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Revvable redblock of choice for itb's with an aggresive cam symfonie

c.slopsma

New member
Joined
Jan 26, 2016
Goodday to all of you.

Got some stuff left over for what could be a nice redblock build.
ITB's, Adjustable cam gear, Modified head & an standalone is what i've got laying around.
Now i was wondering which type of redblock is most suitable to rev. A while back i had
some webers and a cam thrown on an really worn out b23A which seemed to love it. revved
it on the regular to 7k, Didn't even seem to bother apart from blowing oil out of the crank
vent :lol: This time i'd like to have an even more aggressive cam ground and hit something
like 7,5 maybe 8k.:godlike:

Being a budget build and stuff i'd like to stay away from forged rods and machined blocks.
Which base engine should i use?
 
I recommend you get a honda engine. They have extremely light pistons and rods which are what you need in order to rev to the moon. Trying to do this on a "budget" with the heavy b23a rods and pistons is fantasy. If you're at all serious about this, you need lightweight rotating assembly (which means lighter forged pistons and rods).

I suppose after hearing advice and still wanting to do it my way, I would find the redblock engine with the smallest bore possible because it would have the lightest internals... If you wanted to stay OHC, a b21F (not the FT), or don't mind pushrods, a b18.... but those are still not great choices.

What exactly are you trying to accomplish?
 
I recommend you get a honda engine. They have extremely light pistons and rods which are what you need in order to rev to the moon. Trying to do this on a "budget" with the heavy b23a rods and pistons is fantasy. If you're at all serious about this, you need lightweight rotating assembly (which means lighter forged pistons and rods).

I suppose after hearing advice and still wanting to do it my way, I would find the redblock engine with the smallest bore possible because it would have the lightest internals... If you wanted to stay OHC, a b21F (not the FT), or don't mind pushrods, a b18.... but those are still not great choices.

What exactly are you trying to accomplish?

Good point.. The worn out B23A in my 242 was such a fun car to drive, It had a volvo GT6 cam, Weber 45's, 12.5:1 cr, 4.11 gears, welded diff and 7k revlimiter. Unfortunately carburetors and wild cams are a bad match for a engine that also has to do some sort of street driving since the intake air is going to pulse at low revs (<3k) and make for an unstable (undrivable) mixture. At WOT a whole lot of fun and couldn't keep myself from kissing the rev limiter on the regular. The engine didn't fail but i disarmed it to build something slightly more streetable with fuel injection which unfortunately never happend.

At the moment i'm working on a big turbo project for the street & strip 244. But i've gathered and made some nice stuff for an na build. Since the turbo project needs the funds this has to stay a fairly cheap build. Chinese rods might be possible but nothing fancy. Throttle bodies are adapted gsxr1000's, lightweight flywheel is self made as is the adjustable cam gear and such. I'll post some images this evening.

Did you guys happend to have seen the NA build from a guy who names himself Drifts n' lifts on youtube? He seems to revv 7,5k all day on an i believe unopened thin rod bottomend. :omg:
 
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Good point.. The worn out B23A in my 242 was such a fun car to drive, It had a volvo GT6 cam, Weber 45's, 12.5:1 cr, 4.11 gears, welded diff and 7k revlimiter. Unfortunately carburetors and wild cams are a bad match for a engine that also has to do some sort of street driving since the intake air is going to pulse at low revs (<3k) and make for an unstable (undrivable) mixture. At WOT a whole lot of fun and couldn't keep myself from kissing the rev limiter on the regular. The engine didn't fail but i disarmed it to build something slightly more streetable with fuel injection which unfortunately never happend.

At the moment i'm working on a big turbo project for the street & strip 244. But i've gathered and made some nice stuff for an na build. Since the turbo project needs the funds this has to stay a fairly cheap build. Chinese rods might be possible but nothing fancy. Throttle bodies are adapted gsxr1000's, lightweight flywheel is self made as is the adjustable cam gear and such. I'll post some images this evening.

Did you guys happend to have seen the NA build from a guy who names himself Drifts n' lifts on youtube? He seems to revv 7,5k all day on an i believe unopened thin rod bottomend. :omg:

yeah ok
 
Fun fact, a NA b230 with "big" rods will rev over 8k without ejecting the internals. A good clean engine, good clean and cool oil, head and ECU to support the revs. Done.
 
Fun fact, a NA b230 with "big" rods will rev over 8k without ejecting the internals. A good clean engine, good clean and cool oil, head and ECU to support the revs. Done.

