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Thinking about installing a smaller cam in Eileen
https://slantsix.org/forum/viewtopic.php?t=33273		 Page 2 of 3
Author:  Rug_Trucker [ Tue Jan 13, 2009 4:05 pm ]
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Air bleeds in carb is what I am wondering about if it has a stinky idle.
Author:  Bren67Cuda904 [ Wed Jan 14, 2009 3:12 pm ]
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No gas is leaking. I never smell gas unless I've just shut it off and that goes away in about 2 min or faster if there is a breeze. The smell is with out a doubt coming out of the tail pipe.
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Air bleeds in carb is what I am wondering about if it has a stinky idle.
The 570 street avenger and the 390 DPer both smell the same and both idle at 12:1.
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It sounds like the cheap muffler has to go.If you lost that much performance,it must be VERY restrictive,costing you fuel economy as well.I,d suggest a Walker super turbo,I think it,s a good compromise between performance and noise
It has always smelled with a Flowmaster, Dynamax, Magnaflow all run by themselves and even smelled with the Magnaflow And cheap extra muffler.(current setup) The smell is not exhaust related except for the fact that its where the smell is emanating from (while running)
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Part of it is just the price you pay for a cool old car, but being anal about keeping your fuel cool will cut it WAY back.
I understand its not going to smell nice and clean like an EFI engine, but it shouldn't make your eyes water either.

I had read an article in one of the mags that had said that big cams will cause this smell and thought you guy might know something about that and have a suggestion. I believe its cam related just because I've done so many adjustments to this engine and the smell has always been there. The only time the smell was not preset was when I had the original engine in it with the original cam. (super six)
Author:  Doc [ Wed Jan 14, 2009 3:55 pm ]
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A cam with a long overlap event will send some raw A/F into the exhaust.

Usually, a cam with that much overlap will be high RPM oreanted and also have a rough idle but you may have enough static compression or a cam grind that does not cause alot of intake track reversion.

When does the exhaust valve fully close on your current set-up?
DD
Author:  Bren67Cuda904 [ Wed Jan 14, 2009 6:04 pm ]
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When does the exhaust valve fully close on your current set-up?
DD
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http://www.renaissanceracing.com/images/CamCard2A.JPG I am 2* advanced from this card which puts me @ 16*
Is this the info you need? If not, I am not sure what your asking for or more like how to find it.
Author:  440_Magnum [ Thu Jan 15, 2009 7:42 am ]
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I had read an article in one of the mags that had said that big cams will cause this smell and thought you guy might know something about that and have a suggestion. I believe its cam related just because I've done so many adjustments to this engine and the smell has always been there. The only time the smell was not preset was when I had the original engine in it with the original cam. (super six)
OK, I think I understand. Its an excessive rich smell, not really a "raw gasoline" smell. A big cam can certainly contribute to that, and (unfortunately) the lowest-buck cheat probably is bleed-down lifters which are not an option on a mechanical cam engine. My gut feeling is still that degreeing the cam will not help- if you advance the cam it nominally smooths out the idle, but the exhaust valve will be opening very early so you'll still get a lot of partially-burned mixture in the exhaust. If you retard the cam, then you'll kill all your low-end power and you'll have a rougher idle (more misfires) so you'll STILL be getting a lot of unburned mixture.. Big cams have a very narrow "happy" range. If you had a super-loose convertor or this were a manual transmission car you could just up the idle speed and clean things up a lot, but that's not a choice.

I almost hesitate to bring this up because it can be such a hassle to get tweaked just right- but have you tried running your vacuum ignition advance on straight manifold vacuum instead of ported vacuum? Its NOT the way a slant is normally setup (nor any Mopar engine for that matter) but I've actually had a lot of success running my C-body's 440 that way, and one thing it did was really clean up the exhaust smell at idle. This happens because the engine will be idling at 20 degrees or so advance. It won't ping or rattle because the system retards the instant you open the throttle, but the huge amount of advance at idle lets the combustion process go nearer to completion before the exhaust valve opens. Don't change your basic timing at first, and always set the basic timing with vac. advance disabled. Let the idle advance "fall where it may."

If you go that route, you have to slow the idle speed down at the carb, but you walk a "razor's edge" because if anything happens to load the engine up a little at idle the manifold vacuum will drop, the vacuum advance will go away, and it will threaten to stall. Some engines also will *never* achieve a decent throttle tip-in when you do this- my 440 does just fine, but your slant might not Its a cheap (free!) thing to try, but be warned it might take a good bit of twiddling the idle speed and maybe basic timing to get to work right.
Author:  Doc [ Thu Jan 15, 2009 10:23 am ]
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When does the exhaust valve fully close on your current set-up?
DD
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http://www.renaissanceracing.com/images/CamCard2A.JPG I am 2* advanced from this card which puts me @ 16*
Is this the info you need? If not, I am not sure what your asking for or more like how to find it.
Basically, the intake valve is opening early and allowing unburned A/F to go out the exhaust.

Your card values are at .050 lift so the actual intake opening event is happening sooner then 16 degrees BTDC, my guess is that it's more like 40 BTDC with the lash set in the .018 to .020 range.

