When the 99 was introduced I believe they had trouble with fuel pressure when the stoves were used on snow. The problem was that the tank rested on the bottom of the case which chilled it preventing it coming up to proper pressure. In 1972 Optimus formed two bumps on the bottom of the lower case. These raised the tank off the bottom and reputedly solved the problem as snow no longer cooled the tank. This stove has the two bumps so presumably was made no sooner than 1972 provided that the information that I have been given is correct. I have not come across a stove case without these bumps so they must be rare or I have been misinformed. The early 99s had an aluminium heat shield which this stove has. Whilst the pan lifter is made by Optimus it is not correct for the stove. The windshield is a copy rather than the genuine Optimus one and the strap is also not a genuine Optimus one. Regards Bryan
Bryan, Thanks for the history and the photos. I love my single (late) model Opie 99. I call em "mini-Rangers." Chef BC
Hey, Bryan, and All, I believe you are absolutely right about the early 99's having a smooth bottom. The wonderful booklet published by Off Belay Magazine, back in 1975 (Thanks, Rob!!) mentions that exact problem. I am sad to say that I had thought I owned one of the early, flat-bottomed 99's, but alas, cannot find it, now! I do have the other two versions of the 99, but had once thought that I had all three, including the early one you mentioned. "Maybe" it's still buried in the Hobbit Hole, or in a box up in the stove room. But, it's not come to hand, yet, despite some time spent looking for it. Sigh..... Thanks for the wonderful photos and report, Sir! Great stuff, as always! Take care, and God Bless! Every Good Wish, Doc
i've said before that i like and use these 99's because you have a big lid to cook in but another thing is that the tank stays in the case.i found that with the 8 the way the tank pulls out like a mini 111 that you have one more bit to try and make fit when you close it up.with the 99 you just fit the lid back on.
Hi Doc I put the two items on because there were examples of both the early and late 99s but no one appeared to realise that there were at least two versions of the stove I think that this one must be from near the end of the early versions because the tank lid has the five sided centre and the vertical knurling. I have never been able to accurately date the introduction of that lid but think that it was the late 70s or at least sometime close to 1980. On the other hand the lid could be a replacement. Regards Bryan
Hi Bryan thanks for posting this information. The 99 I have was purchased in 1976 from REI in Seattle. It has the five sided centre on the tank cap with the vertical knurling, the alumnium heat sheild and the 2 bumps on the bottom of the case also. The bumps to hold up the tank seem to be outside of the tank. There are a couple of narrow slots also, one to each side of the bumps. The Arno strap that came with the stove is a blue,white,yellow stripe. I no longer have the box or instructions for it.
Hi, Bryan, Thanks, very much! I appreciate your having posted two of the three versions of the Optimus 99, and look forward to seeing the other soon, hopefully in my own house! Thought I had one, but cannot find it, now. I did send one of mine to a Mate in the UK, quite a few years ago, and that might have been the one I remember. But, I have no idea if that was the earlier version, or not. Oh, well..... old and senile: that's me! Take care, and God Bless! Every Good Wish, Doc
I've only seen two caps on the 99's and 8R's, the one you describe, and the cap that goes with the mini pump. Then again, what do I know? Murph
Hi Murph The tank lid that goes with the mini pump has an extended central section to allow the O ring on the mini pump to seal to it. The early mini pump tank lid is on the left with the later one on the right. Both have an extended parallel sided central section for fitting the mini pump. Mini pump tank lids have the long extended section under the lid because there are two valves in the lid. One acts to release excess pressure and the other acts like a pump valve to allow air from the pump to enter the tank. A collector told me that he had bought a mini pump with the left lid in 1975 so the pumps date from at least then and it appears that the diamond knurling was still being used then. This was the last tank lid that Optimus used. I think that there was a slightly earlier version with more pronounced vertical knurling. The knurling on the version shown is more in the form of grooves rather than the pronounced ridges of the slightly earlier version which I think that existed Regards Bryan
I think that the sequence of the Optimus petrol tank lids is as follows Sorry for the quality of the photos but they have been cropped from other photos. The pressure release valve was inside the lid. The centre of the lid unscrewed to expose the spring and piston. These were in use in the 1930s but were probably also in use in the 1920s when Optimus first introduced the extending type of petrol stove These are a sequence of later Optimus petrol tank lids The left one was definitely in use by 1958 but was probably in use earlier. It continued in use up to the mid 1970s. I think that the next one was made by Sieverts and if so it could be an original fitting on Optimus stoves from 1969. The third one appears to have been used for a short period of time as it is relatively rare. The last one is the one that I believe is the last one used by Optimus. Rick has mentioned that it was on a stove bought by him in 1976 so it looks if that was when it was introduced. However the left lid was definitely in use when the 99s were introduced so there may be some about with that lid. Unfortunately lids are easily changed so whilst they are indicative of the age of a stove they are not positive proof that the stove came from the same period as the lid when a stove has been bought from a previous owner and user. Regards Bryan
CORRECTION I have been trying to pin down the date of the change between the tank lid on the left and the vertical knurled one two to the right. It transpires there are at least three other tank lids in use on Optimus petrol stoves in the period between 1962 and 1976. The two left ones are from Optimus made stoves with burners made no later than around 1970 so I assume come from the 1960s although this is not definite. The right one is from an Optimus made stove fitted with a burner that Optimus first produced in about 1970 so I assume that the stove was made between 1970 and 1976 when Optimus stopped making Primus stoves. It looks as if there were numerous versions of the petrol tank lids in use in the early 1970s Sorry for the confusion that I caused Regards Bryan
I thought since we are talking about the 99 I would take a pic of the fuel cap and the bottom of the case on my 99. The cap style I have has 2 flat sides. Not sure what I was thinking.
Resurrecting an old topic. I have looked all over this site and did not find a photo of a 99 'bottom' without the bumps. Is there a chance it could be posted if you have one? I got one last week. They are hot. I boiled 2 cups of 2water in a kettle, and had to turn it down. Thanks, Ken
This thread interests me. I picked up a 99 from eBay in December, and it doesn't have the ridges in the bottom described here. Are these early ones particularly uncommon? -- Mike
Another stovie kindly pointed out to me via a PT that since this thread is in the gallery I probably ought to post some pictures. I grabbed these on my way out this morning - apologies for the quality!
hi Mike Evans, Thank you so much for sharing and congrats! for you have something special there! LIDS: Aside from fact we all know used stoves may have had a lid replaced, but what you do have there is helpful info. Above RickB posted a tank lid (flat sides), above that Bryan posted lids w/hex shaped part (vs the flat sides). Is your 99 one of those 2, if so which 1? If it is the hex shape, is the top hole penta shaped or square? Thx again it is all the better to see the smooth bottom. (re lid, just an answer is easy and that'll work) omc PS If you tire of it i'll send an address u can send it to, the 99 is of no great interest, look, only... 6,000 views! ha
Mike, it looks like you are missing the wind shield. They can be made pretty easy from a sheet of aluminium. There are plenty of examples in the gallery. If you are going to make a wind shield, it might also be worth using the same aluminium to make a pot lid. The 99 didn't come with one but it reduces boil times and saves fuel. It straps on the outside when packed up. You'll see mine in this Link Terry
