| Slant Six Forum https://www.slantsix.org/forum/ |
|
| Pre 72-73 engines https://www.slantsix.org/forum/viewtopic.php?t=30761 |
Page 1 of 1 |
| Author: | Karasik87 [ Tue Aug 26, 2008 7:48 pm ] |
| Post subject: | Pre 72-73 engines |
Do y'all with the older engines have to add lead or something to your gas? How exactly does running the engines that were built before the switch to unleaded gas work? Wow, that question is grammatically amazing. |
|
| Author: | dusterguy225 [ Tue Aug 26, 2008 8:07 pm ] |
| Post subject: | |
I am no expert, but I think all the early 70s engines can run leaded/unleaded gas, or a mix of the two. I know my 74 can. If you have an owners manual, look in there. Thats where I found mine.  Note: The US did have all unleaded gas until the early 90s, but some late 70s and most 80s cars were only unleaded. |
|
| Author: | stephaniebrite77 [ Tue Aug 26, 2008 8:44 pm ] |
| Post subject: | |
When I had the original 1965 engine in the car, I ran unleaded 87 just fine. According to THOR, the only modifications made to the engines were actually in the head, making the valve seats harder. Eventually, if I'd kept that engine (or if I resurrect it) I'll have to install hardened valve seats, but other than that, I don't believe any mods are necessary. |
|
| Author: | SlantSixDan [ Tue Aug 26, 2008 10:18 pm ] |
| Post subject: | |
You needn't add anything. Just keep the engine well tuned and read this thread. |
|
| Author: | Karasik87 [ Fri Aug 29, 2008 4:05 pm ] |
| Post subject: | |
thanks. i was just wondering. my engine is from 73. so i wasnt worried or anything. i was just curious. |
|
| Author: | KBB_of_TMC [ Tue Sep 09, 2008 10:49 am ] |
| Post subject: | |
My '74 Dodge was designed for leaded gas, and when Amoco stopped carrying leaded gas at the end of the '80s they put out brochures claiming that their Silver would prevent valve damage. After a few thousand easy highway miles on their gas I burned an exhaust valve. I discarded my Amoco credit card and have avoided them ever since. The EPA published that you'd wouldn't fry valves on unleaded if you avoided "severe service" - digging deeper, I found the EPA defined "severe service" as towing, driving uphill or over 45 mph. Since then, I use a Mn-based CD2 lead substitute regularly at the recommended concentration for my pre-75 cars & trucks and have never fried a valve. I can still find it at Walmart, but it's getting harder to find. |
|
| Author: | SlantSixDan [ Tue Sep 09, 2008 3:33 pm ] |
| Post subject: | |
Quote: My '74 Dodge was designed for leaded gas
Nope. Unleaded. V8s for '72 and slant-6s for '73 got induction-hardened valve seats making those and all subsequent engines fully compatible with unleaded fuel. The cars didn't get catalysts until '75 to '79 (depending on model and market) so many vehicles were produced with full mechanical compatibility with unleaded but emissions compatibility with leaded. Your '74 was one of those. Quote: when Amoco stopped carrying leaded gas at the end of the '80s they put out brochures claiming that their Silver would prevent valve damage. After a few thousand easy highway miles on their gas I burned an exhaust valve. I discarded my Amoco credit card and have avoided them ever since.
Neither Amoco nor their fuel was responsible for your valve burning. It was pure coincidence.Quote: Since then, I use a Mn-based CD2 lead substitute regularly at the recommended concentration for my pre-75 cars & trucks and have never fried a valve. I can still find it at Walmart, but it's getting harder to find.
You are wasting your money not only on the unnecessary additive, but on greatly reduced spark plug life. There was absolutely no material or build difference in the valvetrain of a catalyst-equipped '77 Aspen vs. your '74 Dodge.
|
|
| Page 1 of 1 | All times are UTC-08:00 |
| Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/ |
|