ratter

your mph is a better indication of the power you are making, ET will tell how well it hooks up, how you drive it etc

When the valves float, they are basically bouncing around out of control and the rocker arms are no longer contacting the cam shaft, when this happens the lifters have no load on them and then some will pump full of oil. When the lifter is full of oil it will hold the valve off it's seat so basically dropping compression on that cyclinder. This is why the car will run rough, after a few minutes of running the lifter will then bleed back down and things will go back to normal. This is the good scenario, the bad one is if the valves bounce hard enough, the collets can dislodge and the valve falls into the combustion chamber, colliding with the piston and doing lots of damage.

you do not need to modify your reg.

food for thought for all those contemplating generics and possibly getting a dyno run to check air fuel ratios, Incorrect air fuel ratio is not the biggest enemy, incorrect spark advance is the killer.

His symptons are exactly what valve springs cause. I would feel bad for him if he paid $1200 + labour and it did not fix his problem.

Not that you want it to heppen but these things can happen when this much is undertaken. Sounds like atomic is taking good care of it as some engine builders would fix it but only if you removed the motor and took it back to them. Reading through the posts, this was not a brand new motor as mentioned above was it?

Walbro 340,341 or 342 will all do the job, the difference between pumps is the size and position of the inlet and they are all rated at flowing the same volume. I have a technical document showing that a 342 will slightly outflow a 340 at certain fuel pressures and voltages

Thanks for the update Gas requires pretty much perfect combustion, so based on the spring issue, they should be replaced so you do not get any backfiring issues.

I've never seen standard springs go 300, and have seen them bouncing at 235 rwkw, but normally would expect to see 270-280 rwkw. Did you tell him you had 60 lb injectors?

Although tuning it may appear to stop the problem, the real problem would not have been sorted.

Congrats on the numbers

Lifters are not normally a problem on these motors, and if a lifter is a problem and they bleed down they tick but do not cause the engine to run rough and then clear up, valve springs are a problem with a bit of added boost to the motor, I hope not for your sake, but I think your problem will return

No problem, hope you get it sorted 100%

Sorry mate, I know I shouldn't assume, but I assumed you must have been trying to control boost with a flash 2 or 3 . Not familiar with the sniper, but possibly the turbo control is still in closed loop which is why your adjustments may not be working. Is the flapper closing all the way, I have seen some port jobs (including some that are posted on this forum) that the flapper can catch and then not close all the way intermittantly, which then stops boost building as it should.

I doubt you are going to get enough control with just the hand unit, you will need a custom tune to get the boost correct and then you can make small changes with the hand unit. Assuming you have no boost leaks anywhere, your port is allowing more exhaust flow through it when it is commanded to be open which is why your boost level is now lower

A port job should include both of those, not just make the hole larger

porting the housing should fix the overboost.

Don't stress too much, these are normal type occurances that show up when rebuilding engines, be thankful your engine builder is doing things correctly and measuring everything rather than just bolting it together. Goodluck with the build

Edit, just realised how old this thread is

we would need the car for possibly over a week to do the gas and do a tune on it also to suit

Not 100% sure on that one, but I think it would be getting close to it's limit although it may be safe enough to use, would need to speak the ALPGWH to find out for sure

no worries mate, hope it goes well for you

using the 60 lb injectors will not work. The car we did (worms) we had to go back to 42 lb injectors.

aside from looks, your tyres may now be unroadworthy. Not sure in your state, but here in vic any sidewall damage deems the tyre unroadworthy and the authorities are looking at these groves as sidewall damage. Some of the later tyres are now just being painted rather than ground.

did they grind a groove in the tyre and then apply the paint in the groove, or did they just paint it?