Harv's McGee injection thread

[FJWALLY]

Very interesting - that little W clip has a big job to do - it has to be rigid enough to prevent any flex or out of synchro between the two injector shafts BUT also be flexible enough to cope with any slight misalignment as you have in that set up - challenging indeed.

[Harv]

The bad thing is that mechanical fuel injection is very sensitive to air/fuel ratio. On a Strommie carb, if the air is opened up too far the car may hesitate, but will then catch up as the carb feeds more fuel. On mechanical injection, the system has no "smarts" (feedback "suck" from a venturi) to correct for an air misadventure. If that W-clip fails the wrong way, the injector goes lean, the cylinder goes hot, and things (...like pistons) start to melt.

Cheers,
Harv

[ardiesse]

Harv,

Does the barrel valve assembly load place loads on the throttle setup?
My X2 experience is that alignment of the throttle shafts is all-important. And the W-clips are not all that stiff in torsion.
So if you have the choice, I'd be inclined to put the barrel valve linkage on the same shaft as the throttle cable attachment.

Rob

[In the Shed]

G’day Harv
Was at the National Motor Museum as part of Bay to Birdwood Sunday. Thought you might be interested in this vintage go fast grey set up

Regards
Stephen

[Errol62]

Ooh err. Luv the zorst


FB ute fixer upper, EK van on rotisserie

[Harv]

Does the barrel valve assembly load place loads on the throttle setup?

It can. The spool fuel ramp is oriented at 90º to the barrel valve shaft. Fuel flowing across the ramp puts a load back on the shaft. It's made worse by any galling, scoring or sticky o-rings. I need to have a good long think about the overall linkage setup once I get the small capscrews, and a bit of a play to check arm angle and butterfly binding.

Was at the National Motor Museum as part of Bay to Birdwood Sunday. Thought you might be interested in this vintage go fast grey set up

Mmmmm... Amos injection. Would love to lay my hands on a set (or Olbis for that matter). Pure Hell has the same Redline throttle arms and w-clips as the McGee.

Phil Green E Dragster Its Pure Hell at Birdswood museum.jpg (721.47 KiB) Viewed 1044 times

Cheers,
Harv

[Harv]

This probably explains the throttle shaft torque issue better.

shaft torque.png (95.94 KiB) Viewed 1034 times

Cheers,
Harv

[ardiesse]

Harv,

Yes. Your second sketch makes clear what I was thinking.

Here's an idea: once you have sorted out Mister McGee, you could go to the National Motor Museum and offer to resurrect Mister Amos. But 124 mph at the end of the quarter? - nerves of steel required.

And do I notice a 186 starter motor? Either the flywheel has a red motor ring gear, or the starter has a grey motor pinion.

Rob

[Errol62]

Red flexplate and power glide possibly


Sent from my iPhone using Tapatalk

[Harv]

Managed to pull apart and rebuild the McGee pump mounting bracket that came with the red motor set. These brackets are used to mount the injection pump in line with the crank, and drive them with a gilmer belt. This particular one has had a hard life – bearings were shagged, bracket had been cracked and weld repaired, and at some stage had been reshafted to suit an Enderle hex drive pump (the McGee pumps are tang drive).

Pump support bracket assembly.jpg (73.64 KiB) Viewed 1004 times

Pump support bracket assembled.jpg (129.85 KiB) Viewed 1004 times

Pump support bracket drive end.jpg (72.04 KiB) Viewed 1004 times

The drive pulley was not recoverable… has had what looks like grinding damage at some stage. Why on earth you would paint it up in gloss black paint afterwards is beyond me.

Pump support bracket drive gear damage.jpg (106.03 KiB) Viewed 1004 times

Cheers,
Harv

[Harv]

Attached below some notes on the McGee angle drive. The angle drives are used to turn the dizzy sideways (horizontal) in order to clear the inlet manifolds on Repco heads (there is only 6” of clearance between the grey motor dizzy hole and inlet manifold). An alternative is to use the early Holden “short” dizzy cap and rotor assembly with the distributor vertical, but they are marginal on a Repco head. The standard “tall” GMH dizzy cap gives you only 8mm to squeeze on the spark plug leads, whilst the “short” dizzy gap gives you a (barely better) 10.5mm. The other benefit of the McGee angle drive is that it also provides a mounting for a fuel injection pump. The four holes that can be seen to the right of the housing are used to mount the fuel pump onto the angle drive. If a fuel pump is not used, the top of the angle drive is blocked off with a simple circular ally plate.

