Patrick we need an update on the project please
Sorry for the late response, life. I have been diverted to other things over the summer months, between hosting guests,early summer holiday, helping son number 1 with a home building project and late summer holiday not a lot happened, oh I also bought a S1 FHC.
However, I am now back in harness and a change of direction on the Low Drag has meant the car build has gone backwards!
I decided to try and get FIA compliance for the car, this meant things like my billet 4 pot callipers and ventilated discs all round have to go.
Back in the day The front brakes were MK9 callipers with a special disc, as the peg drive hubs were 6 hole disc fittings. Now thankfully the hubs are 5 bolt pattern which makes sourcing discs a little easier.
I am fitting MK 9 discs but as ever nothing is quite as it seems, the disc PCD doesnāt match the hub, so they are in for drilling. I have a set of MK 9 callipers ready to bolt on to the adaptor brackets for aligning to the S1 uprights.
Work today centred around lowering the engine/gearbox as the top of the engine and dry sump cam breathers were very close to the underside of the bonnet. I am told very little of a Low Drag shell will fit a standard car, this may apply to the bonnet centre panel as I have never experienced such a problem before.
Taking advice from Crosswaite and Gardner I lowered both assemblies 1/2 an inch. This has knock on effects on other components all of which are now identified and the majority rectified, hopefully all finished tomorrow.
I will post pics later this week.
Oh, if I didnāt mention before the car is now UK registered with a period correct number, thank you DVLA, only took 9 months.
Wow. Thanks for the update. I wasnāt aware that you can get FIA for a new build /replica.
Looking forward to the photos.
Hereās what you end up with if you do a bit of cosmetic drilling to get the look!
Have you discovered yet that not only the 5 hole PCD but also the centre hole is larger than any other classic Jag? 3.25" instead of 3.0" IIRCI had to make adapter rings to get the disc concentric and then sorted out the 5 new holes. Oh, and the pukka adapter brackets I bought fouled the Mk9 caliper bodies and the upright caliper lugs, so a load more fettling was needed there too.
All that work and expense to end up with 2 pot brakes that weigh a ton even with alloy piston assemblies. The joys of keeping it āoriginal specā for the regulations I guess.
I got my block back from the machinist just before I came over, bored to 3.8. To keep it correct for 56/57 I had to use a 3.4 block instead of just using a 3.8 engine. By the time the competition liners were in place because of core shift, and the mains align honed, it had cost me the thick end of three rand just so the embossed lettering on the block read ā3 1/2 Litreā instead of 3.8 Litreā¦
Peter I just had a 3.4 bored to 3.8 did you sleeve yours?
With best regards
Yes. Ultrasound showed the core has shifted or was never that straight. The bores were sounded at 12/3/6 and 9 o clock at four heights and the thickness deemed risky at 0.145ā IIRC. Only two absolutely needed sleeving but I didnāt want a water leak if the block started moving so I paid for all six with high precision performance sleeves.9
Peter, looking very authentic, I take it this was your D replica?
Yup. Hereās my recent (now improved) attempt at mocking up DCO3s. I didnāt mind dropping Ā£350 for a D fuel line and banjos, plus a bit more for good length trumpets, but Ā£3,300 for each of three repro carbs was OTT. So I bought some 1.5ā hex bar and Weber badges and got fettlingā¦
Second pic shows mirror finish cut for the head gasket surface. Never seen a finish like it.
I recall reading that F1 engines do not have head gaskets as they have perfectly finished head and block surfacesā¦
Why is that mirror finishing desirable for this application
Looks very nice Pete, glass-beaded and chamfered to emulate a cast part? Iāve always liked those wingnuts, though (Hmm, maybe what they say about me is true). Why is the plate considered better than the stud/wingnut?
I like the wing nut too Bob but the Weber 45 DCO3 is the correct carb for a D. Sadly, three of them are Ā£10,000/$12,000.
They used the Weber plate and hexagonal 2-screw cover. So although they fool nobody āin the knowā, they at least donāt look like typical DCOEs used on every serious but non-toolroom replica.
I machined a circular recess on one face to fit over the round hole, then cut off the opposite side, filed the rounded shoulders and made the two fake securing screws. It!s a āworseā design in some ways but they are the carbs you see on every non FI D-type.
Back in the day The front brakes were MK9 callipers with a special disc, as the peg drive hubs were 6 hole disc fittings. Now thankfully the hubs are 5 bolt pattern which makes sourcing discs a little easier.
I am fitting MK 9 discs but as ever nothing is quite as it seems, the disc PCD doesnāt match the hub, so they are in for drilling. I have a set of MK 9 callipers ready to bolt on to the adaptor brackets for aligning to the S1 uprights.
When using the MKIX disc on the front, what do you use on the rear?
I have a modified Mk2 solid rear axle on 4,trailing links, with Mk2 discs and D-type single-Cable hand brake. If brake balance turns out to be a problem I will fit a proportioning valve in easy reach on the short tunnel.
What I meant is what size cylinders are you running. I would think seeing you are running the 2.5" on the front, you would need the 2.125" on the rear. You have the āBrake balance Calculatorā I left with you, so you can play.
At least with the DUNLOP callipers you have a good selection of cylinder sizes available fro 1.5" thru 2.5"
MkIX are 2.125 same as standard but bigger pads and disc. Only 2.125ā are permissible in most vintage events I think. Should stay same front-rear ratio with stock rear cylinders but car weight balance with alloy body may need a change?
Beg to differ Peter, MK IX front were 2.5" (Piston Kit DK4058) and the rear 1.875, verified by my 1974 āGirling Brake Parts Catalogueā.
The MK X was originally fitted with 2.125" (Piston Kit DK4052) front and 1.5" rear for the first 1500 vehicles , then the front was uprated to 2.25" (Piston Kit DK4060) and the rear to 1.625".
The 2.25" front was a normal upgrade I did on S1 Eās back in the day.
1 Like
Will certainly cede to your knowledge and experience Norman. My limited knowledge is only about Long Nose D brakes, and somewhat the Lightweights. In both cases the 2.125 piston units were the only ālegalā modification and therefore the part that is made by tuning suppliers in aluminiun.
But surely the 2.25" piston would be a ālegalā fitting as it was a period Dunlop cylinder used by Jaguar on the MK X>