valve gap issue - Page 2

goodscotch · #11 (**permalink**) 08-21-2010, 09:50 AM

Went by to see the head guru, he's still not done, been very busy. He said I have a bad detonation issue. All of the valve stems are marked and all the guides were beat up. What caused it, he doesn't know. The heads have to be surfaced so that's going to up the compression some. We only have 91 octane out here so it's going to be race gas from now on. I've re-done the fuel system and replaced the worn distributor gear. It was well worn. That could account for some timing change.
Oh, Dart Pro1 325 heads.

goodscotch · #12 (**permalink**) 08-25-2010, 05:32 PM

Finally got my heads back yesterday. He did some bowl work, new guides, springs and valve job. After he took .005 off he cc'd them and they are 118 cc's. Shafiroff marked them at -.035 so with his -.005 they should be less than 118 cc's. Hm, no matter, they are all tuned up and it's going abck together and go on the dyno before it goes out again. Thanks for the help.

iwannagofaster · #13 (**permalink**) 08-26-2010, 09:03 AM

That sounds a little odd, but I guess we really can't argue with the head guru. I am glad we could help. If you need anyhting else, just drop us a line.

goodscotch · #14 (**permalink**) 08-28-2010, 08:45 AM

Yes, it does seem a little odd. Visually there's not much material between the valve lip and the head surface. I think maybe we will do another cc check. I believe my son has the neccesary equipment. It's too hot to work in the garage and I'm not going to make the next race anyhow.
I cleaned up the pushrod holes in the heads a little to eliminate any rubbing.
Thanks again.

goodscotch · #15 (**permalink**) 09-06-2010, 10:24 AM

Think we found the source of the detonation problem. The intake was sucking a little oil from the valley. It is a out of the box Merlin X and it didn't fit as good as I thought. Had .100 cut off the bottom and now the mating surfaces are being machined for the proper sealing angle.
Never assume out of the box parts are good to go.

goodscotch · #16 (**permalink**) 12-28-2010, 09:02 AM

Sorry I haven't been back to report. Got the truck all back together and went to the div 7 race in Vegas. My buddy was in the lead for SS nat'l champ and I wanted to watch him lock it up so I figured I would run the pickup in SST. My previous best time at vegas was 11.05 which I figured was right on the SST index. Off the trailer we ran a 10.67, too quick but I was happy as hell. I learned to never assume that stuff out of the box is correct. I won't make that mistake again. Thanks for all the help.