John Bonnett
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Everything posted by John Bonnett
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Recent gallivanting around the Country has slowed progress to a snail's pace but all that is about to change. Well after our few days this week in the New Forest. So where are we as of now with the project? I've now got back all the suspension parts from the powder coaters and they are polybushed up. I've taken a stab at the front springs and chosen as a starting point 120 pound 9 inch open and 2.25 diam. The Gaz adjustable platform shocks are a week away. The car came with 450 pound standard Imp rear spring which are too hard so these have been replaced with chrome bumper MGB roadster fronts which are 345 pounds and hopefully not too far off. I have a problem sourcing an ET30 alloy wheel with 4 inch pcd. The ones supplied for an Imp are ET20 and foul the arches. On the chassis I've started the rear driver's side bracing to match the other side that has already been done and begun a bit of lightening on the suspension towers. The last major piece of work to be done on the chassis is replacing the folded cross member to which the rear shocks are mounted. This part of the chassis has been made wrong. On mine, the cross member is horizontal but it should slope down towards the rear at an angle of 8 degrees to allow the shocks to line up with their mounts on the trailing arms. Before cutting anything out the body needs to go on and some careful measurements taken to make sure the new cross member fits nicely against the parcel shelf.
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Thank you Rob, I had to change the position of the bracing I put in because it could possibly have fouled the trailing arm on full bump. I had to cut out the round tube and put its replacement in a slightly different position. A bit of work but well worth it for peace of mind. Having had good service from Gaz on the two Triumphs I have ordered a pair of adjustable spring seat shocks from them. The measurements I have taken, ride height and bump tie in nicely with the model they list for the G15. These will suit 2.25" springs. I've collected all the suspension parts from the powder coaters and they look superb and for no effort on my part. 🙂 So a bit more progress.
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I've never been comfortable with that type of fixing because there have been instances when the fan has slipped and the plastic ties worn through the pipes on the rad. In this case it is a very nice aluminium radiator which would be even more of a pity if that happened..
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Good progress Hazen. You've taken a lot of care and it shows. Some really nice work.
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I find it quite extraordinary that with something absolutely fundamental to the way the car behaves on the road has not been nailed and written down in tablets of stone. It feels like inventing the wheel all over again. It is almost as bad with the roll cage. Safety Devices have lost the jig for the full cage and the rear cage is listed under Alfa Romeo I guess because of confusion between Ginetta and Giulietta. So what hope have we?
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They can't find any reference to it unfortunately so it's a question of starting from scratch but thank you for the suggestion. cheers John.
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On the way back from Skye I called in to see a GOC member who is a good engineer and a fount of all knowledge on Ginettas. We were talking specifically about G15 front springs and dampers. I found it quite staggering that despite 800 cars being produced there isn't a standard front damper and most if not all cars are fitted with units that are too long and only have half an inch travel before they are on the bump stops. This coupled with non adjustable rear toe and built in bump steer confirms the opinion that the handling of a G15 ranges from bad to awful. This does not stop them cornering like no other and many people confuse handling with cornering but they are completely different. So with this in mind my next step is to to set the wishbone at ride height and source a damper that is in the middle of its travel at that point. Basic stuff you would have thought and amazing that nobody has actually done it before.
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No Brad, a 1mm cutting disc on an angle grinder.
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The rotisserie is proving to be a godsend, allowing full accessibility for welding. I expect most of us are aware of the benefits of 1mm thick cutting discs but the accuracy they offer when cutting out rusty sections and making new ones is astounding.
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Brad if it does work out and you can do the GP de Tours that would be really excellent. It is incredible value for money. Right back to the G15. I'm waiting for some box section to repair the rusty area where the right hand lower wishbone bracket are mounted but I was able to fully weld the ones on the passenger side. Whilst waiting for the material I turned my attention to the rear of the chassis. The piece of 2mm plate a sort of large gusset would be okay in tension but not great in compression. So I cut a enough of it away to weld in a piece of round tube and once that was in the rest of the plate came out. I've yet to cut and fit a couple of bracing tubes.
