92 VX Seeking 50+ MPG

[user removed]

Originally Posted by Lovemy92vx

Can that be remedied?

Make sure the compression test is done with the throttle wide open and preferrably the plugs out of the other 3 cylinders. Cranks faster and gets full atmospheric pressure for the test.

If it's still that low you need the rings replaced and other work done depending on the condition of the cylinder walls.

regards
mech

[Lovemy92vx]

I will have it re-tested. Why is one so much lower?
I just read your comments on "simple ring installation".
Best case/worst case what might that ring job cost?

[user removed]

Done right it's a big bill, been out of the business, In my old shop we were at $26 per hour when I bought it (the shop) and $65 when I left. Get a quote from someone trustworthy.

regards
mech

[Lovemy92vx]

$3,000 engine rebuild sound "normal" or necessary?
Given the compression numbers, is this critical?
Would it explain my fuel drop?
Could the BG's cleaners have cleaned so well, they removed the gunk that made things hold together. (Removing the "glue"?)
I can drive my HX and save $ for VX.

[Lovemy92vx]

"critical"as in continuing to drive it would damage the engine and all it's new parts and maintenance...

[user removed]

ATTENTION

I MESSED UP WHEN, I forgot about your altitude. 120-130 would equal 150-160 at YOUR altitude compared to sea level.

Forget new rings at this point, I don't think you need them.

No additive would mess the rings up unless it was VERY improperly administered.

I would suspect the O2sensor or clogged egr ports in the intake manifold.

There has to be good Honda specific tech in Denver and many members here have Honda specific knowledge far superior to mine.

regards
mech

[user removed]

http://www.healey6.com/Technical/Nom...20pressure.pdf

The chart on this linked page shows compression pressure asa function of compression ratio.

I think your engine is fine compression wise.

regards
mech

[user removed]

Get a couple fuel fills with the board under the left rear tire. you mileage calculations should be much more consistent.

The temp gauge needs to be just below half way up the gauge within 1.5 miles after a cold start or the engine is not getting warm enough. If it is working right, get a MPG reading from a couple of fills and run a can of chevron techron through the fuel.

Maybe a little road trip before the next fill and lets see what the mileage is.Try to fill consistently at the same station-pump.

regards
mech

[cosmick]

As low as 100 will drive, but I'm at 4500' elevation, and up here we consider 140 as low and around 190 as normal for a high-mileage LSx V8. A new crate 5.7L V8 from Chevy cranks around 205-210 at sea level, so 120-130 is giving up an awful lot.
Go to Harbor Freight and get a $20 cylinder hone, go to RockAuto.com and order gaskets and rings, do the whole job yourself for under $300.
Also research the correct cranking compression for your engine back when it was new. If it wasn't near 200, then you'll likely also need to figure out what your engine takes to have earlier intake valve closing. Possibly adjustable timing sprockets, possibly much more.
Actually, research that first. Doing a re-ring is a good chance to swap in higher-compression pistons, possibly have the heads shaved, whatever.
10.0:1 static compression at this elevation gives the same results as 8.5:1 at sea level, so running 11.5:1 up here is no problem, and is better for MPG.

[Lovemy92vx]

Thank you for the quick correction! I've been chasing down a chart I could understand and confirmation of the compression new and lower tolerance.
At coloradoevo.com-forums/showthread.php?t=4683
Dividing the test results by .853 confirms your figures.
What about that "120" though?
I will re-test at least that cylinder. Can it be improved?
I will also re-do your fueling as instructed. I didn't get the part about operating temperature.
Lastly, next time I fill up, should I switch to 91 octane?
I thought I saw that in the manual and the dealer tech advised it.