Serieis A,B vs C,D
 

HI Guys.

So I broke C424 and sourced B589 (20.000 miles) to drop in while we rebuild C424 with a mild street port. I plan to run the new B-series with a T04 making some 450 hp.

Whats the concern/weakness I need to be aware of with b-series vs a c-series?

How did you break the "C" engine?

You will be fine at those power levels. The b and that early c should be no different.
I am also interested in how you broke the 20b
let us know
thanks

Pulled past an Aston Martin DB9, let go off the throttle and put in neutral. rolled for a while just to hear the toyo proxes at 100 mph. As I put it back in fifth and let go of the cluth I noticed the engine had stalled. To late though, the engine was pulled from 0-4000 rpm in an instant with a horrible sound like something breaking! Engine didnt run right after that so I drove it back to my garage and got the Mazda compressiontester out. Sure enough no compression on the front rotor. We havnt had time to open it up yet but Im hoping that it just a new rotor and housing.

Early C? when did they reinforce the Cseries?

the later c series are the good ones.
But your power goals are nothing to worry about.
But keep in mind I dont know everything. Chip at chipsmotorsports would be the man to talk to

Yeah my goals are pretty conservative but who knows, once you get use to big horsepower its never
quite enough is it?

Your goals with the B series is exactly what I am shooting for with mine with stock ports and exhaust sleeves, hopefully I get a good tune and it all works out, good luck.

i wouldn't recommend much more than 400-ish from a standard B code without at least additional studding.

the C code has the same casting as the RE/REW so it is good for 500-600whp before reinforcing the block should be a concern.

the problem with the 20B at this time is you do NOT want to find the weaknesses in the early casting blocks unless you have spare irons lying around, in particular the thick iron which tends to crack first.

i don't know the exact cutoff for the B codes so you may have gotten lucky with the revised versions but i wouldn't assume it. compare the thickness of the upper dowel pin areas on the front, thick and rear irons and it should be equal to your C code if it is the revised version. the early code blocks have thin castings, similar to the FC and earlier blocks which tend to crack under mild detonation or high horsepower levels.

a broken early block can be repaired but it requires external oil feeds and a solid upper dowel installed.

20B 10mm Stud Kit

I dont think this was offered before.

That's rubbish, period.

I was told By the man himself @ CLR that they run all series motors in the drag cars and the key is to put a cut into the support inside the coolant jacket on the housings that pushes against the upper dowel allowing some room to for the stress to go to instead of the dowel . He said he never breaks irons EVER with this method
. I will put it to the test on my #756 @ 550whp level.

I may be a dumbass or just a foreigner but that sentence makes no sense to me!
Please explain this to me like I'm a 5 year old (in 20b years I guess I am!)

So We opened up poor C424 and it turned out that all that happened was an apex seal broke, ripped the housing, exited the exhaust, somehow past through the turbo without harming
the blades (because the engine had stalled?) and left the rotor intact! Im flabbergasted but very happy! Its vintner now so the car in the garage and will be fitted with the rebuild engine
instead of the B series. Ill keen that on the shelve for next time!

Good to hear the good news!

It took me a while to process what carlos was trying to explain also. I will make a picture when i get a chance.

if you are lucky enough to get everything right on the first try, yes it shouldn't be necessary. but check around and you will find many of the unlucky who have broken irons on the early casting blocks.

with these engines especially, when working with virtually irreplaceable parts you might reconsider your standpoint after you have run into the issue. why do you think mazda changed the design in the first place? for drag racers running 800+whp? or because the parts can be broken even at mild power levels in the occurrence of an ignition/fuel issue. i have seen even REW irons break in sub 300whp figures and 20B irons break in the sub 400's. this was due to improper setup, ignition breakup or tuning issues but it only takes one pass to render a block to be virtually junk.

i have also seen similar done by other shops, it is a somewhat ghetto version compared to studding but apparently it does work and i may offer it as a cheaper alternative. tapering the dowel alignment holes on the front/rear irons so that the pins can pivot does do the job.

the only downside is i find that if the engine twists naturally the seals will eventually go south as they get pinched. i have also seen seal walls break on both the inner and outer areas due to the friction involved.