95 EX coupe w/B16 S300 I/H/E

So I take a mountain run and beat the hell out of it. Bouncing between 6500-9200 rpm..
I slow down and cruise for a little and in 3rd or 4th gear I'm going up a steep hill and was impressed with the low end torque it made.. (since I'm NEVER down there) so I pulled this hill around 2500-3500 rpm and kinda just bogged it but it was accelerating a steep hill in 4th gear around 3000 rpm.. IMPRESSIVE! Well I get to my friends house and when I pull up the car is running on 3 cylinders.. I can feel it in the steering wheel and I can hear it in the pipe.. it's all bad..

I get home and do diagnostics..

Cylinder elimination.. (pull wires 1 at a time while running.)
find out it's cylinder 3

compression check..
240, 240, 225, 240 So cyl 3 is a little low, but not low enough to make a "Dead hole".. Keep looking..

Swap 2 and 3 plug wires to see if it's a wire.
the problem stays with cyl #3..

Swap 3 and 4 injector plugs
prob stays with cyl #3

Changed cap, rotor, plugs, different set of wires and new 270cc RC injectors..
problem stays with Cyl #3..

So I start thinking "Maybe I burnt a valve.. That'd cause a missfire and low cylinder pressure.. heavy loads and low RPM MIGHT burn a valve.." So I do a leak down test.. I calibrate the gauge at 0% then lock it on the hose that is now screwed into the cylinder on TDC for that cyl on the compression stroke. perfect is 0% average leak down is 15%+ and moderate leakdown you start worrying about 20%+..

Results
10%, 10%, 10%, 10%

WHAT THE HELLL?!?!?!

So I start the car to drive from my friends shop where I stole his tools to test it and the car idles and revs FINE!!

I'm lost at this point..

So I drive it home.. VTEC a couple times thinking it was a fluke and when I get home it's doing it again, Missing in cyl #3! F#%K!!

So I take my B16 street engine out, and put my B18C? track engine in.. it's 11.8:1 ross pistons, Eagle H-beams, full floaters, flame cut rings, Endyn custom Type-R Oil pump, Horschel motorsports Fluidamper, Crower springs, locks, retainers, super tech valves, and all the skunk s%*t you can think of.. Cams, gears, intake etc..

It starts and runs amazingly well.. I forgot how much power it made.. BUT, when I was swapping the IACV and the TB off my old B16 intake, I happened to see something in the valve train shining me in the eye (Reflection from the sun) just under the cam on cyl #3.. It was the 2 primary rockers!! I just so happened to pull the engine when it was on the intake stroke of cyl #3 and saw that it was in VTEC mode!! THAT EXPLAINS EVERYTHING!!! The low cyl pressure, the low leak down, not to mention the miss!

So what exactly happened..

You know how LMA's are starting to go bad on alot of B's with the old style LMA's?? The same thing is happening to the VTEC return springs.. Mine just so happened to snap..

Rockers 1, 2 and 3.. 1 and 3 are primary rockers, 2 is the vtec rocker.. rocker 1 has a return spring, rocker 2 has a free floating pin and rocker 3 has a pin that has a port behind it that can be pressurized with oil to make it slide out of its bore.. Well when you hit VTEC the oil pressure behind the pin locks them together and when you get out of vtec mode the return spring in rocker 1 pushes the pins back into a neutral position.. Since mine just broke, the pins freely floated around and never disengaged from VTEC since there was nothing pushing them back..

This is fixed with a new $140 rocker assembly from honda PN:14620-P30-000 which is only 3 rockers for one half of one cylinder. =/

I thought I'd post this because I can see it becoming a more common problem with older heads and valve train.. This should help you in your diagnostics so you don't have to go through what I did to figure it out..

Cheers..

 

Wow great post. I found it very interesting!

Here is a DIY for replacing LMA's if anyone is interested!
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/lma-blues-writeup-theory-replacement-w-pics-2564272/

 

WOW.. That's a pretty detailed post!! Who wrote that one up?? lol

 

lol

 

whoa that's crazy haha