440 performance problems!!

[jeff black]

Everything is new and it ran great for about 100 miles. It's a 440 with ported 906 heads, holley street dominator, 850 speed demon, hughes 576/246 1.5 hs rockers, 3500 tci stall and 4.10 rear. I set the timing at 35 degrees total. One day it seemed to be being held back. No strong pull like it had. I noticed when I put it in gear the fuel filter would almost empty. I installed a new holley electric pump. It keeps the fuel flowing, but the perfomance is no better. I have noticed the car seems to run better when I time it by ear, but when you put the light on it, it's completely off the tab. It has a new double roller and the marks are lined up. Or they were when installed. My distibutor is a mopar performance with a vacuum advance which is not hooked up. It ran great without being hooked up before, but now it's really lazy. I'm wondering if that demon carb could be a problem. The car backfired several times when I was messing with the timing and I've heard this can cause problems with these carbs. Does anyone have any thoughts on this?

[floorrtse]

are the carb new? if so ,did you open it and check at inside is free from metal (I been read many post abouth demon carb,there is metal chips inside)just buy 750 demon and open it up,seems to pretty clean inside,but didn´t fire motor up jet so...?

[Kevin Garceau]

Check the powervalve/s

a back fire can pop them, which would cause many different types of issues. But it should run strong on the top end still.

Do you have a new balancer? Could your marks be way off on the old one?

[jeff black]

Originally Posted by Kevin Garceau

Check the powervalve/s

a back fire can pop them, which would cause many different types of issues. But it should run strong on the top end still.

Do you have a new balancer? Could your marks be way off on the old one?

No, it's not a new balancer. It seems wierd that it ran great for a while and now like a 3 legged dog! I do remember adjusting the valves which are Harland Sharp rollers. I went through the sequence and would turn the adjuster with my fingers. When the pushrod just started to move, I gave it 1/4 turn and locked them down. I might have them out of adjustment, but I don't think so. Do you see anything wrong with that method?

[benno318]

i was going to suggest a spun balancer also. before it dropped power, did you re adjust timing or anything else? approximately what comp. ratio do you have? with a cam of that size, you would need at least 10.5-11.0:1 to run 35 degrees i would estimate. it may be as simple as not enough compression for the cam you have?? i would time it on a test drive, sneak up on the advance bit by bit until it is happy without pinging and im sure you will find the performance return. let us know.
ben simpson

[440Ramcharger]

Any excess moisture coming out of the exhaust pipes? Bad head gasket?

[Slingshot383]

Is that cam a solid lifter or hydraulic lifter cam? Sounds big for a hydraulic cam. The spun balancer sounds very likely.

[jeff black]

Originally Posted by Slingshot383

Is that cam a solid lifter or hydraulic lifter cam? Sounds big for a hydraulic cam. The spun balancer sounds very likely.

It's a hughes hydraulic.

[jeff black]

Originally Posted by 440Ramcharger

Any excess moisture coming out of the exhaust pipes? Bad head gasket?

No, no excess moisture.

[jeff black]

Originally Posted by benno318

i was going to suggest a spun balancer also. before it dropped power, did you re adjust timing or anything else? approximately what comp. ratio do you have? with a cam of that size, you would need at least 10.5-11.0:1 to run 35 degrees i would estimate. it may be as simple as not enough compression for the cam you have?? i would time it on a test drive, sneak up on the advance bit by bit until it is happy without pinging and im sure you will find the performance return. let us know.
ben simpson

The compression is 10.0 and this car ran great. One day I took it out and got into it and thought it wasn't running as it did. I thought it felt lazy like the timng was off. I've been messing with it since, trying different timing settings and I adjusted the rockers cause one or two was a little loose. What timing setting would you suggest and do you think my method of setting the valves is ok or do you have a better idea. Thanks,

[mr.b]

had what seems to be the same problem once. my car ran fine and then the next time i started and drove the car it was terrible. found out i had a spun or bad balancer. just that quick. replaced it and started kicking butt again.

[MOPARMANJAMES]

Could be that the timing chain jumped, not likely though. Try another Carb and if you have a pison stop, check TDC on your balancer to see how far off it is. Check to make sure you are getting proper voltage to the ignition and coil.

[perfmachst]

hello, how did you set your valves?? did you crank motor to TDC each cylinder, then set them? this is the most accurate method, and give them an 1/8 turn max. your comment about timing mark being way off, which type of ignition box do you have? I've had the mopar boxes change timing 90 degrees on the crank.just food for thought.

[jeff black]

Hi, I have a chrome box. Maybe I didn't set the valves the right way. I started at TDC and did #2 INT and #8 EXH then turned 90 and did 1 and 4, turned 90 and did 8 and 3 and so on. Each time I would turn the adjuster with my fingers until I felt the pushrod start to move and then turn 1/4 turn and lock down. Sounds like I could have gotten them a little too tight. I did a compression test today and found a difference I'm a little concerned about. #2 cylinder was at 155. Most were around 130-135, but #3 was at only 125. Could inaccurate valve adjustment cause this? Here's what I had. #1-130 #3 125 #5-138 #7-140 #2-155 #4-135 #6-135 #8-130. The #2 cylinder which was at 155 looks as though the adjusters are showing a couple of more threads than the others. Are you saying to start at TDC and do #1 then turn a complete turn to TDC and do 8 and continue through the firing order?

[mopargk]

Never Mind............?........

