500 domi exhaust tunning

acotrel said:

With bigger ports, the result is usually more power up high in the rev range. Unless you have a short-stroke motor with a light crank, up high is not where you need the power increase - lower in the rev range with appropriate gearing, can be just as good pulling power, and easier to ride fast.

Click to expand...

This bike has a heavy Dave Norrish one piece crank and standard 500 Norton Dommie 88 bore and stroke. Clubmans class rules. Ports were not particularly big. 30 mm carbs.

I'm certain 25 years of porting experience could improve the head now. But it did well in the 2005 2010 period.

And yes it wasn't the easiest to ride. The guy who mostly rode it was called Tony McQueen. In his 40s at the time. Tony actually once beat Aron Slight way back when in Ozzie production racing. So he was a pretty fair rider.

acotrel said:

Does a dyno give a good indication of mid-range torque ? With a heavy crank, an increase in torque sometimes does not reveal itself, until the overall gearing is raised and the bike goes quicker. Normally, if you lower the gearing on most bikes, they accelerate faster - my 850 does not do that. If I lower the overall gearing it does not accelerate faster - the crank always seems to winde-up at the same speed, regardless of the gearing. With 5 gears, you should be able to work with a narrower rev-range.

Click to expand...

A dyno is a machine so tyre slippage operator error etc aside yes the measurement of torque hence hp via the normal calculation will be valid over the rpm range.

But for this particular case this bike midrange as explained above was destroyed by megaphonitis.

Swings and roundabouts. It needed a good rider to get the best out if it.

Maybe one more story. Tony is an H2 guy. He raced his own H2 on methanol at Taupo once same day he rode the Dommie. That H2 produced 80 bhp on the dyno, my Dommie showed 50 bhp. Taupo no 2 circuit is very tight and twisty.

He got better lap times on the Dommie than he did on the H2.

He was not happy. That H2 had 80 bhp. But it was very nasty to ride on a very tight circuit.

Be careful what you wish for.

Exhaust info. Photo attached

Header length 44 inches. ID 1 3/8 in

Megaphone. 15 in long. 3.75 in diameter

Short reverse cone. About 2 in long. Outlet 2.25 inches.

I tried maybe 20 variants on the dyno including straight open pipes. Never tested 2 into one. I beleive they give excellent midrange and could well be the best on a tight track with 4 speeds and other than a top rider.

Last thing. I once put much of this info on the web before and actually got told off saying it was far too much for amateurs and no one went to this level etc etc. Which kind of annoyed me - so if that's your opinion fine I have heard it and don't agree. Please don't say it again. I havnt had a days mechanical training in my life and paid for everything myself. Thinking and reading is cheap. And fun.

Fascinating recent history John. I wonder if Doug Hele's very special 61 TT 500 was similar, not much happening below 5000 rpm?
I would guess that it was as they were getting similar power levels to your bike and the " revs to 8000" ability seemed to be very important to them.

It's surprising that your stock cases have held up to racing. From my reading, stock Commando cases generally did not last very long with such high rev usage, even with a racing crank such as Nourish.
I guess the power levels on the larger engine would be that much higher and the Commando cases are obviously not proportionly stronger.

Correction to my earlier post-
The 88 ss was not rated at 40 bhp.
It was rated at 36bhp (engine) . The standard 88 was rated at 29 bhp.

Glen

johnm said:

Valve timing. I used a PW3 which I understand is very similar to your camshaft. With the head off and a push rod onto the followers measure the lift profile of all the cam lobes using a degree disc on the crank. Plot them all on the same spreadsheet and inspect the overlap. Check the profiles both sides match and that the cam is perfectly machined with the correct timing as published. I fully expect the JS motorsport ones will be perfect but beleive me they are all not like that. This next bit is perhaps a bit strange and not necessary for you but the only PW3 cam I could get back then was a 750 one. A Dommie and a Commando have slightly different piston conrod geometry. Different rod stoke rates. This means a 750 cam installed in a 500 will have valve opening at a slightly different percentage of piston stroke. Now does the JS 500 camshaft allow for this? I don't know. On my Dommie I actually RETARDED the cam about 7 crankshaft degrees to allow for this and picked up significant top end hp on the dyno. Unfortunately it destroyed bottom end below 5000 rpm which could only be regained using very long headers. Obviously you must check this cam retardation does not cause valves to hit the piston. I had the head on and off many times getting this correct. Do not use a vernier on the camshaft. They are not strong enough. Use the chain and sprocket remeshing method which give 5 degree steps. RGM make sprockets with slightly offset key slots or worse case use offset keys. This tuning of camshaft can give your 2 or 3 hp at least.

