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HD8 Carburetor rebuild help

AUSMHLY

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Helping a friend restore his 66 BJ8. Carburetors were really in bad shape so we sent them to SUCarbs.com, Dana Britton. What a mistake. Seriously don't use this guy. The day after we shipped them, my friend found his Yelp reviews, all negative, one star. One person had to get the police involved and sued him in small claims. Lots of negative talk on the MG forums about him. So I contacted him the next day by phone and said we changed our mind, please don't open the box, send them back, we'll pay your shipping cost. He said, no problem, he'll send them back. During the next week, I sent him 3 more emails, so I'd have written proof, pls don't work on them send them back. No replies. Long story short, he worked on them. When we received them, we were aghast at how bad the work is. We took them apart because tumbling media was falling out. We found he didn't take the banjo nuts off, and found the inside rusted as was the screen and full of tumbling media. He didn't replace the jet needle, the pin and spring assembly is frozen closed, most original springs were compressed and weren't replaced, etc etc. Now the battle to get my $400 refund (hopefully Paypal will help and band him), being he's not replying to my emails, text or phone calls. How does he sleep at night.

I've used Joe Curto in NY, but he's booked months out. Can anyone recommend a professional rebuilder? How is Apple, British Car Specialists, Healey Surgeons? Any other company/person?

I recently acquired "The SU carburetor workshop manual" and have studied it. I may be able to rebuild these with the moss kits. However I'm unclear about the throttle shaft parts. Joe Curto has a video that shows on each end of the teflon wrap is split O retainer ring. These rings are not available from Moss. Moss sells the "throttle shaft bush" aka as the teflon wrap, only. SUCarbs has the throttle disc, then teflon then metal tube with a cork seal over that. It would appear that the teflon will misalign at the disc because there is no spit O retainer ring for it to butt up against. Moss does not list cork as a seal. Was cork used in the past? Should it be used? What is used in place of it? See photos of the terrible job Dana did and a photo of the throttle shaft set up.

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5jE5MgJATTCFayzxdQV8cg.jpgtn8pNUjtTi66xesqopZhlQ.jpg8VV+61X9TlGr4AtiZpQ53w.jpg
wtvV4BoGQDyR4sLOIwGQZw.jpgO%yYMyUFQr+0DqZgRrS9eg.jpggO11jfhESiOzVkFQqLnENQ.jpg
 
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Wow ... where to start? The banjo bolts, filter and springs are rubbish--toss them (Moss has them, not expensive; keep the bolts if you decide to try yourself). HD8 carbs have no cork on them anywhere--that I can recall or the catalog shows--the teflon 'bush' goes between the two split rings. No need to replace the throttle plates unless they're worn, and if they are the bores might be as well (if they are, the carbs may not be salvageable--inspect closely). A major wear point is the throttle shafts and/or the bushings; Apple did a decent job re-bushing mine years ago (you need a special reamer). The float lids look bad, but I think they're usable; I'd use your favorite rust remover--naval jelly works pretty good--and file a couple notches on the old banjo bolts perpendicular to the threads to make yourself a homemade thread chaser. If the float lids clean up and look usable you'll save about $100/ea. Test the floats in hot water to see if they leak.

EDIT: DO NOT media blast the vacuum pistons or the dashpots; these are finely machined and require exact clearances for the carbs to work properly. Actually, I don't think I'd blast any parts since you might remove too much or the wrong material.

The needle on the right is badly worn; that means the jet wasn't centered properly, and the other looks scored--replace (obviously). Also get two new brass set screws; if they don't secure the needles properly the needles can drop into the jet causing all kind of fun and consternation (running on 3 cylinders). I use blue threadlocker on the screws. Follow the book instructions for setting the needles the proper depth in the vacuum piston. IMO, the HD carbs are a lot easier to rebuild than the other types which require a seal pack around the jet (including cork). You'll need to center the jets in their collars; it's not strictly necessary but the little kit (Moss part# 386-300) has proved useful and worth it to me.

I'd take a shot if you've got the time and patience. Moss has a DVD, but the manuals and whatever you can find on YouTube should do the trick. As long as you don't damage anything expensive you can send them off if you throw in the towel; BCS is closest to us but I don't know if they rebuild carbs routinely.

