Just curious to get a head count here

When your h22/h23/f20b exc. has a cylinder fail because of something mechanical (valve, rings, sleeves, exc) what one has it been?


1
2
3
4

I ask cause 3 times it has been 3 and one time 2 and 3 went on me. Always being loss of compression, bad rings/sleeve. And I just bought a car, 0 compression in 3 with around 200 in the others. It has a h22 smoking like a bitch and leaking oil out the front and rear exhaust flanges! So much blow by, I'm thinking broken ring lands, Can't wait to tear this down.

Edit: cylinder three had melted ringland

I am thinking cylinder 3 runs hotter, makes sense it would because of location.

Thoughts?
Should we be running cylinder 3 slightly richer or pull some timing if capable of doing so with the right tuning set up? I would think coil on plug set up would be necessary for individual cyl. Ign. Tuning

 

The slave cylinder, no troll, just never lost a single cylinder yet.
Changed a few master cylinders too.

 

You must not be pushing it hard enough

 

I am a mechanic with a couple spare cars to drive. If something stops feeling right, I fix it fast. Really though, havn't lost a motor yet to catstophic failure. This new nitrous motor i'm building is top notch but nitrous has a way of humbling the best of mechanics.

 

Yeah, there's no tech here.

I vote that we get this moved to GDD, where you will have a much larger pool of members to vote in your poll.

Mods please consider.

 

I can be your first vote haha, I have only killed one piston so far, and it was #3. I think mine was due to a leaner (hotter) mixture in that cylinder, while spraying nitrous. I was running hot laps at the drag strip, and got the rings hot enough to expand and touch, breaking the ringlands.

Taught me after the fact, do not set ring gap on the tight end of N/A spec when planning to run nitrous!

 

how about you just stay in GDD since you contributed nothing here?

#3 makes sense because it does in fact run hotter due to its placement and firing order. I run a little more fuel in the #3 injector to balance this and keep that cylinder a little cooler.

I do not have any EGT data for this though. Just something I have noticed from reading spark plugs.

 

I've burned up exhaust valves in the number 3 chamber on two different heads (same block though). I have likewise heard that the #3 cylinder runs a little hotter.

 

all separate engines from various preludes I've owned:
-cyl 3 spun bearing and spit rod out the front. (300k+ on the clock all original)
-cyl 3 HG failure. (boosted, shaved the block and head, new gasket, raised torque specs, lasted another 100K)
-cyl 3 broken ringland (boosted, stock pistons), but still drove it for another 50k with no issues besides minor oil consumption and slight loss of power.
-cyl 3 melted hole through piston (boosted, stock pistons) due to broken ringland and HG failure. I replaced the gasket when it blew, not knowing the ringlands were broken, and apparently when I blew the old gasket remnants out of the cyl it spun the rings around til they caught on the broken ringland. combine those multiple hotspots all in one location (exhaust side) with an aggressive tune and exhaust valve lash being too tight, and it was a recipe for disaster which lasted about 20 miles.

these were all 3g prelude engines. and after the most recent one, I decided to cc all my heads because I still have them from each of the above motors, and sure enough the chamber volumes in the heads were all slightly smaller in cyl 3 than all the other cyls, by about 0.5cc-1.0cc. new setup I have in the works I reshaped and polished all the chambers in the head, and set cyls 1 2 and 4 to be even in volume, and cyl 3 to be 0.5cc larger, and will no longer be using stock pistons.

cyl 3 is definitely the hottest strictly according to location, but other factors do contribute too.

 

Steve I have also decided to run a slightly larger combustion chamber in cyl 3 on my next head. And it works out nicely because cyl 3 already has some nickes from broken guides so it needs to be smoothed out anyway.

 

Why not cylinder 2? I mean, 2 AND 3 are both in the center of the block

 

Think about the firing order.

1, 3, 4, 2.

3 is the only cylinder stuck in the middle of two firing events which doesn't allow it to cool as quickly as the others....in theory.

 

i don't get it.

 

heat transfer through conduction.

do you know how the 4 cycle engine works? intake, compression, combustion, exhaust?

 

Oh definitely. But i'm having trouble picturing the RUNNING engine in my mind, with all 4 strokes. I'm not the best at visualizing.

When 3 is compressing, 2 is exhausting. So that means at least one cylinder next to it is NOT igniting. I'm not sure i understood your wording though. You are saying that when cylinder 3 is intaking, 2 and 4 are both igniting?

 

This is not the correct reasoning. Allow me to explain and make further suggestions/theories on the topic.

The firing order is not the culprit:


The firing order of 1-3-4-2 is also 4-2-1-3 which puts the #2 and the #3 cylinder in the same situation; opposing cylinders firing at interval (sandwiching it) between. It is not reasonable to think that the motor always starts by firing cylinder #1. It doesn't matter what cylinder starts the ball rolling.
We are assuming here that there is actually an issue with cylinder #3 based on numerous high potential output motors. I don't believe there is enough data to suggest an abnormal issue as there isn't a trend that I am aware of with factory tuned and assembled motors. This is a modified high output and high abuse issue. So let's go on:

IF, (big if), there is an issue with #3 cylinder that is documentable and not assumed, than there must be further study of the cooling system. All things being equall, every cylinder, head chamber, valve, intake port, etc. are identical and have no dog in this fight. Even the exhaust system can not be blamed for an irregularity IMO, as the length, and shape do not give favor or penalty to exhaust flow. So there may be a thermal issue with circulation or turbulant flow, perhaps cavitation in some small pocket that continually recirculates the same hot pocket of coolant. This theory is speculative. It must be further studied with much more scientific method. Coolant entering the motor from the radiator passes into the cylinder head cooling cylinder #4 first.
This alone should cause one to think about the flowpath as cylinder #3 is next in line to recieve coolant which has been moderatly heated from contact with cylinder #4. It would seem that cylinder #1 would have the hardest time keeping cool but that trend is not being reccorded?

What do you think is the next area to be explored and discussed?
I don't want to ramble on if there isn't an ear or point of view.

 

didnt look at it in that perspective. thanks for a new outlook

 

Haha very true about the firing order theory. Busted

As far as 3 getting hotter I feel it has to do with its placement. With the tranny closer to it. Cylinder one is on the outside completely exposed for more air cooling. Where on the other side, 4 is next to the trans with the block being covered leaving just the head for air cooling and also has the clutch generating heat. So this would cause cyl 3 to get the hottest.

That is just my theory

 

Smokey Yunick had done years of research on the small block Chevy motor for Nascar and hinself to help with the #5 and #7 dilemma with cooling and failure.
He ground different cams and changed the firing order.
He made different crankshafts (the flat crank).
He pulled water directly out of the front of the cylinder heads instead of the manifold.
He reversed the flow of water through the motor.
He tried every known coolant and then some.
He changed flow rates and volumes with scientific accuracy.

He concluded the Chevy motor liked reverse coolant flow (contrary to how it was designed in production) in an ultra high HP, traveling through the heads first and then out the block.
It took him years to do this testing and I left a few things out so not to bore you.

There is a block coolant plug directly in front of the #3 cylinder in a B series motor that may facilitate an additional coolant return to the block and suppliment the cooling capacity a tad. It would depend on the line size and volume being transfered. Also an accurate array of temperature senders would have to be installed at the same location in every cylinder for data verification. Anyone want to volunteer for the benifit of the many at HondaTech.