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Old 07-07-2006, 06:52 PM   #24
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BrickBaller's Avatar
Join Date: Oct 2005
Location: Sacramento, CA
Default Groove results

Well, I finally got the beast up and running and can give some initial feedback. First, here are the grooves I cut:

They ended up being a little wider than I originally intended, and a little bit shorter. When cutting them (triangular file and hacksaw blade) I didn't like having a sharp transition from the angled file area and the hacksaw area - just looked like sharp projections and that can't be good. I ended up filing a bit more to soften the edges, with the side effect of making them a bit wider as well.

I also feel like I was a bit conservative when it came to approaching the edge of the HG. The last thing I wanted was to get too close, and I may have gone the other way. I figure the sharpie marker adds about 1.5-2 mm from the outside edge of the gasket, and I stayed another 1.5-2 mm from the edge of the sharpie marker.

And another disclosure: before disassembly I had a burned valve, so I had reduced power across the range, but the low end torque was nowhere to be found. As RPMs were raised the missing parts of the valve began to play less of a role and power loss was less noticeable. Also, it has been a full 9 months since I drove my Volvo. I know, that's a long time for a valve job but that's not the only thing I had going on.

All that being said, I do notice a marked improvement with grooves. It may be difficult to isolate how much of the improvement can be attributed to the valve and how much can be attributed to the grooves, but they certainly didn't make things any worse. I got caught in traffic on the way home and enjoyed being able to leave it in 5th even when things slowed down to 35 mph.

You don't accelerate very fast, but then again if I wanted to go fast I wouldn't be in 5th at 35 mph. Less gearshifts = longer clutch life.

There is also a big increase in low end torque. Yes, some (most?) of this is probably due to the replaced valve but I'm sure the grooves have something to do with it too.

As far as gas mileage goes, it is too soon to tell for sure. Driving home from my parents' house used to take almost an entire tank (say, 11 gallons) and this time I still had a half tank when I got home. Again, most of this is likely due to the replaced valve, but some is also likely to be attributed to the grooves. I will get some specific numbers posted after I get my speedo/odo fixed.
'91 745 with 15g and MBC
Originally Posted by Quin View Post
that's called a crutch. like a roll cage for a joint.
Originally Posted by casioqv View Post
Tbricks... where half the members need to spends months essentially sourcing and building entire cars from miscellaneous used parts before they can drive a few hours and drink some beer with their friends.
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