I had my recall repaired yesterday with no issues, broken clips or anything. Now mind you, I have no idea what this spring does and it may be a figment of my imagination but when in "D", is seems to shift at a little higher RPM. Is it possible? What exactly does the spring do? Is it just my imagination?

 

Higher shifting may be a result of the battery being disconnected and ECU being wiped out. May take a few days for it to get back down to normal while it learns your driving style all over.

I believe the LMS is tied directly into the i-VTEC system so likely impact of the springs wouldn't be noticeable during normal driving. (given that your normal driving doesn't include much time upwards of 4500rpm )

~SB

 

It did make a difference when I got my Fit back. It's packing a noticible amount of more horsepower, not like 30 more, but I can really feel it.

 

Yep, your imagination. There are 4 LMS in the VTEC valve train. They keep tension between the rocker arm bridge and each of the secondary intake lobes on the cam, so the secondary rocker arm always follows the cam lobe profile. When engine speed goes over about 4000 rpm it's the secondary lobe that takes over operation of the 2 intake valves on each cylinder. There is no relationship to the shift points of the transmission.

geo

 

Crap. I was hoping it wasn't my imagination! Can you tell me why they are called a "Lost" Motion Spring? I thought the recall was to prevent them from breaking or getting "lost".

 

In a standard rocker-type valve mechanism, the valve spring pressure keeps the rocker arm tight against the cam lobe at any position through the rotation except when the valve is fully closed, and that's where the valve clearance of a few thou is set...at the valve-end of the rocker arm...on the non-VTEC rockers. In the VTEC system there are two different profiles on the 2 intake lobes....one for low rpms and another for higher rpms. The secondary rocker arm is not actuated at low engine rpms, so there is no valve spring pressure keeping it against the secondary intake cam lobe. That's what the LMS are for. They keep a zero clearance at the cam end of the secondary rocker arm all through the profile.....hence the term "lost motion". If there were no LMS or if the LMS were broken, the the secondary rocker arm could be wandering in any position through the cam profile and could be whacked hard by the cam lobe instead of rolling around it smoothly. So the secondary rocker arm always follows its cam profile with zero clearance and is ready to take over at approx 4000+ rpm. whew, hope that's clear?

geo

 

.....one more thought.....the LMS name came with the design of the valve train, it's not a term that was coined because of the recall.

geo