Click to expand...

THAT is an excellent and often overlooked point…

worntorn said:

Correction to my earlier post-
The 88 ss was not rated at 40 bhp.
It was rated at 36bhp (engine) . The standard 88 was rated at 29 bhp.

Glen

Click to expand...

And… that’s at the crank… and it would be the best figure from a selection of perfect engines… and it is only a ‘claim’…

A real world prod engine would be less.

So a genuine 40 at the wheel isn’t too shabby Brian !

worntorn said:

Fascinating recent history John. I wonder if Doug Hele's very special 61 TT 500 was similar, not much happening below 5000 rpm?
I would guess that it was as they were getting similar power levels to your bike and the " revs to 8000" ability seemed to be very important to them.

It's surprising that your stock cases have held up to racing. From my reading, stock Commando cases generally did not last very long with such high rev usage, even with a racing crank such as Nourish.
I guess the power levels on the larger engine would be that much higher and the Commando cases are obviously not proportionly stronger.

Correction to my earlier post-
The 88 ss was not rated at 40 bhp.
It was rated at 36bhp (engine) . The standard 88 was rated at 29 bhp.

Glen

Click to expand...

Yes you are correct about the crankcases. This is of some concern given they are totally original 1956 cases. However they are the generator type not armature and therefore thicker around the drive side bearing housing.

I had them crack tested and hopefully they will last. I do have a pair of billet Commando cases on my shelf that could also be made to work but they are considerably heavier.

And yes the real Hele Domiracer was a bit famous for power coming in abruptly with poor low and midrange. Reportedly Phil Read rode it in 1961 TT practice but reverted to his Manx after the Domiracer spat him off.

" Reportedly Phil Read rode it in 1961 TT "

Phil Read woulod be a fascinating bloke to talk to about NORTONs . Daytona , etc , the TWINS ( I Thought ) . Must have A BOOK in him , on em .

RIGHT . ( now ) read your First Post .

A One Piece crank ! shouldbe goodfor 8.500 . Easy .

Flat plane head . Blaugh . ( But its like the Triumph ! So shouldnd bea real worrie . ) NOW the R Triumph Ran 1 - 5/8 Inch intake & 1- 7 / 16 in. Valves . the heads , that is .

If you look downalonga port , you should see DAYLIGHT , at the other end . A light at the end of the tunnel ! . Pshew . That means stuff can get through .
With a head off , A finger over the Garden Hose ( A Flow Bench , if yave a bench , a brick will do ) Aimed Directly down the center , we're talking INTAKE
primarilly .
Usually , on a TRIUMPH , if its any good , initial 2 m.m. it just goes radially , 360 degrees , pretty much , sorta 50/50 aqueous and gaseous . B U T , heres the Rub -

Fully Open -> The Suckers heading pretty much down CENTER BORE : - The Primary H.Duty full bore Bit . Should Folow the piston head down . Past Half Lift .

The Flow Transitions , From the 2 m.m. ( Start of effective port operation ) usually transitioning to periferal / outer circumferance - center arc ing soits ABOUT COINCANT WITH THE BORE WALL ,
Transitioning thru at third openish to pummling primarilly BORE CENTER ,

SO
---
Its Filled the Bore Walls .
Its caught the piston head.
Its pushing thru , so can roll ( like a hoop ) the outhrust -
So its ensured EVEN & Complette chamber wotsit . full of it , no dead spots . and suchlike .

==========================================================

Note :the RACE Twin Heads were Full Hemi ( Like a TRIUMPH ) think there was a pitcher of one , in a Motorcycle HELE interview . A head on the bench , in his grasp , as it were . for the DOMI . Mate .

I fink wotyer gunna havetado , is take the MUFFLER OFF . Go Somewhere ( Pendene sands ! ) and rev the snot out of it . Like our dearly beloved Triumphs , using the last inch of oomph in toid , Patrick .

