I have a 3.4 engine from a Mark 1 I am installing into my 67 340. The question is should I swap dampners from my later engine or leave well enough alone? First photo is late one.

 

Which is in the better condition? The rubber part deteriorates over time. It can separate from the steel, crack or become deformed. As to the design, apart from timing marks, I don't think that it changed much over the years, but someone may correct me on that.

 

It shouldn't make any difference as both are 3.4 litres, use the one in the best condition _ no cracks in the rubber.
If they are both badly cracked, then replace it.

 

Use the one that is in the best condition as long as it takes the Bi V belt pulley.

Very early XK engines did not have a damper. In June 1956, a vibration damper was added to the crankshaft nose to give smoother running, Dampers pretty much coincided with the 3.4 litre launch.

 

What I'm asking is the later engine has what looks to me more like a dampner while the early engine does not. The only thing I've changed is swapping pulleys.

 

Your second photo. Is that thing behind the pulley just a metal pressing with no rubber? If so it is not a damper. Sorry the picture is not clear. You need a heavy iron damper ring with a rubber insert. That would be the correct item to use. Your 1st photo has a damper like my 3.8. Jaguar changed patterns over time.

This is what a new crankshaft damper looks like for a 3.4 engine. Some had spokes. These things are heavy.

 

Glyn, where did you find the June 1956 date for introduction of the damper? I know some very early pictures show engines without a damper, but I thought that all production engines had one. I'm sure I've seen one on an early XK120, though of course it might not have been OE. Can a crankshaft as long as that of the XK6 surviving high revs for long without one?

Next question: do all the long stroke engines, 3.4, 3.8. 4.2, have effectively the same damper?

 

Peter in a number of books by a number of scribes but in this case Taylor's latest book & Dugdale's "Jaguar in America." ~ I read extensively to sort the wheat from the chaff on the Internet. I guess how we all learn. Of course if a scribe get's it wrong so will I.

It was likely only very early engines that did not have them and no I would not run that length of crank without one. However it is a 7 main bearing engine with balancing webs on the crankshaft.

Question 1)

quote " PRODUCTION CHANGES (1955– 57)
The new Jaguar suffered from surprisingly few teething troubles in view of the amount of new engineering it incorporated. The service bulletins that Jaguar issued to their dealers reveal that many minor changes were made to the car’s specification, but that few of these were to counter serious faults. Perhaps the biggest problem was that the Panhard rod mounting on the bodyshell was weak, and a number of breakages were reported. So in May 1956, Jaguar advised dealers to weld a reinforcing plate to customers’ cars, and at the same time introduced an adjustable rod on production, which allowed the correct tension to be maintained. Other problems concerned the rear springs, which could create irritating knocking noises. The first modifications were made in autumn 1956, when a new front mounting plate was added in production and the spring leaves gained rubber ends. Unfortunately, this was not the whole answer, and further reports of problems came in. So early in 1957, Jaguar advised their dealers to check for distortion of the spring mounting clamps. Even that did not cure the problem completely, and the service bulletins would continue to offer suggestions for dealing with the problem right through into 1958. Performance and handling were generally satisfactory. Longer front springs were fitted at the end of 1955 to reduce front-end cornering roll, and in spring 1956 the carburettors were modified to deal with complaints about flat spots in low-speed acceleration. The twin Solex carburettors gave occasional cause for concern for the rest of the 2.4-litre model’s production life, but Jaguar doggedly retained them until 1967. Otherwise, only two engine changes of note were made in this early period. One was in June 1956, when a vibration damper was added to the crankshaft nose to give smoother running, and the other was in November that year when a steel sump replaced the original aluminium type. Most owners had no cause for complaint about the performance of their 2.4-litre Jaguars. Nevertheless, Jaguar Cars were well aware of their reputation as a maker of performance cars and so, to cater for those who wanted more, they introduced tuning kits during 1956. These never sold very strongly, partly no doubt because few buyers saw the need for any extra performance – particularly on Britain’s slow and crowded roads in the pre-motorway era.
credit
Taylor, James. Jaguar Mks 1 and 2, S-Type and 420 (p. 31).

Question 2 ~ as below ~ all use the same. (other than racing engines I'm informed ~ They had some exotic, for the time, dampers)


Classic Saloons

420 Saloon

Daimler Sovereign

Mk I / Mk 1 3.4

Mk II / Mk 2 2.4 & 240

Mk II / Mk 2 3.4, 3.8 & 340

Mk X / Mk 10 3.8

Mk X / Mk 10 4.2

S-Type 3.4, 3.8

Classic XK

XK120 DHC

XK120 FHC

XK120 OTS

XK140 DHC

XK140 FHC

XK140 OTS

XK150 DHC

XK150 FHC

XK150 OTS

XK150 S DHC

XK150 S FHC

XK150 S OTS

E-Type / XKE

E-Type S1 3.8 DHC

E-Type S1 3.8 FHC

E-Type S1 4.2 2+2

E-Type S1 4.2 DHC

E-Type S1 4.2 FHC

E-Type S1.5 2+2

E-Type S1.5 DHC

E-Type S1.5 FHC

E-Type S2 2+2

E-Type S2 DHC

E-Type S2 FHC

Early Saloons

Mk IX / Mk 9

Mk VII / Mk 7

Limousine

Daimler Hearse

Daimler Limousine

XJ Series 1-3

Daimler Sovereign S1

XJ6 S1

XJ6 S2 / Daimler Sovereign S2

XJ6 S3

 

I think that means 2.4 engines didn't have the damper until 1956. Especially as the XK120 that ran out of production in 1954 was, according to your list, fitted with the damper.

 

It's interesting that we're discussing the serviceability of 60-year old crankshaft dampers. From what I understand, they're almost a service item for certain models of a German make well known for the excellence of their 6 cylinder engines.

 

You could well be right. That would make sense. As I say ~ "I read extensively to sort the wheat from the chaff on the Internet. I guess how we all learn. Of course if a scribe gets it wrong so will I." I try to cross reference wherever possible. I have a 6th sense for conflicting info while reading. My awful Virgo tendencies.

 

2e Foto is clearly a broken damper, where top part and rubber is missing completely.
This happens when the rubber is perished.

 

in the USA:
https://www.damperdoctor.com/