Side note: About a year ago, I put a new diaphragm jet in denatured alcohol which is, according to the label, 'at least 50% ethanol' and other nasty stuff and the jet is still clean and the rubber is soft and supple:

JetInEthanol.jpg
 

steveg

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Yes, like Lin, I had my HD8 shafts overhauled with Tom Bryant's custom delrin bushings. My carbs now idle reliably at 750 which they never did before. Bryant has developed a custom boring bar technique which will give an absolutely straight bore through the bushings. He explains that a reamer will only follow an existing bore, which may be crooked. IIRC he has done 2500 of these bushes since the '90s without a comeback. He gives a lifetime guarantee.

He also does complete rebuilds for a fixed price.

I had previously rebuilt them with the flexible PTFE bushings and experienced some improvement in the erratic idle, but not enough.

Can't recommend Bryant highly enough.
 
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AUSMHLY

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Randy, thank you for providing photos, so helpful. Things I noticed and questions.

1. Pin spring assembly. Moss shows a retaining clip, metal washer, rubber washer. I didn't see a rubber washer in your photos? When pushing up the pin to test the carbs, is the rubber and metal washer suppose to rise also?

2. Moss sells the teflon bush. Did you not use that? Looks like you used a cork, grease, spring and a metal cup?

3. You marked the throttle disc. The edge is beveled as how to install it. Is there a top or bottom? On mine, I've tried both ways, and don't see any difference or hear any clink difference. I did notice that no mater how it's installed to make the solid clink sound, I can see a little light around the edges (couple sheets of paper thickness). How close is the fit suppose to be around the perimeter?

4. How do I tell on my carbs if my throttle shaft/disc/bush needs to be replaced? My shaft spins freely. I believe I have the standard shaft with the teflon bush. I've taken the shaft out, no pits, no scratches, feels smooth. How do I know if it the teflon bush needs to be replaced? What determines if any of those parts needs replacing in a rebuild.

5. How to determine when to replace the jet needle? They come in the regular rebuild kit, so makes one wonder if it's to be done or just in case you need to do it.

6. The jet assemble I believe should be replaced being it's rubber. What about the springs that come in the kit. Why do they need replacing?

Lot's of questions. Seems the more I get into the rebuild, the more I question the details.

IMG_2184.jpgIMG_2183.jpg
 
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AUSMHLY

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I'm still finding areas where SUCarbs did not do what his website said. He states, "S.U. Carburetors include new jets, needles, piston springs, float valves, float bowl grommets."
He did't replace the needles, piston spring. (Question, how ever he cleaned everything, seems he did something to the springs. They look different, like they've been dipped in something. They have a rough feel, etched look and no red paint. Is it ok to do that. Did it affect the material? Mine have red paint at the top of the springs. Now I question because there's no paint, are the the correct springs?

What is a float valve? What are float bowl grommets?

He also states "Floats are cleaned and then precisely weighed."
Do these look cleaned? Think he weighed them, lol

2Ihqi5KmSv6kYJ%wrpKupw.jpgGacIitcNQWeuOBkwVhLYwg.jpgfullsizeoutput_1584.jpg
 

steveg

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Ausm - IMO you should not worry about which parts to replace. Rebuilding the carbs is a fair amount of trouble and you don't want to revisit it. Just buy the master rebuild kit and install all the parts.

This book, available from Moss or Amazon, has a step-by-step rebuild with pictures, including the procedure for inserting the PTFE bushings (pp42 - 43). However you will need the little rings in order to do so. You might be able to buy the rings from Joe Curto. If the piston springs don't look like yours buy new ones. Submerge your floats in boiling water and see if any bubbles appear - if so, there's a leak.

screenshot.1735.jpg
If you buy the rebuild kit from Joe Curto, then you'll have him as a resource for questions.

If you can't find the little rings anywhere, still suggest you have Tom Bryant rebush the carbs and fit the shafts. He will drill and fit the levers. All this for a very good price indeed.

Joe Curto has lots of videos on everything SU.

Edit: your floats and springs look pretty rough. I'm running the nitrophyl floats - they weigh exactly the same in grams.

My carbs had about the same amount of daylight around the butterflies when I got them centered. They work fine so I think this must be normal.

Edit 2: according to the XKs Unlimited catalog, the cork, spring and metal cup shaft seal is used on series 1 XKE's HD8s. I'm guessing it was superseded by the rolled teflon seal design used on the BJ8s.
 
