Author Topic: 390 fe using lots of oil  (Read 4158 times)

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390owner

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390 fe using lots of oil
« on: October 03, 2017, 06:57:46 PM »
My 390 is using a lot of oil.(2 quarts at 1100 miles) It has around 125000 miles on a professional rebuild. It is not smoking, the plugs are clean. Any ideas

machoneman

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Re: 390 fe using lots of oil
« Reply #1 on: October 03, 2017, 07:45:44 PM »
Is that 125,000 miles or a typo?
Bob Maag

390owner

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Re: 390 fe using lots of oil
« Reply #2 on: October 03, 2017, 08:30:03 PM »
No typo. This engine runs and pulls as good as it ever did. If it was worn out I should be loosing power and seeing a lot of smoke right?

machoneman

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Re: 390 fe using lots of oil
« Reply #3 on: October 03, 2017, 10:18:27 PM »
Check your valve seals (old, dried up and crumbling) or try some Sea Foam if the oil rings are stuck.
Bob Maag

390owner

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Re: 390 fe using lots of oil
« Reply #4 on: October 04, 2017, 06:20:01 AM »
How big of a pain are they to change without pulling the heads.

machoneman

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Re: 390 fe using lots of oil
« Reply #5 on: October 04, 2017, 07:13:47 AM »
Not that bad, that is IF that's the problem. I'd also check that oil drains at the back of each head aren't plugged with crud. Then, check your PCV valve if equipped. But if those are good to go, then maybe the seals. Here's a vid. Be sure to look at a few others (to the right as this one plays).

https://www.youtube.com/watch?v=ob_4-F-m1FI
« Last Edit: October 04, 2017, 07:16:20 AM by machoneman »
Bob Maag

390owner

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Re: 390 fe using lots of oil
« Reply #6 on: October 04, 2017, 07:15:16 PM »
Thanks I will check out the video

390owner

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Re: 390 fe using lots of oil
« Reply #7 on: October 06, 2017, 07:50:19 PM »
I talked to the machine shop that built this engine about 18 years ago. I told him I wanted around 350 or more horse. He said he would port the heads, balance the lower end, cam and so on. When he built it before he put a rv cam what ever that was then and bored it 60. I was getting 10-12 miles per gallon which is fine with me. But if I have him do this extra stuff for more power will it kill what little mileage I am getting now? I get 8-10 empty and 4-5 towing now. What do you think

steinauge

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Re: 390 fe using lots of oil
« Reply #8 on: October 06, 2017, 09:27:55 PM »
Freshening the engine will likely improve your mileage.What would worry me is if the bores are worn you are already at +.060".

390owner

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Re: 390 fe using lots of oil
« Reply #9 on: October 06, 2017, 09:38:14 PM »
I have two standard blocks I was going to use one of them for a complete build again

chris401

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Re: 390 fe using lots of oil
« Reply #10 on: October 08, 2017, 08:07:34 AM »
I talked to the machine shop that built this engine about 18 years ago. I told him I wanted around 350 or more horse. He said he would port the heads, balance the lower end, cam and so on. When he built it before he put a rv cam what ever that was then and bored it 60. I was getting 10-12 miles per gallon which is fine with me. But if I have him do this extra stuff for more power will it kill what little mileage I am getting now? I get 8-10 empty and 4-5 towing now. What do you think
You should get better mileage than that. I have a 3/4 ton that got better than 6 towing 19,000 gvw. A 390 built for towing should get 6-8+ towing a normal load. A local man says he got a consistant 17mpg range from California to Texas. He was transporting something, can say what though.

EDIT: My engine is a 352 with comparable empty power and mileage of a mid 90's 351. The 352 is stouter towing.
« Last Edit: October 08, 2017, 08:11:17 AM by chris401 »

cjshaker

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Re: 390 fe using lots of oil
« Reply #11 on: October 08, 2017, 11:41:30 AM »
I just checked my fuel mileage on my recent tow to and from Drag Week. I was getting between 7-8 mpg. That's with a '70 F-350 dually dumptruck pulling 9000 lbs with an enclosed trailer @ 60-65 mph, running a BP massaged 390 with a 750 Holley.
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

Heo

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Re: 390 fe using lots of oil
« Reply #12 on: October 08, 2017, 04:58:05 PM »
Dought that would give you a cost of 1.10$ per mile in Sweden :'(



The defenition of a Gentleman, is a man that can play the accordion.But dont do it

390owner

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Re: 390 fe using lots of oil
« Reply #13 on: October 08, 2017, 07:35:42 PM »
Yes that is what I was getting 7-8 towing my 24 foot camper here in the hills. Now it is 4-5. I thinks the miles are the issue as well as the oil usage

390owner

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Re: 390 fe using lots of oil
« Reply #14 on: October 17, 2017, 07:45:32 PM »
I noticed this weekend while pulling my camper there was a lot of blowby smell. I guess I just need a rebuild >:(