LRP

[Johann65]

Kavesh it the guys are utilising AVGAS as an additive with LRP or full AVGAS this is word on the streets in CPT

I used to work at 5-Sqdn in Durbs (1973) and used to boost my regular petrol with 75/25 % ratio AVTUR that had a 130 Octane. Any higher ratio above 25% caused the valveseats to burn!!

[Johann65]

Here are the results of changing from LRP to 93 Octane Unleaded with Wynns Valve guard.

Clean burning

LRP 006.JPG (92.21 KiB) Viewed 1850 times

[Johann65]

Timing needs to be retarded by about 2 deg to stop slight pinging as a result of change to Unleaded 93. Engine running smoother than before!

[C-Body Barge]

Nice going Johann. I too have had great results with the ULP and Wynns lead additive. Firstly I have done a good amount of km's and have advanced my timing rather than retarded it, I don't know by how much as I melted my timing light, and am using a vacuam guage and tachometer to tune. I would guess my initial is close to +7.5 degrees, this is where I was making best power but had pinging under heavy load. I will need to re-look at the entire timing curve but my hunch is I am not too far off 38 degrees total.

[Johann65]

Hullo CBB, I am from the old school and retarded the initial timing from 15 deg to 13 deg BTDC. Cam angle etc is out of my comfort zone Nice snow and sleet here!!

[C-Body Barge]

Hullo CBB, I am from the old school and retarded the initial timing from 15 deg to 13 deg BTDC. Cam angle etc is out of my comfort zone Nice snow and sleet here!!

Hi Johann, 13° seems rather high, is this with the vacuam advance still connected ?
I use a dial back timing light with a built in tach and a seperate vacuum gauge, I plug the vacuum going to the vacuum advance, I keep the transmission in ''D'' I usually turn the carbs idle circuit all the way in till it stalls then slowly turn it out till I see my highest vacuum reading, I then turn the dizzy till I see highest vacuum reading. I then dial the timing in, this is when I take my reading of 7.5° BTDC. I will then reconnect the vacuum advance and take my total timing, this is done at 3000rpm in ''N'' I then adjust the timing again to highest vacuum. usually I dont have to move it much maybe a hair either way, I then bring it slightly back off highest vacuum this is usually just a slight adjustment. I do this all while the motor is at operating temperature.

To check for pinging I have to go for a drive and find a long uphil, here keep the box in high gear and put my foot as hard on the gas as possible before the auto kicks down (on the torqueflite it only kicks down at wot)

I will go through this procedure 2-3 times till I am satisfied, as the most important test is how the drive feels rather than just what the gauges tell me.

I have not experienced any pinging yet with the ULP and Wynns valve guard. just this weekend I have added another 0.5° of advance and turned the idle circuit 1/4 turn leaner.

[Johann65]

Hullo CBB, I am from the old school and retarded the initial timing from 15 deg to 13 deg BTDC. Cam angle etc is out of my comfort zone Nice snow and sleet here!!

Hi Johann, 13° seems rather high, is this with the vacuum advance still connected ?

Vacuum Yes, This is at altitude, at coast it will be significant lower.