Engine shakes BADLY!!

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I would leave the timing at 18 or maybe even go up to 20.that cam needs lots of initial timing.
 
OldmanRick said:
Sound clip?

What did I miss Bruce?
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He posted it in the sound bytes thread. Sounds pretty good to me.

[ame="http://www.youtube.com/watch?v=i2z4epBFRxc&feature=youtube_gdata_player"]340 idle flowmaster mother thumper cam - YouTube[/ame]
 
GEO said:
I think I try getting the initial timing back down to 12 degrees or so and work from there. And set the total timing to around 32 degrees
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With that cam that engine is probably gong to want 20*- 24* initial timing. Your going to have to get a new advance bushing or make your own. I would set it up with 34* all in by 2400 RPM.

Not enough initial timing will also make it hard to start and it will be lazy.

Ignition first, then tune on the carb. In that order or you will chase your tail.

That car sounds pretty damn good by the way!
 
Mad Dart said:
With that cam that engine is probably gong to want 20*- 24* initial timing. Your going to have to get a new advance bushing or make your own. I would set it up with 34* all in by 2400 RPM.

Not enough initial timing will also make it hard to start and it will be lazy.

Ignition first, then tune on the carb. In that order or you will chase your tail.

That car sounds pretty damn good by the way!
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The mutha thumper cam ,intake .497 lift duration 287

exhaust .483 lift 304 duration

And 34degrees total is more than his edelbrock heads with a modern combustion chamber need 32 degrees should be about right .

Now if he was running iron heads with an open chamber he would need the 34 degrees or more to get the motor to rev

isn't large enough to warrant that much timing and it would idle awfully high at 18 + degrees.

As far as a lazy rev the timing curve done correctly will take care of that


And to much initial timing will make it hard for the starter to crank thus hard to start also
 
With that much cam your idle should be around 1000. Run bout same duration on sprint cars and we idle them 1200rpm. Little more lift though. My Duster idles bout like that though, sounds pretty tough.
 
I disagree with just about every single letter of this. He is only pulling 5 hG of vacuum. Last thing he needs to do is retard timing. Secondly, while it is true that the head does have some to do with timing, what has more of an impact is cylinder pressure, which he must be lacking if the engine responds and sounds as good as it does in the video. I think you are wrong on all counts. I concur with the 20-24* estimate. I think it's spot on.


GEO said:
The mutha thumper cam ,intake .497 lift duration 287

exhaust .483 lift 304 duration

And 34degrees total is more than his edelbrock heads with a modern combustion chamber need 32 degrees should be about right .

Now if he was running iron heads with an open chamber he would need the 34 degrees or more to get the motor to rev

isn't large enough to warrant that much timing and it would idle awfully high at 18 + degrees.

As far as a lazy rev the timing curve done correctly will take care of that


And to much initial timing will make it hard for the starter to crank thus hard to start also
Click to expand...
 
Your car sounds just fine...it actually sounds very similar to mine. I personally don't like the gimmicky cams like this (sound nasty, but don't perform like they sound)...but, to each their own. I do like your car though, it will be awesome when you get done.
 
GEO said:
The mutha thumper cam ,intake .497 lift duration 287

exhaust .483 lift 304 duration

And 34degrees total is more than his edelbrock heads with a modern combustion chamber need 32 degrees should be about right .

Now if he was running iron heads with an open chamber he would need the 34 degrees or more to get the motor to rev

isn't large enough to warrant that much timing and it would idle awfully high at 18 + degrees.

As far as a lazy rev the timing curve done correctly will take care of that


And to much initial timing will make it hard for the starter to crank thus hard to start also
Click to expand...

Tune it like you are saying it will be a LAZY Dog. The reason it don't start right away is because there is NOT enough initial timing in it. Sounds like it just cranks freely from what I have read. If there is too much initial timing in it the starter will kick back. That will be your sign there is too much initial timing.

Tune it how you want. 12* initial is a JOKE. It actually sounds pretty good where it is now at 19* so your theory is shot and out the window. Enough said.
 
Mad Dart said:
Tune it like you are saying it will be a LAZY Dog. The reason it don't start right away is because there is NOT enough initial timing in it. Sounds like it just cranks freely from what I have read. If there is too much initial timing in it the starter will kick back. That will be your sign there is too much initial timing.

Tune it how you want. 12* initial is a JOKE. It actually sounds pretty good where it is now at 19* so your theory is shot and out the window. Enough said.
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So you are using the "From what I have read" proof that you are right.

I'm using 30+ years of tuning fast street cars as mine.

Prove my "theory" is shot out the window with some real proof , not something you have "READ" that might or might not be correct
 
I totally agree with Mad Dart and RustyRatRod on the timing #'s. Big cam means lower cylinder pressure so it needs more initial timing. Geo you might have been building fast cars for 30 yrs. + but so have I and Rusty and find every time that more initial timing makes for a cleaner idle and snappier response in something with a cam like this. Not sure how long MadDart has been doing it but I know he has built some real fast cars and found it works that way too.
 
fishy68 said:
I totally agree with Mad Dart and RustyRatRod on the timing #'s. Big cam means lower cylinder pressure so it needs more initial timing. Geo you might have been building fast cars for 30 yrs. + but so have I and Rusty and find every time that more initial timing makes for a cleaner idle and snappier response in something with a cam like this. Not sure how long MadDart has been doing it but I know he has built some real fast cars and found it works that way too.
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Been messing around with Mopar's since I was a kid, grew up with them & worked on them from a very early age. My pops had 2-69 Chargers, 69 Superbee pistol grip 383, 71 Cuda 4spd 340 among others. My first car was a 71 Dart 318 when I was 16. I am now 47. Of course I am a lot deeper into it now than when I was a kid. Lol
 
