D16a6 cam,D15b2 head cam timing
Thread Starter
0.0 BAR
Joined: Nov 2004
Posts: 4
D16a6 cam,D15b2 head cam timing
Howdy, I have just done a mpfi conversion on my D15b2 and am about to put the a6 cam in. Just wondering if you use the a6 cam timing ( mark on plastic shield ) or b2 timing ( parallel with top of head ). I did search and didn't come up with anything. Thanks guys.
3.0 BAR
Joined: Aug 2003
Posts: 3,923
Re:D16a6 cam,D15b2 head cam timing
MR Bone's A6 Cam swap how to (for putting a CRX Si cam into a D15) :
BEFORE cam swap, set your ignition timing at 16 BTDC, the center mark. Bring motor to TDC, swap cams. Adjust lash (.006I/.008E for me) and start motor. Idle will be funky high or low, depending on which way you installed the cam (retarded or advanced).
Let engine warm to normal temps, then use cam gear to adjust IGNITION timing back to 16 BTDC at same rpm as you checked it BEFORE the cam swap. Once you get it right, your cam is now ZEROED. The cam GEAR should read 4-5 degrees Advanced/Retard depending on install
BEFORE cam swap, set your ignition timing at 16 BTDC, the center mark. Bring motor to TDC, swap cams. Adjust lash (.006I/.008E for me) and start motor. Idle will be funky high or low, depending on which way you installed the cam (retarded or advanced).
Let engine warm to normal temps, then use cam gear to adjust IGNITION timing back to 16 BTDC at same rpm as you checked it BEFORE the cam swap. Once you get it right, your cam is now ZEROED. The cam GEAR should read 4-5 degrees Advanced/Retard depending on install
3.0 BAR
Joined: Feb 2003
Posts: 9,089
Re:D16a6 cam,D15b2 head cam timing
hrm.. no real experience w/ this. but i would compare the cams (line up the slots in the ends) and see if the lobs are in different spots. If they are in the same spots, just w/ longer duration then i'd use the stock timing marks.
0.0 BAR
Joined: Jan 2005
Posts: 0
Re:D16a6 cam,D15b2 head cam timing
your not gonna be able to check with the naked eye. late 88 to 91 D16 cams are indexed on D16 alignment. 88 Si (105 hp) cams were indexed on the D15 alignment.
Either way, 90% of the time the cam timing will be 1/2 tooth off. Using a adjustable cam gear (good save Spenser!) you can reset it "straight" up. I'm about to do EXACTLY this on my D15Beast7.
Now, the only dynograph that shows the differece in power...........
Either way, 90% of the time the cam timing will be 1/2 tooth off. Using a adjustable cam gear (good save Spenser!) you can reset it "straight" up. I'm about to do EXACTLY this on my D15Beast7.
Now, the only dynograph that shows the differece in power...........
0.0 BAR
Joined: Jan 2005
Posts: 0
Re:D16a6 cam,D15b2 head cam timing
uh, yes you DO need the adjustable cam gear to properly time the cam.
The D15B2 and D16A6 head castings ARE THE SAME!!!!!!!!!!!!!!!!!!!
Due to the different keyway indexing and different block deck heights, YOU NEED the adjustable cam gear.
The D15B2 and D16A6 head castings ARE THE SAME!!!!!!!!!!!!!!!!!!!
Due to the different keyway indexing and different block deck heights, YOU NEED the adjustable cam gear.
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