Peato40
Well-Known Forum User
Hello All,
My project got to the stage of build, where I started the engine for the first time and it didn't go quite as smoothly as I had hoped. Some timing issues and carb set up still to sort out but I'm concerned about a knocking noise I'm getting from the top end ..... or at least I think its the top end.
A bit about this engine:
L26 bored out to 2.8
Flat top pistons
Big valve conversion
Schneider upgraded springs
Schneider lash pads to suit cam
Fast road cam
Triple Dellorto's
Z story headers and exhaust
Now I learned a lot from PMac about valve train geometry measurement and lash pad selection and believe it to be correct.
I've ensured I have clearance between piston and valve.
Timing is correct.
I just can't figure out where this knocking is coming from. Although very messy, I ran the engine on idle without valve cover and listened and observed working valve train and nothing appeared amiss, other than this annoying noise. I then used my stethoscope and listened to each cam tower in turn and found that the noise gets louder the nearer I get to the timing gear, but then I have no further place to put stethoscope other than front cover, which doesn't give me much feedback.
It very much sounds top end and in sync with cam, rather than crank, but I cannot see or feel anything wrong when I crank by hand. It has a exhaust gasket and I'm pretty sure it's not blowing.
Any other ideas anybody might have would be very gratefully received.
Phil
My project got to the stage of build, where I started the engine for the first time and it didn't go quite as smoothly as I had hoped. Some timing issues and carb set up still to sort out but I'm concerned about a knocking noise I'm getting from the top end ..... or at least I think its the top end.
A bit about this engine:
L26 bored out to 2.8
Flat top pistons
Big valve conversion
Schneider upgraded springs
Schneider lash pads to suit cam
Fast road cam
Triple Dellorto's
Z story headers and exhaust
Now I learned a lot from PMac about valve train geometry measurement and lash pad selection and believe it to be correct.
I've ensured I have clearance between piston and valve.
Timing is correct.
I just can't figure out where this knocking is coming from. Although very messy, I ran the engine on idle without valve cover and listened and observed working valve train and nothing appeared amiss, other than this annoying noise. I then used my stethoscope and listened to each cam tower in turn and found that the noise gets louder the nearer I get to the timing gear, but then I have no further place to put stethoscope other than front cover, which doesn't give me much feedback.
It very much sounds top end and in sync with cam, rather than crank, but I cannot see or feel anything wrong when I crank by hand. It has a exhaust gasket and I'm pretty sure it's not blowing.
Any other ideas anybody might have would be very gratefully received.
Phil