build with a similar camshaft ,it had a dynamic compression ratio that was close to this and it seemed to run good?
|
|
By mikeT - 3 Years Ago
|
Thanks Ted!
would you suggest advancing or retarding the cam ? The cam card says the intake closes at 45 degrees
|
|
By mikeT - 3 Years Ago
|
Dont know why I didnt post the cam card already??
|
|
By mikeT - 3 Years Ago
|
Thanks Ted,
My rods are the C2AE I believe there 6.324 long?
would that change the dynamic ratio?
|
|
By 55blacktie - 3 Years Ago
|
|
gofastmath dynamic compression calculator asks for "IVC @.050."
|
|
By 55blacktie - 3 Years Ago
|
|
Mike T, I just sent a PM. If you didn't receive it, let me know.
|
|
By Cliff - 3 Years Ago
|
|
Steel shim head gaskets and a cut on the cylinder heads will help.
|
|
By charliemccraney - 3 Years Ago
|
I agree, it needs more compression. Build it to take advantage of premium fuel. Do not get caught up with the cost of premium fuel. More compression makes it run more efficiently (and with a cam like that, makes it less sluggish from a stop) which will translate to higher mpg, if that's even much of a concern for a hot rod.
I think the 8:1 dynamic is about the limit for pump gas and gives a bit of a cushion for a bad tank of premium.
|
|
By Ted - 3 Years Ago
|
I took a look at the specs on that Howards camshaft and it does look like a good candidate for your combination. I will have to disagree with the basic rpm range that’s listed for it though as it should indicate a wider rpm band. That camshaft is similar to the one I use in the 312 dyno mule which is a Crower Monarch 280-F which has a 280° advertised duration but the same 238° duration at 0.050” and ground on the same 110° lobe centers. I’ll suggest checking the valve to edge of piston bore clearance as any significant milling of the heads will bring the intake valve dangerously close to the cylinder wall at full lift. Small notches at cylinder wall edges under the intake valves will solve any clearance issues for that but be sure those notches stay above the top ring area of the cylinder.
Howards camshaft 290862-10
Year:1955 - 1963
Make: Ford
Engine: 292-312
Camshaft Type: Mechanical Flat Tappet
Basic RPM Range: 2800 to 5400
Valve Lift Intake: .515
Valve Lift Exhaust: .515
Duration Intake: 265
Duration Exhaust: 265
Duration at 050 Intake: 238
Duration at 050 Exhaust: 238
Lobe Separation: 110
Intake Centerline: 106
Firing Order: 1-5-4-8-6-3-7-2
Quantity: 1 Each
Country of Origin: United States
|
|
By Ted - 3 Years Ago
|
mikeT (1/21/2021)
Thanks Ted! would you suggest advancing or retarding the cam ? The cam card says the intake closes at 45 degrees
That 45° number does not mean much to me without the other numbers. If using the lobe centerline method to degree in the camshaft, then my recommendation is to install it at 105°-106° intake lobe centerline which is 4-5° advanced. This is assuming the timing chain is new. As the chain wears in, the camshaft will retard accordingly.
When I run the numbers through my spread sheet, the intake valve should be closing at 58½° ABDC with 4° of advance assuming the advertised duration is figured at 0.020” lobe lift.
|
|
By Ted - 3 Years Ago
|
Now that you have posted the spec card, it becomes obvious where that 45° closing number came from. It’s from the 0.050” portion of the specs which is not used for the dynamic compression ratio (DCR) calculations. When doing the DCR, you need to use the ‘advertised’ intake closing event number. In this case, it is the 58½° ABDC number you see on the ‘advertised’ part of the cam spec card.
Here are the numbers from my spreadsheet with what has been provided thus far.
|
|
By Ted - 3 Years Ago
|
|
55blacktie (1/21/2021)
gofastmath dynamic compression calculator asks for "IVC @.050."
Unless you set your valve lash to 0.050”, the intake valve will not be closed at the 0.050” value. The advertised duration intake closing number works for DCR due to the advertised numbers for solid cam shafts being generated at 0.020” lobe lift at both sides of the flanks.
mikeT (1/21/2021)
Thanks Ted, My rods are the C2AE I believe there 6.324 long? would that change the dynamic ratio?
While a longer rod does lower the DCR number, it’s takes a major change in length to make a difference. Here’s the same DCR calculation with the 292 rod length inserted. That previously posted rod length was the 312 length. Here is the revised DCR. Not much change.
|