Hot Rods RPM's too high on 700R4

jegs sells a bracket for that carb the will set the tv cable which should be pulled all the way out at full throttle. also that 1200 rpm idle is way to high.

https://www.jegs.com/vpt/Edelbrock/Auto+Trans+Kickdown+Cable+Bracket

 

Yes, it uses a 2/4 band. In O/D it releases the forward clutch. Direct clutch and O/D band on.


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Well, that does make me feel a bit better. If it's reading at double of what it actually is, then I'm running about 2000 rpms at 65. I'll have to play around with the little switches on the back of the tach and see what effect that has.

 

It’s got to be what it’s got to be

 

Seems pretty easy to tell the difference between 2000 and 4000 RPM.

 

It has a huge effect. Get a known meter and verify rpm and then calibrate dash gauge accordingly.

 

An idle of 1200 is really high. Maybe they’re on to something with the tach error? Do you have an external tach/dwell meter or dial-back timing light to check the idle speed with?

John

 

Hmmmmm... (Whoops?)

 

Here is the 700R4 geometry adapter for the Edelbrock 1406 type carb linkage lever:
https://www.summitracing.com/parts/sum-700203#overview

If you don't have it, you need it.

 

I wouldn't drive car until that tach situation is resolved, once it's idling at correct rpm you're good to assess things for when you start driving again. Do you have a lock up convertor or not, if so is the lock-up deactivation function connected through the brake switch? A badly adjusted TV cable will result in a toasted transmission within a very short time. Geometry and adjustment (WoT) are critical for longevity so the correct TV bracket is a must. Engine RPM at 60mph should be between 1800rpm and 2100rpm. I run 3.54:1 with 235.75.15 tyres, engine rpm is approx. 2k rpm @ 65mph.

 

Are you sure you have a stock torque converter? Hi Stall will slip in wrong application . ck pump pressure with a gauge for your model trans. Tell us what motor is in car.. good luck Pete.

 

Tachometers, whether mechanical or electric, are not particularly accurate; some are better/worse than others. However, if you can't hear and recognize the difference between a 600 rpm idle and a 1200 rpm idle, or a 2000 rpm cruise speed or 4000 rpm, it's time to visit your doctor.

 

When it comes to OD ATs and TV cables, you really, really, really need to have a transmission gauge hooked up while testing. If your pressure is too high or too low the trans will either eat itself or wear out in short order.
Also the 700 will downshift out of OD if you fart. Don't expect it to stay in OD for anything other than part throttle cruising.

You would think so but I've encountered folks who are tone deaf to engine sounds.

Neighbor pick up a '64 Impala, he swore the engine was revving too high on the freeway. Go for a drive(before hooking up any tach) and the 283/Glide made all the right 283/Glide sounds while cruising at 60-70MPH. When you are used to driving Escalades, a mechanical fan can be 'loud'.

Kid back in H.S. would never put his car into top gear on the freeway. Engine would be screaming. Another classmate tried to convince him that the higher gears were for higher speeds, no dice. Same kid would be lugging the car on the street in top gear. He was a bit off. Only thing we could come up with was someone taught him 5th was 1st and 1st was 5th.

 

I'd sure know if my engine was running 4000 rpm's cruising speed! My other car with the same SBC, 3.73 gears, and tire size, and a THH350 is running 3000 rpm's at the same 70 mph. It bugs me to have it singing along at 3,000 even though I know the engine can wind twice that easily.

 

And pretty much no tachs, except for tuning tachs, are accurate at <1000 rpms. Relying on the tach on your dash to set your idle speed is really not a great way to do things.

 

1200 is way high unless you have one hell of a cam. If your engine idles like your normal street car you have to me everything is pointing to a 4 cylinder setting in your tach.

 

Used to have a supervisor when I was in the military who would just put the truck in first gear, ease out the clutch and go. Didn't take long for him to blow it up trying to do 40 mph in first gear! The concept of a four speed transmission was completely lost on him.

 

Probably a farm boy from way back. Old tractors didn't allow gear changes while in motion. You picked the gear and went from a stop, just like you describe.

 

the geometry has to be perfect, not close. Ebrock or someone else sells brackets that are an exact fit for the Holly, or Ebrock. The tv cable controls the pressures (have you checked them?) that cause the thing to shift properly. One lesson i've learned with mine is that the cable, wire cable, needs to be taunt (not tight) and not floppy or loose. If you can play with the cable and change the shift points, you've found your answer. BTW, 1-2 on the R4 is around 15 if no guts have been modified. (and just to relax you, wrong tv cable adjustment will burn that sucker up pronto)

 

From post #28 above you said your transmission guy said you need the geometry corrector for your Edelbrock carb.

If you don't have this, you need it regardless of tachometer accuracy, etc. It is the only way the cable position will work correctly with your throttle position.

 

I have to chuckle at this , OD transmissions have only been popular for a little over 20 years , yet some of us are already conditioned to them . I.e. "engine singing @ 3000" ...

 

I had to chuckle at this, he said singing and you say screaming two very different words. I guess depending on your type of music.

 

Better ? In many instances there isn't much difference .

 

I have installed several 200R4 ODs which is similar to the 7004R. I always install a BowTie Overdrive carb adaptor and set the TV cable using a pressure gauge. Can't go wrong doing it that way.

 

I agree. Mine idles at 550ish.

 

It does sound like your (electronic?) tach may be set on 4-cylinder mode.

 

Too much emphasis is being placed on the tach and not enough on the driver. For many years, most cars were not equipped with tachs, and the driver knew if his car was idling too fast, engine overtaxed at cruising speed, or transmission/clutch was slipping. Other than T-birds, Corvettes, and some foreign cars, how many 50s cars were factory-equipped with tachs? My family's 64 Olds Jetstar l was the first new car we had that came equipped with a tach. Our 69 Dodge Monaco didn't have one.