Jensen with a sore head

[Simon]

My Jensen bodied Minor has developed a sore head with 120 psi on number 1 and 4 cylinder and only 50 psi on number 2 and 3 cylinder.

The diagnosis is nothing broken and a blown head gasket. All that remains to be done is to fit a new gasket. What a bore.

Does anyone have any idea what the cylinder pressures should be for a Minor - both dry and wet (oil not water)

[Ian Grace]

No idea Simon, but presumably standard air pressure multiplied by compression ratio should give you a max value?

[Ronald]

120 seems a little high to me...... maybe the head has been skimmed a few times.... which would all add to the reasons why the gasket might blow.....

[Toby]

sorry to hear that, will be able to tell what a sv should be when I check mine, thanks for coil, will post back to you asap, seems to be tight tappets, possible valve on saloon! Hope you made it back ok.

[Highlander]

Simon, Are you back on the road? I have a good cure for a sore head!!!! Highlander.

[Simon]

Alister,
Not yet but will be back on the road for the Watercress Line meeting in October. I have also got to replace the steel sleeve / liner to No10 cylinder head stud. You will not have this problem wiyh the SV engine. I do not think that Minors will run very well on single malt.

[Highlander]

Well done. Single Malt is very good for sv minors - the more you give it the better it goes!!!! I have a question re speedometers. I have never owned a car with the type of speedo we have on minors - should they be steady at say 40mph or do they all sway from 30mph tp 45mph and you guess that half way is your speed? Just off to Reigate re Scottish Dancing but will come home via Wray Lane . This is a test hill mentioned in most hill tests in the 20s. Again there are sleeping policemen at the foot of the climb which stops you having a run at it. The hill has hair pin bends and is fun in a modern but a hard test in our type of car. Any bets on the cricket????!!!! Highlander.

[Toby]

My speedos seem to have some wobble but not that much, judging by revs/speedo they have a slight variation in their reading from time to time. Both mine read around 5mph over, between 25-40 mph actual speed. I have enquired about repairs or calibration but it appears that they are not repairable so it's as well to have a spare! Does anyone know if the regular type of speedo (fitted to 34 minors?) is suitable for sv minors, and if so what numbers should be on the dial? I wonder if the 8 speedo would be close enough!

[Simon]

Alister, Toby,
It might be worth checking the condition of speedo cable and lubricating it. What may be happening if sticking is that it is winding up and the letting go suddenly causing the needle / disc to speed up. Do not forget to look at both the inner and outer. Best of luck.

[Highlander]

Thank all, it is not a great problem and I have had all the 6 years I have owned my Minor. Al all speeds in all gears the speedo just "swings" from side to side about 10mph either side. My question was - has anyone a sv whoes speedo is rock steady? Thanks. Off to Swanage for a week Highlander.

[Trevor Wilkinson]

Yes I do have a speedo that gives a steady reading up to 55 but does start to waver slightly above that!

[Toby]

I thought humans suffocated at speeds of over 50mph? Yes, cable fully lubricated, incidentally you can get very small discreet digital speedos to ensure legality around cameras etc! A Bentley owning friend uses one.

[Ian Grace]

I hate speed limits. When I find myself in one, I try to get out of it as fast as I can.