That?s what Koltan did on drifts and lifts like OP mentioned. He?s on full stand alone with a K cam I believe, or maybe something more aggressive? Also he has a shaved head and some minor port work done IIRC. Stock m46 and welded diff too. His little NA engine does rather well. It?s surely faster than a stock boost factory turbo auto 7/9.
 
Fun fact, a NA b230 with "big" rods will rev over 8k without ejecting the internals. A good clean engine, good clean and cool oil, head and ECU to support the revs. Done.

I'm starting to believe it's doable and am motivated to give it a try. With big rods you mean the ones from a b230fk, fk or forged?



3.PNG

IMG_20180911_092920-1152x648.jpg


Here are the modified flywheel and cam gear. It's bit of a bummer that because of the timing
wheel the heavy one has to be used, Nevertheless got quite a bit of weight off it. Now
it's about 8.5kg with less off the mass on the outside, Initially it was intended to use it on a
turbo build with diesel pressure plate. So it should be plenty strong for this na engine dough.
Cam gear is original with the center milled out and replaced with a slotted piece of
aluminum. Got the head taken apart again yesterday. This time i'll spend some hours trying
to port it. Would it worth spending any time in the exhaust ports?


The vintage lobe profile GT6 cam i had did it's job well. But i'm looking for something
slightly more aggressive this time. It would be good to know what the rally guys are
using.:-P
 
I'm starting to believe it's doable and am motivated to give it a try. With big rods you mean the ones from a b230fk, fk or forged?



3.PNG

IMG_20180911_092920-1152x648.jpg


Here are the modified flywheel and cam gear. It's bit of a bummer that because of the timing
wheel the heavy one has to be used, Nevertheless got quite a bit of weight off it. Now
it's about 8.5kg with less off the mass on the outside, Initially it was intended to use it on a
turbo build with diesel pressure plate. So it should be plenty strong for this na engine dough.
Cam gear is original with the center milled out and replaced with a slotted piece of
aluminum. Got the head taken apart again yesterday. This time i'll spend some hours trying
to port it. Would it worth spending any time in the exhaust ports?


The vintage lobe profile GT6 cam i had did it's job well. But i'm looking for something
slightly more aggressive this time. It would be good to know what the rally guys are
using.:-P

Get a JohnV billet steel or TTV billet steel flywheel with the sensor holes... OR this..


<iframe width="560" height="315" src="https://www.youtube.com/embed/45X58bJYLP0" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Also I had B23ft with forged crank and forged pistons and over revved it and turned a rod bearing. As stated want to rev use later b230 or fully raced out b23 with racing crank and rods and pistons..
 
I'm starting to believe it's doable and am motivated to give it a try. With big rods you mean the ones from a b230fk, fk or forged?

Just the stock 13mm rods.

That Flywheel is probably not the best for high rpm use. Definitely don’t want it coming apart. The older “flat” flywheels have been fine at those revs, in my experience.

Sbabbs flywheel bomb also had a slipping ceramic clutch, which didn’t help keep the FW in one piece.
 
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In that case i'll start looking for a flat faced flywheel. Such a shame not to use the stronger
diesel pressure plate that is laying here new in the box. The idea to lighten it this way came
from the folkrace site. Those guys seem to get away with weakening it even more.


https://folkraceshop.se/skelettsvanghjul-volvo-b230
img_1735_2_.jpg


Made an appointment to take a look at a possible bottom end. The engine is a B230F from i
believe a 740. It's fuel injected and has the distributor on the front, should be low on miles
and fair priced. I recall to have read that the later (88+) engines with smaller main bearings
would have less issues with crank flexing. Would this engine get me to where i need to be with
swapped or forged rods or do i need to look further for an 88+?
 
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IMG_20190723_201227_compress13.jpg



These are the throttle bodies. They came ogiginally on a suzuki gsxr 1000. The bottom plate
is made on the mill and they are spaced to suit. Intake ports and manifolds are ported by
instructions i found on here on the board. I've still got te get myself to do the exhaust ports
since i kind of hate porting stuff. Hoping the engine is going to be what's expected. If someone
lives in europe and has a leftover set of 13mm rods send me a pm please.:)
 
What do you guys think of this cam. It's made by Catcams from Belgium. It requires solid buckets and stronger valve springs but that is something i could live with. How would it compare to say something like the kg7?

Catcams%20rally%20cam.PNG
 
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