ASSUME you have a C. R. Box ?? or ya dunfor .
Think your PIPES match the T 100 .( R )

' We ' ran 1 5/32 on the Bonnie , on 1 1/8 ports . ( The 8 stud flows better'n a 9 , theyvegot the same problem as you . A KINK ) 7800 peak , tooned lenf pipes ( Picked up 1.000 runningem ) Rum to 8100
once it had ' adjusted ' to that absurdety . Settling down there , it would recogitate , and run out quitely ( ( a relitve term , you understand - some might say ' smoothly ) to 8500 . Valve SURGE )

Blah Blah .

I think ' wots up ' is its all still a bit confused ! MAYBE the 1 3/4 O.D. 650 pipes are wot yer afta . A potentially its got 9 grand . 8 is safe . 8-2 or 3 is getting somewhere , if its got it .
The Shallow Angle vale is gunna maybe want more intake than the T120 ( Stock R 61 Cams etc ) .

Its kinda all about " PHASEING " pulse cycles . ( unless you supercharge it )

Id think a big Trux 1200 Tri ' muffler ' mifght doit . Maybe a V&H . A scratched one ( or two ) Borrow it . Knocked about . Who gives a . its a TEST . The 72 REAd JOB i THINK WENT 2-1 FOR MIDRANGE aND LOST NO TOP END . oops . And it was LIGHTER . As an ounce of handlings worth a pound of horsepower . So UNMUFFLED Yours should be good for 50 , at the crank or gearbox ( if it were a TRIUMPH )

No Bottom End . Strewth . A Race Cam - aint got no ' bottom end ' . MATE .
HENCE : the olde

' Half Race '

' three quater race '

' full race '

Designations : still got a bit of bottom end , aint gotta lotta bottom end , and , there aint no bottom end ere . Gotta tough clutch too . Half and three quater will burn out the clutch too . Like a 2S

WHICH is ACTUALLY the FULL RACE Domi Cam . So a " COMBAT " cam is gunna doit nice . Were many a story of hitting a car at 80 out off the showroom , at 8.000 in second . ' the New Combat ' .

So , there we have it .
Id crank the motor forward , so as the carbs go ' straight at it ' Note on the 500-R , Thats Downdraft ( some would quibble ) no matter how you goaboutit .

TRY 1 3/4 pipes ( with NO tight bends ) bout 27 1/2 or 28 inch of them . A Hot rodde would put full length on , get a crayon or paint , put a line down it , and cut it off at the 3rd or 4th burt spot .
About six feet . To catch 3 or 4 overlays of ' pulse ' But youd maybe settle for one , around 30 inch .

TREAT IT as a Short Stroke 650 SS ( them Thruxton jobs were DOMIRACER injuned . Boy . ) So as like its a nest of hornets , on nitro . Keep em all in there . Sequentiall ejection , outta da pipe ends .
Kapow .
THATS were the Mega Matches the PULSE EXPANSION .
Youre doing it in , wth That Thing on the back !

( a short stroke 650 , would match the long strokes piston speed . So youve 650 / 500 = 1.3 x 7000 ( cept call it 7-5 ) so thats 9100 , or 9750 . But the Valve Gear , is only proven to 8.000 Odd .
So , at 8.000 your in there , no sweat . 8200 maybe . 8500 , might do it - if someones dunnit . Reliably . Why Not . BUT the ' phaseing ' The Followers ! Vs Valve Springs , You get a cycle / reverberation , in there
Like castanettes ? IF youve Got It RIGHT . a Harminc ENHACEMENT . Not a harmonic opposition . rooster up . So dithering with a series of springs might gettit . The Olde TERRYS ! & W&S , maybe .
You DONT want Non interacive ' dead ' phaseeing for optimum opperation . But it may be o.k. , at only eight thousand .

o.k. looks like youve got another OIL TANK there , wot'll do it . with STRAIGHT intakes .

Concetrics aint monoblocks . Set em Fully Closed , thropple off . 1 5/32 IS 29.4 , wots 30 . Monoblocks being superior . 32 or 33 ( works 750 ) if its Concentrics . MATE .
the T 120 TT ran 1 3/16 carbs , on 1 1/8 ports . the ' taper ' being a essentiall element . Biga carb than ole . - O'le .

