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Old 02-14-2024, 11:23 PM
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Jengah
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Default Tell Me This Is Safe - Engine Hoist Tab

So I recently dropped my engine and now I need to ship it to my builder. I’ve got to hoist it up off the ground and onto a pallet.

I’ve lifted the same engine before by attaching two lifting points on the aluminum crossmember that mounts to the engine mounts and the third point being at the hoist hook.

I’ve heard people say multiple times that it’s safe to lift the engine by that mounting tab, but as I dig in a bit more, it seems that that tab is just there as a support, when removing the transmission, and was not necessarily intended to support the entire weight of the engine, conversely, I’ve read that the reason it’s located where it is it so that it could support the engine and transmission and that is the center balance point.

I find the whole thing really sketchy and hard to believe since on the M 96 engine it is only held by two small bolts mounted vertically into the block. On a couple of the other engine variance at least one of the bolts goes into the block horizontally, which provides more strength.

Can anyone say with authority that this is indeed a safe, lifting point in the bolts aren’t going to pull out?

Old 02-15-2024, 09:31 AM
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Porschetech3
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Yes, I have lifted hundreds of them with just that lift point, none broken...
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Old 02-15-2024, 11:04 AM
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Yogibara
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2nd that. It's there for that reason. And when it's not there you'll wish it was.
Old 02-15-2024, 01:39 PM
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Jengah
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Thank you both. It's just so hard to believe that two little bolts, in aluminum no less, can hold that much weight.
Old 02-15-2024, 05:37 PM
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Originally Posted by Jengah
Thank you both. It's just so hard to believe that two little bolts, in aluminum no less, can hold that much weight.
One M6 bolt in a grade 8.8 can hold 2600 lbs in a straight pull ....don't know how much the aluminum can hold....lol...
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Old 02-15-2024, 07:27 PM
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Jengah
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Originally Posted by Porschetech3
One M6 bolt in a grade 8.8 can hold 2600 lbs in a straight pull ....don't know how much the aluminum can hold....lol...
Any engineers in here that can calculate what the pullout strength of the aluminum our blocks are made out of?
Old 02-15-2024, 09:01 PM
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Originally Posted by Jengah
Any engineers in here that can calculate what the pullout strength of the aluminum our blocks are made out of?
Need to know the exact aluminum type and thread depth, but the simple answer is: more than enough.
Old 02-15-2024, 09:19 PM
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It's fine, done it many times.
BTW that picture is a 996 Turbo engine.
Old 02-16-2024, 02:29 PM
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Originally Posted by theprf
It's fine, done it many times.
BTW that picture is a 996 Turbo engine.
Yeah, that big clutch Accumulator is the first thing I saw in that pic and was thinking "somethings off here, this isn't a Carrera G96 trans" then saw the oil tank, and yea, this is a Turbo..."
Old 02-16-2024, 02:42 PM
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Yep - it's a photo from the web, but the hook/loop thingy looks the same.
No idea on the type of aluminum or threads. Skip - do you know? I searched and am not finding answers.
Old 02-16-2024, 03:16 PM
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Originally Posted by Jengah
Yep - it's a photo from the web, but the hook/loop thingy looks the same.
No idea on the type of aluminum or threads. Skip - do you know? I searched and am not finding answers.
The Aluminum material used in the M96/7 engines was discussed in the P10W Training classes back in the day, but the exact alloy name-number wasn't given.

I know the Alusil blocks are very simular to Reynolds 390 Aluminum and is Hypereutectic through out, and is very hard and costly to machine, wearing out bits and tooling. The Lokasil blocks are only Hypereutectic on the bores and the rest is low-silicone Aluminum .

Porsche has been increasingly using Aluminum bolts also for weight savings... AFAIK there is no table for tensil strengths of Aluminum bolts either...or there various alloys...

I remember being in a training class On the Cheyenne/Panamera engines and they were showing the "new redesgned light-weight cam phasers", the had reduced the weight in various areas and used aluminum bolts to hold it together.. Porsche was very proud of saving a few grams of weight here......When I held it in my hand a big knot came up in my stomach, this didn't seem like a good idea to me to use aluminum bolts here...Sure enough, the bolts started failing and all were recalled..
Old 02-16-2024, 04:40 PM
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Originally Posted by Porschetech3
The Aluminum material used in the M96/7 engines was discussed in the P10W Training classes back in the day, but the exact alloy name-number wasn't given.

I know the Alusil blocks are very simular to Reynolds 390 Aluminum and is Hypereutectic through out, and is very hard and costly to machine, wearing out bits and tooling. The Lokasil blocks are only Hypereutectic on the bores and the rest is low-silicone Aluminum .

Porsche has been increasingly using Aluminum bolts also for weight savings... AFAIK there is no table for tensil strengths of Aluminum bolts either...or there various alloys...

I remember being in a training class On the Cheyenne/Panamera engines and they were showing the "new redesgned light-weight cam phasers", the had reduced the weight in various areas and used aluminum bolts to hold it together.. Porsche was very proud of saving a few grams of weight here......When I held it in my hand a big knot came up in my stomach, this didn't seem like a good idea to me to use aluminum bolts here...Sure enough, the bolts started failing and all were recalled..
Like the Variocam sprocket bolts?!
Thanks for the info Skip.
Old 02-16-2024, 05:34 PM
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Originally Posted by Jengah
Like the Variocam sprocket bolts?!
Thanks for the info Skip.
Yep, the 4 bolts that hold it together..... I still have a few of the heads of the bolts in my tool box as momento's...lol

It wasn't just the Cheyenne and Panamera either back in 2010, the aluminum cam bolts found it's way into GT3's also....

Last edited by Porschetech3; 02-16-2024 at 05:37 PM.
Old 02-19-2024, 06:48 PM
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Originally Posted by Jengah
Any engineers in here that can calculate what the pullout strength of the aluminum our blocks are made out of?
I have a spreadsheet I made that is imperial but a 5/16"-18 thread is very close to the M8 x 1.25 thread that the lifting point uses.

Assumed parent material ultimate tensile strength (UTS): 42,000 psi
Shear strength : 0.6 x UTS = 25,200 psi
Thread engagement length: 0.2" (about 4 threads, conservative based on reference doc)
Max load per threaded hole: 1400 lbs

I would be more worried about the lifting lug failing, honestly.
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Old 02-19-2024, 06:50 PM
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Originally Posted by QwikKotaTX
I have a spreadsheet I made that is imperial but a 5/16"-18 thread is very close to the M8 x 1.25 thread that the lifting point uses.

Assumed parent material ultimate tensile strength (UTS): 42,000 psi
Shear strength : 0.6 x UTS = 25,200 psi
Thread engagement length: 0.2" (about 4 threads, conservative based on reference doc)
Max load per threaded hole: 1400 lbs

I would be more worried about the lifting lug failing, honestly.
Awesome - thanks for the calculations. I took another look and the entire bolt is only about 15mm long. Not sure if that helps.


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