1972 ST Clone

[yoda]

Really enjoying the write up, good fun and informative. Sounds like lots of work has gone into the details which I always good to see.

I’m with you - while authenticity is important for originals/racing etc, usability is more important to me. You ears will thank you!

[yoda]

Great engine spec, should be great fun.

What was used in the 2.7RS, was it a GE60? Or is that a little more racy than a standard 2.7RS cam?

The 2.7rs used the same cams as the 2.4S.. fundamentally 2.4S and 2.7rs same motor apart from displacement ( and mfi pump had RS spacecam)

James, I think the reference was to the original engine on the car when I purchased it. The car was dressed as an RS replica of 2.8 litres and the cams had a very wild profile believed to be RSR.

Bit of both really. So a standard 2.7RS would be on GE40 cams or similar? I think my car’s engine is on GE60 cams. I was just curious how much difference the GE60s would make as from driving a few cars, it seems pretty marginal. Not at all lumpy / difficult at idle and low revs but seems to have a bit of extra go in the second half.

[BILLY BEAN]

Really enjoying the write up, gear fun and informative. Sounds like lots of work has gone into the details which I always good to see.

I’m with you - while authenticity is important for originals/racing etc, usability is more important to me. You ears will thank you!

Thank Feroz for the kind comments. This is obviously not a proper build thread but a retrospective skim through what I remember and think may be valuable to anyone reading it. Many of the trials and tribulations have been glossed over but I hope to impart some sense of those. There were positives of course but those tended to be few and far between. Yes lots of time spent researching with huge input from Dave O. And whilst there was a desire to get an "accurate" replica the thing had to be usable.

[Darren65]

......So 2.7 litre is not strictly period "correct" but that is where the cases were so I just went with that.......

....I'm not so sure, a 2.7 engine could very well be considered 'period correct'.....as I'm sure you are aware Kirk 2.7 twinplug development engines are mentioned in the Starkey book and it's been suggested these were fitted to ST's that were later developed into RSR's including the Zasada car...pretty period correct if you ask me .......

....I purchased an early 2.4E engine some years ago with 5R/7R cases and with the cases being the perfect age I had the idea of building a second engine for the orange basing it on these development 2.7 engines. I even commissioned Gus Pfister to build a racing type MFI pump for me......sadly all still in boxes but maybe one day....

....will be interesting to hear your experience with the engine and GE40 cam?......I've found the GE60 cam in my 2.5 perfectly drivable although not much of that is below 4K revs!

Enjoying the thread and please keep the photos coming when you can

Cheers,

[BILLY BEAN]

......So 2.7 litre is not strictly period "correct" but that is where the cases were so I just went with that.......

....I'm not so sure, a 2.7 engine could very well be considered 'period correct'.....as I'm sure you are aware Kirk 2.7 twinplug development engines are mentioned in the Starkey book and it's been suggested these were fitted to ST's that were later developed into RSR's including the Zasada car...pretty period correct if you ask me .......

....I purchased an early 2.4E engine some years ago with 5R/7R cases and with the cases being the perfect age I had the idea of building a second engine for the orange basing it on these development 2.7 engines. I even commissioned Gus Pfister to build a racing type MFI pump for me......sadly all still in boxes but maybe one day....

....will be interesting to hear your experience with the engine and GE40 cam?......I've found the GE60 cam in my 2.5 perfectly drivable although not much of that is below 4K revs!

Enjoying the thread and please keep the photos coming when you can

Cheers,

Darren,
Thank you for your thoughts on this particular subject. Yes I have read that 2.7 was possibly in development using earlier cases. Ideally, I would have like to have built a 2.5 as the shell is actually a late 1971 build. However, it was expedient to go with the 2.7. Although as I have said I justified the choice in that the car, if in continual competitive use, would likely to have been upgraded. I remember your plan to build a second engine but as you are aware these things require a significant financial commitment.
Although the engine has been built as yet I have no driving impressions.

[one-two]

as yet I have no driving impressions.

Mic drop

[BILLY BEAN]

as yet I have no driving impressions.

Mic drop

I might be economical with the truth.

[inaglasshouse]

A couple of engine pics from Kirk:

[inaglasshouse]

And a Dyno video!

https://youtu.be/_Npmr7IFZVQ

[mrg3.6]

A couple of engine pics from Kirk:

Interested to know more about that mechanical cold start set-up?

Thx
Martin

[BILLY BEAN]

