free hit
counters
Goetz HG Torquing - Engine/Ancilliaries - The Lotus Forums Jump to content
Sign in to follow this  
Sir Paolo

Goetz HG Torquing

Recommended Posts

Gents,

There has been much discussion about HG fitting, and the associated issues.

 

I have invested in an angle gauge and attempted to use it, but I found it very awkward to secure the stabilizer bar to the side of the head.

 

As such, I'm not confident that I am able to use it with enough accuracy to correctly torque something as critical as a HG.

I do however, have a very good calibrated torque wrench, and as has been mentioned by others, they've used the traditonal torquing methods/figures to secure the head/HG without issue.

 

I'd be interested to know your opinions of this?

 

Many thanks.

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Paul

 

During my time as an apprentice and then tradesman, I came across many sorts of gauges, indicators etc. What do you mean by an angle gauge?

Share this post


Link to post
Share on other sites

Michael,

I believe it's also known as a torque angle gauge.

 

You basically fit it to the socket, and secure the stabilizer bar, zero the guage then turn the required no. of degrees.

Share this post


Link to post
Share on other sites

If you have a good calibrated torque wrench, I don't see how you are achieving anything more by using one of these gauges. (just googled it)

I have done many head gaskets in my time (as no doubt many people on here have as well) and while none of these were a high performance engine, many of them had similar compression ratios.

 

I have not had a HG failure after fitting. Maybe I'm just lucky.

 

If everything else is set up within spec and clean prior to bolting the head on and you faithfully follow the torquing instructions, (which in my experience is following the bolt tightening pattern stepping through progressively i.e. 5 ft/lb steps as an example, up to the max torque) you should not run into any trouble.

Unless there is some trick to the Lotus head and block which sets it apart from many other engines. (such as small cylinder Mazdas, Ford & Holden 6's & V8's, LandRover petrols & diesels)

 

If this is the case and someone wishes to enlighten me, I'm all ears.

Share this post


Link to post
Share on other sites

Apparently the logic behind using a torque angle gauge is that it is less subject to inaccuracy due to friction in the fasteners, as the fasteners are turned by a specific amount (in degrees). Rather than to a specific torque figure (in ft.lb's).

Lotus' TSB-019 detailing the use of the new Goetz HG (and Loctite 572 on the liners), refers to the use of an angle gauge after an initial torque.

As mentioned previously, my concern is that all this accuracy could be lost, if I'm unable to use the gauge correctly.

Hence my preference is no leaning towards the traditional torque wrench method.

Share this post


Link to post
Share on other sites

I have fitted the Goetz headgasket using the angle gauge procedure. The next time I dismantled the engine (not related to the headgasket!) I found that one of the headstuds had pulled out of the block. Once I had had the thread helicoiled and was reassembling the engine with new pistons and liners, I decided to use the original torque wrench method of tightening the head. Well lubricated studs and nuts, followed the original procedure and so far, no problems. This was about 4 years ago, iirc,, so I can't see any magic in using an angle gauge. The theory that working on nut rotation will ensure that the nut ends up in the required position to give the required clamping force sounds good, but with one rattling stud and a stripped thread I thought I'd go back to the "old ways"....

Share this post


Link to post
Share on other sites

John, your tale of a headstud stripping reminds me of a time many moons ago when a bunch of monkeys rebuilt my engine. I was unaware immediately, that they'd stripped a thread in the block, but soon after the HG started leaking.

Before I had time to get the HG fixed, the engine went bang big time on a motorway.

Investigation revealed that a corner of a piston had broken up due to being doused with coolant!

 

However, following further research, I understand that many expert Lotus engine builders continue to use the torque wrench method, and avoid the angle gauge altogether.

Share this post


Link to post
Share on other sites

Another in the series of Douglas family anecdotes....my Gradfather, who had been trained by Rolls Royce, was employed by a local garage (Bobbett's) in Teignmouth, South Devon in the 1950s. When tightening head nuts, this had to be done by feel as they hadn't got anything as sophisticated as a torque wrench; I remember the 1913 Napier "special spanner" was designed to bend when the correct load was reached.....anyway, without the  measuring equipment it was a chancy process. All the fitters had the same system....they would always get the Foreman to do the final check. Thus, if the fitter was getting near and felt things becomng a trifle slack in the turning department, he'd call the Foreman over...who would go around the studs...and exclaim "BLAST!! Thats the third headstud I've stripped this week.......!!" Seems he never caught on to what was really happening....

 

I was in Machine Mart yesterday and fell in love. They sell a 1/4" drive electronic digital torque wrench.....it's beautiful....I can think of no use for it, but I WANT ONE!!!!

Share this post


Link to post
Share on other sites

John, doesn't seem like much has changed recently. Just because people are using torque wrenches doesn't mean things are being done properly ha ha!

Share this post


Link to post
Share on other sites

torque wrench is susceptible to inaccuracy due to changes in friction.  Torque angle method removes friction from equation by using a calculated tension on the bolt related to the thread pitch.

 

I recently changed to ARP head studs... Therefore I couldn't use the Lotus torque angle spec, since the thread pitch on the ARP bolts is fine on the head end and coarse into the block.  Keep that in mind with different studs!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  


×