FrontEngineDragsters.Org Forum
Technical => Matt Shaff's Engine Shop => Topic started by: captmullette on November 15, 2014, 01:53:47 PM
-
I put my old dirt track motor in my 31 ford bracket car, 355 sbc iron double humps small valve , flat top pistons, REED 3/8 mile dirt track cam, my partner cant find my cam card....this motor was built around 85/86 and sat in the back of a truck for 20 something years, rockers were loosened double springs all old and original.......my question is could I be running out of cam or weak springs or both....I just ordered a dial indicator to see what lift I have...thanks, hope I haven't sounded like a complete dumb ass.....as in the header it lays down at 6300 rpms
-
Do you remember what kind of RPM it used to run before parking?
Is the exhaust system similar between the '31 Ford Tudor sedan and the '64 Chevelle dirt track car?
Have ignition and fuel (pressure) checked OK?
-
Is it a solid lifter cam or hydraulic. If hydraulic that about all you will get. If solid I would imagine valve springs are light or ignition issue
-
fuel system checked o.k., same type exhaust, hydraulic cam.....can I help the rpms with 1.6 rockers ? pulled the valve covers and I can turn the springs by hand on a closed valve.....not easy ign. is a procomp 6 al timing at 34 deg. didn't drive the chevelle but my driver said he remembered turning over 7000 ive heard some bad reports on procomp
-
Better get a valve spring checker..
-
Most hydraulic cams are only good for 6500 RPM's. Your old combo may have hit 7000 RPM's but it was on dirt and most likely spinning the tires and probably not producing any power above 6000
-
I think you've nailed it.....1.6 rockers any help.....???
-
we run our valves as if they where on a solid cam
set at 0 with 120 lbs closed 300 lbs open springs
-
1.6 rockers probably won't change anything
-
agree springs first thing to check. Also 1.6 rockers will only add some lift and minor amount of duration will not do a thing for rpm issue.
-
Jumping in late:
If its hydraulic then lash the valves to zero or .002" of lash.
Lifters will pump up solid and should help.
Turning springs by hand does not sound good.
We don't know what the camshaft is but I have an old Reed book.
I will check tomorrow and see if we can find a cam that fits your description.
I would NOT put 1.6 rockers on it unless you know how close your springs are to coil bind now.
Matt
-
matt, I got a dial indicator yesterday and removed the rocker and checked the lift at the pushrod as best as I could, intake .322= .483, exh..324=.486......if you find it in your book I would really like a copy of the page etc. thanks bobby
-
Bobby:
The only Reed cams book I have is a listing of master lobes. I used to have a late 80's catalog and loaned it to someone.
You can guess that was the last time I saw that book.
The best match I can find in the listing of lobes looks like this:
.320" lift matches a lobe with 242* @.050". Didn't see one with .322" or .324"
Most oval track cams that I'v seen have a 106* lobe separation.
Good luck: Matt
-
thanks matt, tearing the motor now changing the old iron double humps to AFR's and new cam.....looking at a lunati voodoo duration.050 is 241/249 gross lift is .525/546 flat tappet hyd. ...any thoughts ? heads are 210's
-
If this is a "race motor" why hydraulic lifters? Make sure to check piston to valve clearance.
-
good question, I guess ill need some input, low budget, old motor, 355 2 bolt main, don't even know anything about the crank, forged or cast, got the heads cheap and really don't know that much about putting together a better motor
-
If your not sure of whats in the lower end you may not want to go over 6300. If you have stock rods and old bolts you could be looking for trouble. Going down the track slow is more fun than a face full of oil.
-
CaptMullette:
We don't put hydraulic cam/lifters in anything. Why would you want a shock absorber in the valve train??
We have used Engle solid camshaft in most budget / non roller builds.
The last small block Chevy 350 drag engine we built we used a 248* / 256*@.050" .356"/.351" lobe lift ground on 110* lobe separation.
We used double hump heads for correct appearance. Perfect virgin 462 castings. We machined them for 2.02"/1.60 valves. NO PORT WORK OF ANY KIND.
Flat top pistons and 10.5 compression ratio to keep it simple.
Enderle stacks and alcohol. Very rich for a safe tune-up. 34* timing.
On our dyno it made 492 ft lbs @ 4300 RPM / 441 HP @ 5500 RPM.
It is for my 17 year old in a FED. Going from a Jr. Dragster this should be a good eye opener. 8)
We did not finish the car in time to make any passes this year.
Its 175" wheel base with a short glide. It should run 9.20's??
-
thanks for the input, sounds like good info for an uninformed person.....me....just trying to do this on a budget and not have to do it twice....do you think that my AFR 210 heads are too much, I can easily sell them and could have my heads machined for 202 valves thanks again for the help, don't want to run 9's just a good fun bracket car,
-
Hello Capt Mullette:
AFR makes a very nice cylinder head but in my opinion the ones you have are rather large in respect to the rest of the engine.
A point of comparison would be a stock Chevy head that has about 150 cc's of intake port volume. They also do not flow air very well.
Your AFR 210 heads not only have 210cc's of port volume but also flow very good. A very low cost head that flows pretty good is the Edelbrock E-Street heads. They are 170cc's and flow much better than a stock GM head. We put them on the lower cost builds and the are made in the USA. They come thru with the valve guides alittle to tight. We hone the guides alittle and check the valve job. Change the studs to 7/16 and check the springs for the camshaft you choose. They would be a better match for your engine. You can find them at Summit for under $1000.
Matt
-
thanks matt, kinda in a corner here, ive already got the AFR's and don't have a $1000 so.......