1slow91

i know its ricey but i use an adjustable gear and i can tell the difference if i ---- with it plus/minus a few degrees
no power really gained or loss just where its at
most likely your timing is retarded so you band is way lower
just my theory

Minor Threat

It'll run, and run pretty well with it off a tooth but it will have nothing for power. I was trapping 95 mph on 10 psi on SOHC engine, that's down about 5-6 mph from what it should've been.

Johnyquest

And on that note--- were you retarded, or advanced? I'm taking a crap shoot on which way it's off. I can't think it straight.


Matt

seerex

Any updates, did you find out what it was.

IowaTCoupe

I dyno'd my D16z6 build a few times after i installed a timing gear, we couldn't get it right. I was using a t3/to4e turbo.

ONe easy solution... buy a timing light from Walmart... look at your timing w/ the light, then return it.

I could only get 230hp with my timing gear off a tooth (looking at the gear from the driver side... the gear was turned clockwise (retarded) one tooth)
The worst problem we had was that the timing gear was made by ssautopoo... a friend had it lying around... and i figured we'd try it out... ABSOLUTE ----... the degree marks are WAY off.



We fixed it, and i pushed 340hp after we were comfortable with the dizzy, and cam gear. Oh yea... we went back to the STOCK cam gear, and slightly advanced the timing w/ the dizzy.

This was @ about 18-24 psi. (i dont remember exactly)



That is exactly your problem. You sparks are going off after your pistons pass TDC... It runs great, very conservative, and will run a long time, and get GREAT spooling because your thermal's are still expanding into the exhaust runners, and into your turbine... but ---- for power.
Triple check your timing gear. my bet is your retarded one tooth. Pay attention, cuz w/ the y8 block, you may not have the same marks on the timing belt cover not the same marks that the z6 block has.

Johnyquest

I think you are right. LOL. 230whp at the same boost is what I made. I already took it apart and put it back together, but I must be missing something. I'm going to advance it a tooth this weekend and I will let you all know!

Matt

b18.

Wasn't posted on here that with a Z6 head you need to use a y8 cam gear, or an adjustable. maybe it was the crank gear. I heard that it has to be compesated for, sounds like you already have the right idea though.

Tom-Guy

Run the Z6 gear on the Z6 head.

Keep in mind that the Y8 crank pulley's timing mark is at 12 degrees, not 16. Mark the Y8 pulley @ 16 degrees, or run Z6 pulley, etc.


Best all-around thing to do if you are doubting mechanical timing is to center your distributor, and check timing. If it isn't dead on or pretty close, you need an adjustable gear. You can set your mechanical timing by adjusting the cam gear until you hit 16 degrees timing at idle *with distributor centered*.

Aside from fiddling a few things to get your engine in synch, there's no difference in the tune since you're running "the same" pistons and head.

PS - is this the Z6 head off your old build? Did a machine shop pressure check it?

Johnyquest

It is the same head from my old build. I didn't bother pressure checking it, because it had been newly rebuilt and checked on the old motor, and only went about 20k miles. It was running fine on the old motor until the day I stripped it down, even with the wristpin eating my bore apart

I had the z6 crank pulley on-- and a warning to you all if you try this: The z6 pulley will hit the timing cover on the y8 block. That caused my z6 pulley to FALL OFF on the highway... and melt the plastic until it did. Luckily I had tools with me to re-attach it, and since have switched to the y8 pulley... But the key in my crank got eaten alive-- took some rigging to get it back together.

I'm going to try advancing the cam like general consensus says I should -- and I'll let you all know. If it doesn't work out, I'll build yet another D. I have enough parts for 2 motors laying around... so, while were on the subject... Let me know if you guys have any d's around.


Matt

Tom-Guy

Don't advance your cam. Check your cam timing via timing light trick I mentioned - that way you actually know what is going on instead of adjusting things blindly.