[dart joe]

That compressions seems alittle low for a 240s dur. cam and 10.1, how did you check the comp. the engine has to be at operating temp, fully charged battery, throttle wide open, all plugs out. i have 10.2.1 comp. and with a XE284H 240/246 i had 190-195, with my new solid 250/256 i have 180-185, it could be overlap in your cam maybe, but it just seems low. the method you used is the currect one for adjusting the valves, not bringing each cyl. to top dead center. just double check the valves and compression. and a 1/4 turn is fine. this may sound dumb but i'll ask, are you sure you put the timing light on #1 cyl., its a common mistake, but i figured i would ask. also, what kind of pistons do you have, how far down in the hole are they, you may only have a 9.5.1 engine. this would explain the lower cyl. pressure.

[dart joe]

heres one way to adj. the valves. starting with #1

int. exh.
2-7 4-8 turn 180* 1/2 turn
1-8 3-6 turn 180* 1/2 turn
3-4 5-7 turn 180* 1/2 turn
5-6 1-2 done.

[dave571]

Does sound like a spun balancer.

As a side note, the 850 speed demon is the wrong carb for a 440 with a cam that has 246 @ 50 duration.(not that it would make it run bad all of a sudden)

You should be using a "mighty" series demon with that much duration. The 850 is a little big unless regular shifts of 7 K are seen or the motor has been stroked to 500 inches, but it should work.

A mighty will be much easier to tune, and give much better throttle response.

[jeff black]

Originally Posted by dave571

Does sound like a spun balancer.

As a side note, the 850 speed demon is the wrong carb for a 440 with a cam that has 246 @ 50 duration.(not that it would make it run bad all of a sudden)

You should be using a "mighty" series demon with that much duration. The 850 is a little big unless regular shifts of 7 K are seen or the motor has been stroked to 500 inches, but it should work.

A mighty will be much easier to tune, and give much better throttle response.

I wonder if I should have used a 750 Holley? That's what I used in the old days and never a problem. I bought this carb because everyone said that were the best since sliced bread! The Holley seemed to have it on both ends.

[jeff black]

Originally Posted by dart joe

That compressions seems alittle low for a 240s dur. cam and 10.1, how did you check the comp. the engine has to be at operating temp, fully charged battery, throttle wide open, all plugs out. i have 10.2.1 comp. and with a XE284H 240/246 i had 190-195, with my new solid 250/256 i have 180-185, it could be overlap in your cam maybe, but it just seems low. the method you used is the currect one for adjusting the valves, not bringing each cyl. to top dead center. just double check the valves and compression. and a 1/4 turn is fine. this may sound dumb but i'll ask, are you sure you put the timing light on #1 cyl., its a common mistake, but i figured i would ask. also, what kind of pistons do you have, how far down in the hole are they, you may only have a 9.5.1 engine. this would explain the lower cyl. pressure.

Yeah, the pistons are probably at 9.5 or better. We wedge plained the heads to bring the compression back up. This was a mistake in boring. We bored it .60 not realizing everyone is selling .55 over pistons. The only thing we could come up with were sixpack pistons which we milled the dome off. I wasn't too happy with this setup, but when I ran the car it seemed to do everything it should. I'm thinking that maybe this winter it might get a different set of pistons. I had already bought the cam when we realized the piston problem. We went with it and it ran great. I had a HEMI RR at the time and there was no comparison. The 440 car pulled the HEMI out of the hole and pretty much stayed there. The HEMI started pulling in the last 100 ft or so, but never caught it. Then I adjusted the valves due to clatter and that's when a 3 legged dog could catch it!

[dart joe]

Originally Posted by jeff black

Yeah, the pistons are probably at 9.5 or better. We wedge plained the heads to bring the compression back up. This was a mistake in boring. We bored it .60 not realizing everyone is selling .55 over pistons. The only thing we could come up with were sixpack pistons which we milled the dome off. I wasn't too happy with this setup, but when I ran the car it seemed to do everything it should. I'm thinking that maybe this winter it might get a different set of pistons. I had already bought the cam when we realized the piston problem. We went with it and it ran great. I had a HEMI RR at the time and there was no comparison. The 440 car pulled the HEMI out of the hole and pretty much stayed there. The HEMI started pulling in the last 100 ft or so, but never caught it. Then I adjusted the valves due to clatter and that's when a 3 legged dog could catch it!

Then obviously the problem is with the cam, make sure you don't have your preload too tight, since you say it clattered, you probably were not getting the full lift of the cam, you said it ran good before you messed with the valves, so i would start there. and check your H balancer. if you get a new set of pistons, get a good set like ross.

[jeff black]

Joe, Ross pistons it is. I was planning on picking up a set before winter and making that my project for the winter. We also used a composite head gasket which I didn't like either. I wanted the steel shim kind, but the guy that was helping me with this used the ones that came with the gasket kit. I'm losing alot of performance with these pistons and that gasket setup. I think a set of Ross 10.1 flattops and a steel gasket is a much better combo and still could be ran on pump gas. I drive this car in the summer quite alot. I just play with it. I build a few other cars to sell, but I've always kept this car for myself. It's a 69 RR, HEMI orange and is new from top to bottom. It was my driver for many years and when I sold the HEMI car I decided to restore this car and just have fun with it. It runs extremely well for not being a high comp engine. The local chevy and ford boys hate to see me next to them at a stop light!