Engine Rebuild Thread

[thebaton]

A thread to discuss engine rebuilds....

Would love to hear from those who have already done it. I was planning on doing a rebuild in a couple of years and have been researching it. Having the coolant run up to the redline several times recently and the thing go into limp mode I`m considering bringing this forward. I might get a second hand engine and rebuild that if skimming the cylinder head to fix the overheating isnt an option.

Love feedback on my wishlist (some of it might just be pie in the sky stuff but its fun to plan/dream)
Gapless piston rings
inconel valves & springs- maybe hollow valves
Any thoughts on different spring shapes? beehive/double etc
Ceramic or DLC coating on Pistons
Anyone know anything about piston bowl shapes? I believe Mercedes have some new shape that is supposed to be better (cant find a link so maybe its another manufacturer but if its new it may not be available in after market but other shapes are)
some lightweight connecting rod (not sure whats available but inconel or titanium might be possible but costly?)

Do these engines use cylinder liners? what are pros cons or is it even possible to bore out the cylinders and fit liners in these engines? Could use ceramic coated liners - are ceramic liners available?

Now this sounds crazy but its not as mad as you think, it would be possible to fit something like a scrap yard SC14 or ARM500 supercharger and wire in an electromagnetic clutch (based on throttle position or boost) with the right tuning. Not as efficient as a twin turbo setup but cheaper and would thoroughly eliminate lag. Even if you set it up to turn off past x psi i.e when the turbo is spinning).
Another crazy idea would be to fit a crankcase vacuum pump - dont think this is legal on road so would also need an electromagnetic clutch but with a switch in the cabin for offroading

What else?

[aids84]

What engine are we talking about here?

If you've got the 2.5 diesel and are experiencing overheating I would be looking at ways to improve head gasket sealing as the issue is caused by shortcomings there. O-ringing of the deck and possibly head studs would be good improvements to make.

None of the cast iron engines use liners. I imagine the 4N15 would have liners in the alloy block, but personally I haven't had one apart to see what's inside.

[thebaton]

Yeah the 2.5, what about a double o ring?

Are there any draw backs to o ringing the deck?
Would you recommend boring out for bigger head studs?

[Longranger1]

With the coolant passages between cylinders I suspect O-ringing the block would be a challenge. Not much meat there.

A custom high performance head gasket might be a better option.

[thebaton]

Could you skim the head and fit a thicker gasket?
Maybe it's just not worth all the hassle??

[snowline]

Does anyone (with actual industry knowledge) know what the failure rate of these engines is?

5%? 50%? It would be nice to know. (hopefully not terrifying)

[snowline]

I spoke to my mechanic today. He services an estimated dozen of the 2.5 Tritons. They are a fairly common car in my neck of the woods. None of them has had a gasket failure. One has had a radiator needing a replacement.

He knows of 2 overheating with the engine block woes.

Take it for what it's worth, but I feel a bit better knowing this.