Should I replace pistons if Ive come this far?

[Akayfortyseven]

Hi all,

Old engine was bust, several issues including a dodgy repair on the block (chemical metal!) and some other things.

Got a 'good' FL engine, which im in the process of fitting.

Im doing water pump and thermostat due to signs of weeping.

Whilst refitting the water pump yesterday I made an error with one of the bolts. In short I wound a 'long' one where there should be a short one, and this made the timing cover prise open very slightly. Once removed the gap has closed back up.

I know this area is RTV'd from factory. Im in two minds about whether to replace the sealant by removing the cover. The gap was very, very slight, but I am now nervous it will leak from this area and it must be easier resealing now than when the engines back in!

Looking into it it seems fairly straight forward to remove the cover (apart from the crank pulley, but I have *really* good impact gun). It looks simple to get to TDC before removing as well.

My question is, if im taking the timing cover off, the sumps already off and 99% of the engine ancilliaries as well, should I pull the pistons and swap these for the latest version?

Im in two minds at the moment. On one hand this engine might be fine, and I can get it in fairly quickly and use the car again. On the other hand, it may be a burner/still not great and I will have to pull it again.

My concern is, am I biting off more than I can chew? I am comfortable with the principle of stripping the engine, its just things like checking tolerances of things im not 100% sure of and as to whether this will end up being an expensive venture. Can I just take the head off, pull the pistons and get them modified, at a minimum?

The car itself is far from perfect. Suspension-wise it is 100%, all replaced recently, same with the brakes. Handbrake cables are being done during this swap (tanks out), as well as some rust removal.

Sorry for the wall of text. Im really not sure what to do!

[shnazzle]

Seems silly not to really. If you have the engine out, what's going to be your next opportunity to pull it to bits and how much more effort will it be?
I reckon if you've got an engine out, do all you can to it while you can.
That's 100% what I'd do. 
New/modified pistons and cleaned up, new rings, re-hone, new pumps, tensioner, chain slipper, chain (depending on age), pulleys.
All the things that basically you'd have to get the engine out for.

If the new block has 40k on it, maybe not. But if it's around 100k anyway then I'd be wanting it in as good as I can get it for another 100k miles without a worry.

[Carolyn]

Now you've tweaked the timing cover- it will have to come off.  It can leak coolant into the sump!

Don't use any old RTV.  Dirko Elring Grey is the stuff. use it on the sump as well.

Your pistons can be cleaned up and the oil holes modified.  If you send them (cleaned up) to me we'll do them on our mill.

You don't have to worry aboutTDC, the crank pulley is keyed, and you'll sort the cam timing when you put the engine together.

The trick is to take your time - no prizes for 'fast'!

We'll coach you through the job.

[shnazzle]

We'll coach you through the job.

That's key here. 

Take your time and if anything is unclear, come back here and check  
Once you've learned you can help others

[Akayfortyseven]

Guys, thanks. I love this site!

Ive got dirko sealant for the sump, assuming the one tube will be enough for both jobs?

What il do for now is get the timing cover off, the chain etc. and the head, I reckon.

Piston wise it looks like they can only come out from the top, rather than the bottom, the crank area looks very tight.

Any links/sources for headgasket, pistons and rings? Ive seen about modding the pistons, is that a case of adding new holes to them?

Thanks again all. Im keen to save it.

[Carolyn]

Pistons do, indeed come out from the top. Modifying is adding and enlarging holes.

Yes one tube of Dirko will do both with some left over.

PM me your email address and I'll send a parts list with links (though some might be out of date).

You'll enjoy it - engine building is fun.

The cylinder head refurbish shouldn't be neglected -though it is a lot of work.

[Akayfortyseven]

Thanks. Will do.

Is there a place the community recommend to mod the pistons or is it a machine shop job with some instruction?

Im sure I can do it, ive done just about everything else on the car now and its pretty much at the point of being dissassmbled fully now.

[Gaz mr-s]

Thanks. Will do.

Is there a place the community recommend to mod the pistons or is it a machine shop job with some instruction?

See post #2  she's done quite a few.

[Call the midlife!]

If you're pulling the head off then get plenty of small freezer/sandwich bags and put the matching valves, springs and lash caps in a bag together, marked with their position in the head. Saves a LOT of time and head scratching later..

[Akayfortyseven]

Thanks. Will do.

Is there a place the community recommend to mod the pistons or is it a machine shop job with some instruction?

See post #2  she's done quite a few.

Oops! Didnt see that. Thats perfect.