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Curious as to why? Cadillac used vacuum with their 500 cid stocker. Is there too little vacuum with the cam that's used?
anyone want a 505 stroker before i throw it in the bin
- Thread starter benno440
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Curious as to why? Cadillac used vacuum with their 500 cid stocker. Is there too little vacuum with the cam that's used?
lewtot184
Well-Known Member
sometimes vacuum advances don't work well with low vacuum engines. not impossible by any means and i prefer them for drivers. the vacuum unit would need to be adjustable. doesn't make any difference how big the engine is or isn't.
Yep, can't tune a lick but somehow all my cars seem to run perfectly, hmmm. Just my personal preference after having a brand new Eddie spill gas out of the butterfly shafts and vapor lock all the time. That's all it is "an opinion".
benno440
Well-Known Member
vacuum at the moment with idle is bout 7hg
hemirunner; I am now running the smallest jet in the primaries the .83 jet and the stiffer blue springs.
I am trying to get my initial spot on at the time being, and looking at buying the 4seconds flat custom bushes which limit at 10* & 14*.
hemirunner; I am now running the smallest jet in the primaries the .83 jet and the stiffer blue springs.
I am trying to get my initial spot on at the time being, and looking at buying the 4seconds flat custom bushes which limit at 10* & 14*.
benno440
Well-Known Member
what dual quad carbs would you recommend? demons? holleys? what size?
lewtot184
Well-Known Member
big motor? 750 edelbrocks for the ch28. why? the stage II and stageIII 426 wedges used the same size carb as a 750 edelbrock. the '67 SS/B hemi cars had a cheater carb that was the same size venturi and throttle bore size as a 750 edelbrock. if the "little" engines can handle it why can't a big one? after all the secondaries are velocity controlled, aren't they? people buy carbs buy cfm ratings, what a shame. most cfm ratings are bogus, especially edelbrock. cfm ratings are taken at 1.5"hg pressure drop. try to pull 1.5". it's a moving target, fairly subjective. big engines want big gulps of air. manufacture's and builders tend to steer people toward the smaller stuff thinking it's idiot proof; nothing is idiot proof. a dual plane intake can use more carburation than a single plane so take advantage of it.
Benno,
It's your money, but I think you would be much better off getting your motor to run right with the carbs you have. When you have a highly modified motor there is almost no chance that a pair of out of the box carburetors are going to run perfectly. A good tuning person can make any carburetor work well, whether they're Holleys, Demons, Edelbrocks or any other brand. I will agree that there are choices to make when you're looking for maximum horsepower, but I take it you're just trying to get the car to be reliable and road worthy. Save your money. Find the problem.
It's your money, but I think you would be much better off getting your motor to run right with the carbs you have. When you have a highly modified motor there is almost no chance that a pair of out of the box carburetors are going to run perfectly. A good tuning person can make any carburetor work well, whether they're Holleys, Demons, Edelbrocks or any other brand. I will agree that there are choices to make when you're looking for maximum horsepower, but I take it you're just trying to get the car to be reliable and road worthy. Save your money. Find the problem.
benno440
Well-Known Member
thanks. well just an update, my lifters have now failed, looking at those rhoads lifters, anyone got any feedback on them?
also looking at a retard unit so lock the dizzy out at like 34* and use the retard unit to start the motor.
also looking at a retard unit so lock the dizzy out at like 34* and use the retard unit to start the motor.
Benno,
What do you mean 'failed' and what makes you think that they are? BTW, in all my years of hot rodding cars (over 50) I've never known anyone that had to use a 'locked out' distributor on a street/strip motor, and that includes many years of working and racing out of a major speed shop. We're not talking 'race only car' here. I know it's easy to get caught up in the glitzy and cool world of race parts, but they aren't meant for cars that have to idle and have good low end as street/strip cars do. My best advice is to find someone that can help you get back to basics so you can drive and enjoy that beautiful car... You know what they say, "opinions are like *ssholes, everybody has one". The trick is to be able to sort out the helpful ones from the rest...
