Lotus Elan

Exhaust gasket.

PostPost by: twincamman » Mon Aug 30, 2010 10:24 pm

you're going to pull the head to replace a gasket and heilacoil the thing for 30 MINUTE JOB?????? think may be the next valve job may be the time to put the inserts in ????? you know what a giraffe is ???? its horse put together by a committee ----ed
dont close your eyes --you will miss the crash
User avatar
twincamman
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2953
Joined: 02 Oct 2003
Location: Niagara falls [slowly I turned]

PostPost by: robertverhey » Mon Aug 30, 2010 10:30 pm

Just getting back to the original question, I may be missing something, but is there a good reason for only replacing the blown gasket? It doesn't take long to whip all 8 bolts off and replace the lot, does it? And a new set of four gaskets is only a fiver......
robertverhey
Fourth Gear
Fourth Gear
 
Posts: 781
Joined: 20 Feb 2007
Location: Sydney Australia

PostPost by: garyeanderson » Mon Aug 30, 2010 11:23 pm

This discussion sounds like that age-old adage that "if it ain't broke now, it will be soon"! Fix what needs to be fixed when it breaks and just drive the bloody thing...

Gary

P.s. = I often wonder how many Elan's were all but totaled because someone was going to "fix" that oil leak that left a spot on the garage floor the size of a coffee can lid? It Sat for 25 years and now it parts or a total restoration!

P.p.s. - just add oil :D
User avatar
garyeanderson
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 3128
Joined: 12 Sep 2003
Location: Massachusetts, U.S.A.

PostPost by: rgh0 » Tue Aug 31, 2010 3:16 am

While studs are certainly the tehnically pure solution, I have been using socket headed cap screws into the heads on my elan and plus 2 for 30 plus years for maintenance convenience with good success. The Elan has the exhaust on and off regularly with changes to exhaust, heads and engines, the road Plus 2 much less so and probably only had the exhaust off 3 or 4 times over 30 years. While thread stripping is a potential problem in practice I have only had to helicoil a couple of the threads in the race heads that I have used over this time and none in the plus 2. If you strip a thread they are easy enough to helicoil in situ so I have not bothered with preventitive helicoiling.

A few preventative measures to avoid stripping threads in the head

1. Clean the head threads and cap screws and use a good quality antisieze such as loctiite nickel antisieze paste.
2. Ensure you engage the threads properly and that they can be tightened up with finger pressure. If they are tight when first started and require effort to screw in something is wrong and stop before you strip the thread.
3. Learn what final torque does not strip the thread but seals the gasket and dont overtighten. I do it by feel and its about 5 to 7 ft lbs but if not confident use a torque wrench to determine a value you are comfortable with.

Where the joint arrangement requires high clamping loads such as a head gasket I would certainly not try replacing the head studs you typically find in an alloy block with bolts. However with the low bolt loads required in the exhaust join you can get away with it OK I believe ( or at least I have)

regards
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7603
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: JJDraper » Tue Aug 31, 2010 6:38 am

I have replaced the exhaust gaskets in situ. It was a 30min job, even with studs, although IIRC I jacked up the engine (piece of wood and scissor jack) and disconnected the engine mount on the exhaust side to give a little extra 'wiggle' room.

I considered Studs, but for the extra hassle decided against it. Interestingly, I changed the bolts on the thermostat housing for studs because the threads were marginal - a PO had fitted bolts that were too short and stripped the top half inch. Studs make use of the remaining good thread and no further problems.

Jeremy
User avatar
JJDraper
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1019
Joined: 17 Oct 2004
Location: Buckingham, UK

PostPost by: alexblack13 » Tue Aug 31, 2010 7:54 am

Aye its not a difficult job, and I certainly would not helicoil the studholes for the fun of it. If it were required well that's another story. Being able to remove the manifold easier is a plus though and so is the bit extra torque available which might help keep the exhaust gaskets a bit longer.. :wink:

Good discussion though guys. Very interesting reading all the different views...

Cheers.

Alex...
Alex Black.
Now Sprintless!!
User avatar
alexblack13
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2357
Joined: 17 Oct 2007
Location: Fife Scotland

PostPost by: richboyd » Wed Sep 01, 2010 5:17 pm

The exhaust flange gaskets are Volkswagen items. The same gasket was used for all of the original air-cooled VW engines (40HP through 1600), so they are easy to get and cheap. A perfect fit for Twin Cam headers (with non-modified ports).

