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#1 Tachometer
Posted: Sun Jan 17, 2021 11:49 am
by Bernie2015
Hi All,
just wondering if my tacho is correct for my car Series 1 DHC 1966 (see photo) much appreciated if anyone can confirm or deny.

#2 Re: Tachometer
Posted: Sun Jan 17, 2021 12:36 pm
by cactusman
Looks right...red section at 5000rpm...7413/11 is the smiths part no.....somewhere in the knowledge section I think there may be a large list of instruments and what was fitted to what and when....you might be able to cross ref against the list
#3 Re: Tachometer
Posted: Sun Jan 17, 2021 3:28 pm
by Bernie2015
Which Series has a red line 5500rpm-6000rpm?
#4 Re: Tachometer
Posted: Sun Jan 17, 2021 3:51 pm
by cactusman
3.8's have the red line at 5500....4.2's at 5000 i be!ieve....
#5 Re: Tachometer
Posted: Sun Jan 17, 2021 3:54 pm
by Bernie2015
Many thanks, I can't find the info on the knowledge base, paperwork never was strongpoint though.
#6 Re: Tachometer
Posted: Sun Jan 17, 2021 4:17 pm
by max-it-out
cactusman wrote: ↑Sun Jan 17, 2021 3:51 pm
3.8's have the red line at 5500....4.2's at 5000 i be!ieve....
Are you sure ? My 1968 4.2 has the red line at 5500 .
#7 Re: Tachometer
Posted: Sun Jan 17, 2021 4:48 pm
by Gfhug
Clausager P81 shows two rev counters, one with the clock (as above) has the red line from 5000 rpm, the second without the clock fitted to an S1.5 shows red line from 5500 rpm.
The S2 Rev counters start red line at 5000 rpm.
Why the S1.5 has the 5500 rpm red line

Anyone got Haddock to see what is shown there?
Clausager P79 quotes “All Series 1.5 had matt black bezels .... while the rev counter had lost its clock and was now Smiths number RV.4612 with the red zone starting at 5500 rpm.”
Geoff
#8 Re: Tachometer
Posted: Sun Jan 17, 2021 5:03 pm
by cactusman
No Mark....not sure....although I do recall reading the red line of the 4.2 is 5000 whereas the 3.8 is 5500......but I might be wrong

#9 Re: Tachometer
Posted: Sun Jan 17, 2021 7:44 pm
by malcolm
My understanding always was that 4.2=5000rpm, 3.8 5500. That's what my handbooks say as well.
#10 Re: Tachometer
Posted: Sun Jan 17, 2021 7:53 pm
by mgcjag
Some 1.5 cars have the 5500 redline and some 1.5 cars have 5000 red line...just like Geoff

#11 Re: Tachometer
Posted: Mon Jan 18, 2021 10:59 am
by Bernie2015
Such a great knowledge base on this website many thanks.
#12 Re: Tachometer
Posted: Mon Jan 18, 2021 11:00 am
by Bernie2015
While were at it do the other gauges look correct?
#13 Re: Tachometer
Posted: Mon Jan 18, 2021 2:00 pm
by christopher storey
Bernie : it depends how much of a purist you are, but I note that the oil and ammeter have the straight sided bezels, whereas the water and fuel look to be the curved bezels - unless it's a trick of light /shadow . I'm afraid i don't know which are correct for your car
#14 Re: Tachometer
Posted: Mon Jan 18, 2021 2:52 pm
by max-it-out
malcolm wrote: ↑Sun Jan 17, 2021 7:44 pm
My understanding always was that 4.2=5000rpm, 3.8 5500. That's what my handbooks say as well.
Interested in why they reduced the max revs for the 4.2 - any obvious reason ?

#15 Re: Tachometer
Posted: Mon Jan 18, 2021 3:57 pm
by malcolm
bigger bore in the 4.2 to get more torque, but less revvy than the 3.8.
#16 Re: Tachometer
Posted: Mon Jan 18, 2021 4:13 pm
by Bernie2015
christopher storey wrote: ↑Mon Jan 18, 2021 2:00 pm
Bernie : it depends how much of a purist you are, but I note that the oil and ammeter have the straight sided bezels, whereas the water and fuel look to be the curved bezels - unless it's a trick of light /shadow . I'm afraid i don't know which are correct for your car
i think its just a trick of the light but thanks for your input Chris.