What do you mean 'failed' and what makes you think that they are? BTW, in all my years of hot rodding cars (over 50) I've never known anyone that had to use a 'locked out' distributor on a street/strip motor, and that includes many years of working and racing out of a major speed shop. We're not talking 'race only car' here. I know it's easy to get caught up in the glitzy and cool world of race parts, but they aren't meant for cars that have to idle and have good low end as street/strip cars do. My best advice is to find someone that can help you get back to basics so you can drive and enjoy that beautiful car... You know what they say, "opinions are like *ssholes, everybody has one". The trick is to be able to sort out the helpful ones from the rest...
Never used Roads "yet" but I did some looking into them and found out some things you may want to consider. I got on they're website and learned that adjusting them is quiet different, you place a fealer gauge (.020 if I remember right) between the rocker tip and the valve, then adjust the rocker until you have .020. So your .020 from the lifter being bottomed out in it's bore, the way I understand it is on fire up the lifters are bottomed (making your cam seem smaller) at 3,500 rpm they pump up and your lift is restored. Pretty cool idea, having a big cam that acts like a smaller one at lower rpm's. Like I said this is just what I "think" I've learned and I'm sure someone will correct me if I'm mistaken. The point is that with this lifter I would think you would need a longer pushrods with the lifter being depressed so much. Best of luck
lewtot184
Well-Known Member
a locked distributor will need a start retard or you'll need a bunch of starters. after talking to mark engle at engle cams about rhoades lifters i'm not a fan. if one set of hydraulic lifters have failed why would you think another set will work? what kills hydraulic tappets? there are some that are just plain junk due to poor tolerances. but, even a good hydraulic tappet will fail if it is taken beyond it's design parameters. fast opening ramps, higher ratio rockers and the high spring rates needed to keep the tappet on the lobe eventually clobber the hydraulic internals. rhoades lifters aren't a solution. they're a different angle on the same problem.
benno440
Well-Known Member
i think they failed because i was out driving and it started ticking so when i got home i pulled covers and adjusted all the rockers, while adjusting 3 out of the 16 lifters bottomed out like they had no oil and a weak spring.
so i got it where i thought was pretty good i started it and no ticking, and then when it got hot it started ticking worse, so i readjusted again and there was about 5 bottoming out this time and now it just ticks bad.
i have dismissed the lock distributor idea and just going to get the 4secondsflat 10* & 14* bushing and see what happens when i set iniital at 22*.
still trying to figure out why my engine keeps overrunnning (dieseling)
another thing i have noticed and not checked yet is that when i set my timing in my driveway and then my idle at 900rpm, i go for a drive and come back home and the idle is now around 1300rpm, not sure if my dizzy is moving, it is tightened down properly.
i have checked the gap between butterflies and wall of the carbs to see if there getting stuck causing my dieseling but they are closed properly.
maybe my spark plugs are too hot? heat rating "7"
maybe my problem is elsewhere, NFI
anyone recommend some good lifters (hydraulic flat tappets)
so i got it where i thought was pretty good i started it and no ticking, and then when it got hot it started ticking worse, so i readjusted again and there was about 5 bottoming out this time and now it just ticks bad.
i have dismissed the lock distributor idea and just going to get the 4secondsflat 10* & 14* bushing and see what happens when i set iniital at 22*.
still trying to figure out why my engine keeps overrunnning (dieseling)
another thing i have noticed and not checked yet is that when i set my timing in my driveway and then my idle at 900rpm, i go for a drive and come back home and the idle is now around 1300rpm, not sure if my dizzy is moving, it is tightened down properly.
i have checked the gap between butterflies and wall of the carbs to see if there getting stuck causing my dieseling but they are closed properly.
maybe my spark plugs are too hot? heat rating "7"
maybe my problem is elsewhere, NFI
anyone recommend some good lifters (hydraulic flat tappets)
Benno,
1300 RPM is too high and is probably some of the source of your dieseling. When the motor is HOT, use a spray bottle with water and flood all hoses and connections, intake gaskets, carb base gaskets and anywhere else that vacuum might be leaking from. The key is to do this WHEN HOT, as that's where the high idle is happening. A leak will change the idle speed.
