Ginetta G27 V8 - bit more than a rebuild

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:20 pm

Currently on garden leave and making some progress on the G27 rebuild so I thought I would start a thread on it to catch up with the last 4 years of it being off the road.

Not quite been sitting on my hands for the last 4 years as I got distracted by other projects - built a Fisher Fury Duratec and have managed to acquire a fleet of 5 Ginetta's

A quick few posts will follow to bring it up to date.

Like this when I purchased the car - by all accounts it was a very well presented car when originally completed - all that dark metallic Blue and fitted with a 350 TVR engine

Subsequent owners decided to personalise the car a little and along the way the engine was tuned by DJE in Nuneaton to stage 2 specification with a few other parts.

Early on I took it along to be part of PPC's Rover V8 article where it didn't discrace itself

A bit later on I had a roll cage made for it and a longer range alloy tank

And then shortly after that I decided to look at the suspension as the handling was not all it should be for such a quick car - The experience of driving the car was exciting - but not always in a good way

So I started the work of looking at the shockers

And one thing let to another where it then sat there for 4 years whilst I got on with other projects.

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:29 pm

So we hop forward a year and I am looking at some of the suspension

Moved to the front of the car recently to have a look at the suspension geometry in detail and clean up the somewhat sorry looking state of the components.

The cars was set up with about half a degree of negative camber on the front and I now know that the only caster is due to the chassis front kick up at the wishbones are symetrical - the front chassis lift is very slight - to be measured - so I doubt that there is Much more than a couple of degrees of Caster. The G33 front hubs are also not great for KPI/SAI being only a couple of degrees and on my car the fabricated steering arm offers no Ackerman. :blink:

Handling would be best described as skittish.

As removed from the top wishbone !!! :ohmy: yes thats no more than 4 threads.

Lower ball joint - this moves ok and without much resistance until you try and turn it with a load on it when it feels like there are rocks in the bottom of it and turning it is not easy.

Under the ball joint on the wishbone there is a strengthening plate - unfortunately there is very little of the weld on this side that joints the two peices together - no weld penetration at all.

The Black Polybush is one of the lower bushes - the Crush tube is only 3/4 the length of the bush!!

The white bushes are from the upper wishbone and are solid nylon no crush tubes and the hole diameters as were the bolts for them are of different diameters - the mounting holes in the chassis however were the same diameter - 3/8" one bolt was 3/8" the other was an 8mm :woohoo:

Putting a positive to all this - at least I am still here to write this up and at least it should not be too difficult to find an improvement in the handling.

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:32 pm

Hop on a few weeks.

I have done a few measurements and been doing some reading up on the technicalities of suspension design recently to get my head around why the car may be as it is.

Firstly the chassis kick up at the front provides far more caster that it first appeared - 5.5 degrees worth - approximately

The SAI/KPI of the upright measures up at around 3.5 degrees

The big head scratcher at the moment is the scrub radius that this small SAI give the suspension - A typical dimension for this is around 25-30mm - The wheels and tyres on my car leaves this dimension at around 100mm.

Whilst reading up about Ackermann good old Duncan dropped me two peices of key information - One not related but corrected an error above that the lower ball joint is in tension and not compression and secondly that the lack of Ackermann is related to tyre slip angles.

I went off and had a good read through a couple of books on the subject which answered a couple of questions that I had had for some time.

Q 1 was why were the uprights on early lotus 7's and the G4 reversed for negative Ackermann.
Q 2 Why did my G27 have zero Ackermann

Simplified - If travelling at low speeds and around twisty lanes Ackermann is great - If going at high speeds on long sweeping bends it can be down right dangerous.

Raised another question as to why on the L7 and the G15's were the uprights put back to the donor position with positive Ackermann. I summise that the use of cars from a track to a road bias.

Perhaps G15 racers can advise if they tweak the steering arms with a bit of heat to reduce the Ackermann effect?

Plenty on the net I am sure to explain Positive Negative Zero and slip angles better, and please I am on a learning curve here so please feel free to advise if you know differently.

Only thing that I am yet to answer is why the large positive scrub radius - its adds feel to the steering to have some positive scrub but....

And then that was it for a further 3 years

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:35 pm

So this brings up up to a point about 6 months ago where I found myself with a bit of spare time in the summer and having pretty much completed the build of of the Fisher Fury.

Here are some of the rather ugly bits I found on this chassis

And a few more

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Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:38 pm

Horrible - so out came the angle grinder - I hate angle iron with a passion and find no place for it apart from small brackets and ramps

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:41 pm

And now we have a lighter chassis that has had a few initial strengthening tubes in - the start of many - and a lightweight tub assembly

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Now we have finally had a bit of summer arrive here its provided an extra bit of motivation to get stuck into it.

I am not sure I am at all popular with the neighbours as I must have done about 10 hours of grinding on the chassis this week :unsure: to remove all of that unsightly sheet metal work that was doing very little for the structure

Today I made up replacements for the handbrake rear mounting bracket - 975g of it that offered nothing but to attach cables to - It has now been replaced by two tubular chassis diagonals that will improve the chassis strength and only weighs 500g

I will be following the "Simplicate and add lightness" rule all the way through

Saw this lovely Lotus Buick at Loton park as well.

