6.2L/ 6.5L Engine Rebuilding

[smganger]

I am in need of rebuilding my 6.5L engine due to loss of oil while driving (oil cooler line failure from a previously unknown repair). It can be started, but make lots of noise/ no power. One option is to rebuild my 6.2L motor to 6.5L. Can the 6.2L be bored out to 6.5L and take the stress of turbocharging? The second option is to rebuild the 6.5L. I think the damage is minimal since I can start it and I have driven it a mile back to my house from the shop. The rebuild will be a complete teardown and machining (crank, block, heads), replacing all bearings, installing new 18:1 comp pistons, phazer timing gears (have now), upgraded cooling (have now), intercooler, and a performance chip to increase boost. I have already installed an FDS cooler. I know that the lower end needs attention as well (4 bolt main bearing caps and a girdle for the block). Can I do all of this with the 6.2L or should I stick with the original 6.5L? What are other modification would be recommended with the engin apart?

Thanks

[Robyn]

Hello and welcome to TDP
Glad to have you onboard.

Well now the only real way to make the decision you are lamenting on is to rip the little beasties apart and see what you have to work with.

To try and overbore a 6.2 to 6.5 is not at all advisable.

You can rebuild a 6.2 and then replace all the 6.5 accessories on it and run it where your 6.5 came from.

You first need to see whats left after the wreck and then go from there.
Inspect the block carefully to make sure you dont have the dreaded cracks in the center main webs.

These will be in the outer bolt holes and progress upward toward the cylinders.

Also what year engine and what is the last 3 digits of the block number (located on the pass side rear of the block just below the head on the bolt flange where you bolt the tranny) something like 599 or 506 or maybe 660 depending on if we are talking 6.2 or 6.5

Once you know what condition the block is in then we can offer suggestions as to what your options are.

Any cracks in the block around the mains may not just jump out at you.
Usually it takes a complete cleaning and a magnafluxing to find them.

You can steam clean the block and then warm the center main webs with a propane torch some and see if any oil bubble out and shows any cracks.

If the block is cracked its game over for that player.
If you have any spun mains, usually its game over too but not always.

The cranks can be ground to .010 under (Actually everything on these engines is metric but this is close for discussion sake)

If the bores are straight and round with no scuffing a light hone and new rings can get you up and going.

Cranks need to be magnafluxed as well to be sure they have no cracks.

Heads need to be inspected carefully too for cracks. Some small cracks in the precups near the ports are ok as long as they dont extend out and across the gasket ring area.

Small cracks betwen the valves is normal but any used heads need to be cleaned and pressure tested to be sure they dont leak.

Any cracks on the firedeck are game over for that head, period.

There are options for some good new heads that wont break your bank account. We can talk about all that later once you know what you have.

Best thing now is to get the little cretures apart and carefully bag up all the gooies as it comes down and mark it for reference.
I use zip lock bags and a felt marker for all small parts and bolt groups.
Once you have everything marked you can box it up and store it for the reassembly.

I like to toss the bolt goups into a can of solvent and clean the stuff as I tear down and then bag it so its already to go once I need it again.

Depending on the condition of things all the lifters need to be bagged up in there own bag and numbered as to what spot they came from so they can go back on the same cam lobe.

The cam can usually be reused unless it has worn or scuffed lobes.

Usually a timing chain on the original sprockets will get that part back into the game again unless there is undo wear.


As far as mods go, A larger custom exhaust is always a good place to start.

On the 6.2 I would possible consider a Banks turbo setup and a free flowing exhaust.

Your 6.5 can benefit from exhaust and maybe a power chip too.

If you are thinking 18:1 custom pistons and such then there is a whole host of goodies for the 6.5 to make it howl

Lets see what you find with the iron and then go from there.

Best to ya

Robyn