My art director has now posted two images and the latest video production.
Engine Build
I had already collected all the new parts and or restored/ rebuilt bits for the engine and the cases were modified. An engine builder had been lined up to assemble everything. Said engine builder was a four hour journey away from where I was living but I felt I could deal with regular visits to see progress on the engine build. I had all parts ready and had a clear picture of what I wanted. All my ducks were in a row so what could go wrong?
A personal issue of some significance put the engine build on hold. After the above mentioned hiatus I reconsidered who was to build the engine. To be honest the four hour journey to see progress on the engine build became a factor. So I visited Autofarm who were much closer to my home and I had used them in the past. So there was a relationship already established. After a lengthy meeting I was provided with a fixed price and gave the go ahead.
My ambition for the engine was something pretty durable and producing around 250 BHP at the flywheel. The build went slowly, as two other engines were in build at the same time but it was all quite progressive. I was kept up to date with regular phone calls and I made a lot of visits too. Matt was an experienced guy with 12 years experience of building air cooled engines so I had a good degree of confidence in the result.
There were no major problems with the build and as can be seen by the two pictures the engine looks the part ( although not quite finished in the pictures) but would it perform?
Nerves did start to get the better of me. Quite a few people " in the know" said that the specification of the engine I had decided upon may not constitute a compatible whole. In other words I could have wasted at lot of money and the engine would be a disappointing dog. (Please note no mention of mongrels: it just would not be a pedigree.) The doubt in my mind was what if the engine was installed in the car and it did not run well or at all and had to come out to be sorted? And then reinstalled. A costly exercise and a little embarrassing into the bargain. I determined that the engine would go on a dyno first to prove the engine was OK. Quite a few dyno places available, some at a distance and some very expensive. Expensive to the point that you could buy a very good second hand car for the same money. Am I suggesting some of the dyno houses were a bit Arthur Daley? Maybe. Would I get ripped off? Was it the right approach after all? Who had the experience to sort any fuelling issues on an MFI pump who also had dyno facility? The latter only led to one place: Neil Bainbridge who also happened to be close to Autofarm. Decision made.
I had a second set of jitters. Although the MFI pump had been restored, modified and an RS space cam installed what if the pump was not right. Dyno time is expensive so a pump that did not perform would cost in lost dyno time.
The MFI pump was removed from the engine and its set up assessed on a Bosch machine for the purpose. Not good. The pump was not set up properly and would have led to two cylinder being badly over fuelled. The MFI pump was re set and put back on the engine.
Dyno day arrives. The engine would not start. Distributer was the issue. I had a UK made 12 plug dizzy. It looks authentic but I had decided to use a Jaguar V12 distributor cap on the basis that they were readily available. The guy who manufactured the dizzy pointed me in the direction of a company who would set it up with the require modified Jag rotor arm and who I was assured had "done lots of them". That might be the case but but the mod did not work. Lost dyno time. I had been talking to Chris at Fenn Lane some months earlier about the modified rotor arm. Chris studied what needed to be done and produced an appropriate arm "just to see". This arm was installed two days later and we were getting a spark in the right places. Great now for a start and dyno run. Wrong! One of the CDI boxes was not working properly. Sent back to the maker. Got lost in the post. Finally found and fixed. Two weeks lost. Neil Bainbridge now in the US. Neil returns after a couple of weeks. Small oil leak on the cross over oil line. Decide to live with the leak for the dyno work. CDI box goes down again and is returned for a second time to be fixed. Neil off to the US again for a couple of weeks. Finally get a dyno run. Engine oil cooler gives way. Clean up the mess and install new engine oil cooler. Run in engine on dyno. Do some power runs. Result. As can be seen from the video of the engine was revved to 8,000 RPM. Pretty nerve wracking. The engine on its modest cam profile produces maximum 271 BHP at 7,250 RPM and stays flat at this output to close to 7,600 RPM. Maximum torque 208 Ft Lbs at 4,000 RPM and stays fairly flat up to 7,000 RPM. Neil, who had not built the engine, thought the result was good. I was delighted. Neil Bainbridge know his stuff.

After the delays, disappointments and extended cost, due to lost dyno time, the engine seemed a good one. Time for cake and to relax a little. Seems my engine specification was fine. Of course the real test was to come in driving the car.

Talking of cake and other comestibles: "Stretch" had purchased a running machine in order to reduce his one pack so that he could fit into his very lovely original Scheel seats. I have a picture of a trial sit in said Scheel. I could post it on here but I am concerned about the Obscene Publications act so don't want to risk it. I suggested Stretch sell the seats to me that he intended to install in his ST and in return I would provide something more suitable and accommodating. SCS make some really nice two seater sofas which will just fit into an early 911. I was of course getting my own back here as Stretch had been merciless when I installed sound proofing in my car.
This saga of pixx taking is not over of course.

[hot66]

Those are impressive numbers on a ge40 . . That’s going to be a fun motor. What C/R are you running ?

[BILLY BEAN]

Those are impressive numbers on a ge40 . . That’s going to be a fun motor

I hope you are right James!

Comp ratio is around 10.2:1

[Mike]

Looking good, but who built the mfi pump?

[BILLY BEAN]

A couple of engine pics from Kirk:

Interested to know more about that mechanical cold start set-up?

Thx
Martin

Martin, as can be seen the MFI pump is in "competition" specification. The typical route when the auto cold start is dispensed with is to a have a simple plate and screw to push in the cold start pin to the hot running position once the engine is warm. Stretch has this arrangement on his ST build.

Not wishing to have to wait for warm up and being a little old and decrepit, did not then want to fiddle in the engine bay, I looked for alternatives.
Tutthill have a manual device but they only fit them to engines they build and it is not for general sale. Henry Schmidt in the US also has a device which is really very simple being a lever mounted on the MFI pump ( like mine) and a bit of cable. But its design was too crude for my liking and at £350 I decided to pass on that and design one myself. I got it made locally to a pencil sketch with some dimensions on it at a cost of £120. It is probably over engineered and it does not look an aesthetic delight but it provides a consistent closure working against a return spring (for absolute certainty). You should note that the Bowden cable passes through a union on the pump bracket used by the pump brace. The lever to close the cold start is in the cab. The lever is a proprietary piece off a lawn mower. (OK Dave that will be good for a laugh) Purchased off the internet along with its mounting bracket.
The only critical area is to ensure the shut off pin that goes into the pump is the correct length. Initially this was too short and did not close the mechanism inside the pump. Hope the above is of help.