M4 Engine questions and advice.
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samfieldhouse
Firing on two.
Joined: February 11th, 2009, 12:32 am Posts: 3324 Location: Chichester, West Sussex
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 M4 Engine questions and advice.
What's the setting for the timing, ie, the flashy line bit on the fly wheel?
Do I set the tappets as I would a normal 602?
Anything else worth knowing/remembering/doing?
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May 9th, 2011, 10:21 pm |
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ken
Agony Aunt - You have a car problem? Speak to Ken
Joined: March 6th, 2009, 1:40 am Posts: 3675
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 Re: M4 Engine questions and advice.
sam, as an M4 is quite a 'soft' engine, with only 7.75:1 CR, I'd reckon that it should be able to run about the same amount of total ignition advance as an 8.5:1 engine, or even a shade more. The 'pin in hole' setup is at 12* BTDC, compared to 8* for the later 602 engines. If you put the 'full advance' mark 7 teeth round from the static mark, that's 35* total, which is a good starting point. Tappets set the same as later engines, to be done _after_ torquing the cylinder head nuts. Back those off 1/4 turn, then torque to 18 ft.lbs, tappets 0.2mm inlet, 0.25mm exhaust. ken samfieldhouse wrote: What's the setting for the timing, ie, the flashy line bit on the fly wheel?
Do I set the tappets as I would a normal 602?
Anything else worth knowing/remembering/doing?
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May 10th, 2011, 1:01 am |
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samfieldhouse
Firing on two.
Joined: February 11th, 2009, 12:32 am Posts: 3324 Location: Chichester, West Sussex
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 Re: M4 Engine questions and advice.
Cheers Ken  I believe mines an Ami 6 M4 with higher compression(?) - same rules apply?
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May 10th, 2011, 1:05 am |
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ken
Agony Aunt - You have a car problem? Speak to Ken
Joined: March 6th, 2009, 1:40 am Posts: 3675
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 Re: M4 Engine questions and advice.
sam, afaik, an M4 engine was 7.75:1 CR, regardless of the vehicle in which it was installed. ken samfieldhouse wrote: Cheers Ken  I believe mines an Ami 6 M4 with higher compression(?) - same rules apply?
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May 10th, 2011, 1:33 am |
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toomany2cvs
Firing on two.
Joined: December 26th, 2008, 9:40 pm Posts: 3332 Location: Surrounded by 2cvs...
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 Re: M4 Engine questions and advice.
ken wrote: afaik, an M4 engine was 7.75:1 CR, regardless of the vehicle in which it was installed. AIUI, 7.75:1 was the high-compression later Ami-spec lump. There's also bigger valves etc as well as the bucket carb. The earlier Ami-spec (and all AK) was 7.5:1 http://www.cats-citroen.net/citroen_aty ... arbox.html
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 Zookeeper of a miscellany of motorised silliness - from 0.75bhp to 9ft tall - now living life on the road in an old VW. http://WhereverTheRoadGoes.com
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May 10th, 2011, 11:19 am |
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ken
Agony Aunt - You have a car problem? Speak to Ken
Joined: March 6th, 2009, 1:40 am Posts: 3675
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 Re: M4 Engine questions and advice.
Interesting, wonder what I'll find when I finally get time to start on Jim Roger's three M4 engines, as one of those has a bucket carb. Mind you, there appear to be some (fairly obvious) errors in Jeroen's list... ken
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May 10th, 2011, 1:16 pm |
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samfieldhouse
Firing on two.
Joined: February 11th, 2009, 12:32 am Posts: 3324 Location: Chichester, West Sussex
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 Re: M4 Engine questions and advice.
It's only going to be 7.?:1 for this year - hopefully I'll get my hybrid m4/28 in this winter with 9:1 pistons/barrels.
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May 10th, 2011, 1:55 pm |
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toomany2cvs
Firing on two.
Joined: December 26th, 2008, 9:40 pm Posts: 3332 Location: Surrounded by 2cvs...
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 Re: M4 Engine questions and advice.
ken wrote: wonder what I'll find when I finally get time to start on Jim Roger's three M4 engines, as one of those has a bucket carb. Do you need a manifold for it...?
_________________
 Zookeeper of a miscellany of motorised silliness - from 0.75bhp to 9ft tall - now living life on the road in an old VW. http://WhereverTheRoadGoes.com
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May 10th, 2011, 2:07 pm |
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Sean
Firing on two.
Joined: April 22nd, 2009, 11:06 pm Posts: 3684 Location: Ecosse
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 Re: M4 Engine questions and advice.
seatbelts? oil soaked crumpled heater hoses ? some Portuguese glass ...give it a more "modern" feel ? best Priice  .....oh its just the engines your working on got a pile of used points and condensers for some reason if thats any use...nah? ok
_________________ Kissing the Lash
 "Any advice of a technical nature is given on the understanding that I've actually done this shit, not just read about it in D*lly club mag some time ago.
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May 10th, 2011, 3:05 pm |
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Russell
Firing on two.
Joined: November 29th, 2008, 10:05 pm Posts: 9259 Location: West Sussex, U.K.
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 Re: M4 Engine questions and advice.
Did the points and condenser and other service bits on the van tonight. It now starts ok and ticks over too which is nice, but when I put the strobe on it I can only get it to move round three teeth or so from tickover to revving the nuts off it. Having driven it it seems to go ok and I'm pretty sure it's not pinking (hard to tell as it's pretty noisy). Am I right in thinking this is down to the advance weights not working properly? Or have I made some glaring error? I don't know much about these old engines so I'm learning myself here too, following what ken wrote I marked 7 teeth round the flywheel and whilst on tickover it hits the first mark it doesn't come close to the second one, regardless of how hard you rev it.
Sam didn't take my advice which was rip the pox thing out and put a nice D*lly engine in and a disc box.
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samfieldhouse wrote: What I like about I2F is that there is no pretence of democracy.
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May 10th, 2011, 9:09 pm |
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