Crack testing blocks

[Ryan]

 Ryan said:

Engine rebuilding/machining at AB Industries (Wellsford, an hour north of Auckland), specialising in crack testing, head rebuilds, acid + alkaline dipping facilities for alloy/metal cleaning, head + block surface grinding, reboring + honing, all machining.

Sweet, if I don't come to Auckland this weekend maybe you could give the block to Rueben and he can give it to me, as he lives 2 mins away? I can skim the heads and/or block face as well, up to you. While we're at it I might as well recondition the whole head lol talk about that later.

[Shale]

Sounds absolutely mint actually. I'll send the block and a pair of heads up to you bro - just give me a hole in the wallet when you get the parts and it's all good The car is going up to Reuben's place next week anyway so it works more than perfectly for me! I might as well get the whole shebang done - get the block and heads skimmed, after checking the lot for health.

<3

[Ryan]

Yep cool, I guess Rueben will text me when it's up here and i'll pick them up and i'll let you know what needs doing. 0211429476 if you need my number bout it

[Shale]

Thanks bro Yeah, I'll probably put the shortblock in the boot of the GT when it goes up later this week. Will keep you informed! Cheers ;D

[aim]

 Ryan said:

I'll do it for free if you want, we specialise in crack testing etc,

That man deserves a DB! Or a box of them! Or rather a box of some other finer beer of his choosing!

[Shale]

Naturally. ;D chullybun of something nice and cold of his choosing is in order!

[log1call]

If you are going yo plane the heads, block and use metal gaskets, have you calculated what the compresion ratio is going to be afterwards? Do you knoow how many times the heads have been planed before?

Do you have a remapable ECU?

EFI motors do not like it when you raise the compression too much.

I only ever plane things if they need it. It's easy to check for warpage and inspect for corrosion.

[Shale]

These are good questions actually - had sort of considered it.

The headgaskets are for a 20G motor - were sold as suitable for early WRX and Legacy, some Foresters IIRC.

This engine is an unknown until it's been cracked open, but as the car's only gone 120,xxx km I'm going to assume until further inspection that it's the original engine. The donor block, however...that is a complete unknown. Any specific way of telling whether it's been machined before or not? All I know is there's a decent likelihood of the block being a little warped considering how it was abused before it landed in my hands. Ran buttery smooth, but overheated - and would lose water at a pretty voracious rate through the radiator overflow.

[log1call]

You can check them with a straight edge and a feeler gauge. You need a good straight edge though, which are expensive. Simplest way for home mechanics is to go to a glass company and get a piece of ten mill thick glass the size of a wet and dry sheet. Use reasonable fine wet and dry with kero or crc and polish the surfaces up with that. Keep the paper stuck to the glass with crc underneath it so the edges don't curl and erode the edges of the heads etc. Work left and right up and down and diagonally. It's easier to wrap your fingers around the short edge of the glass and hold the paper as you rub the glass over the head than it is to hold the head and move it. It will show up corrosion and warpage and take off minimum material. If you notice warpage or corrosion then get it planed. Insist they take off the absolute minimum.

The heads and the blocks both have indicators cast on them that show when they have been planed past the allowable limit. Since you are planning on doing both surfaces and using thinner gaskets it may not be a safe indicator.

Excess compression will cause hard starting, detonation problems and pulled timing, and stain the rings, big ends and the head gasket.

[Ryan]

In the past I usually only lap Subaru heads on a lapping plate just until it's taking off the lowest point, but if you work out how much you want machined off I can do it that way.

[log1call]

It's the idea of planing heads, block and using thin gaskets that has we suspicious.

[Guest boostcut]

obviously you will check valve piston clearance with some bluetac during assembly...

[Shale]

Yup, best to check everything before reassembly after having work like this done.

Is it possible to work out how much is taken off each to get it up to spec, then sort out how thick the gaskets need to be? Because to be honest if they are too thin, then I will simply give 'em to someone whose tolerances are appropriate for them. Gaskets are replaceable. Engine components....err, a little more tricky

[Guest boostcut]

the machinist can cut slightly deeper recesses into the crown of the piston to give the valve a little more room if your worried? if i was you, id do it as it saves alot of dicking around for about 100 bucks. i have done it with a die grinder and an aluminium burr before, you would never have known. aulthough it was on a 12.7:1 comp ratio b16b civic motor that made 208kw in NA form.

[Shale]

It's entirely an option Considering this is a dirty old 20G I'm not really expecting too many dramatics, hence not being too worried (it will never really make more than the stock 220hp), but if it does present problems... it'll be either that or order thicker headgaskets. Both are relatively cheap and relatively painless by the smell of things.

I imagine most of this work generally goes into far more powerful motors, as that's where it counts.