DOHC B6 Information

[Advancedynamix]

You'll need the head gasket for a ZM-DE I believe. The B5ze has the newer style block and head with more oil return passages.

[dliverance]

You'd be making a stroker b5-ze

[FoMoCoMotion]

B5-ZE Piston on left. B6-ZE Piston on the right.

[FoMoCoMotion]

I'll try it and post back to let everyone know. Hopefully I can use a B6 rod to replace the bent one. If they mic out different I guess I'll have to swap the entire rotating assembly from a B6.

[dliverance]

Hi Guys, I have a turbo'd B5ZE from an Autozam AZ3 in my Festiva. I recently bent the #2 rod and have just started disassembling the engine to fix it. I can post pictures of the block, head, intake etc. if anyone is curious. The B5-ZE has the injectors in the head instead of the intake manifold. Any idea if a B6-ZE head gasket will work with my set-up?

I've read that the camshafts are also different:
B5-ZE
Intake-
240* @ .003"
5* BTDC
55* ABDC
40.888mm

Exhaust-
245* @ .003"
55* BBDC
10* ATDC
40.888mm

Overlap-
15*

This link https://forum.miata.net/vb/archive/i.../t-370974.html
says the bore x stroke is 78 x 78.4

This link says the b6 is 78 x 83

https://en.wikipedia.org/wiki/Mazda_B_engine

Assuming it's the same block with less stroke, I think you might be good with the same head gasket. Bore is the same anyway.

[FoMoCoMotion]

Hi Guys, I have a turbo'd B5ZE from an Autozam AZ3 in my Festiva. I recently bent the #2 rod and have just started disassembling the engine to fix it. I can post pictures of the block, head, intake etc. if anyone is curious. The B5-ZE has the injectors in the head instead of the intake manifold. Any idea if a B6-ZE head gasket will work with my set-up?

I've read that the camshafts are also different:
B5-ZE
Intake-
240* @ .003"
5* BTDC
55* ABDC
40.888mm

Exhaust-
245* @ .003"
55* BBDC
10* ATDC
40.888mm

Overlap-
15*

[reddragon]

More info please .

1996 - 2002 Mazda DW Demio/121. 1.3L/1.5L

Some ads do mention 1996 - 2000 Festiva/Aspire, but I havent seen one with this type of radiator.



There are variations in width and thickness depending on which year, type of transmission, oil cooler, one or two pin top mount etc. All seem to have 28mm inlet/outlets. Some have lower outlets go straight out the end of tank, others are angled slightly. Can still get original ones, and there's a few different brands making these on aftermarket
Have a look on ebay Australia, search for mazda 121 radiator. You might recognize a brand that you can obtain locally. Searching for 121 or Demio will give you different results - same car but different regions had different names... so search for Demio radiator to find the ones with free postage from Japan, Malaysia etc.

The standard one that is in my 1997 121 works well. (B3 16V motor) I have never seen the temp guage rise, even when driving her hard on stinking hot 40'C days.

Why?

Extra cooling capacity, stop critters from nesting. Possibly change resonance, harmonic balance..

[Advancedynamix]

It's a shame there isn't another entry to the cavity so you could route coolant through there.

Why?

[shadetree]

More info please .

[reddragon]

I'm pretty sure the cavity that you have found is a space behind the unsealed portion of the oil pump. The plug you are seeing is plugging the oil galley from the pump to the oil filter. You don't want to vent that. Lol

It's a shame there isn't another entry to the cavity so you could route coolant through there.

Have you tried running a B6T using a radiator with 28mm inlet/outlet? Reason I ask, radiator from a DW already has the lower outlet off the end of tank

[ryanprins13]

I'm pretty sure the cavity that you have found is a space behind the unsealed portion of the oil pump. The plug you are seeing is plugging the oil galley from the pump to the oil filter. You don't want to vent that. Lol

The catch can may have a hard time with that?

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[Advancedynamix]

So I put a camera into yesterday's hole. It leads through to what seems to be a decent sized chamber, but chamber is sealed, does not vent. I can see a plug of some sort in there though, which if removed, may allow it to vent, or leak, or something. Either way, I'm still curious.

I'm pretty sure the cavity that you have found is a space behind the unsealed portion of the oil pump. The plug you are seeing is plugging the oil galley from the pump to the oil filter. You don't want to vent that. Lol

[reddragon]

So I put a camera into yesterday's hole. It leads through to what seems to be a decent sized chamber, but chamber is sealed, does not vent. I can see a plug of some sort in there though, which if removed, may allow it to vent, or leak, or something. Either way, I'm still curious.

[Advancedynamix]

I can't say for sure. I'd look for a boss to drill through. It should be an area that's reinforced.

[ryanprins13]

They are common enough to find here locally, just not as common as the earlier style engine.
The head design is superior to the early b6d head, but the intake manifold on the mx3 is too bulky to easily fit in a Festiva with the stock engine location. Also, the lack of a block vent port is a downside, though the added oil return passages make up of some of the issue. Nothing beats a nice big block vent.
For some reason, modern automotive engineers have ditched block ventilation in an attempt at "cleaner burning" engines. This makes no sense to me, as a well ventilated block aids in ring seal and reduces leaks in worn engines. The engines I've built with proper air oil separators run better and use less oil. I think this is a case of follow the leader without question.
In the early part of this century, we saw many examples of engines (particularly turbo/supercharged engines) with oil consumption issues that were directly related to the PCV system on these modern engines. Several manufacturers, including Toyota and Mazda, have had continuous ring sealing issues which have led to heavy oil consumption as low as 50k miles. It's pretty easy to see why, when you know the basics of ring design and function and you take a close look at the restrictive crankcase ventilation on these engines.
The fight for "low emission" often seems like it's counterproductive when you look at the big picture.

All they care about it what it puts out for emissions in their rating test and what their computer analysis says the fuel mileage will be. Doesnt matter what the car does after even 1000 miles to them as far as that goes.
With the block vent- is there anywhere you can drill and tap one in nicely on a b3 or this b6 block that doesnt have one?

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