Try VW part number 111-251-261B.
User avatar
richboyd
Third Gear
Third Gear
 
Posts: 272
Joined: 12 Sep 2003
Location: Seattle

PostPost by: elansprint71 » Tue Jan 29, 2019 11:37 am

Could someone confirm the thread required for the cap screws, is it 5/16" UNF?

Would there be an advantage in fitting Stainless screws?

Thanks.
elansprint71
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 4105
Joined: 16 Sep 2003
Location: Cheshire, UK.

PostPost by: nmauduit » Tue Jan 29, 2019 12:00 pm

elansprint71 wrote:Could someone confirm the thread required for the cap screws, is it 5/16" UNF?
Would there be an advantage in fitting Stainless screws?


the original studs would be UNC in the alloy head and UNF to secure the exhaust - so if you just replace the studs with cap screws you'll have to go with UNC (if you use inserts like Timesert etc you should be able to convert into UNF cap screws).

I'm not sure of a clear advantage to use stainless (of the appropriate grade, some are more brittle), it's not really humid there - but I use a smidge of copper grease.
S4SE 36/8198
User avatar
nmauduit
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1553
Joined: 02 Sep 2013
Location: France

PostPost by: billwill » Tue Jan 29, 2019 12:06 pm

Talking of exhaust studs, what is the logic behind using brass nuts on those studs?
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
billwill
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 4745
Joined: 19 Apr 2008
Location: London UK

PostPost by: nmauduit » Tue Jan 29, 2019 12:30 pm

billwill wrote:Talking of exhaust studs, what is the logic behind using brass nuts on those studs?


brass (contains copper and zinc) would not weld onto the stud like a hot steel nut may tend to do over time, it is less strong (which can be compensated by taller nuts to increase the number of threads) but is behaves like a lubricant. I still use a smidge of copper grease with these...
S4SE 36/8198
User avatar
nmauduit
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1553
Joined: 02 Sep 2013
Location: France

PostPost by: Bigbaldybloke » Wed Jan 30, 2019 7:08 pm

Like Rohan, I?ve had 5/16 unc cap screws securing my exhaust manifold for over 30 years, no problems, just get ones the right length. They don?t get undone that often, are well lubricated with anti seize compound and not over tightened - use the Allen wrench with the long section in the bolt somyou only have the short piece for leverage and it?ll be fine. If you do strip one, as already mentioned it possible to helicoil it with the head insitu.
Change is inevitable, except from a vending machine!
Bigbaldybloke
Fourth Gear
Fourth Gear
 
Posts: 711
Joined: 16 May 2017
Location: Lincolnshire

PostPost by: elansprint71 » Wed Jan 30, 2019 7:23 pm

Thanks for the replies chaps. :D
elansprint71
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 4105
Joined: 16 Sep 2003
Location: Cheshire, UK.

PostPost by: Barney » Wed Jan 30, 2019 8:46 pm

bcmc33 wrote:So I guess I should Helicoil the plug holes too!!!!!!


Reminds me on my original head, #1 plug had stripped and the previous owner had bodged a metal electrical conduit piece set into the head. The centre was threaded to accept the plug.
Basically one of these cut down
super-helicoil.jpg
super-helicoil.jpg (10.48 KiB) Viewed 187 times

Blew it out of the head one day after spirited use and caused minor cracking to bonnet where it impacted.
Elan S2 DHC (26-4399),
Barney
Second Gear
Second Gear
 
Posts: 167
Joined: 13 Aug 2007
Location: North Lincolnshire, UK

PostPost by: 2cams70 » Thu Jan 31, 2019 6:16 am

I wouldn't use a Helicoil to repair a spark plug hole. There's much better inserts such as "Time Serts" or "Lock-N-Stitch" types available for this repair.
1970 Ford Escort Twin Cam
1972 Ford Escort GT1600 Twin Cam
1980 Ford Escort 2.0 Ghia
Peugeot 505 GTI Wagons (5spdx1) (Autox1)
2015 Honda City 5spd.
2cams70
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1008
Joined: 10 Jun 2015
Location: Australia
PreviousNext

Total Online:

Users browsing this forum: No registered users and 18 guests