393 Stroker, Need Cam Help
11-12-2011, 11:26 AM
#1
Thread Starter
Join Date: Oct 2011
Location: ohio
Posts: 4
393 Stroker, Need Cam Help
i have a 393w stroker in my 93 stang and it seems to drop off pretty hard at 6300 rpm. It does have an issue with pushing out the dipstick because i believe the rings aren't sealing right. It had probe piston, eagle h-beam, scat crank, afr205, super victor, 850 proform, 236/244 568/576 lift 108 seperation bullet cam (hydraulic roller). should i try 1.7 rockers instead of 1.6 to pick up more cam or try to re-ring it. its 9:1 comp with 150 cranking pressure. Maybe 6 passes on it and 400 street miles. I need expert help here
11-12-2011, 08:21 PM
#2
4th Gear Member
Join Date: Jan 2008
Location: Louisville, Ky.
Posts: 1,326
Welcome to the forum.
I would solve the ring sealing issue before worrying about a camshaft.
You sure the Drop off isn't the valve springs allowing valve float?
You could try more street miles to see if the rings will seat any better, but I don't know if it will help or not.
I would solve the ring sealing issue before worrying about a camshaft.
You sure the Drop off isn't the valve springs allowing valve float?
You could try more street miles to see if the rings will seat any better, but I don't know if it will help or not.
11-12-2011, 08:35 PM
#3
Thread Starter
Join Date: Oct 2011
Location: ohio
Posts: 4
ya im sure the valve springs aren't floating, im just not sure if the cam is too small or if i get the rings to seat better it will give me more rpms because i would like to shift around 6800. i have almost 7k in this motor and it should have more than what im running
11-12-2011, 11:03 PM
#4
ok heres some things we and my self need to know, A what kind of application is this for? aka street/strip, street car that sees lots of trips to the track, what do you want it to run like when not wot aka does a ruff idle and semi bad drive ability not in your plan? whats your open and seat pressure of your valve springs. Also what ring package did you use? meaning style and material type of all the rings 1st and 2nd compression and your oil ring.
as of now your duration is gonna work well for a 1900-6500 rpm range, more duration is gonna give you a higher rpm range but will lose power down lower. Is this and automatic with a stall or a manual transmission? the lift could probably go higher if the motor and car are more of a strip car that sees street driving. Did bullet spec this cam for you? if they did who did you talk too i personally like Richard and will only contact him for cams.
Let me know and I can help
as of now your duration is gonna work well for a 1900-6500 rpm range, more duration is gonna give you a higher rpm range but will lose power down lower. Is this and automatic with a stall or a manual transmission? the lift could probably go higher if the motor and car are more of a strip car that sees street driving. Did bullet spec this cam for you? if they did who did you talk too i personally like Richard and will only contact him for cams.
Let me know and I can help
11-12-2011, 11:11 PM
#5
5th Gear Member
Join Date: Aug 2004
Location: Arizona
Posts: 4,103
Fix the ring problem before anything else.
I also think with that duration the power will fall off somewhere around where you said it was.
Longer strokes have a way making what you think would be a big cam really mild.
More lift would help too.
I also think with that duration the power will fall off somewhere around where you said it was.
Longer strokes have a way making what you think would be a big cam really mild.
More lift would help too.
11-12-2011, 11:33 PM
#6
11-13-2011, 02:23 AM
#7
Thread Starter
Join Date: Oct 2011
Location: ohio
Posts: 4
ok right now it runs great cruising at 1900rpm real smooth but im 23 and dont care about that, its currently a 5 speed but plan on a built aod over the winter(if money is there). the cam is supposed to peak at 7k in a 351 so if u calculate it a 393 is 6300rpm spot on because of piston velocity, i wanna know if going from 1.6 rockers to 1.7's would be worth the $300 or a diff cam. i want a little bit of driveability but i wanna run 10.8 then put either a turbo or nitrous to the motor ( it was built for a turbo) probly 88mm, but im low on cash right now
11-13-2011, 07:13 AM
#8
M.A.D. Motorsports
Join Date: Jul 2006
Location: Indiana
Posts: 8,014
Don't put the 1.7's in it unless you are going to pull the heads off to clay the motor to check for clearance. With the motor being built you can't just guess or hope it will clear.
Again, what type of material are the rings? Are you burning any oil with it?
You say it peaks at 7k on a 351.....was it speced for a 351 or the 393??
Again, what type of material are the rings? Are you burning any oil with it?
You say it peaks at 7k on a 351.....was it speced for a 351 or the 393??
11-13-2011, 11:27 AM
#9
Still didnt answer a lot of the questions we asked, in terms of if it should spin higher with a smaller stroke motor id say no a cam is going to not make a difference on how high it will spin in the two different cubic inc combos but more of where the power band will be produced. It may benefit you to go to 1.7s but not much you would be better off getting the ring seal issue fixed first and then go from there. if you want to spin the motor to 7k you will be better off calling someone and have it spec'd out for your goals aka call rich at bullet cams stay away from jay allen.