Broken Oil Pump - 351 swap?

[djanis99]

Background
Last couple days I'm driving around trying to diagnose a performance issue. Some sort of a miss... Combined with slight top end tapping noise.

Recently replaced valve cover gaskets - maybe some dirt got caught in galleys?
It only happens when hot - maybe ignition system
Pull into driveway and look down to see no oil pressure - well fuck, that's the problem. Been driving around town for 3 days trying to figure out my drivability issue.

I took the oil pan off 2x this winter to fix the rear main seal. On the second round, the oil pump cracked so I bought a new one from auto zone. I haven't pulled the pan yet to inspect - still trying trying to drown my problem in whisky.

Current thinking
I'm really tired of dropping the oil pan and almost ready to bring the truck to a shop. I'm thinking the bottom end is still good, no knocking, maybe 30 miles with no oil pressure though. 7,000 miles on the engine. There are some other upgrades I wanted to do at some point to increase performance.
23 gallon tank - currently 13 gallon tank and I get maybe 60 miles between fill ups
Pro flo EFI - want to increase mileage
Headers
Performance top end - would like some more power

Hate to replace oil pump and find out afterward that engine is shot... - thinking of maybe upgrading from a 302 to a 351. Is that a direct swap or is there a lot more to it than that?

Any advice on what to do from here is much appreciated. Feel like I have a lot more options now that I may have destroyed my engine.

 

[tatersalad]

I went to a 351 when the oil drive shaft in 302 snapped . The 351 is taller and wider but it can be done pretty easily. I already had a profligate hood so clearance wasn't an issue. Put an explorer front dress on it and it fits great.

 

[SHX669]

Get a decent pressure gage ( for fluids ) and check to see what your actual pressure is . Remove the sender and replace with the gage facing the dial in a direction you can see the needle .

 

[SteveL]

351w is a pretty easy swap. Need to add some adapter brackets for front dress and linkages. I think most of the bronco headers are 351 friendly.

 

[djanis99]

Nit

Thanks for input on 351 ~ is a new hood necessary? Have stock hood and body work is really in mint condition so it will be difficult to match.

Great idea on oil pressure test. Back to basics here - hate to pull pan to find nothing wrong.

 

[bluehair]

Careful, a blown 302 caused my 408.

 

[Remos69]

Thanks for input on 351 ~ is a new hood necessary? Have stock hood and body work is really in mint condition so it will be difficult to match.

Great idea on oil pressure test. Back to basics here - hate to pull pan to find nothing wrong.

New hood is not necessary, but a 1-in body lift sure does help. Even then it's real tight. With the other work you are doing it may be just as easy to put in that one inch body lift and not worry.

 

[jckkys]

A 351 swap needs neither a body lift nor a none stock hood. Just don't use a non stock intake or a cheesy after market air cleaner. The increased low end torque is worth it.
Where did your oil pump crack? I'm curious because I've never seen this.

 

[djanis99]

Yeah, it was weird. The machined surface where the oil pump connects to the engine cracked. There are two bolts and a corner cracked off so one of the bolts would not be able to pull it in tight.

Had thought about just leaving it but as long as you have the pan off might as well just put a new one on. Oh well

 

[SHX669]

Yeah, it was weird. The machined surface where the oil pump connects to the engine cracked. There are two bolts and a corner cracked off so one of the bolts would not be able to pull it in tight.

Had thought about just leaving it but as long as you have the pan off might as well just put a new one on. Oh well

Was your oil pump driveshaft " in stalled " ? If so was it seated properly in the oil pump drive AND in the distributor recess/drive?

 

[Rustytruck]

Make sure if you replace the pump you use a heat treated pump shaft. While you under the truck pull some main caps and check the bearings and the rod bearings not a big job once the pan is off but just awkward and not a job for old backs. Bronco engines are not hard to pull.

 

[broncogt]

maybe 30 miles with no oil pressure though. 7,000 miles on the engine.

Zero oil pressure for 30 miles sounds fatal to me.

 

[djanis99]

Well, thanks to the advice of @shx669 ordered a pressure gauge and tested pressure was 70 psi. Traced down open in the circuit. No new 35 for me. I do have some top end noise and a misfire that I need to track down

So, thank you all for your help and advice.