stressed Posted March 30, 2018 Report Share Posted March 30, 2018 Anyone got a set of 45 webers and manifold for a 4 engine for sale Doing a fast road rebuild and fancy trying some Cheers Stressed Quote Link to post Share on other sites
david ferry Posted March 30, 2018 Report Share Posted March 30, 2018 I may be able to help with a pair of manifolds. No carbs I’m afraid Quote Link to post Share on other sites
Den T Posted March 30, 2018 Report Share Posted March 30, 2018 You do not try webers unless your engine is ready and up to spec or you will waste your money. Quote Link to post Share on other sites
Alec Pringle Posted March 30, 2018 Report Share Posted March 30, 2018 Agreed, you build the engine to suit a specific Weber installation, or an SU, or an Amal, or whatever . . . . . don't just start chopping and changing carbs, it doesn't work like that. Cheers Alec Quote Link to post Share on other sites
Tom Boyd Posted March 30, 2018 Report Share Posted March 30, 2018 Seeing as you are building a fast road engine, Weber’s are a great choice! Make sure you get the correct 45’s though..... I can only help you with new ones Tom Quote Link to post Share on other sites
Den T Posted March 30, 2018 Report Share Posted March 30, 2018 Not required for fast road use. Quote Link to post Share on other sites
Tom Boyd Posted March 30, 2018 Report Share Posted March 30, 2018 Not required for fast road use. Neil/ntc That’s your opinion and that’s great. It’s down to whatever the owner wants, no one else’s Tom Quote Link to post Share on other sites
graeme Posted March 31, 2018 Report Share Posted March 31, 2018 I believe that Weber 40s would be better than 45s for a fast road engine. Cheers Graeme Quote Link to post Share on other sites
TriumphV8 Posted March 31, 2018 Report Share Posted March 31, 2018 The bigger the chokes the more the setting becomes enforcing. If you are an expert you can set the big carbs with big chokes properly. The only disadvantage will be that the engine accepts full throttle opening only at higher revs. So 45 is a choice on cams around 290-300 degrees on with the TR4. That is something the driver learns to compensate while the engine pulls strong also at part throttle and there is a point of throttle position at low revs that should not be crossed. Power will decrease and engine misfires. The point is found very quickly by a sensitive driver and takes a bit to keep the right foot under control even under stress. That is one big advantage of EFI: You have the largest chokes, larger than Weber can employ and still perform well under full opening at low revs. Quote Link to post Share on other sites
openroad Posted March 31, 2018 Report Share Posted March 31, 2018 Hey Stressed, I hope all is well... I have sent you a PM. Cheers, Conrad. Quote Link to post Share on other sites
Paul Hogan Posted March 31, 2018 Report Share Posted March 31, 2018 some years ago when experimenting with carbs it was found that the Weber 42 was the optimum size for power on a 4 pot tr without going crazy on other mods like steel rods and cranks etc. - but 42's are like hens teeth! Ultra rare. As I'm sure Alec will agree, a lot of guff has been written about tuning engines for 'fast road use' when in fact most drivers don't even exploit the power they already have under the bonnet. But as Alec, say's, its no good just bolting on a new pair of carbs and then expecting starship performance to suddenly appear. It just doesn't work like that and all you will doing is throwing money away and being disappointed with the result. My advice is to think about what you are trying to achieve and then start by improving the engines breathing, starting with the exhaust manifold and the rest of the system. Think about it- if you can't get the gas out of the ( exhaust) system more efficiently there is no point in trying to cram more gas in at the other (inlet) end. Hoges. PS On a road car, 2 inch SU's will probably work just as well on a road car and be cheaper than Webers. ( Just my opinion though Tom! ) Quote Link to post Share on other sites
stressed Posted March 31, 2018 Author Report Share Posted March 31, 2018 Thanks for all the good advice The 4 is undergoning a full nut and bolt rebuild so I thought I'd give the engine a bit of poke The comments on just bolting on a set of carbs is well noted so this is the spec up to now Not wanting a full on race spec just something to make you grin on a Sunday morning All rotating components have been lightened and balanced 89mm piston and liners to take it out to 2290 cc 7lb removed from flywheel Crank rebound and genuine +10 OEM shells 280 degree Kent cam Gas flowed skimmed high port head Updated followers Full extraction manifold and system + carbs to suit hence webers etc Cheers Quote Link to post Share on other sites
monty Posted March 31, 2018 Report Share Posted March 31, 2018 Thanks for all the good advice The 4 is undergoning a full nut and bolt rebuild so I thought I'd give the engine a bit of poke The comments on just bolting on a set of carbs is well noted so this is the spec up to now Not wanting a full on race spec just something to make you grin on a Sunday morning All rotating components have been lightened and balanced 89mm piston and liners to take it out to 2290 cc 7lb removed from flywheel Crank rebound and genuine +10 OEM shells 280 degree Kent cam Gas flowed skimmed high port head Updated followers Full extraction manifold and system + carbs to suit hence webers etc Cheers Hi Stressed, That is pretty much the spec. I have on my 4 except for the 89mm pistons/liners. Built by Racetorations with 45 Webers it gives around 140bhp @ the flywheel compared to the standard 100 or so. I have a similar spec. 4A without the Webers which gives around 15bhp less. I have found the Webers to be fine with a steady tick over @ 1000 rpm, no flat spots & a good torque from the engine as long as you keep it 'on the cam'. Not a huge difference from the 4A but worthwhile. I get around 25mpg compared to the 4A with SU's giving around 29mpg. Cheers. Quote Link to post Share on other sites
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