Rich Carb

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Aha! That makes perfect sense! I thought you had already done that when you mentioned that total advance was 34 degrees.

Do you plan on increasing compression with the larger cam?
 
Burntorange70 said:
Well I went out found when the advance was going all in. It was 3000 so I had my girl frind hold revs at 3000 and set the total timing. Then I brought it back down to idle. Now the inital was 15 BTDC. Usually I set the inital at 8 BTDC then rev it up and it would read 34 at 3000.

So to answer your question ramcharger.
I don't know?
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did you recurve it or something? how did it go from 34 total/8 initial to 34 total/15 inital? that cam will require 9.5 or more compression.
 
ramcharger said:
Aha! That makes perfect sense! I thought you had already done that when you mentioned that total advance was 34 degrees.


That was the first time I have set total timing like that. I allways just set inital and thought total was just what it was. Now I know.


Do you plan on increasing compression with the larger cam?
Click to expand...


Do you think I should? It's at 10.5 now.


I am planing on running the stock 340 J Heads for now. My Dad is going to help me port the heads a little. I don't know if he has done any car heads. I know he use to port the head on his Honda 250R when he use to race three wheeler's back in the early 80's. So he knows the basics on how to port.

I was hoping for close to 400 HP with that combo. I wanted to go with a 416 stroker but that will have to wate a few years.

I am putting the money I have now into an ALTER-K front end.
Four wheel disc brakes
Keisler 5-speed
410 gears
and weld drag lights.

I think after all that the car will be about 3070 pounds with a full tank of gas.

It should be a lot of fun!

P.S. Here is a pic of my Dad racing at Pomona back in the day.

100_0332.jpg
 
Burntorange70 said:
Do you think I should? It's at 10.5 now.


I am planing on running the stock 340 J Heads for now. My Dad is going to help me port the heads a little. I don't know if he has done any car heads. I know he use to port the head on his Honda 250R when he use to race three wheeler's back in the early 80's. So he knows the basics on how to port.

I was hoping for close to 400 HP with that combo. I wanted to go with a 416 stroker but that will have to wate a few years.
Click to expand...

I thought this engine was basically stock? A stock 340 will not be at a 10.5:1 compression ratio.
 
Yeah, the early 340's were rated at 10.4:1, but that's a factory rating and I'm betting that if one were actually cc'd and measured right out of the factory (no additional machine work, heads, etc), it would be closer to 10:1.

That's just my opinion and I've never had the chance to break down an unmolested 340, but every other engine i've broke down and measured was around .3 to .4 less than the factory measured ratio.
 
FORGET THE INITIAL unless your running vacuum advance. buy a new M.P. distributor with the fast curve and the orange ecu or chrome ,depending on rpms. beats fing with the springs.did she rev it past 4000 rpm to make sure your mark wasnt moving from 35 degrees? 34 + 14 = 48 degrees, you need 53 degrees,35 total, 18 initial if your running vacuum advance.to do this insert a small hexkey into vacuum pot on distributor and turn it a lil til you have 53 degrees.better yet ,if you dont need or have vacuum advance just plug the carb vacuum line and set total 35 degrees all in by 2000 rpm and FORGET THE DAM INITIAL NUMBER. are you running vacuum advance or not???I need this info to help ya out as your way off.
 
yeah, over the years the carbon builds up the compression for sure ram.
 
rev the engine with the light set at 35 degrees . if it passes the 35 degree mark add more rpm slowly and steady and have your girlfriend watch the tach closely while you adjust the timing light button til the damper appears to have stopped moving,this is where full advanve is coming in at. note the timing light number and the rpm.what you want to acheive is 35 degrees total timing fully advanced by 2000 rpm. If you do use vacuum advance plug the carb vac.line and do as above, 35 degrees by 2000 rpm. now, reattach vacuum line and recheck the timing . you should now see 53 degrees on the timing mark 35 plus 18 initial = 53 degrees,if its not 53 degrees use a small hexhead key, dont recall size and carefully insert it into the vacuum pot. every half turn will advance or retard the ignition timing by 2 degrees, fiddle with it til you have the 53 number remembering after each time you turn hexkey you must reinstall vacuum line to check it. do this procedure right and be prepared to shift fast. if you cant get it right you either arent doing it right or you need a new distributor,but its very simple and the numbers are correct,forget initial as with vacuum advance it will show on the light at 35 degrees mechanical and 18 degrees initial = 53 and these are the numbers ,without vacuum advance 35 degrees full advance in by 2000 rpm, with vacuum advance 53 degrees by 2000 rpm, THESE ARE THE NUMBERS YOU MUST GO BY. I hope this explains it all in detail,
 
basically same as rich carb thread, its the way its done, so hop to it and have some fun. nice rhyme huh? lol
 
minds frying from too many how to timing posts,sorry,need a break
 
3762, I agree in your case with 13.5:1 compression, a ton of gear and a very high stall converter you dont need to worry about initial timing. You most likely have the distributor locked out. If not your converter will flash high enough that your at full advance anuways.

