Hi Torque Starter.

Starter Motor Swap – Replacing The Ageing Bosch With a Modern Hi Torque Starter.

Over the last few years, the old Bosch pre engaged starter motor has struggled to start the writers twin cam engine. Yes, I know there are plenty of twin cam owners who are happy with the old Bosch pre-engaged starters, but to be honest, when they become troublesome, they are a total pain in the butt.

The original starter installed in the writers elan was the Lucas inertia type, that unit also failed to start the twin cam engine on many occasions, and was eventually swapped out for the Bosch, and here we are again doing the exact same thing with the unreliable Bosch.

The Bosch has never been a great starter, despite the fact that it had been repaired two or three times.

It wasn’t until the new and recent 1700cc twin cam engine build was finally completed and re-installed back into the elan chassis that the starter problem reared its ugly head… while the starter would spin the motor without spark plugs installed, it was hopeless with the plugs in as it could not deal with the 10.5 to 1 compression, and the pinion would also snap out of mesh, and make that well known clanking, mashing, screaming sound that only a starter pinion can make when it and the ring gear fall out of mesh, it really is a kind of metallic torture.

It was Time To Find an Alternative.

The search began for a stronger, more reliable starter, but being located in Australia, the reality was that the supply choice would be narrow, unless an import unit was considered, (Take to long and too expensive) but we would much rather source from and support local Aussie business if possible.

The first port of call was CAE Of Castlemaine in Victoria, they promote their Hi Torque, or correctly named, reduction gear starters widely in automotive circles… the hot rod guys love them for cranking their big V8 engines into life.

The initial phone call was made to CAE, and after a quick chat to make sure that we were on the same page re the starter for twin Cam/Lotus elan application was correct – Yes, I was told, they could supply… but there was a two week wait … “Sorry, I said, I cant wait that long”… so I canceled the order.

Then it was back to the computer to carry out another online search for other suppliers, and as luck had it, we found another Company called The Engine Shop, located at Garfield, a small hamlet in Gippsland Victoria. (East Of Melbourne)

After a lengthy discussion over the phone to make sure that what was available was actually the correct type of starter for the Twin Cam Lotus elan application, (They mentioned that they had previously supplied several Aussie elan owners) the decision was made to place an order with the promise that it would be posted out next day.

For the Interest of other Aussie elan owners, (as of the month of June 2019) the CAE starter was priced at $385.00 plus postage, the exact same starter from The Engine Shop was $255.00, plus postage… a vast price difference, don’t ask me why, and we do not know the current list price as of 2022.

So What Does The Hi Torque Starter Look Like?

Just to be clear, the relay and the cable in the picture above was supplied by my local auto electrical business, along with wiring instructions, so that the original loom wiring as employed with the old Bosch starter could be utilized and would function as per normal with out any problems.

The Hi Torque starter has a heavy battery feed terminal, an ignition trigger terminal, and an earth. To keep things operating as per pre hi torque starter, the Hi Torque wiring required the incorporation of a relay. Not knowing or understanding much about electrics, we relied heavily on our local auto electrician who was only to willing to describe and instruct as to what was required.

Another point to note is that the wiring loom in the S2 is far from standard. The loom is the product of local auto electrical whiz kids from the 1980’s, when the wiring loom for the elan was built complete with a full set of relays, which have never given any trouble, this writers S2 does not have the remote solenoid, made redundant because of the modern wiring loom, and not required.

The weight comparison between the two starters is significant, with the Hi Torque starter being far more compact and quite a bit lighter than the old Bosch starter.

The thing with these Hi Torque starters is that they are pretty much all based on the popular Denso series of starters which are employed on a very large range of vehicles, the difference is that the core motor/solenoid and reduction assembly is mounted to a CNC machined aluminium adapter or mounting plate, the plate is machined to fit the ford lotus bell housing aperture and bolt holes, the plate supplied with this starter has the three bolt hole mounting pattern, but the elan only requires two, the plate could be milled further for a neater look. The plate also has indexing holes so that the starter motor can be angled one way or the other, depending on the required orientation. Luckily, the starter as supplied from The Engine Shop was correct and bolted up without a hitch.