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AUSMHLY

AUSMHLY

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What Healey had "start carb - auto choke" ?
Joe Curto mentions this in his youtube video, time line 2:48
[video]http://joecurto.com/hd-float-bowls[/video]
 

steveg

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What Healey had "start carb - auto choke" ?
Joe Curto mentions this in his youtube video, time line 2:48
[video]http://joecurto.com/hd-float-bowls[/video]

Used on many Jags. Briefly used on Healeys. See Moss page "Twin HD6 Carburetors late BN4 to BN7/BT7" - AUC935 drawing
 
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AUSMHLY

AUSMHLY

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School is in session. Throttle shaft 101.
Help please.

The throttle shafts are not pre drilled for the lost motion lever and throttle stop. (Assuming some shafts fit different carburetors, those holes are drilled in different places)
How does one drill those holes accurately? I don't have a drill press, which I assume would be the right equipment.
Like most people, I have a hand drill, some bits and a vise. I would assume hole placement, size and angle are critical.

I've read about having professionals replace the throttle shaft because the carburetor may need to be reamed?
What evidence would require reaming service?

I'm assuming I have the standard size shaft. I'm assuming the shaft is in good condition, the teflon bush may have worn down and needs to be replaced, and that's it.
Why would the shaft need to be replaced if it's rotating within the teflon bush.
How does one tell if the shaft simply needs to be replaced and a new teflon bush applied and that's it.

Since I'm asking, why would the disc need to be replaced? What wears out being they are screwed in place and rotate. Do the brass edges wear from contact with the aluminum carb body?

Being I'm assuming a lot with my questions, I'm assuming owners who tackle a full rebuilding of their carbs, buy the master rebuild kit, which contains the blank shafts can do all the work. Or, do most send the carbs out just to have the throttle shafts installed...because like me, they don't have the equipment or knowledge to do so? But, if no reaming is needed just, original shaft is ok, swap out the teflon bush. Or replace the shaft, then it's down to how to drill the holes. Installing the teflon bushes, the clip rings and the shaft. I removed the shaft, saw worn out teflon bushes, looked at everything and put it all back together, as a trial, can I do this. Not that difficult. Pat yourself on your own back, that-a-boy!

This all started because of the origin of my post. A carb rebuilder did a really bad job on my friends carb. We took everything apart to see what he did and didn't do and all these questions came up. So I removed my HD8 to compare to his butchered HD8. Ya know, since I have my HD8's on the bench, I should look into their wear. Ah, thank goodness the guys on the BFC like to read a lot of questions focused on a throttle shaft.
 

John Turney

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School is in session. Throttle shaft 101.
Help please.

....
Joe Curto has a good video on how to tell if you need to replace the shaft. [video]http://joecurto.com/installation-of-shaftsbushing-in-hd-car[/video] Basically, if you can't feel wear where the shaft rides in the Teflon bushings, it doesn't need to be replaced. The discs may wear a bit at the point where they touch the aluminum body just before entering the shaft. Otherwise, not really.

If you replace the shaft, a drill press should be used to drill the hole for the throttle stop.
 

steveg

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If you're going to do your own work and before doing the work, Suggest spending time watching Curto's videos and reading the SU overhaul postings on Tom Bryant's blog (links above).

Addendum: In Curto's excellent video on HD8 bushing/butterfly/shaft install (John's link above), he states the cork seals were used on the 3.8 E-types and the teflon seals on 4.2 E-types and Healey 3000s.

His H-type video shows removing throttle stop and drilling new shaft:
http://joecurto.com/installation-of-shaftsbushing-in-h-type
 
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AUSMHLY

AUSMHLY

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Guys, I appreciate all the help, guidance. I've recently talked to Joe Curto and discussed my coarse of action. My friend and I are going to redo the poor workmanship Sucarbs.com did. Once we clean all the parts, I'll install the new parts Joe sold me. His feelings are the throttle shafts are ok and to replace the teflon and put back the small split rings Sucarbs threw away (which need to be in place to keep the teflon in place.) Example of how poor a rebuild Dana did, he put the teflon in with out the split metal shims (now they are free to move, will start wearing at the disc edge). He put the unlubricated cork seals over the larger metal shims (not suppose to do that) which created shaft rotating resistance. Because teflon is used, no cork needed, it's a different setup. Cork is used with a sping and metal cap. How is this guy still in business, taking advantage of unsuspecting owners, as so many of his bad reviews on yelp, and many British forms say. Well, from this I've learned a lot about HD8's and that makes me a bit more comfortable with them. I've now advanced from tuning them to knowing what it takes to rebuild them.
 
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