No more head gaskets for the Turbo M100?

[Brit-Car-Nut]

I have just realized that Lotus has placed the turbo head gasket on the discontinued / NLS list. That may be a very important issue since that is a part that is not available from any other source. I tried Isuzu and they show it as being discontinued as well, so be kind to your engine. Parts are getting very difficult to source.

[dapinky]

I'd like to think that this is another example of "We'll make enough for a few years".....

....certainly, about 10 years ago they went obsolete, but then about 6 months later a new batch was made.

If they have now 'sold out' then i would expect another batch to be produced at some stage........hopefully.

[Brit-Car-Nut]

I'd like to think that this is another example of "We'll make enough for a few years".....

....certainly, about 10 years ago they went obsolete, but then about 6 months later a new batch was made.

If they have now 'sold out' then i would expect another batch to be produced at some stage........hopefully.

Unfortunately, a phone call to Lotus ended with a flat "no chance". Isuzu no longer has any and they are not going to have any made because the cost of the minimum order quantity was expected to be outrageous.

I am looking at other sources and gaskets used by people that were racing the Impulse 1.6 Turbo and trying to figure out which head gaskets they were using. Lotus doesn't have any because Isuzu doesn't have any and when I talked with Isuzu US, they are definitely listed as NLS and no intention to get more made.

I hope you are correct, but who can wait 6 months "hoping" Lotus or Isuzu will decide to get a small quantity made?

I was only looking into it because I HAD 3 new gaskets in stock and after I got a request for one, I wanted to make sure I could replace any I sold.

There are custom gasket makers that will duplicate any gasket needed, but the cost will be high.

(I had to get a custom head gasket made for a 1958 Princess R and it was over $500.00 back in 1975. It was for the engine that has the head studs cross-threaded into the block THROUGH the water jacket.

[dapinky]

(I had to get a custom head gasket made for a 1958 Princess R and it was over $500.00 back in 1975. It was for the engine that has the head studs cross-threaded into the block THROUGH the water jacket.

Great engines when running well... completely unstressed 4 litre straight 6 - I'm surprised that the head gasket ever needed attention. (Weighed about the same as a small house, though!)

[Brit-Car-Nut]

It had been badly overheated and the block surface was warped.

The studs are interference threaded into the block BELOW the coolant cavities and removing them left damaged threaded holes that went into the lower crankcase oil area.

There was no way to surface the block with the studs installed and no way to remove them without ruining the block.

We ended up getting a copper composite gasket and added a thin wire under the cylinder compression rings. It took a few trials and gasket failures to figure out the best way to make it happen, but the car drove home - over 200 miles away and had no trouble and was sold t a museum who only wanted it to run occasionally.

[robertverhey]

SJ appear to be carrying head gaskets for both N/A and turbo models.....am I missing something?

[Brit-Car-Nut]

Nope, not missing anything. They have the LAST stock and are down to 9 (or less) gaskets and then there will be absolutely no more.

I ordered several from them yesterday and I am hoping they are really going to send me Original Isuzu/Lotus gaskets, not generic replacements.
Their picture looks to be correct.

(I haven't checked SW Lotus or any other stockist since having multiple packages in transit is usually not cost effective and SJs is an easier place to shop)

Since they get (got) the gaskets from Lotus, they also won't have a source to re-stock.

Maybe Lotus will get enough requests that they will push Isuzu to make more, but across several phone calls, that didn't seem to be a consideration.

I had 3 in stock and now have 2 since I am posting a gasket to an owner today.

I like to keep up stock on any Lotus supply only parts so I tried to order a few more and found out that it will probably be a problem in the near future.

[SteveB]

Hi all. I have not posted on here for years, im sorry to say but life just got in the way. Have kept my SE mothballed for a few years now but with this virus thing thought I should get it back on the road. I found this thread a little worrying and wonder if I should get one in stock before it's too late. But just had a quick look at Rockauto site and there seems to still be a few choices for the Impulse turbo ! I always thought they were the same engine but I'm no expert. Can anyone shed some light for me ?

[robertverhey]

Lotus Marques are listing head gaskets, though I’ve not verified that they actually have them in stock


https://lotusmarques.com/parts/catalogu ... gine-parts

[Brit-Car-Nut]

Unfortunately, Rock Auto sells a "generic" gasket set AND they think the Turbo and NA are the same.

If you looked for Full Gasket Set, you probably found part# APEX AFS3001 for the Turbo but if you look at the NS they list the same number.

If you only looked at Head Gaskets, you probably found APEX AHG301 for the Turbo but if you look at the NS they list the same number.

The head gaskets are NOT the same. The Turbo gasket requires different water jackets and some holes are reinforced.

Do a deep dive on LEC and see how many early owners used the generic Isuzu head gaskets and ended up having to do it all over again.

[Brit-Car-Nut]

Lotus Marques are listing head gaskets, though I’ve not verified that they actually have them in stock

https://lotusmarques.com/parts/catalogu ... gine-parts

As long as they still have existing stock and are not counting on ordering the gaskets as needed, then they are OK until they run out.

This is assuming they are not buying the "generic" head gasket and showing the Turbo part number.

The M100 NA head gasket is A100E6103S and they look very much the same. The difference is in the engineering and water ports.

I know of a couple of M100s in Australia but I am guessing there aren't too many?

Other resellers and repair shops that specialize in Lotus should KNOW the difference in the head gaskets and may also have stock available as well.

You just can't go to your local dealer and have them order you one anymore. Like above, if they have the real A100E6104S in their local inventory, then you are lucky.