The next thing is to hook up your timing light and check TOTAL timing when the engine is just warmed up and then again when it is HOT to see whether or not your problem is tied to the mechanical advance weights hanging up.
What is the brand of your cam and lifters?
One problem at a time, my friend...
1300 RPM is too high and is probably some of the source of your dieseling. When the motor is HOT, use a spray bottle with water and flood all hoses and connections, intake gaskets, carb base gaskets and anywhere else that vacuum might be leaking from. The key is to do this WHEN HOT, as that's where the high idle is happening. A leak will change the idle speed.
The next thing is to hook up your timing light and check TOTAL timing when the engine is just warmed up and then again when it is HOT to see whether or not your problem is tied to the mechanical advance weights hanging up.
What is the brand of your cam and lifters?
One problem at a time, my friend...
451Mopar
Well-Known Member
I have a 505" stroker with the 17cc dished pistons and mild ported stealth heads (I think 10.3:1 compression?)
In the winter I was having issues with fowling the NGK R5672A-8 heat range 8 plugs and went to a hotter NGK plug #2756 (Plug Part # BKR6E-11) this is a 6 heat range.
I do get a bit of run on when the engine is run hard, but I think part of my problem is weak carb return springs (or rough throttle cable?) because it will idle fast, but if I blip the throttle quickly, it will return to a lower idle speed. My cam is a mild hydraulic roller Comp 286HR10 (a bit small for the engine), with 1.7:1 rocker arms, so valve lift is a bit over 0.600". The car is a street car, and I will be putting fuel injection on it in the next month, so I chose the mild duration cam.
Currently running a RPM intake and Holley Ultra Avenger 770 cfm carb.
In the winter I was having issues with fowling the NGK R5672A-8 heat range 8 plugs and went to a hotter NGK plug #2756 (Plug Part # BKR6E-11) this is a 6 heat range.
I do get a bit of run on when the engine is run hard, but I think part of my problem is weak carb return springs (or rough throttle cable?) because it will idle fast, but if I blip the throttle quickly, it will return to a lower idle speed. My cam is a mild hydraulic roller Comp 286HR10 (a bit small for the engine), with 1.7:1 rocker arms, so valve lift is a bit over 0.600". The car is a street car, and I will be putting fuel injection on it in the next month, so I chose the mild duration cam.
Currently running a RPM intake and Holley Ultra Avenger 770 cfm carb.
benno440
Well-Known Member
cam is lunati, lifters are comp cams.
coloradodave, because the springs I have in dizzy at the moment make the total advance come in at 3000rpm ( supposedly) does that mean when engine running and timing light on, to find total advance I need to hold rpm at 3000rpm?
what am I looking for when spraying the water? bubbles? I tried the carby cleaner trick that's how I found my first vac leak ( I left the big plug screw out of the back of the front carb, fixed that though)
thanks for all the help guys
- - - Updated - - -
I had '6' plugs the run on was so bad when I had these. my carb return springs are working really well, I checked that thanks.
coloradodave, because the springs I have in dizzy at the moment make the total advance come in at 3000rpm ( supposedly) does that mean when engine running and timing light on, to find total advance I need to hold rpm at 3000rpm?
what am I looking for when spraying the water? bubbles? I tried the carby cleaner trick that's how I found my first vac leak ( I left the big plug screw out of the back of the front carb, fixed that though)
thanks for all the help guys
- - - Updated - - -
I had '6' plugs the run on was so bad when I had these. my carb return springs are working really well, I checked that thanks.
