SPD Racing FC

i know j/k around

banzaitoyota

AAAHHHH the joys of being an ****-RETENTIVE Design Professional. Since I live by the MANTRA:"Why would I buy something for $20 when I can make it for $75.00!"



I am fabricating my new fuel rails; for two reasons:

1. Why not

2. The fuel rails that came with the TB from Aussiland will not work with my airbox





NOW: onto the dilemma I measure the Fuel Injector bore on the Aussie Rails as 0.430". So I order my ream to replicate this hole. Now My maching capabilities in the shop are very limited as our most peoples. So I visit my welding and fab forum to confirm my process. And low and behold who pops in but Mike-LMR to provide the missing tidbit of information I needed. He provided me the link to the injector dimensional drawings.



NOW the real fun begins. It appears that the injector rails I used as my template are a little sloppy on their manufacturing tolerances. The correct bore size is .425" nominal/.427" max.



So now I need to order ANOTHER Reamer (These things aren't cheap)..



I hope this provides a little insight into why it takes a while to accomplish something as seemingly simple as drilling 2 holes in a length of extruded Aluminum.



BANZAI

TYSON

I don't think you need to ream the holes Banzai. Just drilling generally doesn't leak.

banzaitoyota

I drill a test set (ACTUALLY I TRASHED 8" of Fuel rail) of holes the other day and the fit is ATROCIOUS!



Now in all fairness the bit used was from the Harbor Freight Cheapie 115 piece set. I have since ordered a couple of new bits (Triumph Brand)



I also need to check the runout on the drill press and make sure thats not contributing to the hole size creep.



Unfortunately I do not have a complete Metric Drill Index. The safest solution to this problem is to drill undersize and ream to fit.



The ultimate solution is to obtain/gain access to a good Knee mill with the benefits of rigidity and close tolerances, instead of my drill press. All in good time

TYSON

I agree. I forgot to clarify, I've only seen drilling injector pockets WITH a mill.



Reaming with a sloppy drill press probably won't go that well either though.........

banzaitoyota

Which is why I do have a contigency plan. If my test holes fail. I just pack up my toys and go over to the tech school and use their Mill.

Cheers!

work faster! you have a dedicated barn for your car. I have a frozen 1/2 garage.



btw becareful about the tech school equipment. Some of them are pure crap with dead bearings and runout that would make holes drilled by a hand drill look precise

banzaitoyota

Trust me, Test holes in scrap and a quick runout check are the order of the day





BTW: Tuesday nite I had a 120,000 BTU kerosene space heater and a 100K Propane radiant heater and I was still cold in SC!

banzaitoyota

Kahren was interested in how far the injectors were from the port: ~ 5.75"



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In order to check clearance available for the Airbox I cut up a TII hood I had laying around





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kahren

no i was intersted in how long the runners were, from the rotor housings to the end of the flare on the horn. seems to me about 10-11 inches