fuel pressure drop
Turbo Mini Forums

I need some help here,

My engine has 14cc dished pistons and a 22cc head. 286 cam shaft and its just rebuilt. It ran superb at the std 4PSI, however, now if I push it hard it seems to cut out fuel supply altogether.
Normally at idle I can hear fuel running when I open the tankcap. after pushing and cutting out there is no fuel running anymore.
I have changed the fuelpump and it didnt solve the prob. Next on the list is the pressure regulator I guess.
But can someone please explain why this happens? could it be vapourlock in the regulator?
anyway, all input is appreciated.:cool:

Are you drawing from the standard 1/4" outlet in the tank???

There is a gauze (filter) on the end of this that causes problems.

No, I have an 8mm feed line and an 8mm return line. At the moment I have the filter bypassed.
The return is not T-pieced, its directly back into the tank.
So it is: Tank, fuelpump, regulator, carb. nothing more.

And remember the project is a TM, Turbo Midget
I have no clue how to show pics here, but I have uploaded some in the pics section.

yo... problem solved.

A while ago the pickup tube inside the tank dropped of and fell in the tank. I never repaired it because the project was on the way and I had a full tank anyhow. Lately I have had things sorted and the time came to solder the tube back in place, then all troubles began with the fuel pressure drops.
I grinded the tank open and soldered a 12mm tube in place and welded the thing shut, I also connected a 12mm hose from the tank to the fuelpump.
Problem solved... thanks to Turbodave with the comment if I still draw fuel from a 1/4"pipe. that made me think further.

Its good to hear you got it sorted!

Most people find the promblem and fix it... its good to hear what it was!

Alex

AlexF

your running a 286??

Years ago, I was running an MG Metro camshaft, and decided to give a Kent 286 a try.

Admittedly, I only worked with it in the car for about 4 days, but the fact I actually went to the trouble to remove it after 4 days, speaks volumes.
Tickover wasnt too bad, but low end power was non existant.
Power from 4000rpm-8000rpm wasnt bad at all, but I could barely use 4th gear below 2500rpm.

With the MG Metro cam, I could go WOT at 1000rpm and it would pull well right to 7000rpm.

In my brief experience with a 286, all it did was shift the useable rev range upwards, and kill any low end power/torque.

Last cam I ever used was a SW5 which did seem to offer improvements over the MG Metro cam. It will still pull 4th gear from pretty much idle, right through to over 7500rpm.

That said, different setups are different. Mine was 7.5:1 CR, and using a lot of boost. SO perhaps with a higher CR and less boost, the wilder cam may work ok.

But generally, experience over the years on many turbo engines has taught me, mild cams work much better than big cams on forced induction engines, certainly in terms of road manners. Big cams just dont offer enough, to make them worth it.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

more over lap = less dynamic CR

So without the boost they are naff!

Still hi comp low boost like you say should work.

Alex

AlexF