Lotus Elan

Dist. Timing

PostPost by: tvacc » Mon May 19, 2014 11:50 am

Hi all.
Quick question. I just had the distributor from my 71 Elan, 185 compression, dellortos, rebuilt by Advanced Distributors up In MN. Fantastic work, almost a work of art or looks so pretty.
Any ways, he wrote on the bag that he send it back in 16-18 degrees at idle. 30 something total. Now I know the previous timing was like 10 or maybe less as it was pinging horribly, which is why I sent it to him to begin with. Do I follow his recommendations as I gave him specs of the motor ( he asked for compression readings, cams, and if the car had Webers or Dellortos, or do I try like 10 degrees.

By the way, his work is just incredible.

Thanks in advance.

Tony V
Tony Vaccaro
http://www.lotusowners.com
LOONY (Lotus Owners of New York)
Drive Fast Take Chances
71 Spyder Elan, ElanGTS, 93 Caterham, 05 Elise,
99 Elise190, 91 M100 Elan, 74 Europa, 72 Europa JPS #15, 68 Elan Coupe RHD
User avatar
tvacc
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1159
Joined: 24 Dec 2003
Location: Buffalo NY

PostPost by: alan » Mon May 19, 2014 1:15 pm

imho 10 to 12? is correct and 16 to 18? is far too much.
Alan.B
alan
Third Gear
Third Gear
 
Posts: 312
Joined: 29 Jan 2007
Location: France Morbihan

PostPost by: rgh0 » Mon May 19, 2014 1:40 pm

Around 10 degrees at idle is typically about right. But more important is maximum total advance and what revs it comes in at. A road going twink with a 10.5 comp ratio running on premium unleaded typical needs around 26 to 30 degrees maximum advance. You want the full advance to come in as early as possible while still not pinging this will normally be around 3500 to 4000 rpm. Where in those ranges is best depends on the specific fuel and the specific engine and really needs a dyno to determine.

What advance curve was your distributor rebuilt to?

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7477
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: Galwaylotus » Mon May 19, 2014 8:00 pm

If the engine will start on 16? BTDC then it's ok to use that timing. The more important figure, as Rohan has stated, is the total advance. Too much initial advance will make it harder for the engine to start but you won't know how much that is until you try!
Mechanical Engineer, happily retired!

'67 S3 SE FHC

See Facebook page: W J Barry Photography

Put your money where your mouse is, click on "Support LotusElan.net" below.
User avatar
Galwaylotus
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1357
Joined: 01 May 2006
Location: Galway, Ireland

PostPost by: tvacc » Mon May 19, 2014 9:19 pm

He noted 36 degrees total and 16 at idle. He writes this on the shipping bag.
Tony Vaccaro
http://www.lotusowners.com
LOONY (Lotus Owners of New York)
Drive Fast Take Chances
71 Spyder Elan, ElanGTS, 93 Caterham, 05 Elise,
99 Elise190, 91 M100 Elan, 74 Europa, 72 Europa JPS #15, 68 Elan Coupe RHD
User avatar
tvacc
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1159
Joined: 24 Dec 2003
Location: Buffalo NY

PostPost by: rgh0 » Mon May 19, 2014 10:54 pm

36 degrees is to much maximum total advance for your engine. It looks like you have 20 crankshaft degrees of centrigugal advance in the distributor which is OK assuming the actually advance curve is not to slow or to fast. So set at 30 degrees maxium advance and 10 degrees at idle and you should be about right.

If your still getting pinging retard it until the pinging stops. If you need retards more than about 3 or 4 degrees i would have a look at the actual advance curve you have and get it slowed down with stiffer springs so it reaches its maxiumum at higher revs than it does now.

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7477
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: m750rider » Tue May 20, 2014 10:51 am

Tony

For what it's worth, I have a 1969 S4 SE, Strombergs with crossover pipes and secondary throttles removed, rebuilt head with big valves, stage 2 cams from Dave Bean, electronic ignition 43D distributor, headers. I don't know compression, I typically run about 33-34 degrees full advance and probably about 13 or 14 degrees at idle, so I think his recommendations might not be too far off.

Good luck.

Bob

45/8842
m750rider
Second Gear
Second Gear
 
Posts: 141
Joined: 10 Jan 2010
Location: Asheville area, NC

PostPost by: rgh0 » Tue May 20, 2014 11:10 am

Hi Bob
Tonys engine has Dellortos and these heads breath better and need less advance due to this. I have never seen a road going Weber / Dellorto headed twink need more than 30 degrees total maximum advance, though I guess with some of the modern hi ethanol fuels these days anything is possible

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7477
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: m750rider » Tue May 20, 2014 12:38 pm

Rohan

Didn't know that about Dellortos/Webers. Learn something new every day. Thanks

Bob
m750rider
Second Gear
Second Gear
 
Posts: 141
Joined: 10 Jan 2010
Location: Asheville area, NC

Total Online:

Users browsing this forum: No registered users and 14 guests