Carb Choices - Stick with or Change(Z-S to Holley)

ChasR RR Helper motivation Posts: 10,192 Club RR Member Number: 170	Carb Choices - Stick with or Change(Z-S to Holley)ChasR @chasr Club Retro Rides Member 170
	Oct 1, 2011 9:15:31 GMT Select Post Deselect Post Link to Post Back to Top
	I have finally got the Stag running much better than when it came to me. It is pretty much running on all 8 nicer than before, and it can move. It's still not pulling as well as it could, but before it was dreadful wheras now it can actually be driven. (Ignition side is now fine (New leads, cap, plugs, dizzy is advancing fine and dwell angle checks out OK). Further investigation shows all not to be well with the carbs. Whilst one of them is working fine (and doing more work than the other; read on) the other carb seems to have a habit of losing its dashpot oil (topping that up previously transformed the running). Furthermore the linkages have alot of play present and will need either replacing, adjusting or both (The second carb will not start to open a while after the first one does. To top it off I then found I have some leaky rubber carb gaskets. Before I go and get a few new bits for the carb (a rebuild kit?, linkage ends, rubber carb couplings) I figured I could go with a Holley 390 which is said to bring a number of benefits to the game(On the Stags the stock manifold is used with an adaptor plate on the inlet manifold). My question is, would you persevere with the Strommys or go straight to the Holley? FWIW, it is currently on twin Zenith Stromberg CD175s.
	~~'72 Mercedes W108 280SE 4.5~~ '79 Honda NC-50 '03 BMW M3 Coupe '08 BMW E91 325d M-Sport Touring Pre-LCI '16 Yamaha XSR700 My car history and exploits: leylandlegends.com

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jrevillug Posted a lot Posts: 3,520	Carb Choices - Stick with or Change(Z-S to Holley)jrevillug @jrevillug
	Oct 1, 2011 10:08:06 GMT Select Post Deselect Post Link to Post Back to Top
	IMHO, go for the holley. Zenith Strombergs are lovely carbs - when they work. When they don't they are a whole world of pain. Your sounds as though they need a full rebuild, including throttle spindles and bushes in the bodies. They are probably the top-adjust model (sealed underneath) which adjusts using a special too through the top of the carb. This model is great for not leaking petrol (unlike the bottom-adjust models) but they do lose dashpot oil through the needle adjuster - and I understand sealing the adjuster is quite fiddly. OTOH, the Holley will need jetting properly. But, once it's set up it won't need much attention - the occasional adjustment of the idle speed and mixture - while the stroms will need regular balancing etc. I don't suppose the Holley will be hugely more expensive than a complete rebuild of the stroms either.
	Caution: As the buoys marking the shoals are often out of position, mariners are cautioned to be on their guard when navigating these shores 75 Imp 72 Clan - What? An update? Never!

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ChasR RR Helper motivation Posts: 10,192 Club RR Member Number: 170	Carb Choices - Stick with or Change(Z-S to Holley)ChasR @chasr Club Retro Rides Member 170
	Oct 4, 2011 10:05:04 GMT Select Post Deselect Post Link to Post Back to Top
	It seems you may have been right Jrevillug... FWIW, they are indeed the top adjust model. I have the tool, but am unsure on how to use it. I guess I hold the outer part down onto the piston whilst I turn the allen key? Yesterday I had a bit of a tinker with the carbs. The wear out of the linkages has now been adjusted out so both carbs open in sync. I guess now I shall be balancing them and adjusting the mixture (ATM they are too weak IMO), but with the issues this shall be tricky. As another blow one of the carbs (leaky dashpot item) has play in the spindle (side to side and up and down (to a lesser extent) (I'm not sure if I can see the play but it can be felt, that's for sure). The RHS carb is better but still not quite play free IMO. I'm guessing this would require a machine shop on the case or could I ream the carbs at home? Or can I get away with a little bit of play. I wish to retune it as it is a bit of a pig to start when cold unless I use pretty much all of the choke (once warm it will fire up very easily). I've been doing the costs. If I could do it all myself, it would be around £200 difference between getting the Holley or refurbing the Zeniths (and getting new couplings etc.). If I need someone else to machine them (could a garage do this?) then of course that price differential would change. The Holley apparently comes as a plug and play item for the Stag if I go new via certain stocklists, so a rolling road may not be an issue. Sorry for all the questions but previously I've been quite lucky on carbs and I have only really dealt with SUs! The 'B came with a refurbished set (and as such were a doddle to tune/balance), and my second engine for the Midget also came with refurbed carbs. Hmmm, HS8s....
	Last Edit: Oct 4, 2011 10:06:03 GMT by ChasR ~~'72 Mercedes W108 280SE 4.5~~ '79 Honda NC-50 '03 BMW M3 Coupe '08 BMW E91 325d M-Sport Touring Pre-LCI '16 Yamaha XSR700 My car history and exploits: leylandlegends.com

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