what would be your diagnosis?????

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Confirm the direction your rotor turns and double check you firing order.

Check plug type and 5/8" length.


You can have a flat cam and still have compression, double check.

Tough one,
 
The idle timing can be set even with the polarity reversed. But the problem makes itself known immediately when the rpm rises off idle.This has been my experience. So if it revs up Ok, And the OP has put 80 miles on it,I believe he is good to go on that idea.
 
1) What brand and part numbers of valve seals were used after the tops of the guides were turned down for the spring cups? 'New seals' does not tell the whole story on that. We need to see what type of new stem seals were used.
2) Did you adjust the secondary idle stop screw? (The t-port stop that AJ refers to...) The idle mixture adjustment symptoms point to that.
3) Did you change the PCV to one that closes down at a lower vacuum? The stock Mopar PCV's will not close down properly with these low vacuum levels. The 'idling up' when you close off the PCV hose is a clear indication that there is too much air coming in via the PCV at idle.

You NEED to take care of 2 and 3 above or you are chasing your tail.
 
nm9stheham said:
3) Did you change the PCV to one that closes down at a lower vacuum? The stock Mopar PCV's will not close down properly with these low vacuum levels. The 'idling up' when you close off the PCV hose is a clear indication that there is too much air coming in via the PCV at idle.You NEED to take care of 2 and 3 above or you are chasing your tail.
Click to expand...

I have found that cams of this size, once the T-port sync is set and the timing is optimized,idle-vacuum comes up to where the PCV leakage actually helps with the idle-air bypass. SO FAR, in my experience,the "leaky" PCV can easily be compensated for with the secondary cracking screw. If however the PCV is directly sent into the intake,into the booster tap between runners 7 and 8, that makes trouble. The PCV has to be sent to the carb base for some semblance of reasonable mixture distribution.
As the OP describes the way his is working, is exactly the way I have experienced, and have always been able to make it work, SO FAR.And with any common sbm type 90* PCV. In fact, I use that PCV circuit to help establish the initial amount of secondary cracking, that I will dial in on the upside-down carb on my bench.
Now, I will say that on some combos, and without 4-corner idle,I have run into idle issues with the back running lean from the secondary cracking. And in those cases I sent a little air directly in through the primary plates. Nobody wants to hear that, but I do what I gotta do, to make the engine happy.Some guys compensate with excessive idle timing. That works, but for a streeter,IMO is a poor solution and causes other issues.
So, nm9, I'm not trying to minimize your experiences, only adding mine.

So how about that T-port sync?
 
Isolate the intake tract.

Plug off EVERYTHING that is pulling vacuum from the manifold.
 
rmchrgr said:
Check the polarity on the distributor pickup wires!

There's a little note about it in the MSD instructions. If the polarity is incorrect, the MSD will advance or retard your timing like 40 degrees or something ridiculous like that.

I had a similar issue when I installed an MSD in my Duster a few years ago. The car would hardly start and when it would, it was missing, running rough, wouldn't stay lit etc. The only thing that was changed was the MSD. It was driving me nuts, everything was right.

I posted a similar question to yours on the Moparts race section and an old racer gave me the tip. Took a while for it to sink in, I did not realize what he was referring to at first. I went back and re-read his reply. Eventually I understood and gave it a shot and switched the polarity of the pickup wires - car fired right up and ran great.
Click to expand...

I used this distributor and MSD box on the previous engine and it ran fine.
 
Lancair said:
Confirm the direction your rotor turns and double check you firing order.

Check plug type and 5/8" length.


You can have a flat cam and still have compression, double check.

Tough one,
Click to expand...

All the above has been checked and is good.
 
nm9stheham said:
1) What brand and part numbers of valve seals were used after the tops of the guides were turned down for the spring cups? 'New seals' does not tell the whole story on that. We need to see what type of new stem seals were used.
2) Did you adjust the secondary idle stop screw? (The t-port stop that AJ refers to...) The idle mixture adjustment symptoms point to that.
3) Did you change the PCV to one that closes down at a lower vacuum? The stock Mopar PCV's will not close down properly with these low vacuum levels. The 'idling up' when you close off the PCV hose is a clear indication that there is too much air coming in via the PCV at idle.

You NEED to take care of 2 and 3 above or you are chasing your tail.
Click to expand...

1.They look like Teflon seals. They are white with the clamp around them. I will try and get a picture. I don't think he turned the guides. He just opened up the seat ( very little cutting ) to accommodate the spring cups. He did remove them to get in and cut the seats though. .
2. Have not adjusted the secondary screw yet. Have to get the intake reinstalled.
3. I haven't changed the PCV. It idles up when I remove the hose from the PCV and let it pull air freely.
 
duster360 said:
1.They look like Teflon seals. They are white with the clamp around them. I will try and get a picture. I don't think he turned the guides. He just opened up the seat ( very little cutting ) to accommodate the spring cups. He did remove them to get in and cut the seats though. .
Click to expand...

Were they replaced with new ones? From what I have read, once you pull them it can damage them. That may be part of your oil issue.

EDIT: Especially if he didn't use the protective sleeve over the lock slots.
 
AJ/FormS said:
I have found that cams of this size, once the T-port sync is set and the timing is optimized,idle-vacuum comes up to where the PCV leakage actually helps with the idle-air bypass. SO FAR, in my experience,the "leaky" PCV can easily be compensated for with the secondary cracking screw. If however the PCV is directly sent into the intake,into the booster tap between runners 7 and 8, that makes trouble. The PCV has to be sent to the carb base for some semblance of reasonable mixture distribution.
As the OP describes the way his is working, is exactly the way I have experienced, and have always been able to make it work, SO FAR.And with any common sbm type 90* PCV. In fact, I use that PCV circuit to help establish the initial amount of secondary cracking, that I will dial in on the upside-down carb on my bench.
Now, I will say that on some combos, and without 4-corner idle,I have run into idle issues with the back running lean from the secondary cracking. And in those cases I sent a little air directly in through the primary plates. Nobody wants to hear that, but I do what I gotta do, to make the engine happy.Some guys compensate with excessive idle timing. That works, but for a streeter,IMO is a poor solution and causes other issues.
So, nm9, I'm not trying to minimize your experiences, only adding mine.

So how about that T-port sync?
Click to expand...

PCV is connect at base of carb. Intake is off at the moment, so no adjustment on the transition slot. I pulled the intake to verify a few things before going farther.
 
crackedback said:
Isolate the intake tract.

Plug off EVERYTHING that is pulling vacuum from the manifold.
Click to expand...

Only thing to close off is the PCV. I have nothing else to pull vacuum except the distributor and I have had that port capped from the beginning. All ports on intake and carb have been plugged or capped since before the first time I fired the engine. Except for the PCV.
 
Bad Sport said:
Were they replaced with new ones? From what I have read, once you pull them it can damage them. That may be part of your oil issue.

EDIT: Especially if he didn't use the protective sleeve over the lock slots.
Click to expand...

They were replaced with new seals. He told me he would have to do that because they would be damaged during removal.
 
what spark plugs U runnin and have U tried new ones recently? try looking for electrical zaps when running at night. vacuum of 8 seems low for the xe275/ cam, who is runnin this cam and what is your combo and what are U getting for vacuum. 1 hole at 155 is not the problem
 
duster360 said:
I have not tried a wider gap. When I pull a wire off to check the spark, it throws a heck of a blue flame.
Click to expand...

Yes, but is it at the plug. From my reading about the MSD box, I just picked one up a while back, it is recommended to run a wider gap. Depending on CR, it varies, most times it's around .045.

I'm sure heat range would be a factor as well like mentioned above.
 
Marcohotrod said:
what spark plugs U runnin and have U tried new ones recently? try looking for electrical zaps when running at night. vacuum of 8 seems low for the xe275/ cam, who is runnin this cam and what is your combo and what are U getting for vacuum. 1 hole at 155 is not the problem
Click to expand...

I am using autolite 3924 spark plugs that Edelbrock recommended for my combo. There is a video above that shows the vacuum gauge at idle.

My combo.

