1993 4.0 total rebuild

[Jerry Dean]

hello people glad to find you guys , I have a 93 ranger 4x4 with a 4.0 with 510,000 mile and yes its time for a rebuild due to poor running and failed the blow by/leak down test , since I'm doing a total 100% rebuild I thought it be cool to go over size 0.048 per Doug since I have the good yr block on bore and little hotter cam plus anything else I need to make it run good , I am original owner die hard Fords for life and this will be the only rebuild needed in my time . not want a race motor just a little kicker , what are your thoughts . thanks Jerry

 

[alwaysFlOoReD]

Why 50 thou? That just means less meat for a 2nd rebuild. I would use as small overbore as the cylinders will take, after looking at piston costs.

 

[2011Supercab]

I'd go as little overbore as you can get away with, also make sure you can find rings to go with that size.

Parts are getting harder to find for those older engines.

 

[gaz]

@Jerry Dean ,
I would never overbore more than necessary. If you can get away with 0.010" go that route and enjoy your stronger, longer lasting engine.

If my only option we're to go 0.050", I would get another block before sailing that ship! One thing I failed to understand at one point was that increase displacement from an overbore was NOT the fast track to efficiency; if you want a more efficient power plant, then increase your compression and make your valve train adjustable ..)

 

[Jerry Dean]

Why 50 thou? That just means less meat for a 2nd rebuild. I would use as small overbore as the cylinders will take, after looking at piston costs.

in my time wont require a second rebuild , I was just thinking of ways for alittle more HP while doing a tear down .

 

[alwaysFlOoReD]

in my time wont require a second rebuild , I was just thinking of ways for alittle more HP while doing a tear down .

True enough. Engines last a lot longer now than when I first started. I still have that mindset tho... Lol

 

[Jerry Dean]

@Jerry Dean ,
I would never overbore more than necessary. If you can get away with 0.010" go that route and enjoy your stronger, longer lasting engine.

If my only option we're to go 0.050", I would get another block before sailing that ship! One thing I failed to understand at one point was that increase displacement from an overbore was NOT the fast track to efficiency; if you want a more efficient power plant, then increase your compression and make your valve train adjustable ..)

I like what you say makes sense

 

[gaz]

@Jerry Dean ,
Great, then you see that increasing the displacement by 1.25% should yield 2hp +/- while increasing the compression ratio a full point can offer 8hp +/- (a 400% larger bump than the displacement ∆). Additionally 2 or 3 compression points are not out of the equation since stock is 9:1:
• a 0.035 head mill will yield a point
• 95-97 fastburn combustion chamber heads or 98+ fastburn combustion chamber heads will add a point, from your 93 slow burn combustion chamber heads
• Ford SOCH 4.0l flat top pistons will add a point

Those 3 options are all affordable and compliment a rebuild as these Cologne 60° V6's do respond well to a increase in compression; just take into consideration the extra heat that the process will add and take proactive steps to control it:
• add an engine oil cooler
• 1 or 2 range cooler spark plugs
• exhaust jackets on headers or exhaust manifolds
• improved cooling radiator
• stainless steel cooling hose
• improved flow exhaust system

I use all of the above.

NOTES
* If you want a little more useable power after your rebuild, then lose the crankshaft driven fan/clutch for a 15" electric fan; it doesn't make more power but it does reduce the load on the crankshaft...it makes a noticeable difference driving and at the gas pump.
* synthetic fluids offer another potential reduction on the engine load.
* you may want to consider an aftermarket multi spark ignition, if your not make a street racer, then a multi spark will have a lot to offer your OHV 4.0l at engine RPM below 3,000, where it will live almost 100% of the time.
* K&N offers a 1 million mile warranty on their air filters, making a drop in K&N, at least practical.

 

[Jerry Dean]

Thx Josh I see your point and agree now since this block started at a 2.6 liter then grew to max at 4.0 , I would “try if possible “ to stay with my heads $$ and just get a good builder to work on the flow abit , what are your thoughts on the little hotter cam idea , lifters & pushrods . Your ideas here are much appreciated for me