: '69 472 lead additive?



highonchai
04-09-04, 07:26 PM
Hey all, should i be putting lead additive in the premium gas i put in my '69 472 with 181K on it? Does it require it anymore or will the premium be ok? Thanks a million!

capn_zoom
04-09-04, 08:44 PM
Short answer: It can't hurt.

Long answer: Lead additive is used because the lead in gas not only helped raise octane, it cooled and lubricated the exhaust valve seats . With no lead, the seats can erode over time. I don't know if Cadillac used hardened exhaust seats in 1969 (most carmakers didn't, but with Cadillac you can never tell), but if it did, lead additive is unnecessary. Also, if hardened seats were ever installed in your engine (during a valve job or a rebuild), lead additive is unnecessary. If not, the answer depends on use. The harder or more often you drive the car, the more quickly the seats will wallow out. If you only putt around town or do some low-speed cruising on the weekends, your engine could probably live its entire life without any additive. Driving the car hard, often, or at higher speeds are all reasons to start using the additive. If you ever rebuild, consider getting hardened seats installed. This will enable you to run additive-free.

DaveSmed
04-10-04, 01:40 AM
I figure for what it costs, and the difference it makes, i'll use it. I can definitely feel the difference when I forget to put it in, the car accelerates a little slower, and idles a bit rougher.

highonchai
04-10-04, 02:13 AM
Hmm, sounds good, ill have to do an experiment to see if theres a difference between additive and none, but mostly (for now) it'll just be a show car and something to putz around with. Eventually i'll rebuild, hopefully i wont be forced to, but when i do ill add a few horses and install hardened exhaust seats, after that i'll probably take it on trips and such. But i just cant justify paying almost $2 a gallon up here plus the additive when ill be getting 10MPG tops. So ill fill it up and add additive, and the next tank ill leave it out (cant hurt right?) to see if theres any difference. Thanks for all your help!!:worship: As always: you guys are the Cadillac of Cadillac owners!

lux hauler
04-10-04, 03:17 AM
I read somewhere (or someone told me) that hardened seats in the 472/500 engines wasn't really necessary because of the high nickel content. The heads were hard enough without the hardened seats but I don't know that to be a fact.

garck
04-12-04, 01:15 PM
Isn't lead additive for cars that needed Leaded Gas? my 69 CDV says "unleaded gas only" which makes believe that it wouldn't need lead additive

lux hauler
04-12-04, 11:23 PM
I didn't think any car required unleaded fuel until the mid seventies...'74 or so?

I had a car that was a '73......it didn't require unleaded.
Is it a Cali car maybe?

Sasquatch
04-13-04, 06:43 AM
Would additive help to make the exhaust temp a bit lower? I noticed there is alot of under the hood heat on my 69 472 motor. It is a big block though and I suspect that is normal. What is the normal operating temp of these motors?

Imprl59
04-13-04, 05:13 PM
At 181k I wouldn't worry about the lead additive. The only thing it will do for you is to help stop the exhaust valve seats safe. Valve recession is only a problem in engines that are revved high for long periods of time (drag racing). At your mileage by the time your exhaust seats are messed up (if ever) its going to be well past time for a valve job anyway.

I have pulled apart a couple dozen engines that have been running since the 80s on unleaded and have yet to see an engine with a problem.

Steve B.

lux hauler
04-13-04, 06:53 PM
Would additive help to make the exhaust temp a bit lower? I noticed there is alot of under the hood heat on my 69 472 motor. It is a big block though and I suspect that is normal. What is the normal operating temp of these motors?Normal operating temp is higher than most people are used to. I heard that the temp sensors were factory set to not show a heat problem until the engine reached 256*!!

highonchai
04-14-04, 12:44 AM
woow, yeah ive noticed the heat under the hood feeling a bit uncomfortable.

So i wont worry about the lead adding then, easier for me. Thanks a lot guys!!:worship:

garck
04-14-04, 03:40 AM
I didn't think any car required unleaded fuel until the mid seventies...'74 or so?

I had a car that was a '73......it didn't require unleaded.
Is it a Cali car maybe?


yeah... its a cali car. But did they make a different engine just for Cali?

lux hauler
04-14-04, 04:49 PM
yeah... its a cali car. But did they make a different engine just for Cali?I doubt that the engine is different, just different requirements from the state.
Anyone know what year California started requiring no-lead fuel? I'd almost bet it was earlier than other states.