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K-jet head build for NA

Bump. :)

The B230 intake manifold is crap for flow out of the box and only slightly less crap when ported(it's worst near the injectors). The runners are just too small for great performance and will hold you back, so yes, the K-Jet manifold is better(straighter, larger diameter runners as well as a larger plenum). Some say that the throttle directly under the plenum is good, and others say it’s horrible(including Erland Cox). It is not ideal for air to have to make a 90 degree turn, but good power can be made even with the throttle underneath. We have a 90 degree elbow coming off of the stock TH opening and going to a 960TB with an 850 throttle plate at the moment in the General Leif and it would be over 165whp if we put it on the dyno in the current setup.

I like the idea of injectors in the head, but maybe there is a reason they don’t do it like that on modern cars anymore, aside from direct injection anyway.

Some of the Swedes(Erland) are going away from recommending larger valves for all but the most extreme engines. We’re still using stock valves but in a 405 head that mister Culberro here has played with for us.

For the K cam, you could maybe get away with more than .040” off the head and a .036” gasket, but realistically you will likely need to change your ignition timing. Factory ignition timing was more than needed by 4 degrees when we were around 11.3-11.6:1 with the Enem K13 camshaft at 155whp or so last year. We also blew up our 2.6L stroker a couple years ago and I’m not certain if it was because of an oiling problem, a ground crank problem, or running close to stock levels of ignition timing problem. Maybe so the above! That was a total bummer to have it blow up only 30 minutes into a race weekend. :-(

10.5:1 SCR is probably all I would try to go for if you don’t have the ability to tune the ignition timing(I could maybe burn you some basic chips if wanted at some point). That would be around a 48cc chamber. If you’ll go with a more aggressive cam at some point, you would want to go higher. The common ticket is shave 2mm from the head(with a stock head gasket) in Europe when putting a real, although still smaller, cam in these cars. Larger than the K but still far from wild. They have better gas available to them, but even still it should be ok on our pump gas as long as you keep the timing in check. Do you have an Ostrich and can you go to a dyno? Lol.

Here’s the SCR calculator I’ve been using mostly, and some different SCR calculations with varying cylinder head combustion chamber volumes assuming your pistons are approx. .010” above deck like seems common foe B230s in my experience.

https://www.csgnetwork.com/compcalc.html
 

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Dish on a B230F piston is 8cc. Our 530 head cut 0.103" measures 44.5cc.
What headgasket are you guys running and what is your SCR you’ve calculated? Piston deck height? I can’t remember if you guys are running less timing than stock, as you’re still on the K cam, but that 2.6mm off the head seems like a lot assuming you are running thinner than a stock HG and just the K cam. I know it’s working well for you, though! :)
 
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Thanks for your input! The plans may have changed a small bit, 2 weeks ago I found a 1995 L block in a junkyard so I spent the entire weekend pulling and scooping that up. So now I have a fresh SCP 530 head and L squirter block that I may have the work done to instead of the 398. I do still want the injectors in the head w/ b21f manifold though.

I did a fuel system refresh this past weekend to get it ready for an aftermarket fuel rail with brand new injectors. I found the top of my tank to be covered in rust holes, so I need a new one first.

About the valves, I already bought them so they're going in :-P

About the cam, I already have the K so that is what i'm going to use for now. A more modern/fun one is definately on the radar though:-D
 
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That all sounds fine!

The 530 head is not set up for injectors in it, so you will have to get it machined, or use the 398 head. I don't think there's any major reason NOT to use the 398 head in a non-turbo, it should be just fine, even with the BCP. We are running a 405 BCP with supposedly over 3mm/.120" off and have no related problems in an endurance racing situation where we drive the piss out of it, literally all day long or longer.

The K cam will be fine and fun for now!

