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Iconic 427 runs very rich since new?
Have 600 miles on #1350 and runs really rich (always has). Starts and idles okay at 1000 rpm to 1100 rpm and choke seems fine. Black smoke at all engine speeds. Dyno shows lack of RWHP (-100) and possible ignition issue? Any folks with this engine and Holley 670 with MSD ignition that have experienced the same. Would welcome any tuning tips you may have. Am in OR so too far from BD for checkup there.
Thanks in advance. |
Did the chassis dyno have an afr setup?
My car was running slightly rich and down 100rwhp do to the throttle not opening all the way, which was a result of pedal issues. |
Mike bought a 408 crate motor from Keith Craft and I installed it for him. Later he called to tell me he was getting 6.7 mpg. I set it up for him to bring it Coach's shop. Coach is our local carb guy and all his Cobras are carbureted. Coach tuned the carb by down sizing the jets by several sizes. We called Keith's shop and talked to his dyno guy.
He said they only tune for top end because they do not know what air filter, side pipes, etc that will use which effect air fuel ratio. After the re-jetting Mike reported his mileage at 13.7. No bad for a tune up. So if you bought a dyno'ed crater motor maybe you should look at jetting and timing. Dwight |
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Kevin..... |
Iconic 427
My Backdraft is # 1214 with an Iconic 427 that I purchased from Custom Cars. When the car was delivered to me (KY) it was very hard to start, would not idle or run very well at all. It turns out he engine was 15 degrees out of time. I would suggest the carb adjustment and the timing checked by an expert mechanic.
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@itstock
Yes, air/fuel mixture was measured when dyno. So rich it was about off the recordable scale. The dyno was just used for a base line - 3 pulls. Will tune next weekend and then try again. @ everyone. Thanks for your responses. Now I know it sound pretty standard to have to go through the carb and timing to get it set correctly. |
eedeutsch,
After you got yours tuned do you happen to remember the timing @ idle (~12 degrees???) and then the total advance (~32-36 degrees??) Be good to have a good place to start. Did the springs get changed at all in the distributor. If they are double silver (tightest) then perhaps adding a lighter spring would improve the curve for these Iconic 427 engines? Thanks |
The idle was 10-12. Timing was set at 32 degrees at 3500 RPM. The engine was built by Total Engine Concepts in Riviera Beach, FL. They are very helpful.
Nothing was changed in the distributor. |
Good information...thanks!
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Bill S. |
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A 600 is going to feed a 427 up to about 3500rpm......?
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That sounds like a sticking choke.
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We are not talking a drag racer here. Want to bet which will get the car to run better on the street ;) |
How about we fix his problem and then debate carburetor size?
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One problem solved
1 Attachment(s)
Decided to change out the plugs this afternoon in anticipation of a carb and timing adjustment this Saturday along with the 500 mile checkup.
Found two plugs...one on each side with virtually no gap. See photo. Should not run so rich now. Wish I had discovered sooner. Thanks all! |
RT3 1350, who was your selling dealer? Was it Custom Cars in Miami or someone else?
Kevin.... |
Custom Cars...
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During your 500 mile check up, check your wheel weights. All of my weights fell off after 600+ miles. Apparently who ever put the weights on did not clean the part of the wheel where the weights were mounted. I had to have them all balanced after 700 miles.
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Generally reading the plugs is the best way to determine carb settings. See Holleytv.com for lots of carb tuning help. I have a 670 cfm as well and I went much leaner on jets than stock. I stayed with silver secondary spring, red pump cam, standard pump jet. Idle screws are way in (1/2 turn up from lightly seated) as well.
Any other too rich symptoms? Black exhaust pipe, backfire, gas smell? Could be a timing issue. I am at 15 idle, 37 overall. It varies based upon the camshaft used not the block. Firing order is also cam determined (HO) not block. Get the engine builder info on the cam if you don't already have it. It took me about 3 months to sort it all out. Change one thing at a time and keep a log of changes and the results of those changes. Even when it wasn't running right the Cobra was more fun than a finely tuned BMW.:cool: |
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