The install of the Hi Torque starter is actually easier to do than the Bosch, being lighter and more compact it just seems to slip into place much easier. but there is one thing that had to be done before install, and that was to fasten the battery feed cable and the red wire of the loom to the main terminal, because once the starter is in, the battery cable fastening nut is hard to reach with a spanner once it is tucked away on the upper side of the starter, but its not really a big issue.

What’s The Pinion to Ring Gear Mesh Like?

At first glance at the photo above, it looks as though the pinion will not fully mesh with the ring gear, how ever, the photo is quite deceiving, as you will see in the next photograph.

Note also the indexing holes drilled through the aluminium mounting plate, the holes allow the core motor to be moved around at various angles to suit which ever way is most convenient for the particular application.

This operation must be done before the starter is installed, and its just a trial and error session to get it right, simply unscrew the socket head cap screws and swivel the plate right or left to line up the correct holes, and insert the hex head screws again.

The photograph above shows that the ten tooth pinion engages correctly with the ring gear. The depth or length of pinion tooth meshing with the ring gear teeth measured about 8.5mm, the supplier said that was adequate, but he also said that the mounting plate could be machined a maximum of 1.5 to 2mm to allow the pinion gear teeth to mesh further into the ring gear teeth. The width of the ring gear teeth on the fly wheel is 9mm. We may do that mod at a later date, but not right now.

As can be seen from the photo above, the compact Hi Torque starter fits neatly into where the Bosch starter once lived.

So with the starter installed and the wiring all connected via the relay, it was time for a test run to see how different the new Hi Torque is to the old Bosch.

Switching and turning the ignition key on to start, produced an incredibly strong and urgent, constant cranking motion, no hesitation… wow, it blew me away, the difference was totally amazing. And to be honest, I could not recommend this starter conversion highly enough, even with a battery that was not A1 condition, it would probably crank these starters quite well.

The writer is extremely pleased with the new Hi Torque starter, it should provide many years of service, and it will be a joy to flick the ignition key knowing that the starter is going to do its job every time, unless of course a wiring problem of some kind occurs.

Some further comments in an effort to answer some questions that you might have.

Speaking with the local Auto Electrician, the Denso starters are generally around the AU$280.00 – $340.00 mark. If you have the machining facilities and the engineering skills, you could possibly build your own Hi Torque starter, the set up does not appear to be that complex, after all, it really is just the indexed aluminium mounting plate that you have to get right.

A good second hand starter could be found at a wreckers or recyclers yard for around AU$50.00 to $90.00, and after a good clean up and inspection, a new aluminium mounting plate machined, you could possibly have a Hi Torque starter for much less than the figures quoted earlier in this article.

So that’s about all we can explain to you about these Hi Torque (Gear Reduction) starter motors. I think they are excellent, if you are looking for a new starter for your twin cam engine, and it fits your budget then go get one.

We have no affiliation with the business that supplied the starter, but they were very helpful, and very easy to deal with, and provide back up and service should it be required.

But of course, if you build your own from a starter sourced from a breakers yard, you’ll be on your Pat Malone.

We thought for a moment to display the wiring diagram here, but there is probably little point in doing that, because your wiring loom may not be the same as mine, and it is always preferred that you consult your local auto elec for advice and guidance, unless of course you know what you are doing with the electrics, we would not want you to enter the realm of the prince of darkness again.

So now that the starter has been installed, you are probably thinking what its like, and how well does it start a twin cam lotus, well, we made a recording of the Hi Torque spinning a brand new and tight twink on one of the very first times it was started.

Click the white arrow below to listen to the Hi Starter in action – turn your speakers up.

-There you have it. I will take a Hi Torque starter any day, should have fitted one of these years ago, because they are far superior to the old Bosch starter that was previously in service.