Angle drive assembly.jpg (123.1 KiB) Viewed 988 times

The angle drive housing (item A) is cast from aluminium. It mounts in place of the distributor, with an integrally cast “tang” (item B) sliding into the block the same way a grey motor dizzy does. An allen-head set screw (item C) mounts through the angle drive housing and picks up the normal dizzy hold-down bolt hole in the grey motor block. This mounts the angle drive housing hard onto the block. To change timing, you rotate the dizzy (or magneto) in the angle drive, not rotate the angle drive housing. The weight of the dizzy hanging out of the housing provides a substantial lever. Vibration and suspension bounce put a lot of force onto the tang… and they snap off. Mine had snapped off, and I know of one other with the same problem. I stripped my unit down and sent it to Cycle Weld (Steve Ortis, 23 Kitawah Street Lonsdale South Australia 5160, telephone (08) 83822689, mobile 0412470266). Steve specialises in TIG and MIG repairs to aluminium and magnesium castings – crotch rocket engine cases, barrel fins, gasket faces, fuel tanks etc. He did an absolutely awesome job of repairing the snapped off tang, despite it being very close to the internal bearing mounting surfaces and also needing to be ground flat to let the tang mount flush onto the grey motor dizzy hole. Highly recommend Steve for repairing busted up, used ally parts. When I mount the angle drive onto the meth monster project I will make a girdle to hold the magneto up, preventing it from bouncing and snapping off the tang again. The sideplate screws provide a neat mounting point for the girdle.

The dizzy (or magneto) slides into the angle drive housing in the direction of the red arrow, and is clamped using a short allen-head set screw (item D). End thrust is taken up by a ball bearing thrust bearing with stainless backing washers (items E and F). The thrust bearing assembly is retained in place with a spiral ring (item G). The spiral ring is painful – no “eyes” to grab with circlip pliers like a snap ring, and is lodged firmly into a groove deep inside the housing. The spiral ring does not have the normal “removal notch” that makes them easy to lever out. It has to be levered/picked out with a fine screwdriver without damaging the soft ally housing or spearing yourself in the hand. I may have uttered a few bad words trying to do this. The end of the thrust assembly is sealed off with a small brass cap (item H) that taps into the housing like a welsh plug. The ally housing has an internal brass sleeve to allow the dizzy/magneto shaft to run. The internals of the angle drive (both the thrust assembly and the cross shaft below) were packed with grease.

The cross shaft (item I) looks to have been made from a length of steel rod welded into a gear cut from a grey motor camshaft (item J). The cross shaft has a drive tang on one end to engage the grey motor oil pump. The gear has a slot cut into it to engage the fuel pump drive tang (more on the fuel pump mounting later). The cross shaft is mounted in a simple 6202 ball bearing (item K). The bearing is a firm fit into the housing, but quite sloppy on the cross shaft. This allows the cross shaft to be shimmed up or down to set the oil pump drive tang and drive gear mesh. A simple shim washer (item L) is used to set the cross shaft location, similar to the way that Vertex magnetos are shimmed. The other end of the cross shaft has the normal grey motor dizzy drive gear (item M) held in place by a pin (item N). The pin in this case was a roll-pin, though will be replaced with a solid pin from Vintage Racing Developments.

Cheers,
Harv

[Errol62]

There are still a lot of good resources at Lonsdale industrial area despite the closure of the Mitsubishi (formerly Chrysler of course) foundry and engine plant. Where do you find the time?


FB ute fixer upper, EK van on rotisserie

[ratrod fj]

Harv
tried to send a pm it came back
Can you ring me 0417507220
re need some vanes for my norman hoping you can help
Cheers Grantley

[Harv]

No problem - I’ve got spare vanes in both Bakelite and phenolic. I’m travelling for work this week without a phone, back 26th. Will give you a call.

Cheers,
Harv

[Harv]

After a lot of emails, phone calls and FaceBook Messenger posts, I finally managed to get hold of the McGee Racing clan in the states.

The nozzles that McGee currently list on their website are mainly for US style injectors (early Hilborn, Enderle, Crower, etc.). They are sized based on leak-down rates, similar to Hilborn.
• #8 (0.0225” orifice)
• #10 (0.025” orifice)
• #12 (0.028” orifice)
• #14 (0.029” orifice)
• #16 (0.032” orifice)
• #18 (0.033” orifice)

The original McGee nozzles are not listed on the website, but are available. I’ve sent some data on the meth monster project over to them to get an initial sizing.

Of note:
a) My red motor set was indeed originally built for the Holden red motor, not the blue/black motor suspected by a previous owner (my understanding of red vs. blue/black bolt patterns was correct).
b) Both my (Repco head) grey motor set and red motor set used 0.028" to 0.032” orifice nozzles depending on engine capacity. The 0.018” nozzles in my grey motor set suggest someone has reworked it for petrol use. The 0.034” nozzles in my red motor set would suggest a fairly healthy 202.
c) The grey motor set has the correct 90-degree nozzle with a 3/4” deflector tip, and the red motor set has the correct straight nozzle with a diffuser screen in the bottom.
d) McGee confirmed that they did make three different pumps (see earlier post).

Cheers,
Harv