Engine Dyno Day is Next Week!
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Melting Slicks
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From: Bogart GA
The offset dowel pins work like a cam lobe. Install in the same position and move them exactly the same amount. So yes the offset pin might be a max of .007 and a min of 000. You are using the caming to center the bell housing. Which you know. I use the long allen locking bell housing dowel pins
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Melting Slicks
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From: Bogart GA
OK..... took it out for another test drive. Did better, vacuum at cruise was in the teens. Still goes rich when when I am in the primary circuit at a higher vacuum. My guess is at this point my primary jets are too big. They are quite a bit bigger than what I was running in my 427. The primary jets are 95. The secondary jets are 96 with a 4.5 power valve. I guess I will drop to a 92 and see what happens. I don't know what I would do without my wide band LM-1 logger. I have a map sensor attached to it as well so I can see my AFR, RPM and Vacuum real time as I record it on my lap top in the passenger seat. Supposed to rain tomorrow.....maybe I can get a run in in the morning with the smaller jets provided I have some that size.
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From: Corsicana, Tx
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That's a heck of a lot of jet....but there's lots of things that determine the jet size. You said it was a modified 950....but what did they change...and why???
I can say my 1050 Dominator ran with 82's in primary with a PV and 95's in the rear with no PV.
You've got a lot of fuel going through that thing.
JIM
I can say my 1050 Dominator ran with 82's in primary with a PV and 95's in the rear with no PV.
You've got a lot of fuel going through that thing.
JIM
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From: Reno Nevada
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Thread Starter
Melting Slicks
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From: Bogart GA
What primary jets are you running? If I pick my idle up to 1000+ I can get my vacuum up to about 10". Drops to about 7.5 at 850.
Thread Starter
Melting Slicks
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From: Bogart GA
Also, I cut open the original oil filter used during the engine dyno session and found small silver metal particles in the pleats. Also found a good bit in the magnets that the builder placed on the head bolts on each end at the oil returns. Is this normal during break-in? I have seen all kinds of info from builders in the web. most say some is OK after break-in but it should quickly clear up.
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From: Reno Nevada
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Your jets seem out of bounds for 950 cfm, but there are so many variables like air bleed size, booster type, front power valve...............
We both have big SR cams and idling at near 1100 rpm hot is not a big deal. I've worked on road racing big V-8's that idled near 1800.
Just my opinion, but to stay out of detonation or over cylinder pressure. I have seen and run my own $13,000 dollar motors at all in around 3000 to 3200 rpm
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Melting Slicks
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From: Bogart GA
I only have a 830 cfm My friend runs a 950 modified AED Holley HP and I can ask him.
Your jets seem out of bounds for 950 cfm, but there are so many variables like air bleed size, booster type, front power valve...............
We both have big SR cams and idling at near 1100 rpm hot is not a big deal. I've worked on road racing big V-8's that idled near 1800.
Just my opinion, but to stay out of detonation or over cylinder pressure. I have seen and run my own $13,000 dollar motors at all in around 3000 to 3200 rpm
Your jets seem out of bounds for 950 cfm, but there are so many variables like air bleed size, booster type, front power valve...............
We both have big SR cams and idling at near 1100 rpm hot is not a big deal. I've worked on road racing big V-8's that idled near 1800.
Just my opinion, but to stay out of detonation or over cylinder pressure. I have seen and run my own $13,000 dollar motors at all in around 3000 to 3200 rpm
Last edited by KJL; Dec 21, 2015 at 09:14 AM.
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Thread Starter
Melting Slicks
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From: Bogart GA
Yes, the carb has J-tubes but was told the metering blocks were set up for auto. The carb is not an off the shelf piece. It was built by a company that custom builds carbs for specific applications. I believe they do specialize in race engines for boats which explains the J-tubes. Is my builder feeding me a line of crap and just pulled a unit he had sitting on the shelf that was earmarked for a boat engine? I suppose that possibility exists. If re-jetting cant fix the problem, then I will need to consider other options. I ran a 830 cfm marine Holley carb with annular boosters on my 427 build for years without issues.
