Tach problem with MSD

[Flat4ever]

Hi all,

My car is running with its new engine (2.0 rebuilt with carbs & 290° camshaft)

We installed a Bosch 050 distributr running with points, a MSD 6A ignition box, MSD Blaster2 coil and the 8910 tach adaptor.

First, because the 8910 instruction notice does not say where to plug the tach wire, we pluged it :
- on the MSD box tach output. pointer does not move
- on the coil. pointer does not move

So we plugged it on the white wire of the 8910 tach adaptor and the pointer moves. But does not move correctely... it seems incoherent.

Do you have an idea ?

[red-beard]

Send the tach off to have the guts replaced with modern guts which will work with the MSD. The tach adapter does not work.

[iamchappy]

I have a MSD tach adapter that i used with a MSD 6a that was on my 2.0. It works great never a problem.
Let me know if your interested.

[Alfred1]

Flat4ever,

How is your motor running? Does it make the ~115 hp that you thought it would?

[Flat4ever]

914GT : I cannot have a scope

red-beard: interesting. Wich tach did you install ?

iamchappy : maybe. I have the 8910 adaptor. What is yours ?

Alfred1: I did not go to the dyno, but the car runs nice. I ran 250 km this afternoon in 2 hours !

[iamchappy]

Mine is the MSD 8920 it was used with a MSD 6A , Blaster coil, and was used both with points and later with an Igniter in a OO9 dizzy. On a heavily modified 2.0 type 4 built to a 2.9 with 44 Webber's.

[Flat4ever]

According MSD, 8910 is for points distributor and 8920 for magnetic trigger.

I run my 050 distributor with points... May be I can try your adaptor, make me an offer for your adaptor in my mailbox.

[Flat4ever]

Just some words to say that Chappy had the good answer...

8910 adapter DOES NOT work correctely with stock tach but 8920 DOES. I installed it tonight and my tach runs great now.

[red-beard]

I just checked Pelican's website and they sell the 8910 adapter. Hmmmm. This needs to get to Wayne and Tom.

[Flat4ever]

It is a fact... I bought my 8910 at PP some months ago, after reading the MSD installation subject in the 914 tech tip aera but at this time I think that it is a theorical advice that did not tried the adapter.

Or may be there are some tach that runs well with 8910 and others needing 8920...

[Wayne 962]

The story on these tach adapters (from MSD technical support) is that some cars will need them and some won't (they may be identical year/make/model, etc.). MSD recently changed the MSD unit to accomodate magnetic pickups. I was not aware that they offered an additional tach adapter, nor have I heard of any of the existing tach adapters not working until now.

I'll Eugene look into it...

-Wayne