I can email you some EZK bins and an XDF for you to tinker with(if it's not already in my sticky'd thread). Basically though, the stock ignition timing maxes out around 34? advanced and we didn't lose any power/torque on the General Leif going from 31? down to 29? or so at peak torque on our setup at that time(far from stock). We didn't spend any time dialing it in further as we had already been on the dyno for a while trying to dial in the fuel side of things. So, you could take the stock ignition timing and reduce it a couple degrees and see how it works for you. On my street car(stock b230F, .036" gasket, somewhere around that taken off the head, around .010" piston poke and a Singh groove with H cam), I was having some mild detonation issues with any real load around 2000rpm or so and had to reduce timing there if not using premium fuel or on hot days. That hasn't been on the dyno so I haven't dialed it in aside from lowering the maximum timing at WOT to 32? based on our history with the General Leif.
 
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Is this bad?

This is cylinder #3. The crack doesn’t progress in the ports at the bottom of the seats. Cylinder #1 is also starting to crack but it’s not nearly as bad. the other cylinders are fine.
 
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CC'd the chambers too (why i removed the carbon and saw the crack in the previous post.)

I measured both the volume of water the chamber took, capped with plexiglass with a single hole. I also measured the differential weight before and after the water was added. I zero'd the scale before adding water with cylinder head and plexi on top, and took the weight after. 1 gram h2o is 1cc exactly. I also sealed the spark plug, valves, and plexi to the head with fluid film. This is also the results of about 10 rounds of measurement on each cylinder to be sure.

Cylinder 1: 52.5cc
Cylinder 2: 52.75cc
Cylinder 3: 52.5cc
Cylinder 4: 52.5cc
 
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I don't know what the plan for this car is but you could always consider a cheap KLracing manifold, set of second hand Weber/Solex/Dellortho's, and a FPR. It won't break and outperforms any oem manifold. There is also a volvo r sport document that has the correct jetting in it so you'd be close to have it set up, And then there's the way it looks and the sound they make...:run:
 
I don't know what the plan for this car is but you could always consider a cheap KLracing manifold, set of second hand Weber/Solex/Dellortho's, and a FPR. It won't break and outperforms any oem manifold. There is also a volvo r sport document that has the correct jetting in it so you'd be close to have it set up, And then there's the way it looks and the sound they make...:run:

i already have a kl 421 header but it is made of terrible quality metal and is falling apart already. I have a nice cast manifold and downpipe i'm going to have coated/lengthened for when it inevitably breaks.
Carbs are definite future option, but I enjoy playing around with lh2.4/ez116k for now. I agree, the sound of side drafts on these motors is unreal :cool:
 
CC'd the chambers too (why i removed the carbon and saw the crack in the previous post.)

I measured both the volume of water the chamber took, capped with plexiglass with a single hole. I also measured the differential weight before and after the water was added. I zero'd the scale before adding water with cylinder head and plexi on top, and took the weight after. 1 gram h2o is 1cc exactly. I also sealed the spark plug, valves, and plexi to the head with fluid film. This is also the results of about 10 rounds of measurement on each cylinder to be sure.

Cylinder 1: 52.5cc
Cylinder 2: 52.75cc
Cylinder 3: 52.5cc
Cylinder 4: 52.5cc
Thanks for doing this! We just don't know if the head's been shaved at all in the past which would reduce the chamber size. Which head is this again? A 398?
 
Thanks for doing this! We just don't know if the head's been shaved at all in the past which would reduce the chamber size. Which head is this again? A 398?

Yeah, a 1979 398 casting. I bought a caliper to measure if it's been decked before, it should be here before the weekend. What do you think about the cracking in between the seats?
 
change yer coolant

So I pulled out the '95 530 head i recently got and found a crack, albeit significantly smaller. But it has pretty significant corrosion damage so it might not be any more usable than my 398 without a weld job. Should I just have the machine shop weld the 398 and replace the seats with correct 46 / 38mm seats?

btw I cleaned the carbon off a cylinder and cc'd it and got 54.25cc repeatedly. Both volume and weight. Didn't bother with any of the others. Note the 530 also has a 90 degree edge with a vertical wall before it angles to the walls of the combustion chamber that the 398 does not have. Along with the missing dimple.





 
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9/10 times cracks between valve seats ain't a problem, Just have your machine shop do a leak test.(in a bad with water looking for leaks) Don't know how it's called in english, But in holland we cal it "cilinderkop afpersen".
 
9/10 times cracks between valve seats ain't a problem, Just have your machine shop do a leak test.(in a bad with water looking for leaks) Don't know how it's called in english, But in holland we cal it "cilinderkop afpersen".

With stock valves i'd have no issue running it, but to run 46/38mm valves on the stock seats, they need to be cut significantly. But to have the seats replaced, I should have just went even bigger valves :rofl:
 
So I pulled out the '95 530 head i recently got and found a crack, albeit significantly smaller. But it has pretty significant corrosion damage so it might not be any more usable than my 398 without a weld job. Should I just have the machine shop weld the 398 and replace the seats with correct 46 / 38mm seats?

btw I cleaned the carbon off a cylinder and cc'd it and got 54.25cc repeatedly. Both volume and weight. Didn't bother with any of the others. Note the 530 also has a 90 degree edge with a vertical wall before it angles to the walls of the combustion chamber that the 398 does not have. Along with the missing dimple.
Interesting note on the chamber differences. Good to know. We need this documented in more places.

Regarding the corrosion damage, which damage are you concerned about? The areas where there's no port in the head but there is in the gasket and it's eroded the head surface a bit? That doesn't matter at all, and most of it will be gone after you shave the head .060-.080" like you're going to want to do. You will need to run less than stock ignition timing with that much compression, but you're going to be faster and have a wider powerband for it. It'll be better with whatever camshaft you one day upgrade to from the K cam, as well. Just remember that your chamber volume may go down when you put in the larger valves.

With stock valves i'd have no issue running it, but to run 46/38mm valves on the stock seats, they need to be cut significantly. But to have the seats replaced, I should have just went even bigger valves :rofl:
You don't need larger seats for 46/38mm valves. But, if you want the crack welded up, yes, you might as well toss in larger seats while you're at it. You definitely don't want larger valves though, the stock ones can flow more than you're planning on doing as it is.
 
I measured the deck height of the heads and the 398 was 146.14mm with a cc depth of 11.68mm and the 530 was 146.20mm with a cc depth of 11.76mm. According to documentation, neither are cut probably. 530 has a noticeable lip that the 398 doesn't have. The 530 immediate spark plug area is more shaped instead of just round on the 398.





Regarding the corrosion damage, which damage are you concerned about?
I was most worried about the part that is right under the fire ring of the head gasket. Mostly on cylinder #3. The pictures don't capture it well, but the corrosion is deep. The deepest part of it is 3.3mm deep, and its right on the outside 1/3rd of the fire ring.



You don't need larger seats for 46/38mm valves. But, if you want the crack welded up, yes, you might as well toss in larger seats while you're at it. You definitely don't want larger valves though, the stock ones can flow more than you're planning on doing as it is.
Haha the bigger valves thing was kind of a joke. depending on what i'm quoted I may just run stock valves on the 398 with a skim and let it ride with the crack. dumping $500 + into fixing either one doesn't seem worth it
 
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Ah, I went back and looked, I do see the corrosion at the fire rings now on 3 and 4 in the picture with both heads next to each other.

I think you're onto something. Shave .060+" off the 398, clean it up and slap it on with the K cam and a thinner headgasket for an instant 20hp AND torque boost.
 
That corrosion near the fire ring needs to be fixed for sure... unless you have the head machined so much that it pulls away from the fire ring. Having it welded up may be a good option.

That head may also just be destined for the scrap heap.
 
That corrosion near the fire ring needs to be fixed for sure... unless you have the head machined so much that it pulls away from the fire ring.
For maximum fun, you want 2+mm off, so maybe that's an option at some point in the future. Or yes, find a better head to build up.
 
For maximum fun, you want 2+mm off, so maybe that's an option at some point in the future. Or yes, find a better head to build up.

Fully agree with you there. Stock rebuild should get 1mm off immediately :)
 
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