hi all. My track mk2 has an ABF with twin 45 webers. Its currently running KR cams (according to the bloke I bought it off). Though it may only be the exhaust cam. The head has been ported, flowed, triple angle valve seats. However, I did expect it to rev more than it does. it seems to run out of puff around 6500. Would different cams help here. I must admit I am a leccy by trade so all the mechanical stuff is a bit over my head. I know i will probably need a full RR setup to adjust fuelling etc. Just after some advice if anyone has any ideas. Thanks Richie K
The carbs were set up professionally for the ABF engine (so i was told), so I have to assume they are optimised. I'm struggling to find anywhere near me that can do Webers and have a rolling road.
Never assume Richie...even some professionals can't set up carbs properly. As Jon said...first off check the choke size...36mm is std issue in 45's tho they could have been changed. What inlet manifold is it on...short with a poor bend in it or long and straight?...if the manifold drops down from the carbs to the head it's a poor flow type which won't be helping. Does it have filters?....if so and they're sock type take them off and throw em away...they're total junk and get sucked against the trumpets under load, the pores close up and the engine gets starved of air and goes mega rich..such a great invention sock filters. If normal filters are fitted make sure they're clean. Are the carbs right in front of the radiator?...drawing warm air in direct from the rad won't help. If the carbs are direct in the airflow with no filters that's also a no no...the air buffeting at speed upsets the signal to the auxiliary venturi and screws up the fueling that "may" have been set up ok on a rolling road. Check your getting full throttle...missed by many a tuner. Check the fuel pressure...3.5 psi is what you need...3 is ok. Cam timing...worth checking...tho they normally flatten off around 6k if its out. Is there a good strong pulse coming from the exhaust on idle or when the throttle is blipped...lots of so called performance exhausts are rubbish. I'd check all the above before you look at changing cams.
Sorry about the MASSIVE delay in replying to this. I am now back as one with the car and so looking to sort the bits out. The filter I have are the K&N type oval filters. With 2 feeds from the bumper for air. I'm definitely getting full throttle, I've checked that. Fuel pressure is set at just over 3 psi Exhaust sounds right at idle and on throttle. To be honest, the car feels right for std cams I'm tempted by some larger chokes, a set of 288 cams, HD valve springs and a RR session with some different length ram pipes to play with.
I would start with the RR session, then spend the bucks on bits. Then RR it again. The RR may throw up all sorts of issues, such as not getting enough ign advance etc etc Jon
Good plan. Get a good starting point! After doing a bit of reading, I do fancy a nice revvy valver though! Need to find me a good RR tuner near me.
Go to a RR with carb speciality - they will have a selection of jets etc and (at extra cost) will optimise the carbs rather than simply tune the engine with them.
It looks like you have a short kicked up manifold going by the height of the carbs against the cam cover and the gap between the filters and radiator. They're pretty poor for flow compared to a straighter manifold and you wont be getting the best from the carbs or any cams with it. I'd look at changing that first and getting the inlet length right...260-265mm is the aim from manifold/head face to trumpet tip. Carbs are 118mm long, misab plates are 5mm, so the rest needs to come from the manifold and trumpets...normally 65mm trumpets with a 75mm inlet manifold or 40mm trumpets with a 100mm manifold. If the chokes are 36mm start the jets at 145-150 mains, F11 or F16 emulsion tubes, 175-180 air's, 50F8 idles, 35 pumps. If 38mm chokes then change the mains to 155's and the airs to 180-185...all others stay the same....fine tune from there. Set the idle mixture screws 1-1/2 turns out from fully in and set the balance and idle speed from there. Make sure no warm air from the radiator can get into the carbs. 288 cams are a bit too wild for the std C.R....i'd go with Newman 272's or Piper 285's (274/276 duratrion). The head could still do with a decent skim though...288's need a C.R higher than ideally possible with just a head skim...i.e raised crown forged pistons. Looks a nice car.
Thanks for the info. I'm always learning about carbs, as i've never used them before. I'll have a check of the inlet length next time im at the car. I've just got 2 wide ducts form the front bumper to the sides of the filters. Not sure how else to isolate them from the rad'? The Head has been skimmed, flowed etc. If i get the carbs all set up nicely with a good manifold, trumpets etc. Would they all need setting up again if I then fit some cams? And am based in Lincoln, if anyone can recommend a good Carb RR tuner Thanks Richie K
2ish hours away. Not too far. I'm hoping to get all the new mechanical bits bolted on over winter. Cams, new manifold (if required), new throttle linkage etc. Then get the pro's to pick the trumpets, chokes etc and get it running sweet! Hopefully a little project for me! I may pester you knowledgable guys with more questions, as this is all new to me. Hope you all don't mind Richie K
Just found a better pic of the manifolds. Are these a you suspected? (Short kicked up). Thanks Richie K
