SU Carb rebushing

[german240]

Guys, 

has someone ever tried to rebush the carbs? I know Ztherapy offers this service, However, I would like to try it on my own. I found a comprehensive tutorial here. 

So far I haven't found suitable bushings (brass or Delrin), any advice? Is there any source for new throttle shafts? How have you dealt with worn out shafts/bushings?

Thanks!

[26th-Z]

Tim,

Ztherapy is highly recommended but as you are in Germany, I would recommend looking in England for help.  There is a large Z club and web site ZClub.net

[Namerow]

The author of that linked re-build article really takes SU to task for the use of a brass shaft with brass bearings.  The Hitachi-SU's in the Z use chrome-plated throttle shafts.  Good idea... but they still wear (first the chrome plating wears off the shaft, then the shaft itself starts to wear).  The load on the shaft generated by air-pressure loading on the throttle plate under closed and part-throttle conditions must be huge.

There should be little difficulty in finding a source for appropriate bushes or bearings.  For inspiration, have a look at the Boston Gear catalogue, using this link:

http://www.bostongear.com/products/bearings/molded.html

Note that some SU carb rebuilders replace the OE bushes with seal-equipped roller bearings.  Others (like your author) replace them with either new bronze bushes (oil-impregnated type preferred... ref. 'Oilite') or with an engineered plastic (like Delrin).  If you decide to go with plastic, make sure the type you use is gasoline and ethanol-resistant. 

The roller bearing strategy is claimed to provide smoother action coming off Idle (where the plate and shaft loading is highest) -- and it undoubtedly does.  How much so, I can't say.  You'd need to ask people who've experienced both the bushing set-up and the bearing set-up, back-to-back.

[Patcon]

I would still consider Ztherapy even if I was in Germany. Just might have to get creative with shipping. I think to do it really well you will need some tools unless you have a very well equipped shop. 2 axis clamp table, drill press, reams, source bushings, possibly jets and floats. You will spend half of what they charge just to tool up and buy parts. The other half pays for their expertise and labor, as well as the linkage plating and other misc parts....FWIW

[Namerow]

I agree that the D-I-Y strategy could come with a lot of hidden costs.  It depends on the level of skill and equipment you're starting from. If you can provide the correct-sized plastic bushings, I'll bet you could get this work done quite successfully by a local machine shop for $200 - $250.  If you follow this route, you'll also need to find a supplier of correct-spec replacement throttle shafts.

If you check out some of your country's marque clubs, you may find someone local who does this work on a hobby-business basis (like the guy who did the on-line feature that you posted the link for).  Here in the Toronto, Canada area, I know of at least two guys who provide SU re-bushing services as a hobby business (and at least one of them installs sealed roller bearings rather than bushes).

If you go with the well-respected Z-Therapy in the USA, you may want to consider just keeping your existing carbs and paying them the $200 core charge (you'll see why in a minute).  This would result in an out-the-door price of $880, if I've read Z-Therapy's pricing chart correctly.  Now you have to look at shipping costs.

Z-Therapy's website says that they only ship internationally by way of US Postal Service .  It appears from the USPS website that the largest USPS 'flat-rate' box won't work (12" x 12" x 5.5").  You'd have to go with an oversize, non-standard box.  Assuming a box that measures 24" x 12" x 12" and assuming a shipped weight of 5 pounds (~ 2kg), the USPS online calculator generates a price of $73.80 for their 'economy' delivery service to Germany.  Unfortunately, the fine print for shipments to Germany says that any shipment valued at over $300 requires paperwork from the shipper (meaning that the value of $900 will need to be officially declared by the Z-Therapy).  Later, it says that:

" Germany will not accept any Priority Mail Express International or Priority Mail International insured item valued at more than $500. Items valued at more than $500 will be returned to sender. "

So you would have to use the USPS premium 'Global Express Guaranteed' service (3-day delivery).  For this service, the USPS online calculator generates a base shipping price of $195 for the same 24" x 12" x 12" / 5-pound box.  Add at least $10 for insurance.  Note that I didn't read all the fine print associated with this type of service.  You should.

Z-Therapy will probably add a markup to the USPS shipping cost to cover their in-house packaging and handling costs. I'm going to guess that might be $50.  You'll need to confirm this with them.

When the USPS package arrives in Germany, you'll have to pay customs duties (I'm going to guess 10% on $880) and perhaps/probably your national VAT too (another guess:  15%).

You'll also be paying the hidden costs that your credit card vendor builds into the transaction by way of skewed currency exchange rates.  Add another 2.5% to the ($880 + $195 +$50) shipped price.  Call it $25.

So:  If my estimates are reasonably correct and I got my math right, it's going to cost you about US$1,400 to have a pair of Z-Therapy Hitachi-SU's delivered to your local post office outlet and with all local customs/sales taxes paid. 

[Patcon]

43 minutes ago, Namerow said:

If my estimates are reasonably correct and I got my math right, it's going to cost you about US$1,400 to have a pair of Z-Therapy

Ouch!

That's why I thought creative shipping might be good. Ship it somewhere close and go get it outside of Germany or try to find someone who is traveling and have them pack them in their luggage...