I am not a dealer but I try to keep stock on most of the more common M100 parts for myself and others that might need them. I try to keep 3 head gaskets available all the time.

[robertverhey]

I’ll contact Steve at LotusMarques and check his inventory. He’s listing them as a Lotus Part number which he usually only does if they are the real deal. Will report back to the group.

There’s a lot of M100s in Australia, SE and S2. All in lovely (comparatively) rust free condition! They were sold here new. I’m on my second one.

Robert

[Fetnas]

I picked up a head gasket from Lotus Marques a couple of years ago. It was a genuine Isuzu turbo gasket. At the time I worked only a could of kilometers away from his location and Steve was kind enough to hand deliver it to my work place. That's what I call service.

[robertverhey]

Update, got in touch with Steve at LotusMarques

He no longer has the original kits, is now sourcing kits from Japan and selling for $A270.00 plus postage. Says they are good quality and says they suit the turbo variant. Also said they are getting harder to source.

[TorqueHorse]

I recently snagged a genuine Lotus HG from BCN (thanks!) and it is what I'm going to use for my upcoming replacement. But I also had one that had come in a set from Fel-pro, so without making any claims to the efficacy of either, I did have the opportunity to visually compare them and wanted to share with folks here to do what they will with the info.

Two gaskets, side by side


The Fel-pro with unique stamp marks


The Fel-pro kit (HS 9685 PT)


Detail of the marks on the Lotus one


Contrasting the perimeter seal material between the two (Lotus on top)


Total apparent alignment of holes from the front


Same for the back

[Brit-Car-Nut]

Unfortunately, Lotus still shows two different head gaskets between the NW and Turbo.

FelPro shows the same gasket set (HS9685PT) for both. They also show the same gasket set to fit the (non-turbo)GEO Storm.

Lotus wouldn't waste their time on different gaskets unless it made a difference.

I am still going to follow the results posted on LEC since 2008

The consensus was that only the Factory gasket solved the problem and everyone that posted said they had to do the gasket job over not long after the first pass with the Generic Gasket.

The other gaskets in the head set are OK, but not the head gasket, but you can get them from at a lower cost using a generic set instead of paying FelPro prices.

Isuzu also shows two gaskets: 8944296261 for the Non-Turbo and 8944636780 for the Turbo engine.
If you drop the first and last digit from the Isuzu number, you get the GM number and GM shows the two gaskets to be DIFFERENT!

Who do you think knows more? Rock Auto (FelPro) or Lotus, Isuzu & GM?
JC

[Simon_P]

Torquehorse, I was going to post the same thing after another recent post. It appears that the Fel-pro HG is a good match. It has the tag indicating that it is for the Turbo application, appears to be made from similar materials and is dimensionally the same.

[Brit-Car-Nut]

Then it would not be correct for the other 1.6l engined cars over here, yet, they say it is correct for ALL 1.6l engines.

Since I can return anything from Rock Auto, I ordered a couple (and a couple of OEM from SJs before that) and will try to figure out why so many early posters had gasket failures after getting their original head gaskets replaced.

There is definitely something different between the two versions.

FelPro is a good brand, but I learned the hard way when building up all the MGBs that I had to use the BLM gaskets if I wanted the engines to survive. Complements of Mike Barret at BL, I even had a couple of the factory copper race gaskets which were quite different from the fabric gaskets for the stock engine. There is still most of a .040 over block, decked and deburred with a full race cam, peened and balanced crank, rods Hepolite race pistons and Deves rings plus if I look around all the other bits to someday put it together in the back corner of the storage area. It was going to be used for full-on SCCA racing but I never got around to finishing the rest of the car after we moved south. I think Dave Parker at MechSpec (UK) ended up with the body when he bought out my BLM inventory and took it home to the UK.

I maintained several MG Midget race engines over the years and never had one blow. I even did a couple track days in a friend's Midget just to have fun. I had a regional SCCA license and was able to get a week with Skip Barber's performance school at Charlotte Motor Speedway on the Can-AM course.

I used Felpro for all of the domestic engines I built and had no trouble but they didn't last in the (stock) MGBs or Midgets. (I mean the later, not copper gasket early models Felpro didn't offer gaskets for).

Look at the label for the gasket set as TH posted:

Gasket Set Label.jpg

Other pictures when everything arrives.

[TorqueHorse]

Yeah, not trying to make any claims, just posting what I observe. How you interpret and act on it is up to you

[dapinky]

Since I can return anything from Rock Auto, I ordered a couple (and a couple of OEM from SJs before that) and will try to figure out why so many early posters had gasket failures after getting their original head gaskets replaced.

There is definitely something different between the two versions.

Looking at thye pictures above, the FelPro looks like it could be a good option.

Certainly, it appears dimensionally correct - and, as you say, is a known brand.

I can't comment for anyone else, but certainly the HG that went wrong for me shortly after change was NOT a FelPro unit..... or at least, wasn't branded as such. Also, when layed over the Lotus HG, it was noticably different.

The batch which went wrong 10-15 years ago were all from one supplier (AFAIR), and originated somewhere a long way East of the Grenwich Meridian (a lot further than Norwich!).

It may well be that FelPro units are up to the job - the minor differences between the NA & Turbo gasket are to do with the coolant system flow speeds/volumes so that the two engines receive the optimum level of cooling for their own application - so using a Turbo gasket on an NA may well have no negative effect (noticable), but the other way round may do..... but I'm just guessing here.