$12P Idle MAP Threshold VS Idle RPM

[delcowizzid]

i flat tappet cam isnt designed for 300000km's LOL that and valvesprings measuring in the 40lb max area when you test them does cut output LOL

[vlad01]

I have to disagree with that. I know an engine developer who discards hydro lifers and fits solid flat tappet and they engine last decades with track and daily driven reliability.
The engines this guy builds outlast most modern engines and perform like a race engine.

can you guess what engine this is?

[immortality]

Solid lifter on a hydraulic grind is a bit of odd combination, hydraulic grinds have much less aggressive ramp rates and less total lift which means they need less spring pressures. flat tappet cams seem to last well enough in factory built engines of yesteryear (seen plenty of Holden 304/308's with more than 300,000km's).

[vlad01]

no I mean getting rid of the lot, custom grinds with solid lifters.


Yes factory build would last long in most cases, not all though. its people's upgrades or mods that tend to over look critical details which make them fail quick.

[immortality]

Totally agree, however a lot of the after market stuff isn't of the same quality as some of the factory items, one big one that comes to mind is the quality of the lifters. Been a lot of failures in the last few years because of cheap chinese lifters, not just flat tappet either, same goes for roller lifters.

So, what engine are you referring to?

[vlad01]

vw type 4. aka bay window kombi engine.

[Knackersjewels]

Very old thread dig, but I'm having an issue with a t5 VS 304, will rev hang until vss hits 0, then drop to idle perfectly. Is this idle map threshold the key?