Forum » Practical Engine Building » Ignition Cut and Retard 2 step vs Hydraulic lifters

Ignition Cut and Retard 2 step vs Hydraulic lifters

Practical Engine Building

Discussion and questions related to the course Practical Engine Building


Page 1
Author
61 Views

Ok, so I plan on using an Ignition cut with Ignition retard two step on an LM7 5.3L, which does have Hydraulic lifters. From the module in Launch Control, Andre advises not to use this sort of function if you have Hydraulic lifters as this can cause the valves to hang open until the lifters bleed back down.

So when I refresh this motor, what is the advised lifter I should be going with then?

Thank you,

Damen

Let's start by discussing what you're needing to do. Hydraulic lifters aren't the ideal option with an ignition cut limiter but it's possible to use them if you aren't aggressively retarding the timing. This really depends on the size turbo you're trying to spool and since you have 5.3 litres you may not have too much trouble. the other thing to mention based on your other post is that to spool the turbo against a trans brake and get the engine up to the convertor stall speed you don't want to use retard. To come up on the convertor you need torque and retarding the timing reduces this so it's counter productive. Retard only works on a manual transmission where torque isn't required to reach the 2 step.

Now with all that in mind there are a variety of solid lifters available for LS based engines. Just remember that you'll also need a solid profile cam to go along with the lifters.

Hmmm. So then do I need to do a fuel cut type of 2 step or should I just use just an rpm launch limited set to converter speed and allow the boost to build while I’m on the brake?

Never mind I read that wrong. So I could still use an ignition cut limiter just don’t retard the timing then, correct?