Edelbrock rpm heads
Comp cams XE275HL cam
9.8:1 STATIC COMPRESSION
Edelbrock AirGap intake
Rotating assembly was balanced
Hughes rocker arms
 
Not that this is causing your problem but switch to NGK, I have the number for Edel in my book. Gap at .045" Autolite is for Furd
 
magnummopar said:
Not that this is causing your problem but switch to NGK, I have the number for Edel in my book. Gap at .045" Autolite is for Furd
Click to expand...

Agreed, I just noticed the gap in a previous post and tossed it out there. Stranger things have happened, lol.
 
Ok, so, the intake is off we have to wait. I get that. I also get that you have been fairly systematic and thorough.This points to you either having a lot of help, or that you are fairly knowledgeable to start with.And you have tools.So my guess is you have been down this road a time or two already. And I know it can be frustrating to keep hearing the same thing post after post.
But here it comes again; since the carb is off, get after the T-port sync. It is so easy to do, you'll wonder why such a little thing could be such a big deal. If you need help with this, it's easy to explain, and every cam bigger than about 210@050 needs this addressed to some degree or another. Your cam is not that big, so a minor change can make a big improvement.

Ok, it's Sunday. Sunday is family day,but the kids were home last week, so, I got all day, and so, I'll just jump in here.

-Put the throttle control on the curb-idle stop, and keep it there making sure the choke mechanism cannot interfere. Flip it over,upside down. Get eyes on the transfer ports. They should appear as little square openings, to, in your case, perhaps a teensy bit taller than wide. Use the curb idle screw to make it so. Now, counting the turns, back out that same screw until the screw just comes off the stop, indicating that the primaries are fully closed. Eyeball them and prove it! Write that number down.
-Next, move to the secondary side. With the primaries still fully closed check to see that the secondaries are also fully closed, that the linkage is not holding it open. Then find the secondary cracking screw. Screw it out until the secondary throttle blades just barely stick to the borewalls.Then open them 3/4 turn.
-Now, flip it back right-side up, and turn the idle-speed screw back in the same number of turns that you previously backed it out (you did right it down, right?).
-Finally readjust the mixture screws to the base setting, which for Holley-types is 3/4 turn out, and for most others is 1.5 turns out.Now this is the really,really,really,important part. This is your baseline. If you get lost after this,return to the baseline.This is why you write stuff down;so you won't have to pull the carb off again.

And finally the quadruple-really important part; from here on you will not be touching the idle speed screw again.Unless I, or somebody smarter than me,(and there are lots of those guys) says so. You will be setting the idle speed with idle-air bypass (PCV leakage or secondary cracking screw), or idle timing;NOT with the idle speed screw.

When you get it back together,your target idlespeed will be 700 rpm.Your target idle timing will be 16* to 18*, +/- 2*. For a streeter I like the lower numbers, cuz I have an easier time tuning the Vacuum advance later. And a streeter quadruple-really needs the V-can working.
-If you cannot achieve the 700 in Neutral/Park, with the outlined method, something else is wrong. Either she is sucking air/fuel somewhere or the timing is out too lunch.
-Your mixture screws should now be working.If not, that's the very first thing I wanna know. Nothing moves forward until the mixture screws work and work best at between 1T and 2T.

To be continued; after you are up and running.
 
Marcohotrod said:
what spark plugs U runnin and have U tried new ones recently? try looking for electrical zaps when running at night. vacuum of 8 seems low for the xe275/ cam, who is runnin this cam and what is your combo and what are U getting for vacuum. 1 hole at 155 is not the problem
Click to expand...

an autolite 3924 is good, and does not know if it is in a mopar or ford or suzuki. misfire is why I asked if U tried another set of new plugs, and have U looked for zapping in the dark, and gap from .040"-.045" is good. what I think is for that cam 8" vacuum is kinda low, was wondering if any other members here are running that cam and would please tell us their combo and vacuum #
 
I agree that it's low, but you probably know that vacuum gauges can be all over the place. I never trust their numbers as absolutes, but they are a fine diagnostic tool none-the-less.
My Hughes HE 3037 is advertised at 276* intake duration and pulls over 10/11 at 700 with just 14* of idle-timing. That's on my gauge.heehee
 
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