Engine Machining List 2.2E

[8bit-ash]

Hi all,

I'm heading to Rob Walkers on Friday to get my engine machining done. Looking for advice on my list...

Check everything is in tolerance.

Case -
Do-
Line bore if necessary
Oil Bypass mod

Don't do-
Studs are solid and its being built up pretty standard so not fitting case savers. - Is this sensible?
Piston Squirters (are they needed on a standard rebuild?)

Heads-
Recondition - Guides and seats as necessary

Crank -
What ever is advised. hopefully just polish. Balance end to end.

Cams -
Likely need a regrind

Rods -
Big ends, Small end bushes, Balance

Pistons and cylinders -
Picked up some with under 3000K miles on. measure, balance.

Am I missing anything.

[Gary71]

When he does the heads ask for the exhaust/inlet studs to be timeserted £10 each, but worth for me to recover a variety of stripped, cross threaded and badly helicoiled holes.

I also left all my main case studs in place. Remember to take all the nuts for the case halves so it can be torqued up for the line hone.


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[Gary71]

Oh and get the heads blasted (£76) and refaced (£108).




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[911hillclimber]

I would add a really deep hot chemical clean minimum of everything.
It will save so much time and make the (DIY?) rebuild so much better. Check the flywheel friction face, grind flat if groovy.
Obviously make sure existing valve sealing faces and heads are clean and true.
On my last big build of my 3.2, the machine shop cocked up the re guide and re seat work, so even the great can get things wrong.
The Bruce Anderson book has a great machine shop check list in it.

[8bit-ash]

Cool cheers for the advise guys, i'll add those to the list.

[Gary71]

To be honest Rob just advised everything I'd need and I went with it!

The work was first rate, on time and on quote, so I hope it works out ok for you as well.


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[8bit-ash]

Anyone think piston squirters is worth while and Shuffle pinning the case?

[Gary71]

I didn't need the squirters as my 2.4 already had them, I probably would do this if possible on an earlier engine.

I didn't shuffle pin as it was a stock rebuild and not a race engine with high output.


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[8bit-ash]

Hi all, Rob Walker is questioning whether I definitely want oil squirters seeing as it's a standard road engine build. Any more opinions?

[inaglasshouse]

Anyone think piston squirters is worth while and Shuffle pinning the case?

Re shuffle pinning - I've had various conversations during which I learned:

1) Porsche never did it. Closest they came was the RSR through bolt
2) Porsche only used the RSR through bolt on engines that would run flat out for many hours (endurance racing). A very long way from road use.
3) Thinking about shuffle pinning - if you calculate the clearances you need to leave to be able to assemble the case halves using reasonable force, you discover that the pins probably aren't doing much, if anything, to constrain the cases from shuffling an amount that would matter to the main bearings / crankshaft.

The above from wise men who actually build (mostly race) engines.
But other wise men advocate shuffle pinning....

I am not a wise man, but was more convinced by the anti- than the pro- arguments. Also, as a bit of a chicken with my matching numbers cases, I wasn't very keen on making a bunch of new holes and putting in the pins. Possibility of errors / accidents, possible stress concentrations, etc.

As you may have gathered I decided against for my (road) engine.

Sorry, no opinions on piston squirters. What's the downside?

Cheers, Richard.

[911hillclimber]

First 3 points I feel are very applicable.
To get all those pins drilled, installed and then to align and 'tap' together without tolerances stacking up is asking a lot.

I doubt anyone can actually say that if a non pinned engine that failed would have endured it's loads if it had been pinned.
Can't see why a mag cased stock engine needs it doing.

IIRC all 2.4 cases had squirters, and probably to have one case for all levels of performance in production, standardisation perhaps?

[8bit-ash]

I've discounted shuffle pinning. I don't think they're necessary.

I guess the only downside of piston squirters is the slightly increased risk that something might get machined wrong and an additional cost.
Has anyone ever had these done at Rob walkers? Do they supply the jets/press them in etc or just drill the holes?

[acclassics]

I would add get the case decked both sides (i.e machine flat where the barrels/cylinders mate to the case), as case sag from the weight of the P&C's on a 911 mag case, is not uncommon. The case deck will then give you a flat and parrallel, surface so that the heads/cam tower are all perfectly in line, and you dont end up with tight cams, when you torque up the top end. At the very least take a measurement, but more often than not its a good idea.

[8bit-ash]

Ok, So i'm going to go with the piston squirters, Does anyone have a part number for them or advice as to where I get them from?

[Darren65]

Re shuffle pinning - I've had various conversations during which I learned:

1) Porsche never did it. .........

.....but then Porsche were using brand new cases rather than 40+ year old ones?

I'm light years away from being technical so personally I just went with the advice of Nick Fulljames at Redtek - they pretty much shuffle pin all cases as a matter of course (don't think they've ever ruined one!).

My understanding is that the crank bearings can shuffle a little and cause tight engines(?) which is part of the reason why they routinely pin them......I was amazed to learn that cases can expand and contract by up to 3mm in a heat cycle so plenty of movement going on in the engine bay!

Ultimately I guess it's down to how 'belt and braces' you want to be and as we all know many restored cars hardly get driven anyway so no real issue.....

.....but then surely any car that does actually get used is going to be worked hard!

Cheers,