Blue Motor Transitor Coil and Tacho

[HXsman]

Hi All,

My van (HX) has a WB Blue motor. I recently put in the transistor coil as I was told this is required and was what the blue motors came with. My tacho works albeit it stops at 2,000 revs. Pretty sure it worked properly with the old oil filled coil there.

Any thoughts or recommendations ?

Am I using the right coil?, if not which would you recommend.

253 Quadrajet Blue Motor

Appreciate your help

[wbute]

Get the original oil filled one. If you can find a good second hand original Bosch(I think that was the brand) they are the best. I think you can only buy cheap knock off ones new now and I have had no luck with them. Maybe someone knows a good brand. I know that those GT40 ones are no good reliability wise though from my experience.

[HXsman]

Does anyone know the spec's of the original Coil ?, model number ?.

Ill try and get one

[damienengland]

Does anyone know the spec's of the original Coil ?, model number ?.

Ill try and get one

Picture of WB parts book with V8 coil part numbers. I think the hand written number is the Bosch number.

WB Coil PN.jpg

[HXsman]

Thanks Damian,

Seem they are hard to get ?

Anyone else have any bad experiences with the GT40 (seems like the only available alternative)

Cheers


Dean

[Dr Terry]

I'm petty sure that the issue with your tacho will not be caused by the coil.

BTW the correct terminology is 'transformer' style coil, not 'transistor' style.

The newer style Bosch transformer style coil is a genuine supersession & is electrically identical to the old barrel style (oil-filled) HEI item.

As long as you are using the correct Bosch part no. HEC-716 & you have a full 12V supply to the coil & your tacho is not operating correctly, your tacho maybe the culprit.

An alternative to the HEI coil is to use Bosch no. MEC718 'medium energy' coil which is the item used on the 304 EFI V8s. You can use the smaller diameter distributor cap & 'normal' ignition leads with female HT fittings at the coil & cap posts. You still need a full 12V, but you also need to drop your spark plug gaps to 1.1mm, not the larger 1.5mm used with the HEI system.

DO NOT use the GT40 coil, these are only suitable for Grey motor Holdens, Minis & other old style set-ups which have contact points & a full 12V, with no ballast resistor in the harness. The same applies to the GT40R, which is for points style distributors, but those with a ballast resistor.

Dr Terry

[HXsman]

Hi Dr Terry,

Thanks, I shorted (Bridged) the Yellow and pink under the steering column and removed my relay.

All seem to be working now albeit the tacho seems to stick but that's completely in related.

I'll be sticking with the Transformer coil now . I just wasn't confident about bridging those wires but glad I did now (one less relay under the bonnet)

Appreciate your help

[wbute]

Great info Dr Terry.
The tacho in my ute used to jump all over the place. I got it repaired, turned out it was a dry solder joint.

[agr071]

An alternative to the HEI coil is to use Bosch no. MEC718 'medium energy' coil which is the item used on the 304 EFI V8s. You can use the smaller diameter distributor cap & 'normal' ignition leads with female HT fittings at the coil & cap posts.

So Dr Terry.
Which is the best and/or most efficient system to have?
HEC716 with the large cap or the MEC718 with the small cap?