Exhaust Silencers?

[GSouthee]

HI just what are the 2 silencer things by the manifold and are they effective or restrictive?
   
   Cheers  Gary

[GSouthee]

Hi, well it seems that I am not the only one who has no idea as to the use of the 2 silencer type cans judging by the views and lack of response.
   
   Still I am sure someone will let me know in due course.
   
   Gary

[Jam2]

On a two stroke engine they might be expansion chambers which have the effect of sucking out the exhaust gasses and thus pulling in the incoming mixture. I can't quite see how that would function on a four stroke!  So no help from me.......

[GSouthee]

Hi Yes thats what I thought, it has been suggested that they are pre silencers, however not sure what that would be. Mainly I want to try and find out is whether they are restrictive or nor not. The AC engines Ace seems to have 6 branch manifolds without these so maybe not all that much use really.  Still will keep on trying to find out before I consider  a 6 branch manifold to improve things.
   
   Cheers

[administrator]

The story is that Charles Hurlock had a theory that noise went sideways and they were his solution to the problem.  Mine are blanked off and it doesn't seem to make any difference, perhaps unsurprisingly.

[Robin A Woolmer]

It would be interesting to know what comparative testing AC did!
   Robin
   Apparently Rolls Royce had something similar which may have been the reason AC did it!
   Robin

[GSouthee]

Hi Admin.
   
   My thoughts were perhaps and expansion chamber type set up, but then I thought that going sideways and then back again would upset flow. May just take them off.
   
   Does anyone do a suitable twin 3 into 2 type manifold for the 2 litre saloon or has anyone tried one.
   
   I will do some testing re sound and MPG with and with out the twin cans, first.
   
   Cheers Gary

[Robin A Woolmer]

The Vintage Engines had a cast iron pair of manifolds which probably had better gas flow, & did not have the side silencers!
   
   Robin

[GSouthee]

Hi Robin
   Cheers for that, however will probably go for 6 branch or twin 3 into 2 type banana bunch type.
   
   Cheers  gary

[3.5 Pints at the Bar]

The manifold mounted silencers, are just that: Silencers. Each pulse of exhaust expands into the silencers, dissipating noise into the insulated chambers. As the pressure drops in the pipe, gases flow back out of the chambers. By having the silencers at right-angles to the pipe, and opposite each other, I believe it minimises the effect of reflected pressure pulses reaching the exhaust valves (the effect that Jam2 was referring to above). It needs to be minimised because those silencers are too close to the engine, and the manifold branches are unequal lengths. The down side to these silencers, is the large amount of heat released under the bonnet.

[GSouthee]

Hi 3.5 pints
   
   Yep definitely gets some build up. I have acquired a set of cast manifolds with out the cans so I will be trying these to see what happens before working on a set of extractor type manifolds. Also need to lose the big bypass oil filter that is attached to the manifold for a full flow one mounted down low away from the heat.
   
   Cheers  G

[3.5 Pints at the Bar]

Full flow filtering is certainly a wise move. I noted your mention of installing electronic ignition, as I know of an AC with the "123 Ignition" distributor (with great results). It will be interesting to monitor how well these perform. My wood frame drawings were used in the restoration of your AC in the 1990s. Sadly, I only discovered your AC lived near me, when it came up for sale this year! Best of luck.

[GSouthee]

Hi 3.5pts
   
   Yes I have the full set and the original letter from you to the chap that carried it out.  I also have read in great depth your website, very interesting and useful.
   
   Yes will be going to full flow filter but need to work out what direction the flow is and how to loop the pipe that runs to the the top of the block into it. Also considering fitting an oil cooler into this.
   
   So far the electronic ignition seems to be performing well covered some 160 miles sunday to and from brooklands and it appeared to run more smoothly, it certainly ticks over smoother.
   
   Will see how fuel etc goes over a longer period.
   
   Cheers  Gary

[3.5 Pints at the Bar]

The main oil outlet from the sump's filter body, is the one pointing to the right of the car, with a T-junction for the pressure gauge pipe. The main feed pipe then goes straight into the block to the main bearings. Full flow filters are inserted in place of this main feed pipe. On most installations I've seen, the 2 connections for the bypass filter were blanked off. On one engine, they had fitted a by-pass pipe, but I would have thought the lack of resistance, would cause too much oil to flow down it, instead of into the bearings.
   
   Robin's AC Engine Project website describes a filter that incorporates a relief valve after the filter, to ensure that the correct supply pressure is maintained. This will need an extra pipe for surplus oil to return to the sump.
   
   I haven't come across oil coolers on the 2 Litre, and am not sure if it would be needed?
   
   There are plenty of electrical/electronic upgrades that one can consider: Electronic fuel pump, electronic control-box, and LED lamps including built-in flashing indicators.

[GSouthee]

Cheers for that. I did think that the one with the pressure gauge would probably be the feed, but was not sure. What exactly does the pipe to the top of the block do apart from running to the bypass filter, as I was thinking of replacing the pipe with out the bypass filter in line as it seem to run back to the pump housing anyway.
   
   Re electronic bits and bobs oh no that what I love about the car its all nuts and bolts etc.
   
   I did speak to robin about his oil filter but it seems to be for his new engine blocks only, he suggested Rod Briggs or get a remote filter housing from Mocal or the like. Now need to see what the thread is on the oil pipe.
   
   Only thought of oil-cooler as read about it in the AC 2litre book tuning and improvement part.
   
   Cheers again and as per website very helpful.