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Bugeye Conversion

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ralph_s

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Need some help from the experts...I'm in the process of restoring my 59 Bugeye w/ several upgrades. e.g. drum to disc on the front. Now I'd like to upgrade to a 1275 engine. Is this a drop in replacement? Any change to the drive shaft or motor mounts? Also is the original differential OK w/ this upgrade? I'd like to keep w/ the positive ground, any downside? Final question (atleast for today) I've read the axle's are a weak point. Any comments? Don't want to reinvent the wheel and could use some advice.
Thanks, Ralph
 
All are the same. I am currently doing the same 59 with a 69 1275 and a 64 wiring harness. If you run a 1275 with a positive gound you should run a search of this site. There are a lot of discussion regarding the positive ground. I currently have the original differential in it but I havent gotten to the point of driving it yet. Also, if you are trying to make it look original, as I am you will need to check on the alternator vs generator because of the tach. Others maybe able to help you more but this is where I am at right now, finishing wiring and next will be running new gas lines then brakes, then ... then ....
 
Thanks, appreciate the feedback. I'm going to stick w/ a genetator and found a new tach drive for the generator w/ the mechanical tach.. I'm struggling to pull off the rear 1/4 springs. Have you gone this route w/ any suggestions?
 
My standard recommendation is to keep the positive ground, if you really want it, until you start adding any modern electrical or electronic components that are polarized. You might find, say, a radio that is positive ground, but if you eventually want to add something that is not available in positive ground, you have to replace all the pos-ground parts you've added.

Also, make SURE it's clear at a glance that the car is positive ground. You should minimize the risk that some pimply teenager, who's never seen a pos-ground car, doesn't try to jump-start it negative ground.
 
I'm in the middle of this swap as well -- 1275 from a '74 Midget. I choose to swap to the later diff (a 3.9) but just for the different ratio. Everything else is the same. I'm keeping the positive ground at this point and keeping the generator.
 
Is the differential an exact swap out? Also anyone remove the 1/4 leaf springs? I've gotten the u-bolts off but the 2 retaining bolts are frozen. It looks like I can drop the whole assembly by removing the bolster plate attached to the chassis.
 
The diff is a simple swap, the various diffs are the same other than their ratios for the entire run of Spridgets.
 
You don't need to replace the whole rear axle to change the differential, if that's all you're doing. If more than that, you can find info in the archives about loosening those bolts--it's a perennial problem. (I've never had to do it, fortunately, but I seem to remember a few postings on the subject within the last couple of years.) The differentials are a direct change-out too; these little cars are very accommodating!

If you are putting in a 1275, it's also not a bad idea to get a set of axles from a later car. The Bugeye axles are marginal, even for the 948. They're known to break; I can tell you all about it!
 
Yes, the differential is an exact swap out so is easy (relatively speaking) to do.
I'm just guessing here as no photos to look at of your BE's rear spring mounts but it sounds like the retaining bolts you mentioned are so rusty they are fused to the threads. Unfortunately the problem is pretty common so try a real good soak with the harshest penetrating fluid you can find and see if that helps. Or you can try heat around the bolts but want to be careful you don't burn the car down or damage the springs. In my case I ended up twisting so much on the bolts they broke off and even after removing the plate below them it was a nightmare getting the springs out. Even with the plate removed, the spings are still in a box and very difficult to remove - of course my BE chassis was EXTREMELY rusted so hopefully yours isn't quite as bad.
Roy
 
This was a great find for me today....appreciate all the help and input.
Being newly retired, I need to sign off today and get dinner ready for my wife who is still working!!!!!!!!!!! I don't want to blow my cover and have her think I work on my car all day.........
Thanks again to all.
 
And... that bottom pan/plate is welded in place.
 
Hummmm There are 4 nut/bolts that go through the plate and are accessed behind each seat and from the bottom of the plate. My plan was to unbolt and see if the plate drops out.
 
I LOVE those 1/4 spring mounting bolts. Took 2 cans of PB Blaster and a great big breaker bar on my wrench to break them loose and that was only after a whole lot of scraping out the muck in order to allow the Blaster to work its way to the top of the spring. In everything I dismantled- every piece and part- those bad boys were on the top 5 'worst' list
 
Unless someone else removed the pan and failed to weld it back, it is spot welded and tacked at the edge where it meets the spring box.
 
After the 2 u bolts and the 2 attachment bolts, did the springs slide out?? Looks like the bottom bolster plate is bolted on. Did you remove that plate? I'm in the soak em' and wait phase right now.....
 
When I totally stripped my BE the first time, everything came apart easily including the spring mounts. The PO had followed the rule he taught me 30 years earlier when I was a punk kid looking over his shoulder while he rebuilt it the first time.

AGT=Always Grease Threads

Every time you assemble a bolt and nut, grease the threads. The next guy will thank you.

Glen Byrns
 
Correct the U bolt and the two spring bolts are the only things that holds the spring in place.
 
I think I'll dig out some more 50YO dirt and let em' soak for a few more days. Polish up the breaker bar and have at it this weekend!!!!!
Thanks
 
An impact wrench may work better. The jarring and hammering effect tends to break things loose. I managed to get 3 out of 4 on my car that was very rusty and packed with dirt. The fourth require drilling after it snapped. Luckily, it snapped where the shoulder met the threads instead of right at the head.
 
I have a 1275 Bugeye with the original final drive (4.22) and it has been fine, except the engine tends to rev higher than is perhaps good for a 35-year-old engine in a 50-year-old car, so I am in the process of replacing it with a 3.7 final drive, but not because I have to. I get quite enough acceleration (0-60 in 6.2s) when I drive my other more recent LBC (or is it actually an LGC).
 
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