MG Sports Cars

So I've been having issues with my engine running fine then cutting out(after its been started for a while or started/cut off a few times in a row).
The problem stopped when I removed the 'vented' gas cap and would stay running without issue.

I'm running an unvented tank and a fuel filler neck/cap for a pre 70 car(I believe - the cap will not it on my dads 72).

I thought about it for a while and was wondering if its possible that even though the vented cap(provided through moss), is there a chance that the holes(about the size of pen point) are not adequate enough for an EFI setup?

The answer might be obvious but I thought I'd check here first - can I just drill a relief hole ~1/8" diameter to alleviate this?

Thanks for the help!

Hi Robert. Is this a problem that's been there from the start or one that has cropped up when it didn't exist before? I no expert, but it doesn't make sense to me that an EFI set up would require a bigger vent. More fuel is sucked out, but most of it is returned so doesn't seem like vacuum would build any faster?

Had this problem with my RV8, every time I took the filler cap off there was one hell of a vacuum rush of air into the tank, I figured it would implode the fuel ,tank, I drilled a 1/8th hole in to the fuel filler tight to the neck and it cured it and has not resulted in performance.

I put small hole in my gas cap....but it makes the garage smell of gas. Swaping fuel systems I am just putting in a tank vent.

Sorry for the late reply - I bored out the exisiting two holes and added another set. I noticed after doing this that the particular cap I had from moss didn't even seem to vent to the outside. However I still had the same issue of the engine cutting off(this after a few minutes) - followed by a few cylinders firing when attempting to restart.

I would wait a couple minutes and it would work fine and then the same thing. I thought I might be having an issue with vapor lock/too much heat near the fuel lines however this was not the issue.. Talked to Mr. Towery and looked over a few things. The issue was the fuel filter - despite being new it was just a very poor design.. engineering student got the best of me and and I cut it open to find it was just a giant restriction/was shedding pieces of the filter material. Was designed or EFI - just not very well.

Went over the entire system to check for debris and got a different filter. Broke in the cam and went for a short drive. All I can say is I'm amazed with the torque curve.. I did not have the kahunas in 1st/2nd and 3rd I never got to 1/2 throttle. DIY port on the heads seems to be a lot better than expected as well.


-On my to do list next is to weld in some reinforcement plates for the front spring perches

- Figure out something about the brakes - I cannot stand the feel of the power brakes - maybe I'm use to
the manual setup on my fathers '72' - if anyone has any advice please let me know, i just wanted to change the feel.

-I purchased a posi-trak limited slip diff for my ford 8" rear - however atm it seems to be permanantely locked - I added the supplied(motorcraft?) friction modiifier already. Am I missing something


Thanks!

Robert, your trouble with the posi is most likely due to the light weight of the car. What you can do is lift one wheel off the ground and then see how much torque it takes to turn that wheel with the tranny in gear, Odds are you'll be around 120 to 160 ft/lbs which is fairly normal. Your options are to either re stack the friction plates in the posi to lower the break away torque, or just drive it like that for awhile and pretty soon the parts will wear in and reduce the break away on their own. Once seated the plates wear at a pretty uniform rate so over the life of the unit it's effectiveness continually decreases. That's the dirty little secret of these types of posi units.

Jim

Thank you for the info Mr. Blackwood! I figured it was something along those lines or a possible issue with the weight of the gear oil. Cannot wait to get this thing back out!

Does anyone know a good place to find the larger rv8 radiators? The mustang radiator I had bit the dust(I didn't like it much anyways haha). I have no idea how people run 400hp through these cars, i've never experienced something so violent beore.

Robert, we control the "VIOLENT" part with the "Go Pedal". You will become accustomed to the power and move past the GO stage after a while. Its only violent when you make it! Have a safe summer. : ) PS it will take awhile though
SAFETY FASTER!

Glad you said it - i've been told you always become accustomed and nothing is ever 'too fast' - I can't wait to get it out to a track to open her up. I might be young at 21, but I know theres no reason to open a car up like that on public roads, too concerned about others.

Thanks for the wishes! I've been eyeing your car for a while now as inspiration!