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DIY supercharger option - with EFI!!!

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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
On the crank pulley front, one of the 'early birds' sent me this link, regarding a 'belt-and-suspenders' approach to keeping the pulley secure: Heavy Duty Crank Fastener

I didn't know that the crank was drilled/tapped deeper than is utilized by the OEM bolt, but good to know! I may hunt around a bit to see if I can find a better price, though. Thirty bucks seems a bit dear...?

Joel


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tghw Tyler HW
Denver, CO, USA   USA
1970 MG Midget MkIII "Rosie"
Effectively, it's just a 5/8"-11 cap head bolt with an extra thick washer. The hex drive is 1/2". Shouldn't be too hard to come across. A quick Fastenal search shows they have the bolts for $1-2, around $5 if you want a grade 8 version. The washer is about a dollar. $30 certainly is too pricey.

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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3883974 by tghw Effectively, it's just a 5/8"-11 cap head bolt with an extra thick washer. The hex drive is 1/2". Shouldn't be too hard to come across. A quick Fastenal search shows they have the bolts for $1-2, around $5 if you want a grade 8 version. The washer is about a dollar. $30 certainly is too pricey.

Thanks for the info, Tyler. I believe the above offering I linked to is Grade 12.9, but I wonder if Grade 8 would be sufficient, given that the torque value BMC recommends for the crank pulley bolt isn't all that high...?

P.S. - I'm still hacking up a lung but hope to be out in the shop tomorrow. I believe I'm the hold-up on three or four people firing up their intercooled, supercharged Spridgets, and I need to 'get after it' as my ex-pipe fitter/biker neighbor likes to say!

Joel


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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
Finally felt well enough to fabricate the final iteration of the rear mount today. It is simpler than it looks, and is comprised of three pieces of 3/16" mild steel: (i) a short piece of 1.5" angle iron that replaces the OEM rear generator/alternator mount (works with both - you just need a 7.25" x 5/16" bolt if running a modern alternator like I am); (ii) a straight section of 3" bar; and (iii) another longer piece of 2" angle iron drilled and trimmed to grab onto both rear blower housing mounting ears.

Still missing in these photos is a 'port' let into the flat bar section to allow the electrode to pass through at the rear of an OEM generator or 'stealth' alternator, for those who have one. Forgot to do that, so need to determine precisely where it goes...

Anyway, the new design holds the blower very firmly, allows fore-aft movement (slotted bolt holes cut in seconds with a cheap carbide rotary file) and is not difficult to reproduce. Just a little time-consuming to make up the three components if you're a plodding fabricator like I am. The welding then takes just a few minutes. Part of what took all day was pausing to put together a photo series and take measurements as I went along. When I get another free moment I'll double-check measurements and then send everything to Tyler to generate CAD drawings for free download on the website.

Really, it's fun making them up and the design is pretty forgiving. It's basically just a 65-degree angle and its compliments, drilling five holes with reasonable precision, and some grinding to remove sharp edges.

I've posted FAQs on the conversion on the website, and will soon post the project overview page. Then, I'll rebuild my motor, reinstall it (with the new, larger Datsun clutch), and during that process put together the step-by-step online DIY instructions, similar to the existing ones for the rear disc brake conversion. Well, actually those people ahead of me (on my own project) may contribute sufficient photos to launch the online instructions before I complete my own car. spinning smiley sticking its tongue out

Joel


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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
I've been back and forth out of state on business but found time today to weld up the front mounting tabs, and also trimmed more metal from the lower/inner corner of the rear mount to create clearance for the brake line union (second pic). Mine is a simple 3-way, as I went with a late model mechanical switch in the pedal box, but others with the pressure switch may need more clearance.

Happy to say it's a 5 to 10-minute job to align the blower pulley once the mounts are bolted on--which itself takes a few minutes. I just used a regular carpenter's square, as you can see in the third pic. The idlers are unbolted from the front mount for alignment. (You can also see the thermo housing spacer in this image, and the clearance it creates over the front mount for the upper radiator hose's wall thickness.)

The alignment procedure is:

(i) position the rear mount much of the way forward in the oval holes;
(ii) place blower and insert all four bolts, then snug up the inner/aft blower bolt;
(iii) hold the straight edge against the crank and H2O pulleys, articulate the blower and readjust fore-aft location using the twin bolts into the block and the inner/aft blower bolt as necessary;
(iv) snug up the outer/forward blower bolt and then more securely tighten the inner/aft bolt; and finally
(v) double check alignment and securely tighten all bolts.

As you can see in the fourth pic, the clearance between the blower and the CS121D late model Saturn alternator's case is just sufficient. The OEM Lucas alternator and generator (if someone wanted to retain it) are smaller I.D. so should fit just fine. I'll double-check them before getting the specs to Tyler to generate the free PDF downloadable scale drawings for folks to make up the mounts themselves.