Last edited by KJL; Dec 21, 2015 at 11:00 AM.
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I'd certainly believe it would like 20*+....I'd go for all the initial you could stand and bring in a little for total and "light cruise" vacuum type advance....but just a little. Initial really helps a big cam / big head motor become more responsive.
It also seems like it wants to idle in the 1000 RPM range. Why not? Mine always idles around 1100 and just feels perfect.
I'd see if someone can loan you a different carb. The HP Holley's work well out of the box. I've used the "Street HP's" on some 550+ HP small blocks that also did VERY well on the street. They're a little leaner in light throttle and still work well on the top end with pretty much out of the box settings.
Again, have no idea what was done to that carb...a "Marine" carb is a lot different than a street tune with a stick trans. Boats idle and immediately move into the 3-4000+ range with what could be likened to a super sloppy TQ converter. Even part throttle cruise has a pretty good load on them.
JIM
It also seems like it wants to idle in the 1000 RPM range. Why not? Mine always idles around 1100 and just feels perfect.
I'd see if someone can loan you a different carb. The HP Holley's work well out of the box. I've used the "Street HP's" on some 550+ HP small blocks that also did VERY well on the street. They're a little leaner in light throttle and still work well on the top end with pretty much out of the box settings.
Again, have no idea what was done to that carb...a "Marine" carb is a lot different than a street tune with a stick trans. Boats idle and immediately move into the 3-4000+ range with what could be likened to a super sloppy TQ converter. Even part throttle cruise has a pretty good load on them.
JIM
Last edited by 427Hotrod; Dec 21, 2015 at 11:05 AM.
Thread Starter
Melting Slicks
Joined: Nov 2000
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From: Bogart GA
I'd certainly believe it would like 20*+....I'd go for all the initial you could stand and bring in a little for total and "light cruise" vacuum type advance....but just a little. Initial really helps a big cam / big head motor become more responsive.
It also seems like it wants to idle in the 1000 RPM range. Why not? Mine always idles around 1100 and just feels perfect.
I'd see if someone can loan you a different carb. The HP Holley's work well out of the box. I've used the "Street HP's" on some 550+ HP small blocks that also did VERY well on the street. They're a little leaner in light throttle and still work well on the top end with pretty much out of the box settings.
Again, have no idea what was done to that carb...a "Marine" carb is a lot different than a street tune with a stick trans. Boats idle and immediately move into the 3-4000+ range with what could be likened to a super sloppy TQ converter. Even part throttle cruise has a pretty good load on them.
JIM
It also seems like it wants to idle in the 1000 RPM range. Why not? Mine always idles around 1100 and just feels perfect.
I'd see if someone can loan you a different carb. The HP Holley's work well out of the box. I've used the "Street HP's" on some 550+ HP small blocks that also did VERY well on the street. They're a little leaner in light throttle and still work well on the top end with pretty much out of the box settings.
Again, have no idea what was done to that carb...a "Marine" carb is a lot different than a street tune with a stick trans. Boats idle and immediately move into the 3-4000+ range with what could be likened to a super sloppy TQ converter. Even part throttle cruise has a pretty good load on them.
