Port matching 61x cylinders

Midlake Crisis · 11-30-2009, 05:07 PM

Mr. Klemm, you posted this a long time ago on another thread:

Quote:

Originally Posted by Group K

The 61X cylinder comes with slightly milder exhaust port timings, and offers the option to run less "finished" exhaust timing (which is very desireable on Freestyle spec cylinders). . . . . . .Many 62T cylinder owners decide to "match" the steel sleeves to the aluminum casting at the exhaust port roof ... DO NOT DO THIS ... the result is an exhaust port timing that will yield very poor bottom end power (unless you run compression ratios into the race-gas zone).
Hope that helps.

Respectfully, Harry Klemm

Does that same advice apply to a 61x cylinder regarding not matching the aluminum cylinder to the sleeve port height?

What about matching the width of the aluminum casting to the sleeve on each of the ports?

I just purchased a stock 61x cylinder to replace a stock 62T Raider cylinder I have been running in my Superjet, in hopes of finding some more smooth bottom end power for recreational freestyle.

I just want to do a basic cleanup on it for now if it will help, but want to make sure I don't hurt the bottom end performance, and be conservative with it in case I want to send it in to a builder later for a full port job. The last thing I want to do is hurt bottom end. . .

Matt_E · 11-30-2009, 06:15 PM

It's worth noting that Harry was talking about the exhaust ports (where 62T sleeves have an overhang over the casting), whereas you're talking about the transfer and boost ports, where the sleeve windows are HIGHER than the casting windows.

Midlake Crisis · 11-30-2009, 06:46 PM

Quote:

Originally Posted by Matt_E

It's worth noting that Harry was talking about the exhaust ports (where 62T sleeves have an overhang over the casting), whereas you're talking about the transfer and boost ports, where the sleeve windows are HIGHER than the casting windows.

Good point. I am about to have this 61x cylinder cleaned up and (as you know!) nobody seems to have a definitive answer. It has really surprised me that with all of the collective knowledge and all the porting threads on the two major forums that nobody seems to really know for sure the answer to what seems like such a simple question.

sah255 · 11-30-2009, 09:46 PM

Quote:

Originally Posted by Midlake Crisis

Good point. I am about to have this 61x cylinder cleaned up and (as you know!) nobody seems to have a definitive answer. It has really surprised me that with all of the collective knowledge and all the porting threads on the two major forums that nobody seems to really know for sure the answer to what seems like such a simple question.

I'm pretty sure its been noted several times - the average home hacker can clean up the sides of the transfer ports but touch the tops at your own risk. By matching the top portion of the casting to the sleeve on the transfers, you'll be changing the roof angle and the timing. The question is: why is there such a bad mismatch? Is the casting height correct or sleeve height correct?

Midlake Crisis · 11-30-2009, 10:19 PM

Sure would like to hear from a professional on this one . . .

chriselmore_1 · 02-20-2010, 09:07 PM

bump

Boris · 02-20-2010, 09:17 PM

To the OP.
If you are planing to have motor work done by a professional down the line, why hack on it now ?

Matching the ports if done incorrectly can do way more harm than good. Ports aren't just holes in the sleeves.

chriselmore_1 · 02-20-2010, 11:54 PM

what about that little tab that hangs into the exhaust ports on the top and bottom? what if you grind that flush w the port?

Midlake Crisis · 02-21-2010, 12:09 AM

Quote:

Originally Posted by Boris

To the OP.
If you are planing to have motor work done by a professional down the line, why hack on it now ?

Probably the smartest answer so far.
My cylinder is at Jetworks as we speak.

Boris · 02-21-2010, 12:14 AM

Quote:

Originally Posted by chriselmore_1

what about that little tab that hangs into the exhaust ports on the top and bottom? what if you grind that flush w the port?

If you don't know what those overhangs do and what they are for, leave them alone.
Do some searching and reading on what the ports do and how they work before you ruin a good cylinder.

Not knocking you but I have 4 otherwise perfect cylinders that were "cleaned and port matched" by various people which are now only good for boat anchors.