engine busting up

-
C

chad72duster

Well-Known Member
Joined
May 22, 2004
Messages
665
Reaction score
0
Location
Perdido, AL
Hey guys been a long time.

Need a little help with some engine trouble.

buddy has a 440 in a 67 Cuda.

the 440 is supposed to be a stock steel crank with ly rods and KB 10.5-1 flat tops. the head are supposed to be Indy Cast with 1.81 and 2.14 valves. the cam is the comp hyd 480 lift not sure of duration or lobe sep. The intake is a torker 2 with a 750 Hollye DP, not sure of the jet and squirter sizes. The Fire comes from a Stock Mopar electronic ingnition. the worst part is the fuel pump and fuel lines. it has a 4 psi elec fuel pump through stock 5/16 fuel lines. The tranny is a TCI Street Fighter with a 2500 stall and 3.55 gears. exhaust are shumacher TRI Ys into 2 1/4 pipes choked down I know.

the problem, car the car fires good and runs hard up to about 3500 then it bust up and when you let off it will back fire. Also going up hill under normal conditions you can hear a I think Mild valve knock. Like maybe it has bad gas. Here is the other thing some time it runs fine all the way up to 6200 and pulls like it should.


hope this is enough info for you guys.

Any help would be Great. He just bought the car and is trying to get it to pull right.


Thanks Chad
 
First he could change the things that he is thinking about, like fuel lines, you need more psi from that fuel pump.I remember a electric fuel pump I had once that started to fail and the pressure droped off like the one you have. Those are big heads for the pipes that it has. The nocking sounds like preignition, Witch is NOT good. You need to play with the timming and fuel.
This might help a little.....
http://www.4secondsflat.com/Spark_plug_reading.html
 
Butt, I think after rereading your post, It sounds alot like ignition problems but I'm sure the fuel and exhaust aren't helping at all.
 
I agree. Start by going to a fuel pump that will supply the carb 6-7 psi or one at 10 psi and regulate it down. Also the 5/16 line ain't big enough for that 750 you need 3/8 minimum. The bucking and kicking could be fuel vapor-lock and the higher pressure and larger fuel line will help but check your fuel line routeing that it isn't close to the headers or firewall. Once you've fixed that problem take a look at the advance curve of the distributor, try initital at 12-14 deg and 35 deg full advance at 2400 rpm. Don't forget to check all the ignition wiring and plugs.
 
Pull the Holley, and rebuild it with decent parts. (I like AED kits..) If it did run well before and developed this, I agree it sounds like the carb. You have huge ports for that cam and compression, so carb tuning will be important to keep it happy. I dont think it's fuel flow. 4psi thru 5/16 line will handle things but only up to a point. You know the exh is bad, and the fuel delivery isnt up to snuff for more than a mild car. So you know what he needs to do with those. A cheap Holley Blue and regulator will fix the volume..Dont sweat the diameter, and plumb in a fuel pressure gage, and set the pressure to 8psi. That and the carb rebuild/tuning should bring it around. Also, what ignition box and ballast resistor is he running? The resistor should be .5 ohm or less (usually stamped on the back) and if the control box is orange, make sure it has a good clean solid ground to the engine, not just the fender or firewall. If you have a spare, try popping that in place too. those orange boxes can be problematic.
 
Hey Chad, havn't heard from you in a long time.

What moper said sounds good. You also may want to check the fuel filter. I had one act just like what you said and it was the filter. You never know what kind of care a car had.

Jack
 
Good to hear from you Chad.

I also like the AED rebuild kits for Holleys but I needed to trim a few threads off the acc pump screws to keep them from leaking.
 
Hey Chad---I've been gone a while too! the first thing I would do is bolt on a carb that you know works. Let him try your BIGS. Don't worry about the fuel line right now, that's probably not your problem. I went 11.10 with 5/16 line. Take that mopar ignition off and throw it in the trash. I'll guarantee you that's your problem. I had that ignition when I first got the Cuda and I had the exact same problems. I run a Crane Fireball and have never had an issue. All the above info is good stuff but will do you no good until you get a reliable ignition.
 
AdamR said:
Holy Crap Bretts Alive !!!!! Good seeing you too !
Click to expand...

NO KIDDING!!!!!! :thumblef: ...i was thinking of you the other day and i was gonna e-mail you to see how you are doing..so??..how ARE you doing??
 
dirol.gif
WOW!! Brett and Chad
Welcome back !! All we need now is HawaiiDuster and the gangs all here!!