JIM
Thread Starter
Melting Slicks
Joined: Nov 2000
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From: Bogart GA
answer to your email... sorry for so late... just busy and cold...
https://www.youtube.com/watch?v=3THS_ZPLvUQ
[url]https://www.youtube.com/watch?v=ci
https://www.youtube.com/watch?v=3THS_ZPLvUQ
[url]https://www.youtube.com/watch?v=ci
Thread Starter
Melting Slicks
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From: Bogart GA
Update:
Started car with 92 primary jets. Increased initial timing to 20 deg and tweaked the primary idle screws. Allowed the idle speed to increase to about 1000 rpm. My AFR was about 14.0....a little lean but OK for now and my vacuum increased to about 8.5 inches. Sounded great........ I reved it to 2000 and held for a few seconds then to 3000. The AFR dropped to about 11.5, more than I expected but was interested to see how it would do under load. Immediately after releasing from 3000 rpm, I noticed the vacuum had dropped back to to about 6 and the idle speed was also dropping and becoming erratic. The AFR was climbing steadily toward 16. The engine soon stalled. I restarted the engine and it did the same thing again. This also happened before. The fuel pressure was fine and the fuel bowl levels were OK as well. I am guessing this is a fuel delivery issue because if it were a vacuum leak that massive, I would hear it and the engine would likely increase in RPM before stalling. Any thoughts?
Started car with 92 primary jets. Increased initial timing to 20 deg and tweaked the primary idle screws. Allowed the idle speed to increase to about 1000 rpm. My AFR was about 14.0....a little lean but OK for now and my vacuum increased to about 8.5 inches. Sounded great........ I reved it to 2000 and held for a few seconds then to 3000. The AFR dropped to about 11.5, more than I expected but was interested to see how it would do under load. Immediately after releasing from 3000 rpm, I noticed the vacuum had dropped back to to about 6 and the idle speed was also dropping and becoming erratic. The AFR was climbing steadily toward 16. The engine soon stalled. I restarted the engine and it did the same thing again. This also happened before. The fuel pressure was fine and the fuel bowl levels were OK as well. I am guessing this is a fuel delivery issue because if it were a vacuum leak that massive, I would hear it and the engine would likely increase in RPM before stalling. Any thoughts?
Thread Starter
Melting Slicks
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From: Bogart GA
Update 12-30-15:
Not that anyone is following this ridiculousness..... The likley cause of the lean condition was fuel level in the float bowls. Increase the level to the half way point in sight glass and issue did not return. That said, took it out for a test drive with the 92 jets and not much changed. Car went rich again then stalled. Based on my LM-1 log, I was pulling about 12 inches of vacuum when this occurred so that at least rules out the PV. I decided it was time to send the car to the engine builder to rule out any mechanical issues before proceeding with messing with the carb any further.
Not that anyone is following this ridiculousness..... The likley cause of the lean condition was fuel level in the float bowls. Increase the level to the half way point in sight glass and issue did not return. That said, took it out for a test drive with the 92 jets and not much changed. Car went rich again then stalled. Based on my LM-1 log, I was pulling about 12 inches of vacuum when this occurred so that at least rules out the PV. I decided it was time to send the car to the engine builder to rule out any mechanical issues before proceeding with messing with the carb any further.
Thread Starter
Melting Slicks
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From: Bogart GA
Will update as soon as I hear from builder. I am thinking that it is just more carb tuning. Tuning on an engine dyno vs tuning in the actual car with accessories and likely a more restrictive exhaust would be different I would think. Once I get it performing down low, I will need to do some high RPM tuning as well. Need to find a place now that Dyno Lab is no longer in operation. My good friend Arthur Mulder who owned the operation passed away on Christmas day.
Last edited by KJL; Jan 3, 2016 at 11:39 AM.
Thread Starter
Melting Slicks
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From: Bogart GA
Update: It is hard to believe the car is still at the builders shop. Been there since December 28th. It is also hard to believe this project started back in August of 2014. I indicated that I was not in a rush, coupled with lots of bad weather has limited the times he could take the car out for test drives but we are into month #3 now, time he starts putting some priority on getting it done. I could have tuned the carb myself but I wanted to make sure there was nothing wrong mechanically first. While his customer service may be lacking, I believe he is honest. I will give it a few more weeks. I know if I make any demands to get it done, he will tell me to just come and get it then....business must be good.
Last edited by KJL; Mar 5, 2016 at 09:36 AM.