Maching Cost?
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Laughing Gas
Joined: Jun 2010
Posts: 1,056
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From: Indiana, PA
Maching Cost?
Well, got a 1979 F.250 4wd with a 400 in it a few weeks ago. It had good oil pressure when we test drove it. So after a few test runs around the house I noticed it`s oil psi was at 5. So I went with all the bandaid fixes (new guage, relocate oil pressure sender, etc), I read on here and still nothing. It would start up with 40 until it heated up and then it`d drop to nothing. So, got it tore out of the truck and started to tear it apart. I took a main cap off and a rod cap off. Both had spun bearings and it looks like that will be the story for the whole bottom end of the motor. I`m gonna check the cam tomorrow but it should be good and new.
So I guess to be short my main question is what will it roughly cost to have a crank machined down and the mains and connecting rods all machined smooth?
Thanks
So I guess to be short my main question is what will it roughly cost to have a crank machined down and the mains and connecting rods all machined smooth?
Thanks
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 83
From: NorCal
Well, got a 1979 F.250 4wd with a 400 in it a few weeks ago. It had good oil pressure when we test drove it. So after a few test runs around the house I noticed it`s oil psi was at 5. So I went with all the bandaid fixes (new guage, relocate oil pressure sender, etc), I read on here and still nothing. It would start up with 40 until it heated up and then it`d drop to nothing. So, got it tore out of the truck and started to tear it apart. I took a main cap off and a rod cap off. Both had spun bearings and it looks like that will be the story for the whole bottom end of the motor. I`m gonna check the cam tomorrow but it should be good and new.
So I guess to be short my main question is what will it roughly cost to have a crank machined down and the mains and connecting rods all machined smooth?
So I guess to be short my main question is what will it roughly cost to have a crank machined down and the mains and connecting rods all machined smooth?
I'm wondering why ya aren't doing a full rebuild. At 5 psi, there are likely other parts and pieces which have also suffered from low oil pressure.
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Laughing Gas
Joined: Jun 2010
Posts: 1,056
Likes: 10
From: Indiana, PA
Also if it ends up being a more money than its worth, I might have a 302 I can get off my brother which was just rebuilt and has good oil psi. So my question on it is could I unbolt the bellhousing off my current 4spd and bolt on a bellhousing from a 302 and be good to go?
Hotshot
Joined: Feb 2004
Posts: 10,847
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From: The Shenandoah Valley
Bearings "spun" or just "badly worn" towards center of the shells?
My '77 did same thing in 1992 going to Atlanta, I thought it was the gage, had 75K miles or about that on it. Hit passing gear down near Chatsworth, sounded like a box of bolts. Drove it on, no knocks, to Atlanta to Carrolton to AIR to Carrolton and back to the Shenandoah Valley of Va. Maybe 1000 miles. Had 4 psi when we put a real gage on it. Jacked it up, dropped panhard rod and pan, took a main and rod cap ooff, crank OK, bearings worn bad. New std bearings one by opne starting at front, loosening and tightening the cap before doing the next, new hi vol oil pump, new gaskets, 30K later still holds 60 psi.
Old timer at the local machine shop asked me how many miles when measuring the shells for size (not marked as to size) and when I told him, he said "about due" as he'ld seen lots of 351M do it, but rarely 400s. I think it's a balance issue? I have a 400 on the stand that just needs a cam kit and it's ready, so I likely will never see another problem with the 351M .... haha.
NO, a 302 (SBF) and a 351M or 400 (series 335) do not share bell housing patterns .... or much else. A 302 also isn't going to make torque like a 400.
My '77 did same thing in 1992 going to Atlanta, I thought it was the gage, had 75K miles or about that on it. Hit passing gear down near Chatsworth, sounded like a box of bolts. Drove it on, no knocks, to Atlanta to Carrolton to AIR to Carrolton and back to the Shenandoah Valley of Va. Maybe 1000 miles. Had 4 psi when we put a real gage on it. Jacked it up, dropped panhard rod and pan, took a main and rod cap ooff, crank OK, bearings worn bad. New std bearings one by opne starting at front, loosening and tightening the cap before doing the next, new hi vol oil pump, new gaskets, 30K later still holds 60 psi.
Old timer at the local machine shop asked me how many miles when measuring the shells for size (not marked as to size) and when I told him, he said "about due" as he'ld seen lots of 351M do it, but rarely 400s. I think it's a balance issue? I have a 400 on the stand that just needs a cam kit and it's ready, so I likely will never see another problem with the 351M .... haha.
NO, a 302 (SBF) and a 351M or 400 (series 335) do not share bell housing patterns .... or much else. A 302 also isn't going to make torque like a 400.
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Laughing Gas
Joined: Jun 2010
Posts: 1,056
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From: Indiana, PA
Well I tore the 400 down. The good news is that the cam and lifters look brand new and undamaged. So the only damages is in the bottom end.
I got to looking and its gonna need the crank machined down, the connecting rods re-machined smooth and the mains all machined smooth.
I got an estimate for $200 for all the machining work. So I guess I`ll try that and see what happens.
I got to looking and its gonna need the crank machined down, the connecting rods re-machined smooth and the mains all machined smooth.
I got an estimate for $200 for all the machining work. So I guess I`ll try that and see what happens.
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