Then, I can finally rebuild my 1275 and get her running... at last.

Joel


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nonracer Gold Member Steve Codianni
AZ, USA   USA
Looking good Joel
There are countless hours in what your doing and I know everyone appreciates it , can't wait to see it up and running . I might just have to get another Midget and put one on !

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trevorwj Trevor Jessie
Louisville, KY, USA   USA
No small task to hang a motor onto that blower. winking smiley

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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3893939 by nonracer Looking good Joel
There are countless hours in what your doing and I know everyone appreciates it , can't wait to see it up and running . I might just have to get another Midget and put one on !

Thanks for saying that, Steve.

One result of all that head-scratching and glacial progress is that the rear mount is not just extremely strong; it is actually quite simple to fabricate accurately. Here are a couple of pics showing the pieces: a 4" piece of 1.5" x 3/16" angle iron; a piece of 3" x 3/16" flat bar cut at 65 degrees; and an 11.5" piece of 2" x 3/16" angle iron (also used for the front mount's cantilever strut) with a recess cut out to form the mounting tabs and allow the blower housing to nestle into the mount. The 1" radius is just for looks, to mirror the curve of the cooling/stiffening fins on the rotor chamber; a simple angled cut would work just as well. People without a plasma cutter could easily make the radii with a hole saw (I did it that way originally when making up the front mount).

FIY, this setup is designed to bolt onto any A-series Spridget without internal engine mods, so you could install it on either your '62 or '65. The SmoothFlow modular blower pulley kit allows you to adjust the boost to suit the engine. Also, one of the 'early birds' who snapped up the first run of M45 manifolds is going to confirm that it will fit beneath the Bugeye's arguably more aggressively sloped bonnet. We'll see...

The only non-reversible modification involved in the conversion is cutting the holes to permit the snorkels for the $99 Audi A4 intercooler to pass through the lower valance sheet metal (as pictured in an earlier post in this thread; the intercooler itself slips right into place). However, the Bugeye's tilting bonnet may eliminate the need to modify any sheet metal to install the intercooler. Again, we'll see.

**Note: I had to adjust the belt-tensioner mounting block slightly, moving the tapped 3/8-24 hole down and in toward the crank, to create sufficient room for the $65 SC121D internally cooled, late model Saturn alternator I prefer. So, I need to get the new specs to Tyler to update the free PDF downloadable CAD drawing for the serpentine belt conversion--which of course works with naturally aspirated cars, too.

P.S. I see that you have a Volvo P1800. The wife is buying a Tesla next week, so I am buying her 2009 C30 to help her with the down payment (though I've been bugging her to sell it to me for years). You likely know that the C30's styling cues at the rear of the car come from the P1800 wagon.

Joel


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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3893957 by trevorwj No small task to hang a motor onto that blower. winking smiley


Amen, Trevor. How I wish I would've been able to use your CNC skills to streamline making the prototype of the rear mount, as you were nice enough to do with the prototype for the rear disc brake adapters.

Ah, well. What matters is the end result: a small cadre of intercooled, supercharged Spridget drivers who can zoom up the onramp and avoid getting rear-ended as they merge into highway traffic, or 'steer by throttle' on the Tail of the Dragon, as rumor has it you may have done on occasion...

Joel


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nonracer Gold Member Steve Codianni
AZ, USA   USA
Joel
The 65 is long gone and the 62 already has the 2.2 Ecotec installed ( mocked up not running ) , I figured the P1800 would have some influence on later models and why not it's a great looking car ( that's why I have one ) . Don't know which way I'm going with that car ... LS swap or turbo 2.2 Ecotec if I even get to that project at all . My biggest issue with keeping the A series drivetrain is the 4 speed transmission , we all know its not great for the highway especially when the speed limits are 65-75 . I'm also really only interested in side curtain cars so that makes it harder to find another one but if I do get one its going to have EFI and a supercharger .

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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3895157 by nonracer Joel
The 65 is long gone and the 62 already has the 2.2 Ecotec installed ( mocked up not running ) , I figured the P1800 would have some influence on later models and why not it's a great looking car ( that's why I have one ) . Don't know which way I'm going with that car ... LS swap or turbo 2.2 Ecotec if I even get to that project at all . My biggest issue with keeping the A series drivetrain is the 4 speed transmission , we all know its not great for the highway especially when the speed limits are 65-75 . I'm also really only interested in side curtain cars so that makes it harder to find another one but if I do get one its going to have EFI and a supercharger .

Steve,

Oh, duh... I now recall our correspondence re: your Ecotec conversion; I was then leaning toward a Zetec. 'With age comes digression...' I remain eager to see that whenever you have a chance to get her running.

I should mention re: the turbo Ecotec option that two people have used my M45 adapter/universal manifold to supercharger cars other than our A-series Spridgets--a 240Z and a classic Alfa Romeo. So, should I ever do an engine swap--and a Bugeye would be the most likely recipient--an interesting option would be a supercharged Zetec.