You could pull the valve cover, check the current lash clearances and get a better look at when the intake valve actually starts to open.
You can do this with-out a degree wheel, just find the place at TDCE (overlap event) where all the lash goes out of the intake valve and use the engine's timing marks to get an idea on how far before TDCE it is when the intake valve "cracks open". You may want to try a looser lash setting on the intakes because that will delay it's opening point a little.
DD
Author:  Bren67Cuda904 [ Thu Jan 15, 2009 5:42 pm ]
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I am using MSD's Timing Computer, http://www.jazzproparts.com/product_p/8981.htm
with the distributor locked out. The vacuum can is still there but not hooked up to vac.
Initial is set at 23* and full advance is 25* or with a flip of a switch 29*, both all in at 3000rpm. My advance curve is set pretty aggressive. I believe the advance at idle is whats giving me the nice smooth idle.
My idle is set at 900 rpm and I have always had to shut off the car with it in gear to keep it for running-on. When I was using 93 octane it had no run-on at all when shutting off in gear. I am now using 87 octane and I've noticed every once in a while I get just a pinch of run-on. What is this a sign of, if anything?
The way the cam is set now the power comes in at 3000rpm. Its like flipping a switch. Even at part throttle if the RPMs touch 3000 it starts to set you back in your seat.

What is considered a big, mild and small street cam?
Where does my 240@50 fall?

The car is going to be more of a daily driver and I am just trying to making it a little nicer to drive (going to add power steering soon) by cutting down on the smell some and get a little more fuel mileage out of it. I drive mostly around town and 10 MPG is just a bit ridiculous.
Author:  Dart270 [ Fri Jan 16, 2009 11:48 am ]
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Vac advance will get you something like 1-3 MPG right there.

Cam advanced 4 deg more would bring the power on lower down, or going to a 230-235 @ 0.050" cam would also work well.

Lou
Author:  Bren67Cuda904 [ Sun Jan 25, 2009 5:57 pm ]
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What size cam (@50 please) is in a stock motor (225)?
Sandy, what size cam where you running in your red car two years ago?
Author:  sandy in BC [ Mon Jan 26, 2009 7:31 am ]
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Two years ago I had a Comp 264....lame

Last winter I installed an Erson TQ30/20 m

230 intake/220 ex @ .050 109 + 2

CR 9.5 Valves 1.72/1.50

Runs fine on 87.....good idle...

I had a BBD on an aluminum Super 6....since burned through.

I would call this about as far as you can go with a Super 6 on regular
Author:  440_Magnum [ Mon Feb 02, 2009 7:16 am ]
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I am just trying to making it a little nicer to drive (going to add power steering soon) by cutting down on the smell some and get a little more fuel mileage out of it. I drive mostly around town and 10 MPG is just a bit ridiculous.

A tamer cam will probably help that goal, but it may bring back your pinging due to so much compression (even though you did lower it). With a milder cam you can be less agressive on initial timing advance, put vacuum advance back in play (or mimic it with your timing computer) and bring mileage up a lot that way.

To really get the bang out of a milder cam and all the other things, you may wind up needing a "tighter" (lower stall) convertor. With an optimized setup, its hard to change just one component without having a big ripple effect.

And frankly, your long stroke may be part of it. Long stroke means higher piston speeds, bigger piston-reversal forces, and generally lower efficiency.
Author:  Bren67Cuda904 [ Mon Feb 09, 2009 5:18 pm ]
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I am likely going to go with a custom ground cam that around 220@50, 110 or 112 LS, .500-.530 lift. I'd like my power band to be 2000rpm-5000rpm. While I have the engine out, I'll take the converter back to FTI and have the stall reduced from 3200 to 2000-2200. I am currently running 87 octane and after this change might have to move up to 93 octane. Just as long as I don't need race fuel I'll be OK with that.
I am kind of thinking that this combo should let me eat my cake too. The head port work as some have noted is not the best and with the longer stroke the motor might just like the lower rpm design better. Also less fuel smell with better fuel mileage should also result.

I am looking for a little input on fine tuning some of the specs.
My current cam is ground at 110+4 install advanced 2*. I should be able to have the new cam ground at +2 and it should drop in straight up using my current timing set and bushing.

I have also considered the cam that Sandy's using (220/230@50 109) but feel that it might still be a pinch big. I really want to be rid of alot of the fuel smell and bump the mileage. What is the difference between a 220/220 and a 220/230@50 cam? What things might one notice between the two, all other things being the same?

One last thing. Try to remember that this car is not a drag car. Its driven alot on the street now. I'd hate to give up a huge amount of power, but if thats what it takes, then thats what it takes. The truth is the car will likely see the drag strip about once or twice a year.
Author:  sandy in BC [ Mon Feb 09, 2009 6:05 pm ]
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I arrived at my cam by spending a bunch of time with an online calculater. I was after a specific range of dynamic compression ratio....

My motor is at a true 9.5....where are you at now?
Author:  madmax/6 [ Mon Feb 09, 2009 6:27 pm ]
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I have a identical cam as Sandy,also 2 degees advanced,in the Guzzi car,I set my valves at 18 in,22 ex,Havent played with it much yet but am happy so far,Where do you have your valves set Sandy?and your timeing?
Author:  madmax/6 [ Mon Feb 09, 2009 6:32 pm ]
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Forgot to mention my car is a true 10.7 compression car.I do have to run 1 gal to 10 of 115 race gas ,if i dont it just barely pings,Mark
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