VW head torque with aluminium cylinders

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Neil Spooner
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VW head torque with aluminium cylinders

Post by Neil Spooner » Wed Aug 05, 2009 9:56 am

Hi,
I have a set of the Aluminium Cylinders for the VW 2180cc engine, but have received various ideas on what the head torque should be with these barrels. The Soneria forum suggests some engine cases have been damaged due to the overtorqueing and additional expansion of these alloy barrels.........anyone know the answer please?
Neil
ps, they are the steel lined ones, not the Nikasils.
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PB
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Post by PB » Fri Aug 07, 2009 10:21 pm

Post deleted. Full real name not used.

Rob Swain
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Post by Rob Swain » Mon Aug 10, 2009 3:47 pm

? wrote:Post deleted. Full real name not used.
That's helpful!

At least leave the pertinent info!
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.

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J.C.
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Post by J.C. » Mon Aug 10, 2009 3:59 pm

Must admit, I was looking forward to reading the answer!
Provided it contained no objectional material it seems a bit daft to delete the information.
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Nigel Ramsay
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Post by Nigel Ramsay » Wed Aug 12, 2009 2:48 pm

Well, I'm surprised no-one has posted an answer here!

This is direct from the GtPlanes Type1 Engine Build Book:

"When all 4 cylinders and both heads are installed (pushrods too), Torque the heads using the torque procedure below. However, DO NOT torque up one side and then go to the other side. Torque cylinder #1 and #2 to 10ft.lbs and then torque cylinder #3 and #4 to 10ft.lbs using the torque sequence shown on page 5. (don't worry, this follows! NR). Torque cylinder #1 and #2 to 18ft.lbs using the second pass torque sequence followed by cylinder #3 and #4 being torqued to 18 ft.lbs."

Page 5 shows a plan view of a cylinder head. You have to imagine you are looking at it! (top row of numbers represents studs nearest the inlet ports etc.)

The First Pass sequence is shown as:

7 5 6 8

4 2 1 3

The Second Pass sequence is shown as:

8 2 4 6

5 3 1 7

Actually I personally disagree with the first tightening sequence, I'd go diametrically across the barrels like second sequence, but in the opposite direction - however, 10ft.lbs isn't a lot so there's probably nothing in it.

On the subject of alloy barrels with steel liners, I would personally stick to the same system shown (I used to race a Porsche many years ago and I've ***k'd up more than my share of engine parts during the learning process!)

And finally, you should carefully lap the barrels to the heads - make sure you scrupulously clean the grinding paste off the barrels and heads before assembly (and don't overdo it, you simply want to see a smooth matt grey ring in the head where the barrel mates, NOT A GROOVE!).

Hope this helps.

Neil Spooner
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Location: Colchester, Essex

Post by Neil Spooner » Sat Sep 05, 2009 5:51 pm

Hi Nigel,
Thanks for the reply......wonder why the other post was deleted?
I have the GPAS manual, and am familiar with the content, but the fact that the alloy cyl's will expand more than the cast iron ones is my concern. The Porsche 911 engine (of which I have built many, I used to work for a Porsche dealership) uses cyl' head studs of a particular steel alloy that has a different rate of expansion than std VW ones (I have heard the phrase "unobtainium" used! Its actually Dilivar which was used to try to prevent the ex' side studs from breaking, although it didn't work) Therefore as I see it the loading on the studs and thence the engine case will be different with the additional expansion of the cylinders. There are some posts on the Sonerai forums that suggest that the normal 18ft/lbs is excessive. However, Steve at GPAS gives a torque of 22ft/lbs, I am at a loss as to why the torque should be higher. The 911 torque is 28ft/lbs, but the whole Porsche assembly is a much higher spec'.
Neil
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Nigel Ramsay
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Post by Nigel Ramsay » Sun Sep 06, 2009 7:11 pm

Neil, the other post was deleted because the guy didn't give his full name... the Full Name Police deleted it!!!

I'm sorry if the advice I gave was a little patronising (you being a Porsche man!), you never know on here what level of expertise you are meeting. I'm slightly confused as the Gt Planes book give 18ft lbs, not 22 and it was written by Steve of GtPlanes? Torque for an 8mm studshouldn't be much more than 18ft lbs I feel (8mm recommended over 10mm. 8mm into case saver insert). The alloy cyls from GtPlanes have a steel liner, they aren't like the Porsche Nikasil versions, so the actual head/barrel load will be similar to a steel barrel, hence I venture to suggest leaving it the same.

Neil Spooner
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Joined: Wed Jan 07, 2009 5:22 pm
Location: Colchester, Essex

Post by Neil Spooner » Mon Sep 07, 2009 10:29 am

Hi Nigel,
Thanks for the reply, no need to apologise, I talk complete gibberish at times, and I am highly qualified to do so!!
Steve wrote the GPAS manual (the same one you have I venture) and it was via an email that he advised 22ft/lbs on my enquiry, why he should not have advised this amended torque upon supplying the barrels I don't know.......I have sent him another email to query the higher torque, and will let you know the outcome.
I have used 15ft/lbs during the engine build, and will check and retorque after the first hour of engine runs, and then again at 10hrs. My concern is distortion of the barrels due to overtorquing of the head studs.
All the best (ATB)
Neil
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Barry Plumb
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Post by Barry Plumb » Tue Sep 22, 2009 5:02 pm

Neil / Nigel

Stick to the tightening sequence shown in the manual where the first sequence is 10 ftlb bottom row first.
I understand the reason for this is to compress the push rod tubes evenly. If you try to do the normal diagonal sequence the heads may try to go down onto the top of the barrels cockled (if you see what I mean).
I used to have the alloy barrels with cast iron liners ans always used the VW manual torque figures. Never had a problem with the studs or leakage.

Kind Regards

Barry Plumb

Neil Spooner
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Joined: Wed Jan 07, 2009 5:22 pm
Location: Colchester, Essex

Post by Neil Spooner » Tue Sep 22, 2009 8:12 pm

Hi Barry/Nigel,

Thanks for your input, I will stick to the recommended tightening sequence, as you say Barry, it is to ensure the push-rod tubes are compressed before the heads seat on the barrels. Once the engine has run an hour or so I will retorque to 18ft/lbs.

All the best and happy landings.

Neil
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Nigel Ramsay
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Post by Nigel Ramsay » Tue Sep 22, 2009 8:16 pm

Thanks Barry, I'll take your advice too!

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