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Engine tuning questions - video included....
#672772
04/17/10 07:06 PM
04/17/10 07:06 PM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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So I've finally bolted my exhaust on so it's a little easier to hear myself think under the hood. I'll preface this by saying this is my first actual ground-up rebuild of a v8. I don't have anyone around as an official "mentor", nor do I know anyone I can bribe into acting as one. I'm having a hard time getting a "smooth" idle out of the engine. A couple of things: Starting with the carb IMS's at 1.5 turns out, adjusting the screw on the right outward produces no results, while I continue screwing out. Hmm? Going counter-clockwise (out) with the left screw produces a small increase in idle, but since my idle isn't rock solid stable, it's too difficult to determine. If both screws are bottomed out (accidentally did this earlier), the engine will still run and actually idle pretty well. Hmm? If I unplug my vacuum gauge from the carb base plate, there is no discernible difference in idle speed or quality. These above factors lead me to believe I've got a vacuum leak. The question is: how can I have 22" of vacuum at idle and still have a vacuum leak? Also, you might be able to hear it in the video, you might not. It almost sounds like a "miss" but it isn't constant in the firing cycle. It just isn't smooth, and you can see that when I point the camera at the dwell/tach meter. I do not have any clue if I've timed the engine right. I do not, currently, have a dial back light. I've got a standard light and if I disconnect the vacuum source going to the distributor vacuum pot (and plug it), and shine my light at the balancer at idle, the line is almost an inch below where the 10 mark is on the lower aspect of the timing indicator. I hope that makes sense. Where do I go from here? This will eventually be my daily driver, and I want it to be rock solid. The truck starts on the first crank, throttle response is crisp and sharp, and the engine refires and runs after it's hot and turned off. Please help me get in the right direction here. Thanks, and cheers -Pat  Link to the video: http://www.youtube.com/watch?v=Qn3f48QKhTA
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672773
04/17/10 09:45 PM
04/17/10 09:45 PM
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Joined: May 2005
Posts: 598
NC, USA
davenc
mopar
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mopar
Joined: May 2005
Posts: 598
NC, USA
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Pat,
Here are a couple of thoughts...in the video the vacuum gauge was at 18 inches, not 22. If the car runs with the IMS closed, then it is getting fuel from somewhere other than the primaries. This could be via a carb leak (bowls not tight), or the secondaries are open too much. Cover the primaries with a rag to block them, and see if the motor still runs. Then, try the same on the secondaries.
What sort of cam and carb does the the engine have? I assume it is a hydraulic cam? The vacuum is fluctuating some, but not a huge amount.
Do the engine run more smoothly at 1500? 2000?
Regards,
Dave
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Re: Engine tuning questions - video included....
[Re: davenc]
#672774
04/17/10 10:47 PM
04/17/10 10:47 PM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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Quote:
Pat,
Here are a couple of thoughts...in the video the vacuum gauge was at 18 inches, not 22. If the car runs with the IMS closed, then it is getting fuel from somewhere other than the primaries. This could be via a carb leak (bowls not tight), or the secondaries are open too much. Cover the primaries with a rag to block them, and see if the motor still runs. Then, try the same on the secondaries.
Thanks Dave. I'll give that a shot tomorrow.
Quote:
What sort of cam and carb does the the engine have? I assume it is a hydraulic cam? The vacuum is fluctuating some, but not a huge amount.
Hydraulic RV cam and 1406 Edelbrock carb. Not a "hot" setup by a long shot. Its in my 1980 ramcharger.
Quote:
Do the engine run more smoothly at 1500? 2000?
Regards,
Dave
Engine does run fine at higher rpms. It just doesn't like sitting still at idle. I suppose I really should learn how to properly time an engine from start to finish.
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672777
04/18/10 06:40 PM
04/18/10 06:40 PM
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Joined: May 2005
Posts: 598
NC, USA
davenc
mopar
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mopar
Joined: May 2005
Posts: 598
NC, USA
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Pat,
With respect to timing, there are three things to consider on a street vehicle, initial, total mechanical, and total with vacuum. For starting, leave the vacuum disconnected from the distributor, and the vacuum hose plugged.
The amount of initial the engine will need will depend on several factors, including the size of the bore and the amount of overlap in the cam between intake and exhaust valve timing. With a stock 440 and a RV cam, the motor should not need a huge amount of initial, and if you have a stock distributor too much initial will lead to too much total mechanical advance at higher rpm.
How does the motor run with the initial timing set to 10 degrees before top dead center (BTDC)? I would suggest starting somewhere in the 10-12 degree BTDC range, and see if you can get the carb adjusted to the point where you think the idle is good.
To check the total timing, you will need a dial timing light. I know you stated you don't have one right now, and given that, you need to stay conservative on the initial to not end up with too much total. Factory distributor may have 26-28 degrees in it (don't remember the specifics), and a BB with iron head will likely run best with 36-38 degrees total.
Regards,
Dave
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Re: Engine tuning questions - video included....
