| Author |
Message |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2745
Registered: 10-2002
| | Posted on Thursday, October 09, 2003 - 6:20 pm: | |
Just got back from a long drive in the Dusey. It's runs much cooler with more advance. Driving that car is a real trip. I'm going to use reg. gas from now on.
Thanks |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 548
Registered: 5-2001
| | Posted on Thursday, October 09, 2003 - 6:04 pm: | |
Use of high octane gas is just a waste of money for your application imo. I can't think of any reason why it would do any harm though.
The sin is to not have enough octane in a hot, high compression engine, under a significant load. In this instance, burn will begin prior to the spark igniting it. Sufficient octane will delay the beginning the beginning of the burn of the mixture until the spark begins it. Once burn is initiated, octane has no effect. It does not burn faster nor does it burn hotter or provide any more power. |
Hans E. Hansen (4re_gt4)
Intermediate Member
Username: 4re_gt4
Post Number: 1725
Registered: 4-2002
| | Posted on Thursday, October 09, 2003 - 5:28 pm: | |
James: You have mail. |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2728
Registered: 10-2002
| | Posted on Monday, October 06, 2003 - 5:00 pm: | |
Hans
Not only do I have it but it's a bound book. Very Nice. |
Hans E. Hansen (4re_gt4)
Intermediate Member
Username: 4re_gt4
Post Number: 1705
Registered: 4-2002
| | Posted on Monday, October 06, 2003 - 4:56 pm: | |
Just kidding, James. Do you actually have an owner's manual for the Dusenberg? It would make for some great reading. I wasn't sure if cars this old even came with manuals. |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2713
Registered: 10-2002
| | Posted on Sunday, October 05, 2003 - 6:56 pm: | |
Hans
It does but I still can't figure out if Modern gas with it's higher octane has any effect and if so what? Should I use high test or reg? Probably reg. right? |
Hans E. Hansen (4re_gt4)
Intermediate Member
Username: 4re_gt4
Post Number: 1703
Registered: 4-2002
| | Posted on Saturday, October 04, 2003 - 1:53 pm: | |
James: Shouldn't the owners manual explain this? <g> |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2710
Registered: 10-2002
| | Posted on Friday, October 03, 2003 - 7:36 pm: | |
Mitch
No. Mine is a 31. They didn't use superchargers until 34. From what I can tell fuel of that era was about 60 octane and varied quite a bit. It is very low compresssion. 7 Liters, straight 8 dual overhead cams. 4 valve heads. 260hp. I have been using hi test but feel that may be a mistake. The way I was told to set adv. is start on full ret. and then move to full adv. Pull from low rev in high gear and listen for det. Back off slightly.
It does seem to run hot unless it's near full adv.
Water pump and rad are fine. Before I bought this car it was a trailer Queen that probably hadn't moved except onto the show field in years. I'm trying to turn it back into a driver. |
Mitch Alsup (Mitch_alsup)
Intermediate Member
Username: Mitch_alsup
Post Number: 1153
Registered: 4-2002
| | Posted on Friday, October 03, 2003 - 7:26 pm: | |
James, after re-reading you Duesburg post--too much octane may be making it impossible to get sufficient advance (with the current adjustments)! Causing unburned fuel to burn on its way down the exhaust.
With 60 octane it should be running 6:1 compression ? Does it have a {turbo/super}charger? |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2708
Registered: 10-2002
| | Posted on Friday, October 03, 2003 - 4:51 pm: | |
Even though it originally ran on about 60 octane unleaded?
Thanks |
Mitch Alsup (Mitch_alsup)
Intermediate Member
Username: Mitch_alsup
Post Number: 1149
Registered: 4-2002
| | Posted on Friday, October 03, 2003 - 4:19 pm: | |
I agree with hans--more octane widens the range where spark advance is "reasonable" |
Hans E. Hansen (4re_gt4)
Intermediate Member
Username: 4re_gt4
Post Number: 1700
Registered: 4-2002
| | Posted on Friday, October 03, 2003 - 2:44 pm: | |
James: I can't possibly see how high octane would hurt. Since your car has a rather 'un-scientific' advance setting, I'd think that you'd have more flexibility in timing. ie - the high octane should be more forgiving of errors in setting the timing. |
Ken (Allyn)
Intermediate Member
Username: Allyn
Post Number: 1194
Registered: 10-2001
| | Posted on Friday, October 03, 2003 - 10:59 am: | |
When I got the timing corrected on my Lotus from zero to 12 degrees advance, I intially ran 5 degrees C hotter. Everyone said this wasn't possible, in fact it should run cooler. Turned out my cooling fan switch was shot! Now it's running almost 5 degrees C cooler than before I advanced it, so on my car at least, more advance made it run cooler. |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2704
Registered: 10-2002
| | Posted on Friday, October 03, 2003 - 9:48 am: | |
Mitch
Is there any reason to use high octane in this motor? Does it help or hurt. Will higher or lower octane effect running temp? |
Mitch Alsup (Mitch_alsup)
Intermediate Member
Username: Mitch_alsup
Post Number: 1144
Registered: 4-2002
| | Posted on Friday, October 03, 2003 - 9:41 am: | |
There is a narrow band of advance where an engine can absorb the most power from buring a mixture of gasoline and air. Less advance and the mixture is still buring when the exhaust valve opens, too much advance and some of the power produced works against the engine producing power (more pressure on the compression stroke). Either one leads to higher temperatures either in the oil (too much advance) or in the headers (too little). |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2698
Registered: 10-2002
| | Posted on Friday, October 03, 2003 - 8:25 am: | |
Mike
Thanks. The problem I was having was in my Dusenberg. That car has a cockpit adjustable ADV/RET lever with a range of 20deg and an automatic centrifugal adv/ret of 40 deg. I was having trouble keeping it running cool unless I got the adv as high as possible with the cockpit control. I guess this system allowed you to calibrate timing manually to different gas which in the 30ies varied and was low octane. |
Mike Florio (Mike_in_nevada)
New member
Username: Mike_in_nevada
Post Number: 48
Registered: 6-2003
| | Posted on Thursday, October 02, 2003 - 8:45 pm: | |
I have personal experience on this one. My '75 308/GT4 would run at 90 C on the water and 270 C on the oil. I changed the oil temp sensor, no change. The static timing was spot on at 7 degrees BTDC. I tried different kinds of oil, no change. I was getting ready to drop the pan and check the oil pump when I mentioned the problem to an expert engine machinist I know who builds dragster motors for a living. He said check your timing advance.
Rear distributor advanced cleanly to 35 degrees. Front distributor advanced to 10 degrees, then stopped advancing.
My friend explained it to me this way: retarded spark heats up the piston, not the valves, head or combustion chamber. The piston heat is transferred to the oil via the con rods and the crank. The head doesn't see the heat, it all travels to the bottom end.
I am in the process of rebuilding the distributors now. (As soon as I get this *(&*&^ Allen Distributor machine I bought on EBay up and running). I am positive this will solve the problem. |
Philip Airey (Pma1010)
Member
Username: Pma1010
Post Number: 466
Registered: 7-2002
| | Posted on Thursday, October 02, 2003 - 2:14 pm: | |
Jim
I've always heard less advance = higher exhaust temps. Too much advance stresses the rods. Now over to someone with a more complete understanding... |
James Glickenhaus (Napolis)
Advanced Member
Username: Napolis
Post Number: 2690
Registered: 10-2002
| | Posted on Thursday, October 02, 2003 - 12:21 pm: | |
Could someone please explain the relationship between Advance/retard and engine temp.
Thanks |