Engine Rebuild - to use running in oil or not?

[cnprior]

Hello,

I've just rebuilt a 24V V6 ford engine. I am at the stage of getting ready to prime the oil pump (going to be using the garden sprayer type method - until oil comes out of the cam lobes at the top of the engine and rotate the engine after a period of time to coat the journals all the way aorund) and fill it with oil.

There is some debate on the correct type of oil for this engine (originally out of a Grandad Scorpio), but I have seen stated by many that 5W/50 fully synthetic or 5W/40 should be suitable.

I've read multiple posts about running in engine oil, containing a high zinc content being good for the first 200 miles......and 'mineral based' to help the piston rings bed in.

I've contact millers oil for their advice, but to be honest over multiple posts the advice became conflicting and left me more confused than when I started.

How would you guy's approach a freshly built engine with regard to first start up and what type of oil to use for the bedding in process?

Thanks,

Chris

[SturdyHSV]

Everything I read / people I spoke to said a 30 weight non synthetic oil (synthetics are too slippery and can stop the rings bedding in apparently)

Seems to have worked for my LS so far, but am only 1,300 miles in.

[boombang]

What did you do and what did you replace as part of the rebuild? How comfortable are you with the post machining clean-up?

For example fresh bores and new rings I would use mineral oil for a short period then dump the oil and filter.

If new cams / lifters I'd have coated them in a specifically designed lube on install - especially noting bedding in new cams needs revs and idling is a killer.
If ground cranks / new bearings the same.

That said I have never used breaking in oil, just a mineral oil of the appropriate weight.

[drmotorsport]

I know the old school method was to use a non synthetic oil of a similar grade for bedding in, however such oils seem to be rare these days. Millers do a specific running in oil and i've always used that in my race engines after a rebuild.

[cnprior]

Thanks for feedback so far.

New rings, shells, different cams, bores honed, but not over bored.

I would call it a refresh than a blue print build.

Assembly lube has been used throughout.

[twibs]

I used millers running in oil drove it like a granny and it lasted 10 minutes, burnt oil.
rebuilt and used millers again, drove it like normal and 10000 miles in uses very little oil.
Wilko also do a cheap mineral oil which is ok for the first fire up whilst you run the cams in.
Drain then switch to millers.

Main thing is ensure its spotless clean from machining and oil pump is free of debris if its new.

[Zener]

10/40 mineral and just drive it various loads etc do not drive it slowly or anything silly like capping revs to 3k RPM etc etc , its a bucket cam-gear style engine so no need for paranoia over cam break-in etc unlike a push-rod flat tappet engine , the first 50/100 miles are vital IME for proper piston ring break-in/ultimate seal , once this window/slot of opportunity is missed its missed

[CrutyRammers]

I've used it for both my rebuilds, for the first few hundred miles, then drain it, change the filter, and put the standard stuff in.

[HJG]

As above, be sure to vary the engine speed and load. Imagine an escalating staircase graph of x axis =time and y axis = load. Do this and vary the RPM across it.

[Evoluzione]

Use either a basic mineral or Millers break in oil.
Run it hard.
End of story

[DVandrews]

Evoluzione said:

Use either a basic mineral or Millers break in oil.
Run it hard.
End of story

What he said, have built 300+ engines with new pistons / rings / liners always use cheapo 20/50 or Millers depending on owners sensibilities.

Dave

[cnprior]

OK - now bought 20w/50 mineral oil, garden sprayer to pressurise gallery once oil pump fitted.

Next in the saga......

Purchased oil pump, brand new as I felt the previous one should be replaced after severe carbon build up in the engine, probably resulting in its demise. Pump purchased 2 years ago, in a sealed plastic bag......cut it open, put some oil into it and tried to hand prime it......was completely stuck.
Thought it was me being a bit 'namby Pamby', thought of using a drill ont he shaft - but surely oil pumps should move easily enough.

Left it alone, went for a cuppa - as I have a habit of when stuck getting progressively bigger bars and hammers - which has cost me a lot of time in the past......better to walk away some times. So decided to open the oil pump up last night to have a look-see.......rotor casing and rotor both had rust in several places. IT has been stored in my garage which is dry and fairly warm........but 2 years after purchase no hope in sending it back.

So I decided to 'polish' it up with wire wool as best as could be, no chance......moved onto buffing pads, nope.....eventually used some 80 grade sandpaper into the squares of the oil pump......cleaned the most out, but very difficult to get out. Cleaned with brake cleaner and then rebuilt it.

Oiled the pump, primed it off the engine, spun it - rotated smotth as hell compared to the rust prevented attempts 24 hours previous. Happy that I have done my best, put the oil pump to one side ready for fitting.

Then I goto bed.....head starts imagining engine with catastrophic failure as I take my wife out for first drive / date to Cleethorpes next summer !

So, I cannot easily afford £120 for another pump.....but I know it is the right thing to do....but what are the realistic chances of rust debris really wrecking an engine? There are filters, the rotor does not touch the casing lobes inside the pump so shouldn't dislodge any further material, oil journals are all large and clear.

In an ideal world - I would replace the pump, but I'm thoroughly skint (for good reason I will explain another time)......realistically what are the chances of this such a bad idea to carry on? I see so called engine rebuilds taking place on dusty floors, stty rags being used to 'clean' crank bearing surfaces.....how much of a risk is me using this oil pump?

[stevieturbo]

pictures...how bad can it be ?

[GreenV8S]

If there's no possibility of metal-to-metal contact and all the metal surfaces are smooth and clean I don't see any reason to expect any problem. It's not as if you're going to leave bits of rust waiting to flake off. And presumably the pump outlet is straight into the oil filter so anything that you missed won't get far. As long as the surface the seals run on are clean and the mating surfaces are clean, I'm sure it'll be fine.

[cnprior]

Here are a few pictures.....

[cnprior]

[cnprior]

[cnprior]

[stevieturbo]

clean it, prime with some oil/vaseline and put it back together and never worry about it

[Zener]

This ^