DCRB

Hey guys I have a question regarding rebuilding my h22. Cylinder two has some pretty bad scoring but it looks like it's mostly visual scoring unroll you get below the ring line (where the piston would be at bdc). However the scoring doesn't actually catch a fingernail at all, it's all visual. I know the helms manual says if the cross hatching is visible and in good shape to not re home just re ring it, but I want a second opinion on if I should have it re honed and call it good or should I have it bored over. As far as I can tell the wrist pin might have been binding up, the piston skirts are destroyed. Goals for the engine aren't crazy, just a solid runner for my cb7. Just going to have bolt ons and a retune

Aradin

It's different with the H22 due to the FRM sleeve material. You're not supposed to see a "cross hatch" or any marks at all really. Otherwise I would agree with the helms manual suggestion, but that's not the case with these kinds of sleeves. FRM is supposed to be a completely smooth finish and should look a sort of dull gray. The factory service manual states that H22s must be serviced if there are "vertical scratches that run the length of the bore". If there are no scratches, you can simply rering. That's obviously not the case here. Personally, I would not put that back together with the walls in that condition. Take it to a good machine shop who is familiar with the FRM sleeve material and have them bore it to 87.25mm. It's important that they know how to finish the bore as well, as it is a different procedure than an iron sleeve motor. Good luck.

DCRB

Thanks for the reply. I've been talking with a local shop (vip performance) about machine shop suggestions and they gave me the name of one they use. My normal machine shop had no idea about frm sleeves

Aradin

No problem. It's not uncommon for a machine shop to have little or no experience with FRM material. It's not very widely used. I worked closely with a machine shop for 2 years with guys that had 30+ years of experience and they told me they just "bored and honed it like anything else." Needless to say the engines didn't live very long after and there were a lot of issues with them coming back to the shop again. You may try looking for a shop that is familiar with Porsche engines if you can't find anything else. They would be more familiar with the FRM material.

ShinsenTuner

iTrader: (1)

There's whole threads about this on here... from what I gathered, the FRM material requires a special honing tool made of a specific stone that is very expensive to purchase and uncommon. Definitely need to find a shop that either specializes in it or has experience with such things.


My personal H22 will be sleeved to avoid this issue and give me the freedom of running any forged internal.

h2.4

If your cylinder bores look like that, It is most likely going to be out of round anyways. It's not gonna matter if you get a good hone on it. If I recall the Honda service manual says something about 600 grit hone with no more than 15 cycles. If I remember....

the171

h22s are pretty cheap, it will probably cost less to find a buy a motor in good shape than to rebuild it.

PrecisionPerformanceParts

If the machine shop calls or emails Sunnen, then they will provide them the procedure for honing the block, if that is all it needs. Here are some details:

What´s the proper method of honing an aluminum cylinder liner in the new Honda block?
The Honda block is not a high silicon block. No special lap paste is used. Honda uses Fiber Reinforced Metal (FRM) in the SR series engines. The cylinders are made of up of fibers of carbon and alumina (aluminum oxide) in the aluminum alloy. Boring and honing exposes new hard surfaces of these materials providing the interference for piston rings and skirts.

You must use a fixed hone or a manual/auto hone cabinet when finishing your bores. Tom Hawkins from Sunnen technical services group, recommends the following abrasives and usage:
• Auto machines - roughing JHN-623, finishing JHN-818
• Portables - roughing C30-J63, finishing C30-J84.
Use a normal pressure and 45-50 RPM while honing with standard hone oil (HO-10 or HO-50).

Honda recommends five cycles of honing at a time, removing the hone to clean any aluminum embedded in the stones and checking material removal rate for final bore size.

AERA reports the following: For FRM cylinder bores during manufacture, a rigid hone using a GC-600-J or finer stone designed for non-ferrous metal was used to finish the cyliders. Honing pressure should be adjusted to 29-43 psi (200-300 kpa) while rotating at a 45-50 RPM. This should result in a crosshatch pattern of 60 degrees for proper ring seal. To prevent stone loading and debris build up, cleaning the stones every five cycles is recommended.

After honing, scrub the cylinders with hot soapy water. Rinse with clear water and dry. Solvents are NEVER recommended for cylinder cleaning as they only redistribute residual hone oil and grit into the finish giving a false clean appearance.

Special thanks to Sunnen and AERA for their input.

yahdey

Thanks for the info! I'm opening up one tomorrow, and it is nice to know what I could be looking for.