[hamblock]

Hello I have a G13B swapped '96 Sierra that was leaking water into the oil and have taken it to a cylinder head repair place and they have told me that the cylinder head has "gone soft" and that it would be pointless to machine it flat seeing as it is already soft.

I want to put money into the car if it's feasible.
Just concerned I'm beating a dead horse trying to get a money pit going again.

So any idea on what I should do?
My options that I'm thinking of at the moment are:
1. Try find a replacement head
2. Get the head repaired
3. Fill with cylinder head crack repair product (not favoured)

Some help on making a decision about what to do if possible and if anyone wants to buy a Sierra...I know a guy

Thanks

[Brenno]

Replacement head would be best. Can you buy new from the internets?

[Gwagensteve]

I’ve heard this a few times and I still find this puzzling. Annealing aluminium requires the item to be heated to 300-400degrees C for THREE HOURS then slowly cooled. I’d be surprised if those conditions could be met in a running engine with a cooling system.

I’ve also heard that Suzuki aluminium heads have some surface hardened layer that shouldn’t be machined through but my research indicates this is cutting edge technology now let alone 30+ years ago.

I would request hardness readings to support their claim.

[hamblock]

Brenno wrote:

Replacement head would be best. Can you buy new from the internets?

Yea I figured buying one would be the best option just seems to be at minimum ~$500 to buy a new one.
Any idea on where I might be able to find one?

[hamblock]

@Gwagensteve

I believe the damages happened on a trip from Sydney to Newcastle (~2 Hours) where the radiator blew up and allowed the engine to heat up too much I would say. So there is a real chance it may have reached that temp over that long of a time.
The guy at the cylinder head repair shop said if he put his hardness tester on it that it wouldn't even give a reading.

My options at the moment are:
1. Find a cheap replacement for the cylinder head
2. Find a replacement engine
3. Scrap the whole car and choose a new project car lol

[Gwagensteve]

Hmm, interesting reading - http://www.acl.co.nz/wp-content/uploads ... -Heads.pdf

So yes, heads can go "soft" to around 65 Brinell, down from 90-120 depending on heat treatment.

Straightening or overheating can do it, and the effect starts as low as 290˚C.

Interesting there is no discussion about heat treatment to restore hardness.

I don't like comments like "wouldn't give a reading" - if the normal hardness range is 90-120 Brinell and a failed head is too soft to read what's the minimum his hardness tester can read? 89 Brinell? 66 Brinell? - I'm a bit pernickety about this sort of thing - I work in QA/QC in the NDT and Inspection industry which includes quite a bit of metallurgy. We don't deal in "nah it's too soft" or whatever - we have units to measure this stuff as per the ACL document above.

Personally any replacement head will need to be hardness tested (by someone who has a hardness tester that has adequate range for the job) because if a head has come off a block, what's the bet it's because the head gasket failed or the engine otherwise failed?

G13B engines are now getting very old and they're a poor engine choice for a Sierra. The've typically outlasted a swift GTi by the time they've made it into a Sierra.

I'd put a G16B Baleno engine in the car. Much higher chance of finding a good motor, much better engine for a Sierra, no harder to fit. (for different reasons)

[vet 180]

If the head has gone soft junk it. I wouldn't trust the block either if that much temp has gone through it. I have had a head go soft before and did re-use the block, however it was a cast iron block.

Go a G16b Baleno engine and enjoy the extra power. You could consider a swap to an M series, but its a bit more involved.

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