Hewland MK8 to MK5 gears

I have Brabham BT21C with a Hewland 4-speed MK 8 gearbox with a Torsen Diff and 9:31 CWP. It was used for SOLO II competition so it is geared very low. I have a Brian Hart twincam that will be going to Ted Wenz in a couple weeks that should be a strong engine. I would like to upgrade to MK5 gears. I know I need a new 1.125" layshaft and the gears but don't know what else is needed. I'm assuming at this time that the forks and bearings are all good. Could someone provide me with a parts list and maybe some recommended gear ratios to at least get me around a track reasonably well. Thanks for the help. Its been over 40 years since this car has seen a track.

Ratio choices depend primarily on which track you will be running on. Someone will probably chime in if you tell us where you intend to run .

First gear will now be fixed.
So second will need to be hubbed

You will need two new Layshaft spacers for the larger OD of the layshaft .
Possibly a new layshaft nut . MK5 will be a 7/8-20.

Fork set up . bearings and all the other components will remain the same
Fixed first layshaft
Hubbed second
3 sets of top gears
Two layshaft spacers

I have some good used gearsets available

I have good assortment of new Webster MK5 gearsets at $240 each. 570-223-8870

Thanks Scotty82,

I'll start putting a parts list together with your recommendations. This car hasn't seen a race track for at least 40 years so I have a lot of work to do. I wish the car still had it's original MK5 gearbox and this would be easier. My next step will be to get the frame to David Irwin for refurbishing this winter. Then I will work on the gearbox and suspension. My goal will be to complete this in two years when I turn 70.

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Originally Posted by scotty82

First gear will now be fixed.
So second will need to be hubbed

You will need two new Layshaft spacers for the larger OD of the layshaft .
Possibly a new layshaft nut . MK5 will be a 7/8-20.

Fork set up . bearings and all the other components will remain the same
Fixed first layshaft
Hubbed second
3 sets of top gears
Two layshaft spacers

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Quote:

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Originally Posted by bob darcey

Ratio choices depend primarily on which track you will be running on. Someone will probably chime in if you tell us where you intend to run .

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Thanks Bob,

My guess is I will try Roebling Roads first because my neighbor in Titusville, FL races Porches and they often rent the track for club events. It'll be a good place to get some of the bugs out. My home track is actually Watkins Glen which is about 1 1/2 hours from my original home I still own. I'm still a member of the Finger Lakes Region SCCA. The first race I ever saw was a F1 there in 1966 or 67.

Quote:

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Originally Posted by Robert J. Cavanaugh

I have good assortment of new Webster MK5 gearsets at $240 each. 570-223-8870

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To Robert and Keith,

I'll keep both of you in mind when I start buying parts. It'll be a few months because I will soon be heading to Florida to commission a Liquid O2 plant for SpaceX. They keep lighting those big candles and we can't keep up with the demand. It's good to see an American company so successful.

Quote:

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Originally Posted by macbt21

Thanks Scotty82,

I'll start putting a parts list together with your recommendations. This car hasn't seen a race track for at least 40 years so I have a lot of work to do. I wish the car still had it's original MK5 gearbox and this would be easier. My next step will be to get the frame to David Irwin for refurbishing this winter. Then I will work on the gearbox and suspension. My goal will be to complete this in two years when I turn 70.

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You could do a lot worse than sending the entire gearbox to Scotty for a rebuild. After 40 years sitting all sorts of things can happen, especially if the box had fluid in it (even residual) for all that time.

Quote:

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Originally Posted by Robert J. Cavanaugh

I have good assortment of new Webster MK5 gearsets at $240 each. 570-223-8870

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Hi Robert would be happy with your email adress.
Thanks.

[QUOTE=kent_racer;588708]Hi Robert would be happy with your email adress.
Thanks.[/QUOT cavtrack@gmail.com