Mad Dart said:
Been messing around with Mopar's since I was a kid, grew up with them & worked on them from a very early age. My pops had 2-69 Chargers, 69 Superbee pistol grip 383, 71 Cuda 4spd 340 among others. My first car was a 71 Dart 318 when I was 16. I am now 47. Of course I am a lot deeper into it now than when I was a kid. Lol
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Gotcha Louis. I knew you had been around a while and know what your doing. Didn't realize you were that close to my age.
 
fishy68 said:
Gotcha Louis. I knew you had been around a while and know what your doing. Didn't realize you were that close to my age.
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Well I can say that I know just about enough to get into trouble! If I get stuck on anything there are a handful of guys on here that have helped me figure it out, you being one of them Tracy! :D

Crackedback, 70aarcuda,turbodart68 , you guys have all helped me in big ways.
 
I don't usually run stock 318's with less than 10-12* initial timing.

12* on this guys mill is not going to run well at idle and off idle. You'll have stacking issues with a really fat idle to keep it running. Mess up the fuel curve in every single circuit from idle to WOT.

Do a test, if you reach in and twist a SB distributor CCW and it picks up rpm, IT WANTS THE TIMING! That's not picking a number and saying this is where I want it to run. It's about finding the efficiency point at idle. Sometimes the starter is the limiter. Find the point where the starter or dial it in timing allows you to set initial, whichever point is lower. I have a 340 with a 508 hyd right now that is locked out at 36* and it starts OK, POS wouldn't run well with 12* timing if you wished on a lucky star! :). It started off at 8*... A mini starter does wonders to help here as well.

Car sounds great to me the way it is. If it lights off with no kickback issues on the starter, it's fine. I chuckle everytime I go to a show and hear cars cranking for a long time, needing the pedal stabbed/floored to get it to start... that's what low initial timing gets you. :)

People have plenty of ways to do things. If it works for them, OK, I wouldn't do some of the stuff suggested in this thread.

Pick your parts, pay your money!

Here are a couple for the proof side of the equation.
http://www.forabodiesonly.com/mopar/showthread.php?t=225756
http://www.forabodiesonly.com/mopar/showthread.php?t=84627
 
My car lights up really quickly has been24 degrees initial.drive it daily in traffic .it would be a big pain to start and like Louis said a lazy dog with only 12 degrees initial.....
 
When my son goes to cruiz-ins, or thru the drive-ins, he often knocks his timing back a bunch, to get "the lope",..

then pulls around the corner and bumps it back up for power,.. lol
 
Wow thanks guys! Sorry I have been away, Xmas getting in the way. Anyways I'll try and up date you guys on what's up..
Higher initial is WAY better for this 340' when had it down below 17* it wouldn't idle, so she wants the advance. Crackedback is right , if I advance it , the idle does go up. Right now as I said earlier i have it at 19-20* initial. Witch puts me at around 38 total. Does msd make a different bushing to get that total down even more. Obiously I put in the black one to give me the shortest, but that's 18*,where I'd probally be better off around 14*.
Anyways on to newer problems, trying to dial this engine in. Me and my dad ( who many of you know, from here) have been saying this carb was built on a Friday from day one. I am not a carburetor genus but I'm getting better as this project goes on. I wanted to make sure that this carb didn't come with 2 power valves. So today I had some free time and decided to take it off, take it apart and see if I could find anything wrong. Took it apart today , put it back together, started the engine up and noticed in drive at 750rpm had only around 3" of vacuum.
So I bumped up my curb idle to 900 and was able to get the vacuum around 5".
Now, I revved the engine at got a carb backfire...hmmmmm, only did it once or twice but now I have a hesitation when going from idle to a snap of the throttle. (in park).

Here some details of the carb and let me know if you thing anything sounds out of place..
Holley 750 d/p no choke.
Pink accelerator pump cam @ number 1 position. Same with secondary.
Squirter on is a 28 ( to small??) and 31 secondaries.
I have my idle screws set at 1 turn out.
Not sure what jets rights now.

I checked plugs last week , and I'm getting a fouled dry carbon color. I'm thinking my plugs are too cold of a temp. There ngk br7s I believe. Not 100% sure right now, flyfish has the same plugs. Could this be part of my problem?.???


I know I'm going on like a story here but just thought the more info for you guys , the better you can help me out.
Still getting shake from engine, still being a paint to start one warm (free spin) until I pump the gas and Matt and get it to spark.

Thanks for all the compliments guys. Thanks for all the help. Merry Christmas
 
flyfish said:
Your car sounds just fine...it actually sounds very similar to mine. I personally don't like the gimmicky cams like this (sound nasty, but don't perform like they sound)...but, to each their own. I do like your car though, it will be awesome when you get done.
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Ya I know. If the cam dosent perform good enough for me and continues to be a pig, I'll be upgrading.
Live and learn.........:banghead:
 
Somebody on here, I'm sure Cracked knows..........made some special bushings to limit advance curve to less than what MSD offers.

Listen to guys like Cracked. He knows of what he speaks.
 
67Dart273 said:
Somebody on here, I'm sure Cracked knows..........made some special bushings to limit advance curve to less than what MSD offers.

Listen to guys like Cracked. He knows of what he speaks.
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I always listen to cracked, he definitely knows his stuff!! Flyfish as well
They have helped me out many times since the start of this build.
 
340,Cracked ,Mad Dart,Bad440 (how's that,for a law firm name? ..) Been through some wars. Talk to two of them on occasion. Unreal knowledge,all three.
 
Yeah they all definitely know what there talking about. To bad there not my neighbors Lol.
 
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