Our friend HOBOT thinks the micro step , 1 5/2 direct to 1 1/8 ENHANCES ' gas flow ' thru tumbling fill of port wall , like onna da bore offa da piston . Man /

So , as per our good friend Freddy Dixon , REMOVE ANY IMPEDIMENTS , check all fits and finishes , once its going right , then think about any ' improovements ' .
most of them may well not be . I think your ( maybe ) overcammed . And its not getting enough in it , and cant get out of it . here aint no real ' phaseing '
It should Jump Up ( raise incline ) on the graph . from 4500 , where its inclination is lessr than earlier .


Like has been said , Get it right UNMUFFLED . Then theres your ' base line ' .
maybe you want a bit more intake than exhaust timing , with that Flat Head .

Id look at Pre Unit Triumph RACE timing . Ex should near match . In open maybe earlier 5 or 10 . Shut about the same / OR that BSA Spitfire Grind !! after all , your after
broad range / top end ( Power available from half revs ish ) J P S 3S was ' daytona ' Commando cam . 2S was early P.R. , was Domi full race .
Theres some 40 thou. base circle dicrepancey /
Which explains the 4S - a 2S full race with 40 thou off the heel . Which explins the early Villiers buit 2S mish mash self digestion , in the tunnel , there .

So , back off the hyper , and dial it in . T 12 ran strong from 3500 ( road cams ) 100 R ran strong ( Race Cams - on the cam ) from 5.000 . So you CANT BE FAR OFF .

in fact , Its likely GOT the 50 , Ex uncapped . Now . Potential for a lot more . 60 anyway , if youve got 8500 in the valve gear . as long as it dosnt ' fall off ' ( diss phase )

( valve SURGE ( lookitup ) is de - phaseing . transition harmonics off opperation , in the valve & spring , mass - spring - frequencey . So fit a Brock Energy Polariser . see G.M.

Thanks to everyone’s input and info. @johnm thanks for your info which is very much appreciated there’s never to much info to read especially on the 500 domi’s are you putting your 500 back together?

I’ve attached a picture of my one piece crank it’s very light it’s one of the last ones from Mich Hemmings with 1.75” big end journals. And pistons with a thin 0.020” copper head gasket
The curved manifolds I’ve just had made they give a nice smooth curved track in to the head like the commandos which was much better that the manifold I had on which gave a sharp bend in to the head so the flow was like hitting a brick wall before picking up again,
everything I have on the bike is to club rules and just trying to make the best of what is there, I’m going to have a busy winter on the dyno so I’ll keep everyone posted on my progression with the 500 domi, I use the same dyno all the time as I can see the results time and time again. Also a picture of my dyno results from last year to this years gain in midrange power with longer inlet manifolds and silencer change

Brian Riley said:

Thanks to everyone’s input and info. @johnm thanks for your info which is very much appreciated there’s never to much info to read especially on the 500 domi’s are you putting your 500 back together?

I’ve attached a picture of my one piece crank it’s very light it’s one of the last ones from Mich Hemmings with 1.75” big end journals. And pistons with a thin 0.020” copper head gasket
The curved manifolds I’ve just had made they give a nice smooth curved track in to the head like the commandos which was much better that the manifold I had on which gave a sharp bend in to the head so the flow was like hitting a brick wall before picking up again,
everything I have on the bike is to club rules and just trying to make the best of what is there, I’m going to have a busy winter on the dyno so I’ll keep everyone posted on my progression with the 500 domi, I use the same dyno all the time as I can see the results time and time again. Also a picture of my dyno results from last year to this years gain in midrange power with longer inlet manifolds and silencer change

Click to expand...

Your bike has extremely good components. Everything is there to make a very quick bike. Except possibly the head. That's a bit of an unknown to me. Do you have flow data for it?

Re your dyno run. The upper part of the runs above 5750 look a lot like carb vibration or mixture problems to me. I have seen shaky curves like that before and it was usually mixture. Although now I have printed the plot out and can see the fuel ratio looks OK. Definitely looks like something is holding it back above 5750. Power is building well before then.

I'm assuming your ignition tests good. Sometimes condensers can do that too but generally more strongly erratic

My Dommie is going back together very slowly. I had to get a new frame because the old slimline frame cracked so many times. But at the moment friends are preparing 3 bikes which are going to race in this year's Manx Classic races so I am helping them.