[Re: davenc]
#672778
04/18/10 07:07 PM
04/18/10 07:07 PM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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Quote:
Pat,
With respect to timing, there are three things to consider on a street vehicle, initial, total mechanical, and total with vacuum. For starting, leave the vacuum disconnected from the distributor, and the vacuum hose plugged.
The amount of initial the engine will need will depend on several factors, including the size of the bore and the amount of overlap in the cam between intake and exhaust valve timing. With a stock 440 and a RV cam, the motor should not need a huge amount of initial, and if you have a stock distributor too much initial will lead to too much total mechanical advance at higher rpm.
How does the motor run with the initial timing set to 10 degrees before top dead center (BTDC)? I would suggest starting somewhere in the 10-12 degree BTDC range, and see if you can get the carb adjusted to the point where you think the idle is good.
To check the total timing, you will need a dial timing light. I know you stated you don't have one right now, and given that, you need to stay conservative on the initial to not end up with too much total. Factory distributor may have 26-28 degrees in it (don't remember the specifics), and a BB with iron head will likely run best with 36-38 degrees total.
Regards,
Dave
Thanks again Dave 
I'm away from the truck right now (husbandly duties of hanging useless crap on my pristine, hole-free walls), but I'm almost positive if I were to run the truck at 10* btdc it would stall. When I shine the light down there as it is, idling like you see in the video, it's probably at around 16*. Could that be very wrong?
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672780
04/18/10 08:39 PM
04/18/10 08:39 PM
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Joined: Jan 2003
Posts: 17,904
S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,904
S.E. Michigan
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Judging from the way it comes down to idle quickly when you goose the throttle (in the open header video), I don't think there's a vacuum leak.
However you're there and I'm not, and it's always good to satisfy or deny any feeling it might have a leak....
so I recommend testing for vacuum leaks with water instead of carb cleaner so you don't eat up your new paint. A spray bottle with a "stream" adjustment on it works well. Any leak hit with water and sucked in will slow the idle down a bunch.
Rich H.
Esse Quam Videri
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672782
04/18/10 10:37 PM
04/18/10 10:37 PM
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Joined: May 2005
Posts: 598
NC, USA
davenc
mopar
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mopar
Joined: May 2005
Posts: 598
NC, USA
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Pat,
Yes that vacuum reading is lower than it should be for a stock-ish BB. It makes sense to eliminate the simpler stuff first. Zippy's method of finding a leak is better than what I suggested, and you should try and cross leaks off as a possible cause. Remember to spray anywhere that could suck air...any hose (entire length) that is connected to the carb, the carb to manifold gasket/sealing, and the manifold to cylinder head gasket/sealing.
When you get a chance, let us know about the cam installation. There was just another thread today in this forum about cam socket timing marks, and how easy it is to get it wrong the first time you install a cam, particularly if not degreeing it in.
Also, did you pull any plugs to see if there are any abnormal signs (oil, sooty, etc)?
Regards,
Dave
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Re: Engine tuning questions - video included....
[Re: davenc]
#672783
04/19/10 12:38 AM
04/19/10 12:38 AM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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Quote:
Pat,
Yes that vacuum reading is lower than it should be for a stock-ish BB. It makes sense to eliminate the simpler stuff first. Zippy's method of finding a leak is better than what I suggested, and you should try and cross leaks off as a possible cause. Remember to spray anywhere that could suck air...any hose (entire length) that is connected to the carb, the carb to manifold gasket/sealing, and the manifold to cylinder head gasket/sealing.
When you get a chance, let us know about the cam installation. There was just another thread today in this forum about cam socket timing marks, and how easy it is to get it wrong the first time you install a cam, particularly if not degreeing it in.
Also, did you pull any plugs to see if there are any abnormal signs (oil, sooty, etc)?
Regards,
Dave
I've also heard of using propane to check for vacuum leaks. Is that the "drier" method?
It would make sense to have a higher vacuum reading like I was getting with 16*+ of initial advance.
The cam, chain, and crank were all left alone during my rebuild. Their relationship with one another was not touched, and the engine ran perfectly fine. The only thing that I did move was the distributor drive gear to prime the oil pump. I suppose I could have dropped it back in out of orientation. I just don't understand the sporadically unsteady idle. Could me having the distributor drive gear installed on the wrong tooth cause that?
I guess my next step is going back to basics. Find TDC on compression of number 1, make sure rotor is pointing at number one wire at that point. Go from there?
Finding a vacuum leak with those other methods is a little difficult, especially because the idle climbs 100+ rpm sporadically on it's own, just while it's sitting there....
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Re: Engine tuning questions - video included....
[Re: Joshs68]
#672785
04/19/10 01:24 PM
04/19/10 01:24 PM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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A couple of things that I found out this morning:
While checking the distributor diaphragm (it does hold vacuum), I noticed the reluctor had an arrow on it, indicating it's direction of rotation. Mine is obviously for a small block, as it's arrow indicates a clockwise rotation. How much, if any, does this matter?
