lean miss???

[justaZcarguy]

And no, this is not like a "near" miss.

Which to me is kinda like "giant shrimp".

ANYWAY, after replacing the intake / exhaust gasket on the 260 motor (L28/N42 combo, triple mikunis, cam, hemisphereical pistons, bored, polished / ported head, header bla,bla,bla...) I get a slight, quick "pop" of a backfire at around 2k on the tach...

Lean miss? I'v checked all the nutz and they are tight. Done the spray test vacumn leak thing and found nuthin'....

The good news is that I HAVE NO IDEA HOW TO ADJUST THE MIKUNIS.

sorry, didn't mean to yell :stupid:

Suggestions???????

Thanks all!

Hope your Friday the 13th was well....

Bri

[smg1404]

Are you getting a hesitation at the same time the backfire is happening??? You could be experiancing a flat spot between the place where the primaries are doing all of the work, and the place where the mains take over. This is not unusual... My webers have a similar issue... It can be tuned out ,to some extent. But maybe not completely.,You may have to adjust your driving style if this is the problem.... It may not be possible to completely get rid of it, without sacrificing some performance in another rpm range.

[justaZcarguy]

How are ya????

Could be...the problem was MUCH worse before the intake redo, you could actually feel the air hit your fingers upon backfiring and when I shot carb cleaner in the area it was like getting a shot of NOS.

When the choke is on it seems to change. Doesn't seem to do it as much...

Funny thing is, the engine runs smooth at an idle and above the "troubled area".

The guy that built the engine was over this weekend and said that if he and his father figured right, it was pushing around 300 h.p.. I won't have any idea how accurate that is until I get the clutch and water pump redone. I know this much, even WITH a spun clutch it wants to GO.

Looks like it's centerforce time.

He said that they tried to cheapo out with a stock clutch and it was history in about 20 miles. It just couldn't take it.

Any other suggestions on clutch??? He got about two years on the centerforce, so I figure it works. I thought about having Ot's friction supply make me a paper / fibre setup.

Anyway, thanks for the advice on the popping....

Have a great Saturday...Watch out for those corners :devious: