| Home  Blogs Help Search Login Register  
« previous next »
Pages: 1 2 3 [4] 5 6 ... 8 Print
Author Topic: Supercharging a Bagheera  (Read 67948 times)
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #45 on: November 24, 2009, 08:35:43 pm »

Back on the blower project with 11 days to go before he has to be running for the December 6th MECUK meeting!

I have fitted all the valves to the head and the inlet manifold is bolted on. Much of the time has been taken doing preparation work such as cleaning threads, finding new (stainless) nuts and making sure I have everything necessary to just "throw it together". It does seem to be progressing well and I hope to have the head back on the engine tomorrow (Wednesday). Then it is all the "minor" things like the carb and extending the old throttle and choke cables to the new linkages, connecting the two vaccum connections to the same vacuum point between the carb output and the blower suction. The blower gauge needs to go onto the inlet box where it will read the actual pressure being generated.

But what about the ignition system and its automatic Advance/Retard mechanism?

I put the question this evening to Mick Ward of the Simca Club who is running a supercharged Simca Rallye 1100. (I think)....

...Brain picking again if I may...

I haven't yet studied my (and your) books on the subject of ignition advance with the blower but your first thoughts would be appreciated..

A standard engine, if I have got the concept right, has its tickover ignition setting according to the book. This is when the inlet manifold vacuum is at its highest. When the throttle is opened, engine speed increases and manifold vacuum decreases. The auto-advance/retard diaphragm increases the advance to give the flame time to get established just as the piston gets to TDC. In a sense this is necessary also for the blown engine except that too much advance can cause destructive detonation. So maybe the mechanism to advance the spark needs to have a maximum limit at perhaps lower revs? Do you have any experience of how one would achieve this with the rather basic distributors we use?

How about:- Disconnect the auto A/R system and set the advance to suit the max power situation and forget about the tickover?

Alternatively mess with the dizzy springs to get a different curve.

I have been recommended by the guy who made the decompression plate to a USA company called "MSD" (I think). They make a sophisticated electronic ignition package designed for Blown engines where the driver can select an advance curve while on the move. It also responds to actual manifold pressure and adjusts itself. Sexy stuff but expensive too. I have yet to ask Lumenition whether they have anything similar.

Makes my brain hurt, all this thinking!

Andy Owler
Logged

Back in business for fun!
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #46 on: November 25, 2009, 08:43:07 am »

As allways a wonderfull work. Grin

I think the MSD is described in Vizard book (powertune BMC A )
Having seen your pictures, I'm also thinking that the inlet manifold for single weber like on a Murena might have been easier to match and potentialy giving a better flow.
I've several of these and lately I cut out the water supply from one of them.
The idea was to see how I could adapt it to a 1200S engine (different angles) but also to not heat the mixture.
Not feasable !
Actually, thinking about it, you might take an advantage of this by having a replacement of an intercooler : connect these pipes to a small different radiator (in front) with an electric pump and voilà ! you'll cool the mixture. This would however be more appropriate to a turbo engine.

The very good news is that normaly in about 12 days we might see your completed engine  Cheesy

Keep going !
Logged
suffolkpete
Sr. Member
****
Posts: 456



« Reply #47 on: November 25, 2009, 08:50:59 am »

The vacuum advance is to give more advance when running at higher engine speeds on a light throttle when vacuum is at its highest.  Centrifugal advance progressively advances as engine speed increases and this is the one you would have to alter.  You would probably not notice a huge amount of difference if you disconnect the vacuum except perhaps in fuel consumption.  I guess you'd have to fit stronger springs in the ditsributor but I have no idea how to determine the type to use other than trial and error.
Logged
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #48 on: November 25, 2009, 09:34:23 am »

Spyros wrote..I'm also thinking that the inlet manifold for single weber like on a Murena might have been easier to match and potentialy giving a better flow.

Yes it does look a bit clunky doesn't it? Hardly "gas flowed"!

I had always imagined a row of nicely curved stainless steel inlet pipes like the "bunch of bananas" in the Alfa V6 and many other modern cars. I would still like to do that but getting the concept working and  proved seemd to be more important than going for aesthetic perfection at the start. Plenty of time for development!

Thanks for the kind words.

Andy
Logged

Back in business for fun!
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #49 on: November 25, 2009, 09:38:22 am »

Suffolkpete wrote...
Centrifugal advance progressively advances as engine speed increases and this is the one you would have to alter.

I read something in the Allard-Shorrock instructions about fitting a ring in the dizzy. I wonder if this limits the travel of the centrifugal advance?

I was only thinking of the vacuum advance mechanism. You have opened a new line of thought. Thanks very much.

This is a good time to be looking at the dizzy as it is much easier to get at without the head in place. Good timing too (no pun intended!).

Thanks

Andy
Logged

Back in business for fun!
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #50 on: November 25, 2009, 07:23:23 pm »

Spyros wrote..I'm also thinking that the inlet manifold for single weber like on a Murena might have been easier to match and potentialy giving a better flow.

