low power output? b230a rally motor

We don't run an idle motor either. The engine idles around 1200-1300rpm when warm, but that's fine for a race car and helps increase camshaft life anyway.

On our headgasket, we normally use the Hylomar gasket dressing to help it seal. So far, it hasn't been a problem on any of the cars we've re-used it(one of them three times, two others, twice). That being said, for peace of mind, you could get a replacement. I just would NOT recommend a stock gasket if your pistons are indeed flush with the block's deck. You ideally will have between .030-.040" clearance there, or slightly less, but not much if revving the engine to 7000 and beyond. Our current engine has around .025" clearance on the tightest cylinder on the piston center line, so excluding piston rock(roughly measured, I'm no machinist).

so hopefully tomorrow after work ill get the exhaust manifold and down pipes off the car. The head isnt finished, but the chambers are worked , and the ports are worked too. i want to polish the chambers some, and then its ready for the skim.

I measured teh chambers at 48cc each one.

I got it fairly accurate first time by doing one chamber, then using masking tape made the outline and copied it the the next one etc.


I havnt measured the cc of the piston, but its the same as a b230E if anyone knows the size of the dish on that one? Anyway, with the compression calculator, if i say 3cc for the dish, piston comes to the top of the bore, and i go for 44cc chambers, its like 12:1. if i change the 3cc to 0 it dosnt make much difference. I put 41cc of fluid in one of the chambers tonight, and measured that, and i need to skim 1mm from the head.


Is there a limit to how much you can skim? i think im still under 2mm, but just want to make sure.

ive booked it in already for the rolling road in january, there is a long waiting list for the guy!


thanks again for the help!

Avtovaz said:

Is there a limit to how much you can skim? i think im still under 2mm, but just want to make sure.

ive booked it in already for the rolling road in january, there is a long waiting list for the guy!


thanks again for the help!

Click to expand...

I wouldn't worry until your over 4mm removed off the head.

Most of the dyno shops here are booked out 2-3 months as well. Everyone is really busy right now!

thanks, its unreal, everyone must be building their cars, waiting for the covid stuff to finish... cant wait to get the car out again!

thanks

Nice work! I may have some b230E pistons in the back of the shop somewhere but my measurements will be rough if I can find them. I guess it's not so easy to measure when they're in a motor that's installed at a slant, hah.

I also get 12.1:1 with 0 deck height, 3cc dish, 44cc chamber, 96mm bore, 80mm stroke and a 97mm gasket that's .027" thick.

It's 12.8:1 with 41cc chambers and the same info as above(or with flat topped pistons and 44cc chambers).

As far as how much to shave off, Erland says he normally takes off 3mm and shoots for 16+ bar of cranking compression. The amount he takes off, I am sure, varies depending on the cam and rest of the build, but that was his response to me when discussing our setup with a 264? at .050" camshaft(ENEM C2 copy?). We have around 3mm removed on our 405 head on the General Leif with no issues, yet, after 3 endurance race weekends this year. You previously said you have 1.8mm off, so another 1mm would still put you at just under 3mm off. If you feel like your compression ratio is too high, you can put a slightly thicker headgasket on. A .030" or .036" will still both be within the good piston-head clearance goal of .030-0.040" and lower the compression to 12.66:1 or 12.4:1, respectively.

Go for it! I look forward to the results.

i had a look at my engine today, it has the dish in the pistons, i also have another block, and the dish is much deeper. I could nto measure them. I found the pistons come to the top of the bore, dead on, but there is some lash in the piston to bore, so it can come out of the bore in effect! i presume if it missed before, it will do again even if i skim the head?

also the exhaust manifold, its got one m8 size hole, and the rest are like m10? is that right? it can fit quite ok or quite badly with out knowing it.

thanks!

That is all correct. The larger hole is normal I think. Also, shaving your head more won’t bring the head closer to the pistons. The headgasket determines how close they are. Your valves will be closer, but likely not a problem.

These B230A/E pistons have my ears pricked up. KG advertises the dish as 0.6mm deep, and the F piston as 2.2mm deep. That would put the A/E volume somewhere around 2.5cc, all things being equal except the depth. If I fired a set of those in the B230FNA (that's the code we've given to the engine in the race car), we're talking 12:1. I like.

Do you guys know if the bore variations are the same across all versions of the same engine family? That is to say, is a "C" or "D" bore in my B230F the same as a C or D in a B230A/E? I would assume so, but I continually find that "they're all the same" bites me in the ass every time.

i think somewhere i read they are 3cc, but cant remember. i dont know about bores etc.


so i know as of the cam this is a kinda broad question, but what cc do i really want to make the chambers?

Im going to take a pic of the chambers, brother can scan it in, and give me a cm2. I know the chambers are not straight sided, but itll give me a good idea to work out what to skim off the head.

head is now ported, to what standard i dont know lol, also the exhaust has had some working to it too, i recon itll free up some more bhp defo.

thanks again for all the help.

Avtovaz said:

so i know as of the cam this is a kinda broad question, but what cc do i really want to make the chambers?

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I'm not really sure what you mean here?

the cam is 300deg, i dont know its exact figures, but the cam affects the compression. So, i dont know what size to make my chambers, what compression ratio to go for.

What I think is that you should shoot for a dynamic compression ratio of 8.0:1 to start, which is probably going to be more static compression than you'd think. That will require you get valve timing events from the manufacturer. If you've already got the cam, they should help you with that.

I'm not really sure why we focus on static compression ratios. I do it too. Maybe it's because they're easy to measure. In reality, what you want is a proper relationship between the cam and compression ratio.

Definitely because SCR is easy to measure/calculate. You can adjust ignition timing to suit as needed for your camshaft’s duration(within reason).

DCR is hard to calculate because valve timing isn’t advertised.

Regarding the 300 degree cam, we still have no idea what lift that’s measured out at, so it’s basically worthless information. Except for camshafts that are being sold by the same company, we have no idea what that means.

ok i see, ive emailed kl racing to see if i can get any more info on the cam. I dont want to skim the head and take too much off, im in no rush atm to get it sorted.

not much use but the reply





Hi

the info is on the webpage:


Dur p? k?rspel 300 grader
Kamlyft 12,9mm
Nockvinkel 108 grader
TDC lyft ca 4,5mm
Ventilspel 0,35mm


Thanks

Best regards


Krister Lood

Hi
there you go in english

Major on driving 300 degrees
Comb lift 12.9mm
Cam angle 108 degrees
TDC lifts approx. 4.5mm
Valve clearance 0.35mm

Yep, Also asked them for more info.. I responden that the guy who grinds these cams should have it. It would be nice if they could ask him or bring me in contact.

No response.

Avtovaz said:

Is there a limit to how much you can skim? i think im still under 2mm, but just want to make sure.

Click to expand...

Not sure from a material and cooling passage perspective.
But there are 2 things you do need to consider:
A. skimming an OHC head brings the cam closer to the crank.
But the belt lenght and teeth patern stays the same and they still have to mesh.
This means that the cam timing will retard if you do nothing about it. (the effect of cam retardation is that the powercurve will shift to higher up in the rev range)
You can compensate for the head skimming by using an adjustable cam pulley.
B. The length of the cam belt stays the same so when you use it on a skimmed head the cam belt tensioner needs to take up more slack to get to the proper tension.
Make sure you still have enough adjustability on that tensioner to get to the necessary tension. Maybe you need a shorter cam belt. It has been a long time ago but i seem to remember that a Ford Pinto OHC belt fits (same inter-teeth distance, same teeth shape, same width) and is a bit shorter

If only the people at KL Racing would tell us WHAT LIFT the 300? of duration is measured at, we might have SOME idea of what the heck that camshaft is good for. It won't tell us valve opening/closing though, so you can't calculate a rough dynamic compression number until Culberro sends a camshaft to Shoestring for measuring.

Regarding shorter timing belts(you will need one if you aren't already using one but I'm sure you are): https://forums.turbobricks.com/showpost.php?p=6100628&postcount=11

you can add to that list VAZ 2105 cam belt, its the same as the pinto one, and i asked for that in the shop to get " oh its the same as a pinto one !!!" LOL!

I think im going to get 0.040" taken from it, and itll be in the right ball park.