460 Ford Forum banner
1 - 7 of 7 Posts

Registered
1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
Joined
265 Posts
Discussion Starter · #1 ·
So, I've decided to roll a fresh set of rod and main bearings and replace the oil pump on the 351M in my 90LX. I've pretty much got it all planned out on dropping the k-member for it, but would love any assistance on actually rolling in the new bearings, checking everything with plastiguage, and replacing the rear main seal. Have like almost non-existent oil pressure when it's warmed up and I'm just trying to make it last till I get my big block and the car ready for marriage! 馃榿
 

Registered
1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
Joined
265 Posts
Discussion Starter · #2 ·
211 views and nobody has anything they could toss in as far as nuggets of aid? C'mon, I know we gots too much experience on this board for that! 馃
 

Registered
1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
Joined
265 Posts
Discussion Starter · #3 ·
Question: may be a stupid one.. should I do the rods first and flush out the journals then the mains and flush out those journals? Or start at the front and work my way back? I wanna try to clean out all the old stuff in the crank that may have been doing any damage as the bearings are showing signs of wear from dirty oil. Even tho I've flushed out the engine with kerosene before I ever cranked it, then used 10-30w with 1 qt of tranny fluid for only about 2-3 hrs total run time at maybe 10-15 mins at a time to help flush it, then 20-50w. The whole bottom end smells like burnt oil too.. I pulled 1 rod, copper showing on the top 1/2 and the bottom wasn't far off, and just the bottom of 1 main, it had a lot of copper showing. If my caliper measurements were correct there was .006 of wear on the main shell I took out. Thank you for your time and patience.
 

Registered
Joined
693 Posts
We did the kerosene thing a few years ago.The truck had been sitting for years and we didn't plan on keeping the motor long term anyway so why not? Put straight 30 in it and went for a drive.It ran OK...for about 10 min.Lost oil pressure and it locked up.Supposed to have run fine before parking.Waste of good kerosene!
Your situation...Drop the crank a little and do the mains first.Just push out the old,stick in the new. Rear seal will be the most difficult but not bad. As far as oil pressure goes,I had an old 400M that had ZERO pressure at idle,went up to about 30 at speed.Ran fine for the year I had it,sold the truck to a friend who drove it for a year.He sold it and it was still running.
 

Registered
1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
Joined
265 Posts
Discussion Starter · #5 ·
Awesome!! Thanks for the info! That's gnna be really helpful! I wasn't really sure where to start on the process. It smells really burnt in the bottom end too, I plan on plenty of brake cleaner, and to be sure to use Ultra Slick on all going back, with a new oil pump. Will prime it before firing too. I'll post my progress, hopefully it'll help someone else in the future!
 

Registered
Joined
693 Posts
The kerosene treatment sounds like a good idea but it probably frees up a bunch of sludge and whatever that ends up in the oiling.Really don't know what happens after that but I would guess that is what is causing your burnt smell,among other things.When you get it running,I would immediately change oil right after it warms up...and maybe repeat the process a couple times.I wouldn't use 20:50 to raise pressure as these M motors aren't known for their high psi anyway.Don't mess with Plastigauge.The crank probably won't be a thing of beauty but unless a bearing spun or worse,close your eyes and stick in the new bearings.
 

Registered
1990 Ford Mustang LX 351M powered!! Project Cherry Bomb!!
Joined
265 Posts
Discussion Starter · #7 ·
Oh I just used the kero to clean up the top end and I did use a lil extra that went thru that I dumped out after spinning it thru with a drill on the dizzy.. I never ran the engine with it in it.. I got some good cheap 10-30 for it for this first run, I still dunno WTF I'mma do with the Frankenpan oil pan this dude chopped up and built for this thing... SMH...
 
1 - 7 of 7 Posts
Top