After some tube notching therapy I have completed one side of the car - the other sides tubes to be prepared this and perhaps some tunnel design as the engine is now sitting under the chassis.

I have also welded up 90% of the unwanted holes in the chassis - Just need to drill a few holes here and there to get all the sealed in debris out.

Board is behind to get an idea of the finished effect.

Not quite finished this A pillar yet as still looking at what I can do to add some additional triangulation going forward to the front suspension towers. Also giving thought about what to do with them as most of the metal is doing nothing - Significant weight reduction will happen but have been thinking about complete removal.

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:43 pm

Just to prove that this has some V8 relevance

The top rail angle iron has gone

Engine needed to be in to make sure nothing fouled as its all a bit tight

Also needed to get the engine in to measure up and position for the new engine mounts

Old and new chassis mounts

Also want to get a couple of more chassis tubes in amongst this lot

Its all progress though and now I have a the main tube in I can start designing in the tunnel / backbone - Which I and going to try and make a bit of a feature and have the tubes exposed and panel the inside :unsure: see how we go with that one. Also having thoughts about drilling and swaging the the big box sections that end up in the car but that may be a step too far.

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:46 pm

Both sets of engine mounts - the factory mounts and the original builders efforts have been removed and replaced with mounts of a more simple design.

These will be joined by some better presented brackets on the engine.

After dropping the engine back in I have completed the engine mounts - total weight of the entire mount is a bout the same as the unused factory mounts that I removed from the chassis let alone the later shipyard structure mount that I removed.

Far more elegant :laugh: not decided on the colour yet or if any holes are required.

Of to buy tubing at the weekend

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:48 pm

The engine mounts are pretty lightweight and its about saving weight against what was there previous more than ultimate weight loss - at the moment

The sierra switchgear is being dumped so I have been taking weight from the steering gear

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All this being reduced to this

And saving this

Which really surprised me and that excludes all of the switchgear which is another 500gm's - so thats 1.5Kg just from around the steering wheel

I also picked up my lightweight dash - the original dash assembly was 2.3 Kg

The new one is 800kg and I have not yet cut out all of the holes for the clocks or trimmed it.

All of these little changes and weight reductions all add up. "Everything you remove lighten before you put it back"

The other engine mount - no holes yet

The new mounts lower the engine more than before which means the clearances are all a bit tighter

One of the attachment bobbins left over from the G15 Chassis works I will be making up another and using them to make a strut brace - there was a bit of RHS bolted across which looked poor, the rusty looking square is where the original bracing RHS was welded an had to be cut off to get the engine in as the water pump and pulleys stick out quite a way on the Rover lump.

The old GF bulkhead and tunnel parts offered up to check the original clearances and angles

A bit more tube notching therapy tomorrow during the bank holiday to continue the progress and probably tack a few tubes in and a bit of work on the lathe to make up a few bushes bungs and bearings.

I was tempted to start it up

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:51 pm

I finished the brace - well that part of the brace anyway

It weighs in about half of the original which was just horrible

I also carried on with the weight loss on the steering column by parting off the part of the boss that carried the Sierra steering lock mechanism - just nee a bit of thin plastic tube to slip over it to tidy it up

I also had a look at the rear suspension bushes - I had some from another project that were a hard Polybush but the crush tube was only 12mm and not 1/2" and the poly was 1/16" to big in diameter and the flange section was also a 1/16" to wide so I put them in the freezer and then modified them all in the lathe so now have some nice stiff poly rear suspension bushes.

The pedal box on the car has been bothering me for sometime, it's in the wheel-arch surrounded by exhaust headers and exposed to whatever the tyre throws as it and very inaccessible for maintenance it has to be up two inches above the floor as the 2" chassis rail blocks the positioning of the M/C's.

The option is to make the pedals pendant type and have the M/C's inside the car behind the dash I can also lower the floor and have a sealed front bulkhead the same as the passenger side and maybe find a little extra width and length in the pedal box at the same time. I made something similar for an old Dutton I rebuilt and that worked quite well apart from being a bit of a challenge to get the reservoirs above the M/C's without coming through the bonnet.

More steel required - will needs some 30mm x 6mm strip now - back to the sketch pad to see if it will fit.

So whats been going on with the tunnel?

The weight loss is coming to an end and now its weight gain time

but before that a little more weight loss :laugh:

Going are those ugly side sills in heavy old glassfibre a test part was formed and fitted to see how it would go

I am liking that alot so I may drop down and see my local alloy supplier and folder to get a couple of panels made up for further trials

The central back bone tubing has started and I am quite happy with it now - it took a fair bit of thought to figure where and what shape I wanted it and it now flows quite well with the rest of the works so I am happy to carry on with it.

Throwing bits onto the chassis to get a visualisation

Putting a kink in to get a little more "me" room

This assistants got a bit bored by all of the tea drinking and sitting about looking.

