Cylinder head refresh?

[d.n.d.]

Evening gents,

My caR is approaching 125,000 miles. I was considering doing a cylinder head refresh, at minimum to give it new valve stem seals. I read valve springs can weaken over time, is this true? I am aiming for longevity here, because I do not intend to ever sell this car. It is completely stock except for a header and exhaust system. I do not track the car, I only take it out for fun drives on country roads.

If this is true, would anyone happen to know someone with a spare set of brand new OEM intake valve springs they would be willing to sell? It looks like the intake springs are discontinued

And on the subject of a cylinder head refresh, I would imagine it would not cost much more to take the head off and install new OEM piston rings right? I forgot but I read somewhere the block can remain in the car, it would not require a full engine out. I would be tempted to do rings plus a new headgasket.

Thanks for your time, stay safe everyone.



PS And thank you everyone for the help with my previous thread, I managed to get in contact with an individual who has a window sticker for a Canadian ITR.

[coolhandluke]

What issue(s) is/are leading to this rebuild? I have a few questions and this will help clarify before I/others make recommendations.

[d.n.d.]

Hey how you been coolhandluke!

Actually the engine is fine, other than slightly weak compression numbers. When I got the car it registered 190/180/185/195 PSI, that is a bit low for a B series no? They are supposed to register 220+ across all 4 cylinders.

As a follow up to my first post, I would probably refresh the bottom end along with the piston rings and cylinder head in the same go. As in new main and rod bearings. But I would defer such a big job until it hits 186,000 miles or thereabouts.

I would also be tempted to rebuild the gearbox with new synchros while the engine is out, since about 1 out of 20 times it does not go into first gear. The car was tracked by at least one previous owner, so maybe the synchro is worn? I use Honda MTF fluid.

[00DC2R]

The cylinder head refresh is not a big deal and can easily be done in short time...depending on what labor you are performing, i.e. you pull the head, drop it off at a machine shop, they perform the work and you reinstall. The machine shop should have the ability to hot-tank clean, check the level of the head mating surface and mill if necessary and of course replace your valve seals and the rest of your valve train. I would absolutely recommend a new head gasket at that time.

The block however is a different story. Although it is "possible" to swap rings while still in the car, I would not recommend this. From a mechanic's perspective, a lot of the work would have to be done under the car in order to drop the oil pan, windage tray and girdle, pop the pistons out of the top, inspect the cross-hatch of the cylinders and hone if necessary while leaning over the engine bay, gap the new rings, reinstall the piston/rod assemblies and size new bearings and double check with Plasti-Gauge while underneath the car again. This is all much easier while on an engine stand and the mechanic is comfortable with good light, vision and access to all the tools necessary. In short, drop the motor if you're considering new rings and/or a bottom end refresh. If the motor hasn't been hammered on, Honda motors are praised for their reliability and can easily last 250,000+ miles under normal driving conditions. If after you do the refresh and your compression numbers are still low, perform a leak-down and that should tell you if your rings are bad. BTW, do you ever get puffs of blue smoke when shifting and more when spirited driving?

[d.n.d.]

Wow thank you for the detailed reply!

I actually have never looked in my rear view mirror when I do pulls to redline, but I will definitely check that when I drive the car this summer. If I do get puffs of blue smoke when shifting or spirited driving, what would that indicate? My rings are gone?

And yes I agree, if I am going to refresh the bottom end then I am willing to drop the engine for it. Aside from the sub-optimal compression numbers my car is healthy as far as I can tell, it has great throttle response with zero hesitation.

[00DC2R]

Blue smoke is indicative of burning oil. B series motors do burn some but an excessive amount could be more concerning. Worn rings or some scoring on the cylinder walls could allow more than a "normal" amount of oil to pass and burn off out the exhaust. Once your cylinder head is refreshed, it's logical to think that it should be relatively air-tight. A poor leak-down test would likely show that the air is passing downward into the block, thus worn rings or cylinder scoring. When you have the head off, you can visually inspect the cylinders for signs of scoring or wear and even run a bore gauge most of the way down them.

[d.n.d.]

I see, ok thanks for the info. I appreciate the insight.

If the burning is that severe then it should show on the dipstick when I check the oil level right? I have never had to top up oil, as long as I keep it out of vtec. In vtec it only burns a trace amount of oil, maybe 1/8th of a quart.

[00DC2R]

Exactly. Missing oil can only go two places...on the ground or out the exhaust. My R hardly burned any when I worked close to home and would drive normal but when I started commuting on the freeway with its short gearing and high RPM, I would lose about one quart between oil changes .

[aklackner]

Exactly. Missing oil can only go two places...on the ground or out the exhaust. My R hardly burned any when I worked close to home and would drive normal but when I started commuting on the freeway with its short gearing and high RPM, I would lose about one quart between oil changes .

This was about what I was seeing between standard intervals on a brand new RDOT block (a touch extra compression and tuning from Church) and JDM trans when I was doing ~30mi/day nearly all on the freeway above 60.

When the motor was tuned Shawn worried me with the amount of smoke he was making it blow. Made me so nervous I had to take a walk. When he was done with it though it was incredible! He just said they all burn oil pretty well when you get them high into the power band.

[d.n.d.]

Exactly. Missing oil can only go two places...on the ground or out the exhaust. My R hardly burned any when I worked close to home and would drive normal but when I started commuting on the freeway with its short gearing and high RPM, I would lose about one quart between oil changes .

Ah that sucks. But your rings are ok right 00DC2R?

Thanks for the info guys. I will check in the summer for any blue smoke and go from there.