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Sorry Brad. Quite so. I didn't mean to hurt its feelings. 🙂
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And don't forget La Coupe Florio at Saint Brieuc end of August. A great hill for the Midget.
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I certainly will Brad. It was a great shame it didn't work out when we were very close to you in June. But we have sent our entry off for the Grand Prix de Tours 23, 24, 25 June next year. It's based in Chinon now. The lunch on the Saturday is something you would never believe followed by afternoon tea at a winery in Chinon. Sunday there is a closed road circuit to hack round. Fancy joining us? http://www.grandprixdetours.com/
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Mezzanine? Now you really are showing off!!! 😀 I found some more rust in the lower wishbone mount area so I've cut that piece out and it is now ready to have a new piece of metal inserted. I could see no reason why Ginetta used a couple of four inch bolts for the lower wishbone mounts so I decided to replace the brackets. The new ones were cut from 40 x 40 x 3mm wall box section and worked out quite nicely. To make sure all the holes lined up the brackets were assemble onto the wishbone and offered up. Despite being tightened up the metalastic bushes prevented the brackets from sitting properly. So I machined up a couple of solid temporary bushes in brass which did the job. The new brackets are now tacked in place.
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I bought the units from Wickes when they were on offer Brad. Amazingly cheap and offer dust free storage. But there is never enough space is there? No need to be envious. I don't have room for two classics and another one being restored and still space to move around.
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Some of you may remember that I made a rotisserie out of a couple of engine stands. I've just dug it out and fitted the chassis to it. It should still work with the body fitted which will make life a whole lot easier when it comes to running the services down the tunnel. It will also be a great help when the underside is panelled. A bit of effort but I hope worth it.
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A very nice piece of work there Hazen. A tribute to your patience and attention to detail. Nice to have a bit of help eh? 🙂
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My experience is very limited but the P brackets came with the car and are the same as the one on a local G15 and the one in the picture.
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I've just been making up some new anti-roll bar brackets. I found a pair of polybushes which had the right O/D and width, just the hole in the middle needed enlarging to 3/4". I found that by pressing the bush into a piece of tube I could hold it in the chuck on the lathe and drill it out quite easily. The bushes would slide onto the ARB but I could see no way in the world to fit them into the Ginetta P brackets. So I made these hinged ones which seem to do the job.
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Now that has a familiar ring to it Mike 🙂
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I've put an additional cross member in to give a bit of support for the suspension mounting. It was an interesting exercise to put the sleeves in at the right depth and correct angle. Amazingly, the coolant tubes slide straight through without touching. Lucky or what? 🙂
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And the added benefit is that the chassis will be protected. I can leave the bit under the tunnel open or fit a hatch and put hatch in underneath where the throttle cable goes onto the pedal. Sounds like we might have a plan. 😉 Thanks to everyone who has and is offering their thoughts. This is a joint project after all 🙂
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Agreed on all counts Nick; thank you. I'm thinking about panelling in the underside of the chassis with NS4 18swg aluminium bonded and riveted. I'm hoping this working with the floor will help things. What do you think? rgds John
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Nick has made a very valid point and as a result I'm not going to continue with the idea of welding in the coolant pipes. I'm grateful to him for his timely observation. On a general note I've never had any trouble with subsequent cracking after welding stainless to mild steel using 309 stainless rods. This extract confirms the practice; As an example, when joining 304L stainless steel to mild steel, the most commonly recommended filler metal is 309L. During the welding process, the weld becomes diluted with some of the stainless steel from one side of the joint and some of the mild steel from the other side, mixing in material from each side of the weld. The goal is to create a final weld deposit whose chemistry is compatible with each side of the weld joint. Using 309L filler metal achieves this goal when joining 304L stainless steel to mild steel.
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That's a very good point Nick. I'd not thought of that. But would the expansion at a temperature of less than 100C be significant?