Bits actually tacked up showing the shape of the tubing - Worth the extra effort involved with all the complicated profiling of the tubes to get a good join.

Only one pair of tubes are actually at 90 in two planes every other tube is not actually a parallel with any other which makes setting up cutting and welding a bit complicated

Its all progress.

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:55 pm

Tunnel design is complete and the main tubes are in. It will also be triangulated along the sides for extra strength and to provide a prop catcher. I was never a fan of only having the glassfibre to protect me should a UJ let go.

I also needed to find a little bit of extra room around the pedals so the bellhousing got lightened :laugh:

I have also moved the tubes that I installed above the diff area so that the central tunnel extends backward and in line. It also allows me to install and remove the diff from above without need to take apart the suspension - this will also allow me to flat floor the area under the diff and extend out to the wishbones.

Been working out the location and arrangement for the pedals an M/C's to get them out of the way of the heat from exhausts and road crud.

Given myself the challenge of cutting an notching 6 tubes every evening. I hate to think how many evenings its going to take to get it all done :laugh:

Have also decided that I don't like this step so its going which makes life a bit more complicated as is on the head rest cover and starts on the doors - but It just does not go with the rest of the car - same as the sills really - there are no angles on the body at all apart from the sills and these things

Also just a quick pic to show the angles on the tunnel

Dropped into the steel merchants on the local industrial estate and picked up a short 2.5M length of 30x6 mild strip to make the new pedals from - £3

Previously the main steel - 6 M lengths
2 x 25 tube
1 x 19 tube
1 x 20 box
1 x 25 box
40 x 3 strip
25 x 50 box 2 x 2m

Set me back £40 so not breaking the bank yet.

This evening I managed to cut 7 tubes although only notched and angled one of them

before retiring to the design board to work out lengths, leverages and heights to get the the pedals in the right place. Need to cut a couple of pedal pads tomorrow along with the notching I didn't get done today.

I must also get some resin ordered to start doing a bit of Glass work before it gets too cool. I also want to get the chassis done and so I can get some paint on it before it gets to cold.

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 1:58 pm

Keeping up with the cutting and notching and making up no end of little brackets and fixings.

The alloy pattern is down with a sheet alloy supplier to make up the new style side skirts.

The latest round of fabrication has been on the rear suspension mounts and the main mounts for the roll cage

And a few more of the smaller side triangulation tubes of which there will be many.

Need to work on the curve of the sills a little more to get it as I want it but I like the look as opposed to the rather angular affairs that do not reach the bottom of the chassis

Also added a few more tubes

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 2:00 pm

Which brings us right up to 2014 and me handing my notice in at work and being sent home on garden leave to two months. Paid to work on the car - that will do nicely.

As is the norm with these design as you build projects sometimes when you think you are really getting there

And are quite happy with the set-up and the pedals are all going in well and the pacing in the footwell is also better than expected

Looks right and all in the right place

You suddenly decide that - Nah I can have that better if I just move that bit

:laugh: :laugh: :laugh:

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 2:03 pm

And back to the pedals again

Couple of supports for the rack and a tube for it to pass through so that I can reinforce.

Few more tubes and we are getting there

Looks like this from a worms eye view

There is still miles of welding to do.

Right then, take the existing throttle pedal and chop it up. I am trying to re-use as many of the original parts as I can where and when I can.

Straighten bits and change the angle until you get what you need

Then weld them all together and stick them with some hot metal to the chassis in a place where you feel is correct and comfortable. Oh and drill holes. never forget to drill holes.

Then get on with the next on the list.

back to the other end of the car and the roll over cage. This was originally welded into the car. In order to have it as an optional fitment and have the opportunity to change it easily as and when the mood takes me I am making it bolt in

Trim the old welded plates off and size up some MSA size plates for 3 off fixings

Cut up a few spacers

And trim and prep in the old metal turner - Suitable for M10 which is a size larger than required by the regs.

Holes in the plate and holes in the chassis

Spacers being trial fitted.

And then the holes having the weld preps done after removing all of the swarf

Next stage to get some welding done

Darkspeed · Post by **Darkspeed** » Wed Feb 05, 2014 2:05 pm

And a weld

And some more welds

And then some linishing back

And the all done

List for tomorrow is some little brackets here and there and quite a few triangulation tubes - if time allows I may start with the ventilation of the suspension "things" :laugh:

Started off with doing the triangulation along the tunnel

Welded in the bracket for the throttle cable

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Bit closer to show the new "kink" in the bulkhead closing steel to add a little extra foot room

Dropped the Petty strut in to check the clearances

Always put the cablse and connections in place to make sure things are not going to clash

All fits and all clears - need a better shot rather than this blurry one

Dash was in for ergonomics - the dash clocks are actually to far apart as they are both obscured by the wheel. The 4 clocks need moving over to the left as the right hand one is blocked by the wheel slightly.

Some captives welded on

Seat belt bushes one of the next jobs

And got the list of jobs for tommorrow already sorted out. B)