Fast Eddie said:

Yes I realise you need silencing, but trying straight pipes on the dyno will at least tell you if the megaphone shape is the issue. My understanding is that so long as the silencer is perforated, and a larger ID than the end of the pipe, it has little to no effect on power. A silencer designed to take Supertrapp discs allows a lot of tuning by adding / subtracting discs and different reverse cones.

Megaphones can have a huge impact, both positive and negative, especially so with a big cam, so def worth trying straight pipes IMO, I’d leave them long and cut of a bit at a time on the dyno.

I used to run very shallow megas on Triumphs, with silencers, and they worked great but when I tried them on my Commando they were no good at all.

I have a copy of Steve Maneys 2:1 design, it’s for a Commando but would probably fit on yours enough to test on the Dyno if you wanna borrow it sometime?

My dyno man claims that on numerous occasions bikes running 105 race fuel have gained a few (up to 4) BHP when switching to super unleaded! Seems totally wrong and counter intuitive, but def worth a try.

What about head porting? What’s been done and by whom? I built an 850 with JS parts and was happy with it. Then I got Comnoz to port the head and got an extra 9 BHP just from the porting work. It definitely ‘unlocked’ it !

What are you doing for sparks? Is that an actual mag, or a mag housing containing an EI? Are you 100% sure your sparks are good?

Click to expand...

I’ve got them at 40” at the moment so definitely worth trying chopping and adding to see where works best.

Really?? The dyno I use the guy swears by esso supreme it to he said it’s worth a line above the last tune so I’ll be taking some with me in a Jerry can.

I’d love to but my head is the early one where the exhaust ports are different angle to the later heads so might not fit but always up for trying stuff. Where abouts are you?

The porting was done by mick Hemmings porter, but I was along to see Len at the cylinder head shop he said the porting looks good but there is room for more improvement so I’m going to dyno it again next month with the new inlet manifolds and after porting for a comparison
Who are comnoz? What did they do to it? That’s a massive gain.

The mag I’ve just got from JS it’s a new Joe hunt mag it has a great apart and using NGK B7EPS Spark plugs

Your A/F ratio on the red runs is rather rich, that alone cudda cost you a lot.

I agree with John that the spikey nature of the graphs above 5.5 ish doesn’t look great.

Brian Riley said:

I’ve got them at 40” at the moment so definitely worth trying chopping and adding to see where works best.

Really?? The dyno I use the guy swears by esso supreme it to he said it’s worth a line above the last tune so I’ll be taking some with me in a Jerry can.

I’d love to but my head is the early one where the exhaust ports are different angle to the later heads so might not fit but always up for trying stuff. Where abouts are you?

The porting was done by mick Hemmings porter, but I was along to see Len at the cylinder head shop he said the porting looks good but there is room for more improvement so I’m going to dyno it again next month with the new inlet manifolds and after porting for a comparison
Who are comnoz? What did they do to it? That’s a massive gain.

The mag I’ve just got from JS it’s a new Joe hunt mag it has a great apart and using NGK B7EPS Spark plugs

Click to expand...

I’m in Oxford.

Comnoz is Jim Comstock, Norton guru in USA.

If I were in your shoes I’d try and source a downdraft head and send to him. Or talk to him about getting a semi finished Fullauto head so he can machine and finish it accordingly… now there’s an idea… !

He’s built some fine 500s including a LSR bike.

johnm said:

Your bike has extremely good components. Everything is there to make a very quick bike. Except possibly the head. That's a bit of an unknown to me. Do you have flow data for it?

Re your dyno run. The upper part of the runs above 5750 look a lot like carb vibration or mixture problems to me. I have seen shaky curves like that before and it was usually mixture. Although now I have printed the plot out and can see the fuel ratio looks OK. Definitely looks like something is holding it back above 5750. Power is building well before then.

I'm assuming your ignition tests good. Sometimes condensers can do that too but generally more strongly erratic

My Dommie is going back together very slowly. I had to get a new frame because the old slimline frame cracked so many times. But at the moment friends are preparing 3 bikes which are going to race in this year's Manx Classic races so I am helping them.

Click to expand...

Thanks John I’m getting Len at the cylinder head shop here in the uk to port it and I’ll get a flow sheet of him to show you, the head is the pre down draught head it had the 650/750 inlet valve and standard exhaust size valve

Yeah it’s a pain when it drops off like that as it feels like it wants to go I’m hoping this new manifold improves things a little as well as the winter work I’m going to do also and check each time in the dyno to see where it’s at.