493charger
Member
I too have a 500" mopar, had the ticking issue and found out that Comp had a bad batch of lifters. I replaced them with standard lunati lifters and haven't heard from them since... I also disassembled and cleaned them before I installed them.
How is your cam installed? Straight up, +-X degrees? I was running mine at +4 and I too had a hard cranking issue with high initial advance. You need to consider this when setting up your distributor. Too much advance, with an advanced cam, will definitely lead to run-on. Been there.
I don't know much about edelbrocks, but you have low vacuum and that creates a weak "signal" to the carbs. With a holley, a weak signal wreaks havoc on the idle circuit. A smaller carb, or one with smaller venturies with have a better signal with low vacuum. You are using 2 500's, so I'm not sure how that will affect things.
How is your cam installed? Straight up, +-X degrees? I was running mine at +4 and I too had a hard cranking issue with high initial advance. You need to consider this when setting up your distributor. Too much advance, with an advanced cam, will definitely lead to run-on. Been there.
I don't know much about edelbrocks, but you have low vacuum and that creates a weak "signal" to the carbs. With a holley, a weak signal wreaks havoc on the idle circuit. A smaller carb, or one with smaller venturies with have a better signal with low vacuum. You are using 2 500's, so I'm not sure how that will affect things.
Yes. Hook up your timing light and see what the initial timing is (at your 900 RPM idle). Then, assuming your harmonic balancer is marked, or you have a timing tape on it, run the motor RPM up while watching the timing indicator on the front cover. The RPM at which the balancer marks quit moving is the RPM that all your mechanical advance comes fully in. Let's say that your initial advance is 12*. When you run the RPM up, let's say that the marks quit moving at 3,000 RPM and the 34* mark on the balancer is even with the '0' mark on the timing indicator. This means that the total advance in the distributor is 34* minus the 12* initial, or 22*.
With the MSD distributor it's really easy to change the distributor advance total and the RPM at which it comes in.
When you test for vacuum leaks with a water spray bottle, you're looking to 'flood' the area you're testing. The water will change the 'sound' or RPM of the motor as it gets sucked into any vacuum leak. Some people use carburetor cleaner (Berryman's B-12 or equivalent) but you need to be aware of really hot surfaces. The Berrymans will cause the motor to speed up when it gets drawn into a vacuum leak. Your choice. Remember to test the timing both warm (900 RPM idle) and hot. The vacuum testing should be done while hot.
With the MSD distributor it's really easy to change the distributor advance total and the RPM at which it comes in.
When you test for vacuum leaks with a water spray bottle, you're looking to 'flood' the area you're testing. The water will change the 'sound' or RPM of the motor as it gets sucked into any vacuum leak. Some people use carburetor cleaner (Berryman's B-12 or equivalent) but you need to be aware of really hot surfaces. The Berrymans will cause the motor to speed up when it gets drawn into a vacuum leak. Your choice. Remember to test the timing both warm (900 RPM idle) and hot. The vacuum testing should be done while hot.
Tex013
Well-Known Member
Benno,
just an aside IMHO . The cam you have is small when seen from a stroker motor , I ran a 248@050 hyd in my 440ci motor - its kind of big there . Your motor is more than 10% bigger than mine but you have similar duration .
the dual quads are not a problem , I have used a dual quad modman on mine idled ,started and ran fine on the street , I have around 5" of vacuum at idle . Diamondback Engines have some real helpful info on their website when it comes to dual eddies .Do have them set progressive or 1 to 1 ?
With 9.8:1 comp a standard temp plug should not be a problem .
A friends 440 motor had similar issues - pinging carrying on etc . It ultimately came down to the wrong cam and how it was installed.
Check when your advance does come in , not when the springs say it does especially if your idle is at 1000 or near . My advance is all in by 2200 and idles in gear at 840-50 .
If the starter is kicking back you have too much advance .
