Need help with a dimension for a transverse leaf 289 Kirkham

[blue sky]

If anyone with a leaf spring 289 Kirkham could confirm the following dimension, I would appreciate it. Is the centerline to centerline dimension from the left rear wishbone mounting chassis bolt to the right rear wishbone mounting chassis bolt 21 1/4"? Was suggested to me that dimsnsion was greater and I want to make sure before finishing some work on a rear tower. Thanks so much.

[MAStuart]

21 5/8

[blue sky]

Thank you very much.

[krausewich]

Kirkham dims I have are
21-3/16 Rear
24-1/8 Front

None of these match up with other ref. numbers I have (width/height), so Kirkham's do their own thing for better or worse.

[MAStuart]

AJ The computer I was using had a bad keyboard so the answer was short. The dimension was not from a Kirkham car. It was from Chucks drawings. Center points on his drawings are 21 5/8 and are 1/2 inch above the 3 inch main rails. I do not know if these dimensions are correct because I have found other problems in the drawings. One other note Chucks drawings are for a car with nonadjustable suspension.

Mark

[blue sky]

Mr Krause, Thank you for giving the data. That will be benefical to me.

Mark, I was informed that the early 289 chassis David was making was tooled from an original car. I am not sure what is being done now. I have contacted Chuck about a set of drawings but he is on holiday right now. I want to pop up to his place and look at them to see if they are complete and accurate enough to build from. I don't have CAD so I will need a dimensioned set. A long time ago I started reverse engineering an original car and have some info but not a lot. I wanted to check what he had compared to what I have. I looked at some of the dimensions that was on the Thomas drawings and they are considerably different to what I had recorded. The car I measured was a very early rack and pinion car so don't really know if there was a variance between that and the latter R & P ones.

[LMH]

Somewhere, I have (but can't find now of course!) a photo of an unloaded spring showing the rise at the center to be about 3.25" and the length approximately 38" measured from bolt hole to bolt hole where the trunnion mounts on the spring. It was from an original R&P car.
Larry

[blue sky]

Originally Posted by LMH

Somewhere, I have (but can't find now of course!) a photo of an unloaded spring showing the rise at the center to be about 3.25" and the length approximately 38" measured from bolt hole to bolt hole where the trunnion mounts on the spring. It was from an original R&P car.
Larry

Larry, I think you are referencing the yoke to yoke centerline of the upper front suspension. The front left to right wishbone mounting centerline of a Kirkham is 24 1/8" which is what I believe matches an original.

[MAStuart]

AJ What did you come up with dimensions? Keep in mind the Dimension I am giving are for a coupe. This should not change things because they are based on a leaf sprung car. No my drawings the pick up points for the front control arms are 24 1/4 inches apart and the spring eyes are 38 inches apart when the spring is compressed flat.

With all the different numbers for different cars i get a headache trying to figure what is right.

Mark

[blue sky]

Originally Posted by MAStuart

AJ What did you come up with dimensions? Keep in mind the Dimension I am giving are for a coupe. This should not change things because they are based on a leaf sprung car. No my drawings the pick up points for the front control arms are 24 1/4 inches apart and the spring eyes are 38 inches apart when the spring is compressed flat.

With all the different numbers for different cars i get a headache trying to figure what is right.

Mark

Mark, Quite awhile back I was given the dimension of 24 1/8" by an owner from his original car. I did not physical take this measurement myself. There is another person I want to ask on this and hopefully over the weekend I would like to pop down to a shop where some Mk2 cars should be. I am not knowledgable with the coupes so I could not provide reliable information. I thought the base of the chassis was still fabricated by AC Cars which most likely would have been the same with suspension pick up points. The motor mount towers were lower in height than the roadsters (this is based on the drawings and reproduction Daytona's I have seen being made).

[Jac Mac]

In this pic you can just see the start of the scalloped area in the RH chassis tube for starter and bell housing clearance along with the similar relief in the chassis cross tube that allows for the lower engine/trans position in coupe, at one stage I wondered if this only applied to 2286 which had the 390 fitted initially, but I now think all original coupes have this. ( arrows to areas concerned. This pic also confirms use of gas welding to add coupe body support structure )

[1985 CCX]

great stuff guys, remember the early cars were most likely slightly different as they are hand made. Exact is not a Cobra thing......

[CompClassics]

GOODYEAR BB or "wets" suck because they are a race tire, a wet race tire at that! The design of the tire was to be used in wet racing conditions on a closed circuit race track. People that use them as they were designed tend to like them.

[LMH]

I think you meant to post that in the Goodyear tire thread John.
Larry