gday,

I recently had a top end hesitation problem occur and I can't work out what it is. The car is tuned fine, replaced fuel filter, put a 10mm fuel line on, have a regulator on at 4 1/2 psi. I replaced the plugs, leads, dizzy cap and rotor. Now it only occus in first gear at high rpms. Its like a slight stutter then it keeps reving, and then stutters again etc. 2nd to 4th are fine. (can't exactly test 5th out at 6000rpm ) . I went to rotary shop and they seem to think it might be the ignition coils. I was told they are like $400 each. Any ideas on what is causing this problem?

Cheers,
Heb.

 

$400 each? Tell me what shop it is so I can stay away from it. Assuming thats your problem you can get MSD coils for way cheaper.

Have you checked that the trailing ignition is actually working?

 

$400? STAY AWAY FROM THAT SHOP! I doubt its the coils. If its was , it should stutter at hi rpms, regardless of what gear your in. Same for any other ignition problem usually. What carb/intake are you using? 4.5 psi is kinda high for the stock Nikki. You may be over rich.

 

Give us all the heads up on that shop! What's the name?

The stock nikki is known for going rich at high rpms. This is because the air bleeds are sized small to work with vaccum operated secondaries. There is no accelerator pump shot for the opening of the vacuum operated secondaries, so a rich mixture is benificial.
(Remember what kind of driving the carb was initially set up for- rarely seeing 6000 rpm!)

The usual other complaint is the lack of adequate fuel at 6K rpm due to a clogged (even slightly) fuel filter.
The power responce is the same, but for different reasons.

I think you are going rich because you say it loses power and the regains it. If you were going lean, you wouldn't be getting the power surging back.

I think the problem you are having is that your secondaries are not opening in first gear...
Well, they probably open very briefly for a second and only a little bit. But the car is geared so low in first gear that there really isn't significant load on the engine enough to prompt the secondaries to open.

Open the secondary box and remove the spring. Reassemble it, and go for a drive.

Tell us what happens.