The T9 would be the most logical tranny, I suppose, as there are numerous bell housings out there for that combination. But since I now have a competent production CNC shop literally next door, with an owner who likes doing my Spridget-related projects as a break from his Sandia Labs, et al. bread-and-butter gigs, making up an adapter plate for whatever tranny made sense is no longer as daunting as it seemed just a few years ago.

Joel


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Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
I experimented with different belt lengths and ended up slotting the hole for the upper/inboard idler, providing what amounts to preload adjustment. That has the corollary benefit of moving the tensioner farther through its arc of travel--which wraps around the crank even more (though it is wrapped more than stock as it is). The belt j-u-s-t misses the lower/outboard idler (first pic). Looks like the final adjustment to the latest iteration of the front mount is going to be moving the lower/outboard idler at a 45-degree angle down/in toward the crank. That will increase this gap--though that really isn't necessary--but more importantly will increase the wrap around the alternator a tad more.

I also drilled out the blanked expansion tank port on the hi-flow thermo outlet for the expansion tank I'll be using with the VW Rabbit radiator (second/third pics). In addition to providing better flow (fourth pic), the clearance for the upper hose is better at the apex of the front mount's angle iron (last pic). I can pretty easily work on the OEM hose with the original down flow housing, as was of course designed into the housing spacer/temp sensor mount. But I will recommend that people go with the bigger diameter outlet.

I'm finally done with these mounts, so will be dismantling my engine for the rebuild shortly. Can't wait to see what kind of boost she generates with the this configuration and an intercooler--albeit at 6,000 ft. / 1,820 meters elevation.

Joel


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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
Sometimes, you stare at a problem for so long you imagine that you’ve exhausted all options... and then an even simpler solution presents itself. I was just firing up the plasma cutter to make the parts for the 'early birds' mount sets, thinking I was done with the mounts' R&D, when I realized that all we need is a single (2”) idler pulley rather than two idlers. See the first attached photo.

The small idler pulley is just slipped onto a single, longer (8.5”) 5/16-18 bolt (or all-thread) that passes through the rear mount, both alternator/generator ears, and the front water pump mounting ear, and the threaded end of which then serves to mount the idler, which in turn just sits on a spacer sleeve to align it properly in the fore-aft dimension. See second and third photos. Easy peasy!

What we get is dramatically better wrap on the alternator. The amount of wrap on the water pump pulley is a bit less, but the water pump requires very little energy to turn—and we're using a 5-rib belt, which is really grippy.

However, in the unlikely event that we notice inadequate cooling due to slippage on the water pump pulley, all we have to do is either: (i) reinstall the second small idler on the front mount--which means just drill one hole for a bolt with spacer sleeve for fore-aft alignment; (ii) make up a simple 'T' block that fastens to two of the bolts holding on the timing cover--but obviously with longer bolts (I like this option a lot; the part is simple to make out of the same 1.5" x 1" aluminum used for the belt tensioner mount); or (iii) use the same (new) method and insert a longer bolt where the front engine mount bolt is (directly below the water pump pulley in this photo) and just insert a longer bolt and spacer.

The latter's only downside is that the belt length would have to be spot-on to keep the tensioner from bumping into the second idler, but there are so many lengths in that range it's unlikely one wouldn't be right. However, the 'T' block is so easy to make up that I'd likely go that route anyway.

All of these options work with the belt camshaft drive that at least one early bird is using, by the way.

Very cool!

**Update: Dayco 5050565 (Gates K050565) is just a hair too short. So, I'm ordering the next two sizes up, and will post the results when they come in: 5050570 (57.09"winking smiley and 5050580 (58.07"winking smiley.

Joel



Edited 3 time(s). Last edit at 2019-03-07 01:34 PM by Yankeedriver.


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Denis Avatar
Denis Denis Hill
Bearii, Nth Victoria, Australia   AUS
Joel, I doubt you will have slip with the water pump as its on the tight side of the belt. " Looking good"

Denis



68 B roadster, Daffodil yellow, supercharger, Burgess SC head, SC cam, Mikuni HSR 48 carburetor and engine built for supercharging.

73 BGT V8 conversion starting with a bare shell. Built the engine "3.9L Rover" early in 2016 with high comp pistons and a few other nice bits, plus a T5 ford trans. Started on the body late 2016 and complete late 2017, Did all the work myself, mechanical, body. paint etc.
Finished and going well, great to drive and quick. Now has a nice 3.23 LSD.

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Yankeedriver Avatar
Yankeedriver Platinum AdvertiserAdvertiser Joel Young
Albuquerque, NM, USA   USA
In reply to # 3902634 by Denis Joel, I doubt you will have slip with the water pump as its on the tight side of the belt. " Looking good"

Denis

Excellent - thanks for weighing in.

Joel


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