I am pretty new to flatheads, can someone tell me if they prefer a certain type of oil. Also, how about the transmissions and rear-ends. The trans and rear are in a 1948 F4. Thanks for any help.

Paul S

 

I have had several Flatheads over the last 40 years, I have never had one that has been rebuilt. My current one is a 51 Flathead 6 cylinder in an F1 pickup, it had sit for 15 years prior to my purchase. I always try different oil weights and find the one that the engine uses/leaks the least amount between oil changes. On my 51 I started with 10w-40w, and it went through it like water, and I could hear what sounded like main or rod noise. Even though the oil pressure was a rock steady 55psi. I changed it and added one Qt. Mobil One, and 20w-50w for the rest. It seems to like this weight much better and it's much quieter.
Years ago they ran straight 20w or 30w after a rebuild, then would up the weight as the engine would wear.
This is just my experience, you can find many sites on the internet that have articles on Flathead oil usage.
As far as the trans goes just regular 80w-90w gear oil is fine. I use Valvoline Synethic gear oil in mine.
Rearend, use Hypoid or Multi-Purpose lubricant SAE-90

Hope this helps
Rod

 

Hello, thanks very much, this was exactly what i was looking for. Thanks!


Paul