A Twin Cam Something

This Forum is here for each member to post pics of his/her Gemini project cars. Keep it to one thread per car.. if you get more pics etc, add them to your existing thread, DO NOT start a new one
F3ARED
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Re: A Twin Cam Something

Post by F3ARED »

Ive tried a few sources for the ARP studs; VPW was stupid expensive. Rocket Industries were the only ones that had them in stock. Interesting about the chains, the ones Ive got seem to be ok in that there is no perceptible play in the links. What struck me as odd is that there is a removable link in one of the chains. Im stuck on the tensioners with mine. Both of mine have heavy wear and I cant seem to find anything that looks like 100% swapping in.
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

78 TD Gemini Sedan - R.I.P
81 TE Gemini Sedan
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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Just some photos of the set up stage of the manifold build.

Measured the distance from the top engine mount bolt on the block to the bonnet (about 750mm) on the wagon and and used that to work out there will be 120mm of clearance from the top of the twin cam rocker cover to the bonnet – That limits the top of the carby to about 30mm above the rocker cover to fit 85mm filters. I allowed 40mm side clearance but only 15mm for the dissy to minimise the skew on No 1 and 2 runners.

The two after market manifold I looked at (gemini and cortina) don’t compensate for the engine tilting back but set mine to sit flat with the engine installed. The set up is simple enough using two L shaped braces (set at 90 degrees exactly). Once happy with the height tack weld the front bracket to the head flange. Then set the tilt on the carby flange and mark and tack weld the rear brace. Then you can play around with the carbys fitted to the carby flange to get the position and clearance then tack weld the carby flange to to the braces. Recheck the whole thing. Don’t go to crazy with the tack welding as the braces come off after the runners are fitted.

Readers beware, this is my first go at this but I am following advice from someone who has done it before.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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Getting close. A couple of mounting points for the linkages and that should do it.

My MIG is just a bit small for this job and the welds a bit lumps but not too bad.
F3ARED
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Re: A Twin Cam Something

Post by F3ARED »

You really arent hanging about on this. What are the carbs, 44IDF?
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

78 TD Gemini Sedan - R.I.P
81 TE Gemini Sedan
tobytj
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Re: A Twin Cam Something

Post by tobytj »

40 IDF with 30mm chokes. It's for road use and I am after more mid range response than top end power.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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Manifold finally finished. Faces machined flat, inside of runners and flange faces blued with gun blue and finished with “aluminium” high temperature paint over etch primer. The machining took up to 2mm off at the edges so I am glad I chose 10mm plate instead of 8mm. Next time I will bolt the flanges to a length of 100 by 50 channel minimise the heat distortion during welding.

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Found a brand new water pump at the little parts store in Richlands. It was listed for a 1972 to 1976 Chev Luv G161 motor (different motor to a G161Z) but it is the same water pump as a G180W or G200W. Checked the Rockauto site and they have the same water pumps available for $US 40-70, so still available new.

Just arrived!! a package from Precision Shims in Melbourne with the shims I need to reset the lash on the valves. Waiting still for the 30mm chokes for the IDF’s to finish the carby rebuid.

That leaves the dissy to be reassembled and a cap and rotor button to be found – (if I ever identify the dissy parentage), sort the exhaust and custom left front engine mounting that I have a design for in my head
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Slow progress. The IDF’s have been soda blasted and re kitted with 30 chokes, 130 mains and 55 idles for the initial setting. Linkages worked out to be a simple matter of some M5 rod to set the ball fittings to the correct length.

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I was all ready to go hunting a bolt store for a M16 x 1.5 bolt to drill out to make a banjo bolt for the heater pipe fitting to the water pump, but noticed that the crank pulley bolt on a G series engine is the right thread, if 10mm to long. A bit of work on the drill press and new banjo bolt in place.

Image
F3ARED
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Re: A Twin Cam Something

Post by F3ARED »

Worked out what your putting it in yet?
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

78 TD Gemini Sedan - R.I.P
81 TE Gemini Sedan
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Probably my wagon. That will leave me a excess of a fully balanced G180Z.

I have half been expecting on of the kids 3 Geminis being used as daily drives to need an engine transplant but they all seem to be running strong. Perhaps they have learned the meaning of care (Ha! the youngest got a flat in Newmarket last week and kept driving to ferny Grove - scratch one good Perelli P3).
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Jonno
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Re: A Twin Cam Something

Post by Jonno »

Get it in the wagon then bring it down for next years nationals.
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tobytj
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Re: A Twin Cam Something

Post by tobytj »

My planned exhaust solution is the standard twin pipe headers that (so I have been told) require more clearance for the left front engine mount.

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The photo above is a standard left hand Gemini mounting bracket offset forward by 59mm. The new bracket picks up the two 12mm normal mounting points and a 16mm mounting point behind the generator.

59mm is the spacing of the bolt holes on a standard Gemini engine mount. The adaptor plate only need 3 holes at this spacing.

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Note that the new mounting holes are 8mm lower than the originals to allow for the thickness of the adaptor plate.

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With a little bit of minor cutting and the dipstick tube fits too.

A mount from a G200 in a Rodeo would have probably done the same job. If I did this again I would make the backing plate one piece, cut the back off the mounting bracket and weld to the plate – easier to set up and would look neater.
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Jonno
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Re: A Twin Cam Something

Post by Jonno »

Nicely done!
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tobytj
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Re: A Twin Cam Something

Post by tobytj »

Haven't converted this thing to a sea anchor yet but lost my password so no updates for a while.

Distributor solution found after much mucking round. Could not find a cap to match the dissy I have so put that to one side. Purchased a Datsum 1200 electronic dissy (really cheap) which, on paper should have fitted. But did not engage fully with the gear on the cam. Difference must be tiny but it just would not lock in the last 5mm.

Plan C cut down Gemini dissy using drive gear from the original. I have set up just on points to start with but have three electronic conversion setups laying arounds.

Obtained a stock exhaust manifold but unfortunately the matching engine pipe and flange was bent and rusty. So made a new flange and now have to get some pipes bent to make up an engine pipe set that avoids starters, engine mounts. Couple of myths busted in this process.

Myth 1 G180W exhaust flange is the same as Tx Gemini. Nope. Very close and you can get a TX flange gasket fit by extending the rear bolt holes. This assumption casued me headache as I initially made a Flange plate to match a TX gasket.
Myth 2 If you move the engine mount forward on a plate you can use a standard exhaust manifold and exhaust. The jury is out on this one. My measurements say a standard engine pipe will hit or come extremely close. Can't really tell till the engine mounts are loaded. Suffice to say my custom engine pipe will have extra clearance.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Engine pipe and flange fabricated.

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Gemini G161Z distributor modified to fit a G200W

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All I need now is car to put it into
F3ARED
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Re: A Twin Cam Something

Post by F3ARED »

All I need now is car to put it into
Thats the fun bit....

Which dizzy drive shaft did you use/cut down? If you used the 161z shaft then that would mean the Magna swap that everyone used to use on the SOHCs could be modified to work
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

78 TD Gemini Sedan - R.I.P
81 TE Gemini Sedan
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