I pulled the plugs. Not pretty. #1's ground strap was all but touching the electrode and is pretty much a solid black color. The others appear a bit better, with no coloring on the ground strap or electrode until about half way down the ground strap.
I also decided, while the plugs were out, to do a quick dry compression test. Numbers don't look good. I only got through cylinders 1 (125psi), 3 (112psi), and 5 (115psi).
I'm going to take a couple shots of the spark plugs and post them in a bit.
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672786
04/19/10 01:29 PM
04/19/10 01:29 PM
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Joined: Aug 2007
Posts: 6,097
Valencia, España
NachoRT74
master
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master
Joined: Aug 2007
Posts: 6,097
Valencia, España
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Quote:
A couple of things that I found out this morning:
While checking the distributor diaphragm (it does hold vacuum), I noticed the reluctor had an arrow on it, indicating it's direction of rotation. Mine is obviously for a small block, as it's arrow indicates a clockwise rotation. How much, if any, does this matter?
its in relation with PHASING
http://www.hotrodhotline.com/md/html/rotorphasing.php
http://www.msdignition.com/uploadedFiles...tor_phasing.pdf
BB are CCW and use a diff notch for the location pin. Thats for the diff movement of the vaccum/pickup plate too.
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: Engine tuning questions - video included....
[Re: NachoRT74]
#672787
04/19/10 01:34 PM
04/19/10 01:34 PM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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Quote:
Quote:
A couple of things that I found out this morning:
While checking the distributor diaphragm (it does hold vacuum), I noticed the reluctor had an arrow on it, indicating it's direction of rotation. Mine is obviously for a small block, as it's arrow indicates a clockwise rotation. How much, if any, does this matter?
its in relation with PHASING
http://www.hotrodhotline.com/md/html/rotorphasing.php
http://www.msdignition.com/uploadedFiles...tor_phasing.pdf
BB are CCW and use a diff notch for the location pin. Thats for the diff movement of the vaccum/pickup plate too.
So then the answer is that, yes, it does make a difference?
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672788
04/19/10 02:18 PM
04/19/10 02:18 PM
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Joined: Jan 2003
Posts: 17,904
S.E. Michigan
ZIPPY
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 17,904
S.E. Michigan
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The reluctors have two roll pin slots, one with a CW arrow next to it and one with no arrow. For a big block, the roll pin should be installed in the slot that does not have an arrow near it.
15" of vacuum at a "normal" advance, and noticeably more manifold vacuum when the advance is cranked up is quite normal, and is what I'd expect for a mild cam in a low compression 440.
Rich H.
Esse Quam Videri
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Re: Engine tuning questions - video included....
[Re: ZIPPY]
#672789
04/19/10 02:51 PM
04/19/10 02:51 PM
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Joined: Aug 2003
Posts: 4,481
Mesa, AZ
Pat_Whalen
OP
super gas
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OP
super gas
Joined: Aug 2003
Posts: 4,481
Mesa, AZ
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Quote:
The reluctors have two roll pin slots, one with a CW arrow next to it and one with no arrow. For a big block, the roll pin should be installed in the slot that does not have an arrow near it.
15" of vacuum at a "normal" advance, and noticeably more manifold vacuum when the advance is cranked up is quite normal, and is what I'd expect for a mild cam in a low compression 440.
Thanks Zippy
So I could just pull the roll pin out and put it in the other slot for the side that has no arrow, correct?
Here are a couple shots of the plugs. #1 looks like something may have impacted it, sending the ground strap close to the electrode. When is it a safe assumption that plugs cannot simply be cleaned up with a small wire brush and actually need to be replaced. These are new, with zero miles and about 2 hours total of operation on them.
Cylinder #1:
Cylinder #5:
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Re: Engine tuning questions - video included....
[Re: Pat_Whalen]
#672791
04/19/10 03:44 PM
04/19/10 03:44 PM
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Joined: May 2007
Posts: 701
Northern California
lilcuda
super stock
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super stock
Joined: May 2007
Posts: 701
Northern California
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Quote:
The cam, chain, and crank were all left alone during my rebuild. Their relationship with one another was not touched, and the engine ran perfectly fine. The only thing that I did move was the distributor drive gear to prime the oil pump. I suppose I could have dropped it back in out of orientation. I just don't understand the sporadically unsteady idle. Could me having the distributor drive gear installed on the wrong tooth cause that?
You said that the engine was rebuilt, but now you're saying that the cam, crank & timing chain were left alone. Did you just do a re-ring? Big difference between a rebuild and a re-ring. What was done to the heads?
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hm,didnt you say early in the thread that the engine keeps running with the(5minute space where im trying to remember what those 2/4 carb screws are called)aaaarrrgh,those 2 small screws at the side of carb.when they are screwed in to light bottom,the engine should stumble and stop.so,check your fuel inlet valve and power valve maybe.also the cranking compression are almost down to the factory recomended limits,but not yet so i bet its something simple. 
