holley on essex advice (scimitar)
Discussion
Hi, first post......... I need some advice on running a 390 holley/swaymar on a essex with stage 2 (big valve ??) heads, tubular manifolds and an apparently well balanced engine.
My position is I have just acquired a 5a scimitar with a crunchy noise from the engine, not sure if it top or bottom job yet. It has an R. S. spec engine built by Robin Rew in 1988 for £586 !! with a new carb at £140. As it doesn’t work I have acquired a replacement engine , however, does anyone know what an R.S. spec was so I can determine if anything is worth salvaging. What kind of carb would be put on this spec? BHP? Ideas welcome
The second part of my request is I have a replacement engine, the above mentioned 3.1 Essex with many improvements ( Is the oil cooler necessary?)
After reading about the 390 holley on this site I am confused as to whether it's overkill for the engine and whether a DGAS will provide enough respiration for the engine.
I don’t intend to redline it every day but want a bit of poke now and then. A few posts suggest a well balanced holley is great for day to day use but others suggest a healthy holley is difficult thing to achieve and maintain.
Is the hassle for a few extra bhp worth the bother or should I stick the DGAS on the 3.1 transplant engine? What kind of output/economy could I expect from both options? Cheers. Si
My position is I have just acquired a 5a scimitar with a crunchy noise from the engine, not sure if it top or bottom job yet. It has an R. S. spec engine built by Robin Rew in 1988 for £586 !! with a new carb at £140. As it doesn’t work I have acquired a replacement engine , however, does anyone know what an R.S. spec was so I can determine if anything is worth salvaging. What kind of carb would be put on this spec? BHP? Ideas welcome
The second part of my request is I have a replacement engine, the above mentioned 3.1 Essex with many improvements ( Is the oil cooler necessary?)
After reading about the 390 holley on this site I am confused as to whether it's overkill for the engine and whether a DGAS will provide enough respiration for the engine.
I don’t intend to redline it every day but want a bit of poke now and then. A few posts suggest a well balanced holley is great for day to day use but others suggest a healthy holley is difficult thing to achieve and maintain.
Is the hassle for a few extra bhp worth the bother or should I stick the DGAS on the 3.1 transplant engine? What kind of output/economy could I expect from both options? Cheers. Si
By RS spec I assume you mean RS3100? The Capri RS3100 was essentially a homolagation special and the engine on the version sold to the public didn't actually offer much more power than the standard 3 litre.
Seem to remember the standard Weber being good for up to around 175bhp. Wouldn't have thought the Holley was overkill on a 3.1 any more than a twin choke on a 1.6. Vacuum secondaries from memory so only acting as a twin choke anyway at modest speeds.
Seem to remember the standard Weber being good for up to around 175bhp. Wouldn't have thought the Holley was overkill on a 3.1 any more than a twin choke on a 1.6. Vacuum secondaries from memory so only acting as a twin choke anyway at modest speeds.
Dont bother,my brother run a Holley 390 carb on a Swaymar manifold
(costa bloody fortune) on a tuned essex piper f/road cam reworked heads full janspeed system etc,it made slightly more bhp at the redline but was total shite to drive on the road flatspots awful fuel consumption, oh and before anyone jumps in, this carb was new with all the proper mods for this conversion inc secondary metering plate and two rolling road sessions,one was carried out at rovercraft(i know a few years ago now) after recommendation. We came to the conclusion(inc rovercraft) the carb is just to big and cannot meter fuel accuratly enough for this small capacity motor,we refitted the 38dgas webber and throttle response was back fuel consumption also,the bhp was little changed with torque up everywhere,the manifold had been matched and ported to the heads but the carb was stock,he sold the swaymar/holley combo and never looked back,the only carb system to use on this engine is the three downdraught webbers as in the original X Pack,me personally i would use 6 bike throttle bodies on a megasquirt system,i have fond memories of this motor it was simply a gem (good torque)if you know how to build and maintain the thing properly,the cologne may have been more free reving but the Essex out torqued it,i could go on but keep that Holley way from the this six it dont work,you can use a 40DFI carb on the stock manifold but thats got to be hard to get now and only increases the power on a tweaked motor,good luck.
(costa bloody fortune) on a tuned essex piper f/road cam reworked heads full janspeed system etc,it made slightly more bhp at the redline but was total shite to drive on the road flatspots awful fuel consumption, oh and before anyone jumps in, this carb was new with all the proper mods for this conversion inc secondary metering plate and two rolling road sessions,one was carried out at rovercraft(i know a few years ago now) after recommendation. We came to the conclusion(inc rovercraft) the carb is just to big and cannot meter fuel accuratly enough for this small capacity motor,we refitted the 38dgas webber and throttle response was back fuel consumption also,the bhp was little changed with torque up everywhere,the manifold had been matched and ported to the heads but the carb was stock,he sold the swaymar/holley combo and never looked back,the only carb system to use on this engine is the three downdraught webbers as in the original X Pack,me personally i would use 6 bike throttle bodies on a megasquirt system,i have fond memories of this motor it was simply a gem (good torque)if you know how to build and maintain the thing properly,the cologne may have been more free reving but the Essex out torqued it,i could go on but keep that Holley way from the this six it dont work,you can use a 40DFI carb on the stock manifold but thats got to be hard to get now and only increases the power on a tweaked motor,good luck.
Thanks for the advice guys. It looks like I'll be using the DGAS, as it's 175 BHP rating is enough for the old engine . The holley sounds like too much trouble to set up and maintain, but swaymar/holley's make good money on Ebay when they come up, so I'll be flogging mine in the near future to pay for the transplant. Cheers.
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