I have tuned a 510ci sixpack motor and never had the problems you have .
good luck
Tex
just an aside IMHO . The cam you have is small when seen from a stroker motor , I ran a 248@050 hyd in my 440ci motor - its kind of big there . Your motor is more than 10% bigger than mine but you have similar duration .
the dual quads are not a problem , I have used a dual quad modman on mine idled ,started and ran fine on the street , I have around 5" of vacuum at idle . Diamondback Engines have some real helpful info on their website when it comes to dual eddies .Do have them set progressive or 1 to 1 ?
With 9.8:1 comp a standard temp plug should not be a problem .
A friends 440 motor had similar issues - pinging carrying on etc . It ultimately came down to the wrong cam and how it was installed.
Check when your advance does come in , not when the springs say it does especially if your idle is at 1000 or near . My advance is all in by 2200 and idles in gear at 840-50 .
If the starter is kicking back you have too much advance .
I have tuned a 510ci sixpack motor and never had the problems you have .
good luck
Tex
benno440
Well-Known Member
there 1:1
I will make these checks on the weekend and get back to you guys
just bought 2 x 2" HVH supersucker carb spacers, been tld it will hep my idle quality and low end torque also
I will make these checks on the weekend and get back to you guys
just bought 2 x 2" HVH supersucker carb spacers, been tld it will hep my idle quality and low end torque also
383man
Well-Known Member
Sorry to hear of all your problems Benno. You have got a ton of good advise hear but its so much advise it might confuse you. If you can find a very good Mopar tech in your area I would advise to let him look it over and work with it. It is just less confusion if good tech checks it out and diagnosie it and tries the right things to do.
That said I run a 440/493 stroker and I love how it runs. A few quick notes on what I run is I like alot of fast timing as I run very light springs in my dist. It runs about 25 initial and 37 total all in by 2000 rpm. I built good quench in the eng at 10.6 comp and it uses Indy EZ heads. It runs fine on 92 pump gas. No ping at all and no trouble starting as some of the initial is the fact the springs are so light that some advance is already in at idle. So while cranking its not as much and it cranks good. I use an Indy dual plane intake with an 850 DP and the driveability is great. Perfect throttle resonse at any RPM in any gear as I use a 727 with a Dynamic 9.5 converter that flashes about 4200 and drives normal as I drive my 63 everywhere. I run a solid flat tappet cam as I have never cared much for hydraulic cams. My cam is 264 & 270 @ .050 with a 110 LSA and I have it in on a 106 ICL. The lift is .588 & .592 but I use 1.6 rockers for .628 and .632 lift and it works great for me. Just enough chop in the idle that I love and great power.
Good luck with yours as hang in there and you will get it. But like I say if you can find one good tech let him alone work with it and see if he can help you. Ron
That said I run a 440/493 stroker and I love how it runs. A few quick notes on what I run is I like alot of fast timing as I run very light springs in my dist. It runs about 25 initial and 37 total all in by 2000 rpm. I built good quench in the eng at 10.6 comp and it uses Indy EZ heads. It runs fine on 92 pump gas. No ping at all and no trouble starting as some of the initial is the fact the springs are so light that some advance is already in at idle. So while cranking its not as much and it cranks good. I use an Indy dual plane intake with an 850 DP and the driveability is great. Perfect throttle resonse at any RPM in any gear as I use a 727 with a Dynamic 9.5 converter that flashes about 4200 and drives normal as I drive my 63 everywhere. I run a solid flat tappet cam as I have never cared much for hydraulic cams. My cam is 264 & 270 @ .050 with a 110 LSA and I have it in on a 106 ICL. The lift is .588 & .592 but I use 1.6 rockers for .628 and .632 lift and it works great for me. Just enough chop in the idle that I love and great power.
Good luck with yours as hang in there and you will get it. But like I say if you can find one good tech let him alone work with it and see if he can help you. Ron
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