Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[mantaray]

Over the last few weeks, I have been doing a top-end rebuild on my V6 2.5 engine.

Today I got the cams fitted and timed her all up, then started to refit all the auxiliary parts, all was going well until I went to fit the oil pressure switch. Only to find that the threads are fu**ed. but to make matters worse, it has already been helicoiled, so the oil pump housing is US. 

I'm now not sure what to do, I could try and replace the housing, but a) I don't have a spare and b) That crank bolt is very hard to get out. Or I try and find another bottom end and swop my heads onto it.

What do you think would be the best option? 
Has anyone got either a later (M8 bolt) oil pump housing or a good bottom end/whole 2.5 engine?

[Nick W]

It's only a switch, could you get one with a bigger thread than the standard M14, and tap it out to that?


Changing the oil pump is a horrible job, although loosening the crank bolt isn't that bad to do.


How the hell does anyone strip an oil pressure switch, let alone twice?

[Bigron]

Overtightened to "cure" an oil leak, maybe?
There are better devices than helicoils that were mentioned on here, but I can't remember what they are called; someone clever will be along later to advise you.

Ron.

[aaronjb]

Overtightened to "cure" an oil leak, maybe?
There are better devices than helicoils that were mentioned on here, but I can't remember what they are called; someone clever will be along later to advise you.

Time-sert, amongst others, will likely seal better with a little of the right Loctite on the threads; but the kit is extremely expensive so if you only need one you're better off finding a decent machine shop - which is a problem when the engine is stuck in a car, I suppose!

[Doctor Gollum]

If you're bothering to do a top end rebuild, why would you not refresh/replace the oil pump

After all, unless the cam belt snapped, a top end rebuild would only be required if a weak oil supply has caused excessive wear of the valve train

Replacing the pump would see the crank seal replaced and also solve the oil pressure switch leak and would reseal the sump completely, all being the primary source of Omega oil leaks...

A CBA approach will guarantee a CBA result 

[Nick W]

If you're bothering to do a top end rebuild, why would you not refresh/replace the oil pump

After all, unless the cam belt snapped, a top end rebuild would only be required if a weak oil supply has caused excessive wear of the valve train

Replacing the pump would see the crank seal replaced and also solve the oil pressure switch leak and would reseal the sump completely, all being the primary source of Omega oil leaks...

A CBA approach will guarantee a CBA result 

Because it's an expensive awkward to fit part that doesn't normally need replacing. A badly repaired thread is a good justification for doing so.


Presumably you would replace all 24 tappets(£6 each) and valves as part of a top-end rebuild too? You're likely to be the only one: most of us consider flushing the tappets**, polishing the valves, a quick lap of the seats and new stem seals to be the whole job. And that would only get done if the heads have to come off for some other reason.


Working on the V6 short block is simply not going to be cost effective, especially when you consider how reliable and durable it is.


** I had two that were noticeably worse than the rest, and had already bought 4 new ones at £2each - they only had 4 - so replaced them.

[Doctor Gollum]

I wouldn't necessarily replace everything but at some point the crank seal will leak, and will involve removing the pulley... At that point the oil pump is only bolts to remove
Might as well get done whilst the top end is apart 
Pulling the upper sump isn't specifically required for that job if the OP doesn't want to...