In a street car with higher gearing, lower stall, lower compression and a heavier car initial timing is very important. It will improve low end response and idle quality.

The stock 340 cam will like 12 to 14 degrees initial. The XE274 is going to want to see 16 to 18*

My 500hp 340 was set for 22* initial and 36* total. That was 11:1 compression [email protected]" solid cam, 8" converter and 4.30 gears. If it were a pure race car I would have just locked the timing out.
 
it has no bearing on the converter stall rating adam,it just adds 65% more spark advance which will make the car not only launch harder but trap better also. this applies to most mopar engines with few performance mods also for max performance ,even a basic hopped up 14 second street car.so ya locked the distributor down as most racers do and normally most run full advance at idle.you now see converter is not a factor in this,its the added spark advance that pulls all the way thru the trap. 22 initial and 35 total =57 total, in by what? being I dont know your combo I cant comment further but why run so much spark advance when you can attain less, which is better and try the 53 number ,all in by no more than 2500 rpm, 2000 prefered,22 initial make your car harder to start with more spark advance if its a bad boy engine?try the 53 number all in by 2000 rpm and foget initial, as the cam, unless its a runt doesnt change setting the total as described above . imo your running 3 or 4 degrees too much in the pot . like I said I dont know your combo but mine is not locked down and is streetable, but its a weekend warrior .
 
I never check initial as it means nothing to me ,its always total.watch the results of the procedure i outlined for burn, cause its gonna burn a lotta rubber.take care
 
Were do you get 57* total ? I said 35* total which would be 22* of initial and 13* of mechanicle which - 35* total.

And stall does have plenty to do with it. If your advance is all in by 2200rpms and your running a 4500rpm flash converter your flashing right over initial advance in to your total advance. So in a race car with a high stall converter your right, Initial doesnt matter as much.

No in a street car with a stock converter that will flash to maybe 2200rpms initial will make a big difference be cause your timing isnt coming in till after the car is all ready moving.
 
just going by mopar performance reccomendations and past experience adam.think about it adam ,your numbers dont add up.22 plus 23 is 45 degrees total. I disagree , the above procedure is correct and converter has no bearing other wise why would a race car lock in at 1200? its about the added spark advance.so your saying I should set total 38 all in by my launch, which is around 3500 rpms?if so why are the racers locking in their 4500 converters at 1200? added spark advance plain and simple.at 1200 lock in your running around 75% over stock ,yes and that makes the car go faster.the 35 degrees by 2000 to 2500 max is what a hipo street car wants.
 
bad eyes adam, and my mind was on you using vacuum advance.I stand behind my posts,except that one,lol. above procedures are correct,also your full advance is coming in with a 2200 converter as the M.P. distributors are built with 2000 rpm full advance curve already in them .they do vary somewhat these days curve in them so theres really no need to argue over this as 65% degree spark advance will make the car rev much faster throughout the powerband. it works on both race and street strip cars just a matter of when advance comes fully in . its always total street strip car,always total on race cars,initial ? you own a distributor machine? how would you know what your distributors running without one? always total. think about it, take care .ps, above postings explain how in detail, read them, good night.
 
first reply you stated 22 initial and 35 total which would =57 degrees running vac advance so no apology on my part. im not a mind reader
 
you changed what you stated in your first reply adam.take care
 
I need to go back over my numbers as well, but my mark moves a little as well Someone stated that if the damper bounces the chain is stretched, but it is not that old......
 
mopar3762 said:
you changed what you stated in your first reply adam.take care
Click to expand...


Yes, I had my math wrong. Sorry. But I still stand by my statement. Initial timing is very important in a street car. Your car isnt isnt what most would consider a street car.
 
in a stock car ,yes its important ,in a mildly modified street car you always set total.
 
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