Center-fill hood hole location help

[irl]

I bought a center fill neck and there is not much info here on actually installing them. Found nice shots on the different pieces mounted but not a technical description of the process.

Im sure everybody has there own way. I have the tank ready to drill, I have the center of hood located and Im guessing the best way to do this it to determine the right hole location in the hood. Once the hole is cut, it seems I could jockey around the neck form the top and bottom to determine the tank placement. I will be sure to post a series of shots so that is is documented for the future but I am hoping someone has the hood hole placement measurement form the top of bottom of the hood.

Thanks!

[boba]

Finish your tank first then locate the hole in the hood.

[Porschenutt]

I want to do this to my car also, please take and post lots of pics

[Plavan]

I used a plumb bob attached to an aluminum L metal piece across the fenders. I placed a mark on the fenders so I could raise the hood and put the plumb bob back in the same place.
It will point to the center of the hood, then you can center the center fill to the plumb bob. It lines up center fill to where you will drill the whole in the hood. Measure 5 times, Then drill hole. It worked.

I thought about training a 5 year old to lay in the trunk and mark the spot, but the plumb bob worked better

[ben parrish]

Haven't done it but I would install the fill tube then use heavy grease on the filler rim. Lightly close the hood and the grease will transfer to the underside of the hood....problem solved......ok, not my idea but it made great sense to me.

[irl]

Ok, here's my plan. I'm going to work on getting the neck on the tank first. I'm going to string a line across the fenders and drop a plumb bob down at the center point on the string. That will give me the center of the tank to cut the hole. Not sure how get the neck height right yet but I'm thinking that the top of the neck opening should touch the hood so when it is cut out the cap just crests the opening. I'll take a bunch of shots.

In regards to the hood hole the grease idea doesn't seem to be that precise when the hole has to be pretty exact to be sure the gap is uniform around the cap.

[wachuko]

Very timely thread... doing the same for my SC->RS project. Thank you for the ideas!

[bigel]

Mangnus Walker has a pretty thorough, if not step by step, post on this very topic...

Looky here: o.k.. CENTRE HOOD FILL GAS TANK. This...

[irl]

Wow so I was all set to mount the neck on the tank first but he cut the hole first??? What to do??? He has a neck from Marek and I have a neck form TRE. Mine has the dog bowl riveted on to it already so I cant lower the neck down the hole because the the pipe isnt that long. I think Im going to finish the tank first.....I think?

[drcoastline]

Personally, I would go about it like this.

1. Re-mount the tank.

2. Align the hood with proper gaps. Tape off fenders at gaps, cowl and latch panel so I could apply measurement indicators.

3. Find center of hood left to right.

4. Double check #2 & 3.

5. Transfer center line to tape on cowl and latch panel. String a line.

6. Determine about where I want filler to come through the hood.

7. Transfer those measurements to tape on fenders. String a line.

8. Check lines against gas tank to ensure neck is going to fall where I want it on the tank.

9. Make adjustments

10. Re-check 7-9.

11. Place filler neck on tank check against string-line.

12. If necessary make adjustments.

13. When satisfied of location drill hole in hood.

14. align filler neck to hole, transfer filler neck contact point to tank.

15. Tack weld filler neck. One maybe two tacks.

16. Check placement of neck against hole in hood.

17. If necessary grind off tacks. adjust neck re-tack. When satisfied make alignment marks on tank and neck.

18. Remove neck, cut hole, align adjustment marks. tack again. Check alignment against the hole in the hood.

19. If satisfied remove tank complete weld finish tank.

20. reinstall tank.

The important thing is to have the hole in the hood perfect. As you do not want to be adjusting the hood screwing up your gaps. You can make slight adjustments to the tank location to center against the hole in the hood to provide perfect alignment.

Remember the rule: MEASURE TWICE CUT ONCE. In this case Measure three, four or five times. Drill once.

[drcoastline]

Oops, see this is why you measure twice cut once. Even though I proofed this twice I still didn't explain thoroughly.

Between steps 12 and 13 you will be transferring the adjustments to the hood to determine the hole placement.

[Marek]

Also from experience

Remember to mount the "foam" under the tank first,
it can resault in a few mm hight difference ,
so the cap will, be in a straight line with the hood

For my kit , you got the hole in the hood plate ,
which you can see in Magnus tread
this allow to adjust the hole a bit,

and remember that old tanks, can contain a old fuel vapors
which can be explosive ...boom

Regards
Marek

[bigel]

Originally Posted by Marek

...and remember that old tanks, can contain a old fuel vapors
which can be explosive ...boom

Regards
Marek

++ Yes, inert those fuel tanks before welding!!

[Mark Morrissey]

Originally Posted by Marek

...

and remember that old tanks, can contain a old fuel vapors
which can be explosive ...boom

In New Jersey our explosions would be
bada bing bada BOOM

[wachuko]

I have two kits, one from TRE and one from Marek... could not resist to see where, more or less, it would be on the car... I got the kit for the RS project since in the RSR we had the fuel filler flap on the upper corner of the hood... anyway, just for giggles, I try to measure where it would be. I wanted to get an idea how low from the top edge of the hood it would be. I use the RSR for testing... the hole, in the case of my car and using the Marek's kit (body shop has the TRE since that is the one that first got here), is around 18.75 inches from the top edge of the hood...

[Chuck Moreland]

I would cut the hood first. Then drop your tube through the hole to position on the tank.

Use a marker taped to a stick to reach down through the tube to mark the position on the tank.

Reference the position of the tube to the fenders and cowl.

now you can raise the hood and reproduce the position of the tube using the above references.

Cut the contour of the tank to the tube base. Then tack weld and confirm hood alignment. When good, finish weld.

Now it's easy to mark and cut the hood contour in the tube.

And roll the edge of the hole in the hood, no question.

[bigel]

Originally Posted by Mark Morrissey

In New Jersey our explosions would be
bada bing bada BOOM

'Bada BOOM' fo sho...

[cnielsen]

I agree, this is how I did mine.

I would cut the hood first. Then drop your tube through the hole to position on the tank.



Use a marker taped to a stick to reach down through the tube to mark the position on the tank.



Reference the position of the tube to the fenders and cowl.



now you can raise the hood and reproduce the position of the tube using the above references.



Cut the contour of the tank to the tube base. Then tack weld and confirm hood alignment. When good, finish weld.



Now it's easy to mark and cut the hood contour in the tube.



And roll the edge of the hole in the hood, no question.

[irl]

wachuko, that 18.75 to the center of the hole not the top correct?

[wachuko]

Originally Posted by irl

wachuko, that 18.75 to the center of the hole not the top correct?

To the center, correct. But keep in mind that it was with the one from Marek. TRE is a bit different... Plus I did not have the filler neck held in place with those cool corner magnets.

All I am saying is that it was a simple test to see more or less where the hole would be...

What are you getting as a measure with the TRE??