Yes it does look a bit clunky doesn't it? Hardly "gas flowed"!
Yes yes ...
But a thick piece of aluminum would have been enought to join that manifold to your right angle part.
You wouldn't have had to TIG weld this box


Today I read some documents about the adaptation of Constantin blower on old peugeot.
They changed the advance to zero.
Logged
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #51 on: November 28, 2009, 04:25:18 pm »

Some others are trying ...

http://translate.google.be/translate?u=http%3A%2F%2Fwww.simca-competition.com%2Fles-autos-des-membres-f19%2Fma-r2-turbo-t1739.htm&sl=fr&tl=en&hl=fr&ie=UTF-8
Logged
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #52 on: November 28, 2009, 10:56:44 pm »

I regret that I was not able to make the link work! I think the translation got in the way, plus the need to register to access the site.

Can you summarise this item for me please?

I had not seen this Simca Competition site before. Interesting!

Andy
Logged

Back in business for fun!
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #53 on: November 29, 2009, 12:35:57 am »

Can you summarise this item for me please?

The site is purely Simca Rallye oriented. With a little bit of other things.

So here it is :
Simca Rallye 2 Turbo
First with a Constantin compressor with belts and a ratio of 1.9 (can go up to 2)
<= this image is coming from this site. Please visit it for more details
And injection.

But we wanted another gearbox, so we head for a 5 speed.
First we tried an Alfa but the oil didn't run in the right direction.
So we tried a 5 speed from a R5 Alpine Turbo but we had a problem (doesn't say what)
So we went to a 4 speed VW, knowing that then we could replace it by a 5 speed Porsche

But then we realized that this compressor has to turn in ... the other direction

So we throw the compressor away and went for a turbo.

To be continued (I suppose)
Logged
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #54 on: November 29, 2009, 05:46:17 pm »

Thanks Spyros for the Picture!



Andy
Logged

Back in business for fun!
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #55 on: November 29, 2009, 05:58:06 pm »

Mick Ward of the Simca Club UK made these comments about the yellow Supercharged engine in the "My Project" thread. They seem to apply also to the layout of the Spyros engine picture...

  I was looking on the  MatraSport forum for anything on supercharging and spotted the pictures of the yellow engine with a DCOE weber attached to the blower.  This engine is in a 'period' group 4 SIMCA 1200S coupe which has appeared at a number of shows in France..  You note the position of the distributor.  The top of the timing cover is the original position for it on the upright, anticlockwise versions of the engine used in the 1000s and 1200S coupes.  The 1000 cam has an extra bit cast on the end with a extra gear to drive the distributor.   The gear driving the cross shaft inside the block then just drives the oil pump.  The hole for the distributor on the transverse engines is covered by the base of the water pump on the 1000 block..
                                    All the best                      Mick

Andy Owler
Logged

Back in business for fun!
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #56 on: November 29, 2009, 06:15:34 pm »

I might have other pictures of this supercharged Simca 1200S. Let me try to find them

Also, I've sent an email to the guy of the previous picture.
Logged
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #57 on: November 29, 2009, 08:32:26 pm »

Not my picture (cannot find them  Huh)

Logged
andyowl
Sr. Member
****
Posts: 456


New exhaust "straight through" - good sound!


« Reply #58 on: November 30, 2009, 08:49:47 am »

Interesting to see the whole engine space!

I like the pressure relief valve on top of the inlet manifold. Simple and self resetting. The one I received with the Shorrock Blower is a 6mm 1/4R Norgren pneumatic relief valve which although better than nothing, is grossly inadequate to relieve the explosion pressure caused by a backfire through the inlet valve into the inlet system. I am planning merely to omit the last hose clip on the 50mm pipe where it enters the inlet box. The explosion pressure will cause the pipe to blow off and make the system safe but it will probably not reseal. On the motorway this would be a problem but on a sprint or hillclimb track it is just an inconvenience and better than blowing out a gasket or suchlike. This picture gives me an idea of how I can make a similar safety valve.

How do they get at the spark plugs? Unlcear! On my system they are more accesible than usual thanks to the absence of the carb(s).

The plastic "oil catch tank" on the right side is also interesting. I am hoping to direct the vent from the rocker cover into the inlet tract as usual. Not yet designed though!

More news follows... We are almost there!

Andy Owler
Logged

Back in business for fun!
Spyros
Sr. Member
****
Posts: 323

I'm a real donkey!


WWW
« Reply #59 on: November 30, 2009, 10:19:13 pm »

Changing the spark plugs ?
It makes me think of the Mi16 conversion of the Bagheera of a German friend.
I had the impression that to change the oil filter you had to remove the engine.

Allthough... his car is running since a long time. And a remote oil filter would address the issue.
Here... not so easy ... but interesting work anyway
Logged
Pages: 1 2 3 [4] 5 6 ... 8 Print 
« previous next »
Jump to: