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Ok so I’ve done quite a bit of research on this topic. Both here and on Honda-tech
and I’ve noticed that none of the post have a definitive answer. I have found lots of conflicting information and would like to try and sort this topic out for myself and for anyone else that may need it. Lots of people asking about D15B1 block and A6 head compatibility. I’m in need of a head for my 90 hatch STD with the B1 motor and have found what I believe to be an A6 head from a 90 Civic Si.
So far my searching has taught me that…
-the stock B1 head and A6 head are from the same casting. Apparently the only real difference is the cam profile (springs too maybe?) and that this head will bolt on perfectly
-that apparently to be able to time this combo properly you need to run a different cam gear (y7/8) on the A6 head?
-After some more research however I have found that the part number for the stock cam gear on both the stock B1 and the stock A6 head is exactly the same. The website (hondapartsnow.com and every other site) also state that the part number is compatible with every model of 1990 Civic (STD/DX/LX/EX/Si)
-if this is correct I see no reason why I would need a y7/8 cam gear.
-there is also lots of confusion as to what timing belt to use.
I would like to state one last thing, I’m open to any form of criticism and would appreciate any help I can get on this topic. This is not a race car by any means and I know what a dog the B1/DPFI combo is and I’m ok with that, I’m after gas mileage and dependability since I drive a ton of miles for work. I notice one of the main reasons this questions stays so open ended is because everyone starts chiming in with “why would you want to waste your money on that…” or “why don’t you just swap a blank into it…” and I’d just like to try and stay on topic.
Any information/help is appreciated. Thank you all very much.
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This is the head I have available for purchase. I would use a stock B1 head (pm9-5) but there’s none around me for sale.
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Pm3-4 head designation.
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Stock B1 cam gear.
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Stock cam gear compatibility.
 

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Buy parts for a d15b7 out of a 92-95 civic LX or DX

the PM3 casting is the same as that.

You are correct about the camshaft difference, the d16a6 cam is a slight upgrade for the stock d15b2 and d15b7 engines, the OEM type combo you are creating.

EDIT what I mean is, you are basically creating a d15b7. so factory and 3rd party parts exist to make the process smooth.
 

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93 4d lx, z6,ported, port matched, compression bumped, balanced, manual swap
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One of the best honda heads, the difference in belts is because of deck height difference in the 1.5/1.6 blocks, so use the belt for the 1.5. The a6 head with the tiny bit larger valves seems to wake up the dpfi injection, my wifes 90 auto lx 4 door averaged 42 mpg highway with the a6 head and the b2 lx auto cam, had some snap down low as well.
 

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I recently done almost the same thing you are doing (B7 with A6 head and cam), only exception being l used a Y8 head gasket (thinner than stock) and l milled about 50 thou off the head. It did run with both the b7 cam gear, and the Y8 cam gear, but l couldn’t get cam timing set to spec. I ended up using an adjustable gear. Set cam timing to spec, and it was a remarkable difference! You’ll need a dial indicator and degree wheel to do this accurately. If l remember correctly, intake valve should be open about 22 thou at True TDC, in direction of rotation. Use the D15 timing belt. Good luck…
 

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Start with a Y8 cam gear, and head gasket to account for the cam timing issue due to the 5 mm difference in block deck height. Sorry but I have no idea on the timing belt's and such.

D15B1 to D15Beast7, should be a thread hear about it. The build equaled my numbers.
 

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89 EF 4wd sedan
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Start with a Y8 cam gear, and head gasket to account for the cam timing issue due to the 5 mm difference in block deck height. Sorry but I have no idea on the timing belt's and such.

D15B1 to D15Beast7, should be a thread hear about it. The build equaled my numbers.
The A6/B1 cam gear has timing markings for both 1.5 & 1.6 deck heights. Not sure why the Y8 cam gear is needed.
 

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Dont need to mess with anything.

A non-oem d15b7 is essentially being built, like I stated before. Nothing special. Buy d15b7 parts. Simple as that.
 

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Brokedick Millionaire
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The A6/B1 cam gear has timing markings for both 1.5 & 1.6 deck heights. Not sure why the Y8 cam gear is needed.
because it does matter for the 1/2 tooth cam timing error.

But what do I know about it.....I'm the one who discovered it, and dynoed it in Sept 1999.
 

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because it does matter for the 1/2 tooth cam timing error.

But what do I know about it.....I'm the one who discovered it, and dynoed it in Sept 1999.
Always happy to learn, i'm just pointing out that the 1.5/1.6 cam gear has two marking timing marks to suit both deck heights and to correctly time out the 1/2 tooth timing error. If you're timing with a 1.5 deck height you match the horizontal marks to the head casting. If you're timing a 1.6 deck height you ignore the horizontal marking and match the 7 oclock mark to the timing case pointer (which in turn makes the 1.5 deck height horizontal markings appear half a tooth out).

When i said "I'm not sure why the y8 cam gear is needed" is because i don't understand why you would use the Y8 gear if the stock gear has the marking to correctly time both deck heights. Is the Y8 cam gear the same as just timing the stock cam gear to the 7 o clock marker to suit 1.6 deck heights? Could you explain?

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Brokedick Millionaire
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The Y7/Y8 cam gear is timing for the 1.6 deck height and flat with the head like a 1.5L The 1.5 and 1.6L marks on the Pm3B cam gear are one tooth apart or 10mm, neither mark will correct the 5mm/half tooth cam timing issue.

Honda in 1988 did use 1.5L timing marks for the 1.6: as the cam was ground on a different centerline, why the 88 Si got 105 chp rating.

Honda changed so much little items on the 88-91 Production EF's it is mind boggling. 22mm vs 24mm crank snouts, different clutch splines and diameters. Different drilling for oil supply holes on the countershaft and mainshaft....89 CRX HF was an 88 Lightweight chassis.
 

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The Y7/Y8 cam gear is timing for the 1.6 deck height and flat with the head like a 1.5L The 1.5 and 1.6L marks on the Pm3B cam gear are one tooth apart or 10mm, neither mark will correct the 5mm/half tooth cam timing issue.
Dunno what happened to my post, but here it is again:

I went through this recently, and that wasn't my experience. If you time a 1.6L the 1.5L marking on the PM3B cam gear is bang on half a tooth off (not a full tooth). The 1.6L is timed using the 7oclock mark (not the 1.5L horizontal markings) here's a 1.6L timed to TDC u sing the 7 oclock marking per the workshop manual:

Crankset Automotive tire Motor vehicle Gear Bicycle part


The 7 oclock pointer on the cover that lines up with the engine mount is behind the engine mount stud here, but i can confirm it lines up like the workshop manual indicates and is shown in that pic at TDC.

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The y7/y8 cam gear might show the timing marks flat with the head, but they're not required to correctly time the motor as far as i can see?
 
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