Just got the b17a1 running with the new pr3 pistons and I thought it was rod knock but it just sounds to fast and doesn’t really get to loud. Does it when ya give it gas. Question is… should the motor be timed differently? Should valve adjustment be different? Could it be rod knock? Could it be the old 89 octane gas I put in to travel? All input welcome and thanks.
Any ideas
Did you put the piston in the right way. The wrist pin is off set so they only go in one way. If you put them backwards you will get pistion slap. If a machine shop assembled them for you and they put them on the pistons for you, you can still turn the assembly around and put them in backwards. The numbers on the side of the rods and the squirt hole determine how they should go in the block. You probably need to check your book to make sure you have assembled them correctly. The timing is the same ,valve adjustment is the same you may want to use a highter octane gas but I do not think that is the noise you are hearing.
Are you sure it’s piston slap? Could you be mistaking detonation for piston slap?
You should definitely use a higher octane with a b17 and pr3 pistons.
i mean i havent driven it yet because i am scared it could get worse. However i am leaning more towards a slight rod knock for the fact that when you 1st start it up its a loud knock and then quiets down. It doesnt really get louder when you rev it but you notice it when you rev it make sense? weird? Also if you hold it like around 3500 rpms you cant really hear it. So tomorrow i am gonna drop the pan and replace the rod bearings.
yeah you need higher octane gas with that setup. what are you tuning with? what are your AFRs?
Same exact problem!
I just changed my Pistons, rods, and rod bearings for brand spanking new, but mine sounds like there’s some knocking on the first piston.
Can you tell where the piston makes the knocking/slapping noise?