Lifter Pump Up

[voldo 1]

Hi there,

 

Alright, so I always hear about mi16 / gti6 engines experiencing hydraulic lifter 'pump up' at around 8000rpm. Has anyone actually experienced this, or is it just an old wives tale?

 

The reason I say this is two fold:

 

1) I work for an aftermarket camshaft company and we do many camshaft profiles for all sorts of racing cars - including those with direct acting hydraulic bucket style valvetrains (such as the Nissan RB / Mazda B6 etc).Although lifter pump up in old style pushrod applications is common (1950s/60s tech), we have never had an issue with modern direct acting lifters pumping up at high revs.

 

2) We have a hydraulic profile here for a peugeot 405 touring car which has 260degrees at .050" (i.e. a full race cam). This cam will make power way past 8000rpm.

 

Cheers

[petert 589]

'92 Bathurst 12 Hour. Conrod Straight claimed at least one of the McLeod Citroens. Rev limit was 7500.

 

http://en.wikipedia.org/wiki/1992_James_Hardie_12_Hour

Edited February 3, 2012 by petert

[voldo 1]

I'm a Kiwi, know Conrod straight pretty well!

 

Why didn't the other 5 mi16 powered cars do the same thing?

[welshpug 1,661]

could have been drafting something quicker

Edited February 3, 2012 by welshpug

[petert 589]

They didn't fiddle with the standard rev limit. Lot's of cracked guides.

[voldo 1]

And there is concrete evidence that it was the hydraulic lifter pumping up that caused the motor to fail? Did it burn valves?

 

I need to put one on the spintron.

[petert 589]

I got the ECU, another friend got the head. So can't recall. 260º is certainly out there for a hydraulic profile. Good luck with your testing.