The ignition is the new Joe hunt magneto from js motorsport it’s a great magneto I’ve changed the condensor to a bright easycap 370nf condensor which works extremely well with NGK B7PES plugs to.

I’m gutted I can’t get over there this year but I’ll be at Goodwood revival this year

Fast Eddie said:

I’m in Oxford.

Comnoz is Jim Comstock, Norton guru in USA.

If I were in your shoes I’d try and source a downdraft head and send to him. Or talk to him about getting a semi finished Fullauto head so he can machine and finish it accordingly… now there’s an idea… !

He’s built some fine 500s including a LSR bike.

Click to expand...

Ahh cool I’m up near Newcastle, I’ll be racing at Oulton park in August with the Lansdowne.

Thanks for that I’ll look him up

Fast Eddie said:

Your A/F ratio on the red runs is rather rich, that alone cudda cost you a lot.

I agree with John that the spikey nature of the graphs above 5.5 ish doesn’t look great.

Click to expand...

The red line was last year when I had the GP carbs on no matter what we did on the dyno and track we couldn’t get them to run right that was the huge hole I had in the mid range. The blue line is this year with mono blocs on and longer inlets. I agree with you both on that I need to find why it’s doing that. My theory is it was the old type manifold as the charge came in to the head on an angle it caused massive turbulence as it hit the inner port wall and stalled, so I’ve made some new smoothed curved type not to far off like the commando ones but on there sides to try on the dyno and I’ll post the results when I get my slot next month on the dyno. Picture of the old type manifold with a sharp angle in to the head and the new smooth curved type hopefully should improve the flow

Here’s some eye candy of Jim’s work, 500cc LSR called Sir Eddies Rocket.

Caution, may be damaging for your wealth…


I must say Brian, with those bent manifolds and unkown head porting, your head is starting to look like the prime suspect to me.

I believe Steve Maney is in the U.K. at present, maybe worth a chat with him about the head.

Norman White is also an option of course.

But looking at what you’ve already invested in that bike, putting the best possible head on it only seems logical to me. I really would consider the Fullauto / Jim Comstock idea in your shoes.

But then again, I have always been rather good at spending other people’s money !!

Fast Eddie said:

Here’s some eye candy of Jim’s work, 500cc LSR called Sir Eddies Rocket.

Caution, may be damaging for your wealth…

Thread 'Sir Eddy's engine (2015)'

Jul 24, 2015

Getting to the last mods on Sir Eddies LSR bike.

It was necessary to go back to Norton lifters to achieve the 10,500 rpm engine speed. The barrel was not built to hold Norton lifters and the bores were a little too large so I had to install aluminum bronze sleeves and build provisions for tabs to keep the lifters from rotating.

Here are the profiled lifters in place.

Here is the cylinder head. The ports are pretty nice but the 1mm oversize valves are somewhat shrouded in the bathtub chambers witch limits the flow potential.

The blue...

• comnoz
• Replies: 112
• Forum: Norton Commando Forum

I must say Brian, with those bent manifolds and unkown head porting, your head is starting to look like the prime suspect to me.

I believe Steve Maney is in the U.K. at present, maybe worth a chat with him about the head.

Norman White is also an option of course.

But looking at what you’ve already invested in that bike, putting the best possible head on it only seems logical to me. I really would consider the Fullauto / Jim Comstock idea in your shoes.

But then again, I have always been rather good at spending other people’s money !!

Click to expand...

You’ve got me thinking now

Brian Riley said:

Thanks John I’m getting Len at the cylinder head shop here in the uk to port it and I’ll get a flow sheet of him to show you, the head is the pre down draught head it had the 650/750 inlet valve and standard exhaust size valve

Yeah it’s a pain when it drops off like that as it feels like it wants to go I’m hoping this new manifold improves things a little as well as the winter work I’m going to do also and check each time in the dyno to see where it’s at.

The ignition is the new Joe hunt magneto from js motorsport it’s a great magneto I’ve changed the condensor to a bright easycap 370nf condensor which works extremely well with NGK B7PES plugs to.

I’m gutted I can’t get over there this year but I’ll be at Goodwood revival this year

Click to expand...

I'll be interested to hear how that mag holds up. I may need to get a JS condenser for my Morris mag. It's been excellent but condenser is 20 years old now