440 build need help again :)

[yannick47]

right the engine was rebuild...it has an kb 237 pistons with eddys heads on it,edel 1407 carb and wieland 8009 intake with headmen headers(evrything else is stock (cam,crank etc)we started the car up(with no problems )and let it idel for about a day or 2 with no problems.........finally took the car out for a drive and it would backfire alot under acceleration ...took it back to the garage to check timing etc..Anywas my mechanic old me that becase of the new pistons and heads we had to put spacers on the valve shaft to lift it up......is this the right thng to do?????or could it be something else???

 

[67 B-body]

Did you do the camshaft break in procedure "Before" the engine was left to idle?
What kind of oil did you use?

 

[yannick47]

Did you do the camshaft break in procedure "Before" the engine was left to idle?
What kind of oil did you use?

we broke in with 2500 rpm if im not wronge??and mobil 1 20W-50W

 

[Red63440]

Basically he is telling you that your valves aren't closing all the way. You can go with different length push rods (adjustable) to allow the valves to close or add spacers under the rocker arm assemblies to raise them. The back firing is caused because the valve is partly open when the engine hits the compession stroke.

http://chucker54.stores.yahoo.net/rocshafshim.html

 

[yannick47]

Basically he is telling you that your valves aren't closing all the way. You can go with different length push rods (adjustable) to allow the valves to close or add spacers under the rocker arm assemblies to raise them. The back firing is caused because the valve is partly open when the engine hits the compession stroke.

http://chucker54.stores.yahoo.net/rocshafshim.html

yup think thats what he was telling me ...

or add spacers under the rocker arm assemblies to raise them.

is it alright just to put some washers on??(any draw backs etc?

 

[Red63440]

yup think thats what he was telling me ...

is it alright just to put some washers on??(any draw backs etc?

No, you can't use washers....they are spacers that go under the round rocker shafts and are purchased in .010, .020 and .030 thick. There should be a small amount of play in the rocker when your valve is closed. To fix this problem correctly would mean taking the heads off and having the machine shop grind the top of the valve stem to get the right clearance. If you click on the link on the above post it will take you to Mancini and the spacers.

 

[Meep-Meep]

My solution is to run adjustable rockers but those are expensive. The shims as shown above will do the job if that's the issue.

Did you happen to mix up two plug wires? Have you verified your firing order to be correct? 1-8-4-3-6-5-7-2

 

[Red63440]

That would also solve the problem but I also thought of the cost. I assumed that the fiiring order was checked when he said that they checked the timing
"etc" but that would also be something to check before shims were considered.ottytrain2:

 

[lewtot184]

if your using a stock cam, lifters and rockers without a bunch of milling to the heads or block, you don't have a problem of too much preload on the tappets. the problem is someplace else. carb too lean? low fuel pressure? cross firing with the plug wires? wrong plugs? distributor issues? not a rocker arm-pushrod-tappet problem; unless theres a lobe wore off the cam.

 

[Cazbah362]

Agree with Lewtot184. Did you check and ensure you did not put your plugswires in the wrong order. Did you check your timing? Next, if you let it idle for a long period of time, could you have fouled a plug or two? Did you put your rockers in the right order (If they are stock ones)

Your mechanic must be really good to be able to jump right to point of the .010 or greater off rocker are contact after a build. This should have been something caught on the build - because all the parts you descibe are or should be to factory (or very close) specs. And to get to fire, cam break in and test drive seems a little late in the process - Just my opinion, that is where I would start.

 

[Bruzilla]

That would also solve the problem but I also thought of the cost. I assumed that the fiiring order was checked when he said that they checked the timing
"etc" but that would also be something to check before shims were considered.ottytrain2:

I had a 440 put into a 73 Roadrunner several years ago by a well-known engine shop in Tampa. I fired the car up, and when I floored it all I got was hesitation and backfires. I went back to the shop, and... wrong firing order! Even the best techs can overlook the simple things.

 

[67 B-body]

I would check the ignition closely if it were me.... When I hear an engine run poorly only under load, it's usualy related to ign troubles, specificaly the secondary portion of the ign circuit "coil, cap / rotor, plug wires, plugs, and poor ground". Also check for proper voltage to the + side of the coil......
I only asked if you broke the cam in during a previous post, because you said it started right up, and left idle for a couple days run time.... That will kill a mechanical camshaft for certain! Also, I would run a different oil if I were you....... Brad Penn is a good one available today to protect that NON-roller camshaft your running!!! Also you wont be replacing your fuel pump pushrod because it's somehow a 1/4" shorter than it should be..??

 

[yannick47]

the guys at the shop had taken out the rockers cut out 20 piece of shim sheet measured it with a feeler gauge (.15)and put it in instead of spacers....now it works perfectly trottle down and no hesitation/backfire....anyways ive ordered them spacers so i get the right stuff in

 

[Red63440]

Glad things are ok now......ccasion14:

 

[yannick47]

Glad things are ok now......ccasion14:

:headbang:..ay idea about how many horses ill get out of this setup?/an estimate(think the stock 73 440s had290??)?and the eddy heads have 84cc chambers if that maters

 

[yannick47]

ahhh bad news... m car started backfiring again...;( its been doing s for 2 days ...i normally happens in the morning (dont know why and thre just small pops out of the exhaust((dont know if this is backfirng...)and it backfired(properly throgh the carb)today..been driving the engine in about 30 ...50 mph cause the engine was rebuild rebuild..backfired happen on acceleration 3rd gear..and dint happen after that (irrelevant of speed/gear any suggestionss?

 

[black64]

Only thing I can think of after reading your post on back firing in the morning is moisture inside your distributor cap causing spark tracking to ground. Or Can you see any arching with hood up and engine ideling and maybe crossfiring on the plug wires because of dampness or moisture? Any carbon tracking inside your distributor cap?

 

[67 coronet]

the spacer thing sounded weird to me,never heard of edy heads being shorter than stock.you said cam was stock,used or new with same specs?
your prob sounds to be ignition,possible check for advance issues.check to see if vac advance is hooked up correctaly,and not leaking vacuum.distrib advance needs to be reverse vacuum,and not direct motor vacuum.

 

[451Mopar]

first thought is carb is too lean.
Rocker shims should be used to correct rocker arm to valve stem geometry, not lifter pre-load (although it will work.) Correct way to set lifter pre-load is with the correct length pushrods.

 

[yannick47]

the spacer thing sounded weird to me,never heard of edy heads being shorter than stock.you said cam was stock,used or new with same specs?
your prob sounds to be ignition,possible check for advance issues.check to see if vac advance is hooked up correctaly,and not leaking vacuum.distrib advance needs to be reverse vacuum,and not direct motor vacuum.

i use heady heads with kb 237 pistons on an 73 engine stock cam used(anybody here runs this setup????)....and about the vac advace its not connected from the distributorr??should i hook it up??

Did you happen to mix up two plug wires

i put in a new set of msd street wires...but me mech had bend 2 sparkplug ports so it wounldt touch the headers...could this cause it?