Line drilling carb bodies for new shafts

Last night, I figured out a simple way to drill out the carb bodies for new shaft bushings.  I got some 5/16" ID and 3/8" OD bronze bushings from McMaster Carr.  I have a reamer that I purchased, but the particular reamer that I got was tough to use - the flutes were cut at the end so that pulling it back through the carb by hand was very difficult.  Frustrated,  I started thinking of how else to do this.  I thought of making a jig for my lathe - which is probably the best long-term solution - but came up with a way to do it on the drill press.

I took a piece of 1" thick maple and drilled a 5/16" hole through it.  I counterbored a hole for a bolt head on the back.  I then glued (using gorilla glue) a 5/16" bolt through the hole so that it when the board was sitting on the drill press table, the bolt shank was standing like a flagpole, over which you can slide the carb bodies through the thottle shaft holes.  Cut the bolt off so that it is just long enough to pick up the very bottom lip of the "upper" hole.  Be careful to square the drill table to the bit, then position the fixture so that the tip of the bit touches the middle of the new post you made.  Clamp the board to the table in this position.  Then, with the carb body in place, drill you centralized 3/8" hole - or actually use 23/64" first to make sure you get a tight fit.  Then, flip the carb body over and repeat.  The holes you drilled will have a shoulder where the drill did not go all the way through the aluminum, as the bit will stop when it hits the steel post. 

I'll post pics today.  I did a pair of carbs this way, and it worked very well.  Pics to come.

Transmission Day - Part Deux

A few weeks ago, I had Geoff and Tom (JackAlley and Team Evil) come up for a day of transmission and carb rebuild workshop-training sessions.  I showed Geoff how to rebuild his carbs, and the the three of us figured out how to take apart my transmission, but we never got it back together.  This Sunday, Tom is returning to help me reassemble the transmission and hopefully get it, and the engine, back in my car!  Then I'll be driving again - whoopee!  BUT, I still have to pull my front shocks and send them to Worldwide to get them re-built, as they leak mightily.  I am motivated now to do that, however.  Other winter projects left undone as yet include replacing the drivers' side oil seal on my rear axle/hub.  If we get time, maybe Tom can help with that, too - as it kicked my @$$ and bent my cheater bar the last time I tried.

Stay tuned to this channel for further updates.

New Carb Stub Stacks

I am so excited - I just got my new carb stub stacks from Steve Ash in the UK.  He is on the MGA cars BBS in the UK and was nice enough to have about 50 sets made up for the board members that wanted them.  These promise to give about a 5% to 7% boost in power, and better throttle off-idle response due to improved laminar flow on the intake to the carbs.  They are machined aluminum, and very nicely turned out.  I am thinking that I can use one to make a casting mold out of plaster for additional copies - but I think I'll take one to a local machine shop and get a quote on making further copies - that way any time I rebuild a set of carbs, I can include a set as an option.  When I get the transmission and engine back in (this Sunday I hope - more to come on that) I will be anxious to give them a try!  I'll post a full report below when the time comes!  Woo-Hoo...very cool!  Thank you Steve!

DIY zinc plating of small parts

Many of the parts on my carburetors were in good shape, but the plating had worn off and they were rusty.  I think the original plating was cadmium.  You can buy easy-cad plating kits from places like Caswell and Eastwood, and that is certainly a good - though expensive - solution.

I decided that, with the internet as my teacher, I would try to plate small parts myself using a home-brew kit.

Care and Feeding of SU H4 Carburetors (used on the MGA 1500 and 1600)

SU carburetors work very, very well.  Replacing your SU's with a Weber is normally not an "upgrade" - it's an admission of defeat.  A Weber carb is harder to dial in and will likely leave you with throttle lag and a lumpy idle.  SU's have a reputation for being leaky and requiring too much maintenance, but that is undeserved - set them up properly and then leave them alone.  They only have about three moving parts, and none require fiddling with - and if they are set up wrong, fiddling won't help!  Fix your SU's and you'll be happy.

I just recently rebuilt the third set of SU's since I learned how by rebuilding my own several times over the last couple of years - I kept doing it over as I learned more and I wanted to do it right.  I find that I really like this aspect of working on these cars.  Though I am not about to put Joe Curto out of business (he is the SU carb God and has rebuilt thousands of them - and I do buy parts from him), I think I will start working on carbs as a "side project".  I am already looking for any old sets that are available cheap - let me know if you have some non-working carbs you'd like to sell.  A "new" set from Moss motors costs about $1500, and a professional rebuild is about $300 or more per carb (MGA's have two).  I can generally rebuild a set for about $150/carb in parts - so those costs are not really out of line with the labor required, and the tools you have to buy.  I now have the reamers and taps and dies that I need.  I also figured out how to strip and zinc plate parts at home (to be a separate post) so that good parts don't have to be replaced just because they're rusty.  However, if you are interested in how your carbs work, and want to be able to service them yourself, there is no reason that you can't tackle this job!  This is by no means a definitive treatise, and I am only familiar with the type of SU's on our MGA's, but for my own benefit, and maybe - if you are reading this - for yours, I wanted to write down a bit of what I have learned.

Introduction to my blog!

March 20, 2012

I have been restoring a 1957 MGA roadster for about 10 years or so.  I bought it around 2001, and finally started work on it about 2005 or so.  I finally got it running and more or less "done" in the spring of 2011.  The restoration is never really done, though - you can always find a project!  (Unless you have a 10 point concours car that you are too scared to drive, and where's the fun in that?)  I love the car, it's really fun to drive, and simple to work on.  A few years ago, I had a blog that I had been keeping - a "restoration diary" - but when Fairpoint took over from Verizon, I lost access to that page.  Here I will try to record some interesting things as I continue in my MGA ownership journey.  For example, I have learned a lot more about SU carburetors than I ever thought possible, and should probably record some of what I now know for my own benefit, and for any others who might be interested.  I spend a lot of time on the community boards at www.mgexperience.net, www.mgcars.org.uk.  There are many MGA websites, but www.MGAGuru.com is the place to start anytime you are looking for anything MGA related (thanks Barney!).  Glad you stopped in - drop me a note or feel free to comment!

JIM in NH