383 stroker problems
Thread Starter
Safety Car
Joined: Sep 2009
Posts: 4,142
Likes: 24
From: Simcoe Ontario
383 stroker problems
strokers, what do you guys run for fuel in your strokers, i have a MSD ignition run premium fuel my comp ration is 10.67:1 and i have a pre-ignition or detonation problem. Is fuel additive the only fix or has anyone got any other fixes. If not what is the best fuel additive to use? MSD also makes a timing advance/retard control that is remotely adjustable from a dial in the cabin, like to know if anyone uses one of these and will it help my detonation problem and oh yes, i am running a built glide behind it with a 3000 stall convertor have a set of world sportsman 2 cast iron heads 64cc chamber and a Comp cam .490 lift adv duration 274int 286exh, dur at .050 is 230/236
Last edited by vt65; Oct 2, 2009 at 10:33 PM.
Le Mans Master
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From: "You may all go to Hell- and I will go to Texas- Davy Crockett
St. Jude Donor '12
10.67 c/r shouldn't be a problem with premium (93 octane) assuming you aren't running too much advance. Steel or alum. heads? You can get away with a little more squeeze if you run alum. heads to get rid of the heat. Also you can run a little higher comp. ratio if you overcam the motor to kill off some of the compression. Just my opinion. D
Le Mans Master
Joined: Nov 2008
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From: columbus oh
10.67 c/r shouldn't be a problem with premium (93 octane) assuming you aren't running too much advance. Steel or alum. heads? You can get away with a little more squeeze if you run alum. heads to get rid of the heat. Also you can run a little higher comp. ratio if you overcam the motor to kill off some of the compression. Just my opinion. D
Drifting
Joined: Apr 2004
Posts: 1,302
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From: Allen Park Mi
10.67 c/r shouldn't be a problem with premium (93 octane) assuming you aren't running too much advance. Steel or alum. heads? You can get away with a little more squeeze if you run alum. heads to get rid of the heat. Also you can run a little higher comp. ratio if you overcam the motor to kill off some of the compression. Just my opinion. D
i think with that much comp on a 383 with a short duration cam.. he is gonna have a higher static and dynamic compression than most of us who run 11 to 1 with the old OE cams.
make sure you don't have a vaccuum leak and get that thing on a chassis dyno to be sure you aren't too lean.
Best of Luck
Le Mans Master
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From: MA
larry
Last edited by redred65cpe; Oct 3, 2009 at 08:20 AM.
Instructor
Joined: Sep 2002
Posts: 227
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From: Barnstable Mass
Check Your Plugs
Most often overlooked cause of pre-ignition is a plug that's running too hot. Go down a heat range and see what happens. I had a C-4 a while back that gave me 240 counts on the knock sensor at WOT. That count dropped to only 5 with one range cooler plug.
My 383 has essentially the same cam as yours, but I do have aluminum heads.
My 383 has essentially the same cam as yours, but I do have aluminum heads.
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Le Mans Master
Joined: Mar 2005
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From: Rocklin California
I have a 383 stroker running on 91 octane. 32* at 4,000 rpm. Has Dart Pro 1 Platinum aluminum heads, 72cc, 200cc runners, 2.02/1.60 valves, 1.6 roller rockers, Lift .544 in/ .555 ex. Comp Cam hydraulic roller 230/230 @ .050. Compression is 10.3:1. Makes 450hp/450tq on dyno. No ping ever!
Last edited by Kensmith; Oct 3, 2009 at 11:46 AM.
Le Mans Master
Joined: Jan 2005
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From: Lake Wylie SC
!0.67 actual is way to much compression to run with steel heads.
No way around it and if you cannot get it down to at least the high 9's you will always have trouble without race gas. Forget about additives and they work about as well as good vodka does.
Then there is the cam issue......... what is your cranking compression? For steel heads cranking compression needs to be about 165 max and preferably less. If it is not then more duration will help you to bleed it off but then you have less time to get your valve out of the way if your clearance is tight......especially on the exhaust side.
What is your LSA?
I am a BB guy but there are some good SB guys here who can steer you right.
Doug
No way around it and if you cannot get it down to at least the high 9's you will always have trouble without race gas. Forget about additives and they work about as well as good vodka does.
Then there is the cam issue......... what is your cranking compression? For steel heads cranking compression needs to be about 165 max and preferably less. If it is not then more duration will help you to bleed it off but then you have less time to get your valve out of the way if your clearance is tight......especially on the exhaust side.
What is your LSA?
I am a BB guy but there are some good SB guys here who can steer you right.
Doug
Last edited by Shurshot; Oct 3, 2009 at 04:08 PM.
Safety Car
Joined: Mar 2009
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From: Corpus Christi, TX
I have had very good results with 104+ max octane boost. I get some ping when the motor is hot without it on 93 octane, but with the additive it runs flawlessly. 38 total timing at 3000 (no vac.) .040 over 427 with 10.25 compression (found Speed Pro L2300 forged replacements for stock 390 HP pistons), stock closed chamber rectangle port heads, and Crane solid cam 238/246@.050 lift. Cranking compression is 180.
Safety Car
Joined: May 2003
Posts: 4,797
Likes: 239
From: Ocean Township NJ
strokers, what do you guys run for fuel in your strokers, i have a MSD ignition run premium fuel my comp ration is 10.67:1 and i have a pre-ignition or detonation problem. Is fuel additive the only fix or has anyone got any other fixes. If not what is the best fuel additive to use? MSD also makes a timing advance/retard control that is remotely adjustable from a dial in the cabin, like to know if anyone uses one of these and will it help my detonation problem and oh yes, i am running a built glide behind it with a 3000 stall convertor have a set of world sportsman 2 cast iron heads 64cc chamber and a Comp cam .490 lift adv duration 274int 286exh, dur at .050 is 230/236
Did you measure all involved components and calculate it?
If, in fact, your SCR is 10.67:1, it is too much compression for a "small" cam of only 230/236 duration. You will need to run race gas in order to prevent detonation.
Download and run Comp Cams' Cam Quest 6 and model your SCR with your camshaft.
I'll be willing to bet that your cam likes AROUND 9.5:1 SCR with 93 RON gas!
Drifting
Joined: Dec 2005
Posts: 1,360
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From: NORTHEAST
Make sure you not using a dial back ling with an MSD ignition and we have built some engines with 11:03 on pump gas with Vortec heads no pinging problems, Timing curve is important and dynamic compression is important as well.
Safety Car
Joined: Mar 2009
Posts: 4,191
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From: Corpus Christi, TX
The LSA on that cam is 110 degrees (Comp Cams XE274H). I used to run the big block version of it in my 66. Other than a rough idle it's quite a good cam and should give him about 175-180 # cranking compression. Aluminum heads or additive will cure the ping problem.
It's not 1970 anymore. We're all just going to have to deal with it one way or another.
I would not use that cam again in a big block because it dies at 5500 rpm - just like someone shut the key off, and that was with their recommended lifters and springs. When I changed back to a solid lifter cam, the motor rips right through 6300 without even a crackle of a misfire.
It's not 1970 anymore. We're all just going to have to deal with it one way or another.
I would not use that cam again in a big block because it dies at 5500 rpm - just like someone shut the key off, and that was with their recommended lifters and springs. When I changed back to a solid lifter cam, the motor rips right through 6300 without even a crackle of a misfire.