Party-Time.gif
 
The Orange boxes are the problem with those Mopar ignitions. If you don't want to replace the whole ignition, at least get the chrome box.
 
hey great to hear from all of you guys..

Craig is down in vegas building the world. i still hear from him once in awhile.


I work constantly and stay broke.


Hey Brett you dont think that 950 is a little much for that small cam??

I have a MSD dist and a cran HI6 box that i can put on to test the ignition hopefully this weekend.

My concern is the ping under low strain. Is this detonation and what is causing it.

I dont think its the fuel pump because the busting up happens under all circumstance not just when you get on it.

Some of you smart guys help me out.
 
replace the power valve, check your timing curve, adjust the vaccum pot if it's connected. Light load is PV territory, and it may be a good one in there, but it may be too low for what the engine likes. If it's running a 5.5, try a 6.5. It really only needs to be shut at idle, so I try for the highest number that will stay shut at idle, in gear. Also check your centrifical springs..maybe one let go, of the set screw holding the cent. limit slipped...
 
Hey everyone! been working a lot. Ya know how it is. Chad throw on the 950, it will at least tell you how bad his carb might or might not be. You'll have decent velocity with the 950 and it might surprise you how well it might work assuming he has some decent gears in the rear etc? The detonation is due to ignition problems not carb. Have your buddy buy a new ignition because if his mopar ign isn't broke now it will break. I can almost guarantee that is the problem.
 
cool
i will loan him my MSD and carb since niether are doing anything but collecting dust.

I figured that the 950 would be a little much for the 480 lift cam. I dumped out all the bad gas and put in some better 93 and it helped.
I still has a little ping to it. If you take up the timing tp anything above 5 or 6 it pings like hell. Will swapping the ignition to MSD improve the Ping?

I is getting better I will help him as much as I can.

thanks Guys.
 
MSD wont do much to stop pinging. But, you can jet up a little, and the MSD wont have any trouble dealing with a richer mixture. I would jet up the primary side 2 sizes, and see if it still pings.
 
Chad, set the timing to 32 total at 2500 rpms and don't worry about initial right now. If the dist is working properly and no one has messed with the advance curve my guess is you will be around 10 degrees initial give or take. If the new ignition doesn't help with the pinging after setting the timing then we have another issue.

Pull his carb and drop in a new 5.5 or 6.5 PV--the rear should be blocked off. Then check the jets. Start at 72 front and 78 rear. Flip the carb upside down and make sure the butterfly's are not past the transfer slots at idle. If so you will be using the idle and main circuits at the same time and it will confuse the carb and your air idle screws won't work. There is a small set screw for the rears that you can only see when the carb is upside down. Once you have that done then turn all the air idle screws completely in and then back all of them equally out 3 ( half ) turns equalling 1 and a half. If it is a double pump then my guess is the squirters will be around 31 or 33 which is fine. Make sure all vacuum fittings are plugged unless you are using them. This setting should be a good starting point to tune from. Put the carb back on and warm up the engine to operating temp to set the carb. Hook up a vacuum gauge and if it is a auto you need to adjust the air idle screws while the car is in gear so have help and be careful. Start by turning the air idle screws in or out until you get the highest vacuum reading. Whatever you do on one side you need to repeat on the other. You will need to adjust the idle screw from time to time. If your air idle screws have no effect then you aren't idling on the idle circuits meaning your carb has an internal issue or your front butterfly is to far past the the transfer slot. Then check for vacuum leaks etc. That cam isn't big enough to need more than 10 to 12 degrees initial timing so you shouldn't need more timing to help the idle. Good luck and I'll check back in to see how you came out.
 
All good suggestions but I would swap known good carb 1st before I went & tore into existing carb.Also check all gounds,timing,possibly swap known good orange box & then dist.
Rob
 
I have gotten most of the ping out but why does it ping when i give it more timing.

I tryd to give it about 15 int degrees and it pinged its axx off. I had to set it back to about 5 int to get it to run half axx. The Vac advance is fine and seems to be working.

It still bust up a little around 3500 to about 5000 rpms. I am going to stick my BIGGS 950 on it just to see what will happen and my buddy bought a Blue pump to go on it. I have anothe Mopar Dist I am going to stick on there for ***** and grins and see if it works.

Any suggestions for and intial timing start.
 
You must log in or register to reply here.
-

Back
Top