So my son has been rebuilding our 300 inline six engine from our 1984 F150 in his high school shop class. The engine was completely torn down, machine shop checked and cleaned and then reassembled by my sons class with the teachers guidance. All new internals other than reused Pistons as it only needed honed. Well, after weeks of waiting today was the big start up with everything installed back in the truck...My son stated that it started but within 30 seconds the oil filter blew off from what looked like too much pressure. They tried another filter with the same result. I need some help to know what to tell him to do or check before major damage is done. As far as I can tell they followed all the steps on reassembly, clearances checked on bearings, lube on all journals etc. I have read in my frantic searching online that maybe an issue with pressure relief valve in the oil pump? Clogged oil galleys? Hard to imagine since all parts are new?

I haven't rebuilt an engine since I was in high school but I swear I remember having to prime the engine before the start up. My son indicated they did not do anything like this and did not prime the pump during assembly...Could this be a problem?

Please help me with any advice that I can pass on. I am sick to think we sunk all this time and money just to maybe have to start over again!

 

Are you positive you are installing the correct filter? The only time I've seen the filter blow off was when the wrong filter was installed.

If you think it's too much oil pressure have you checked the pressure with a mechanical gauge?

 

Thank for the reply.

My son said they did check for the right filter and also checked to make sure there was not an old gasket left on the block, etc. He informed me they actually blew through 3 filters!! I am going to cross check tomorrow too just to be sure! (It's so hard not being there to see and know what is really going on!)

It was at the end of the day so they didn't get far enough to check with a mechanical gauge yet but will tomorrow. Ugh...this sucks.

Any thoughts on the lack of priming the pump or engine? Is that something that should have or needed to be done on a 300?

Any other ideas?

 

Doing a prime might help diagnose the problem. Like if the oil pump shaft is hard to drill, then maybe uhm I donno...

I'd stick an oil pressure gauge in the system and prime the engine with a drill.

 

Doing a prime might help diagnose the problem. Like if the oil pump shaft is hard to drill, then maybe uhm I donno...

I'd stick an oil pressure gauge in the system and prime the engine with a drill.

 

More details! Oil filter blew completely off? Might check the threads on the spin on adapter thingy.
Still I would spin the pump with a drill to verify oil pressure as said above. I screw a mech oil gauge directly into the block for break ins.
Doesn't the shop teacher have any clue to what's going on?

 

What name brand oil filter? Were all three filters from the same source?

 

I also think using a drill to spin the pump at this point is a good idea. I'm guessing a stuck pressure relief valve in the pump. If the pump was stored on a shelf for a long time it may have gummed up enough to make it sticky.

FYI I often have to use other sizes / types / brands of filters in applications where a normal FL-1A filter is just too big to fit the chassis and none of these other types of filters has ever blown out. If the threads are correct and the rubber seal seats properly it should not blow out.

What a great learning opportunity for those students.

My son built a Mustang GT engine for his brother's roadster in Auto Shop class. Learned a lot.

 

Sometimes I wonder about the shop teacher but I can't complain too much considering the opportunity he is giving him to hog up the space in the shop. He didn't get to work on it today but tomorrow they are going to look to run the gauge on it and try a few different filters. The rubber seal on the filters are what is blowing out. The first filter I know was a motorcraft FL-1A because I bought it. The other two were napa's. My son is going to see if they have means to spin it from the dist. hole and check the pressure.

Another thought...is it conceivable that if he used too much moly lube on the bearings it could affect pressure...?

 

Avoid NAPA filters if possible, the one I used didn't stop oil from draining when the engine wasn't running.

An oil pump priming tool for a SBF works on a 300.

 

I DID have a blowout on an SBC filter seal because the old seal stuck to the block when the old filter was removed and I installed a new filter over the old seal, which then gave me two seals stacked. It was too much and it blew out the seal. This was when I was running SBCs so that tells you how long ago that occurred.
Check to make sure there is not a seal stuck to the mounting pad.

 

It is the relief valve in the pump. I had an old Ford that I streched the relief valve spring because of low oil pressure at hot idle. Cold it would peg a 100 lb gauge an it didn't blow the seal and it was an fl1 filter. My guess is you won't be able to spin it with a drill the pressure will get to high really quick.

 

Has the gasket on the filter adapter been checked for proper alignment?

 

The NAPA gold is made by WIX, they are a good filter, imo. The cut-rate el-cheapos, I dunno?