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B234 16V

M

MattP

New member
Joined
Mar 24, 2003
Location
Kansas City, Missouri
Can you cut deep enough valve reliefs to

make this a non-interference head on a B230FT block? Would you want to? The possible destruction of the top end

is a worry for me after potentially putting a lot of money into the head conversion in the first place. This

obviously would be for a turbo engine and cutting the valve reliefs would only drop the CR. Shouldn't be a

serious problem for a turbo motor? Thanks for your input. Trying to think ahead here.

1969 P1800 B20E
 
heh, this question is asked approximately twice

a week. go check out brickboard.com int eh faqs, they have info on it, and search this board, there are quite a

few threads
 
i have just had a set of turbo

pistons done for the 16v conversion with flycut reliefs on the pistons. the interference bit refers to what

happens if the cam belt breaks, and there is valve to piston contact. i have had a freind do this on a b230, and

the result was the sprocket sheared of the crank pully. so in effect the 16v is set up the same and the same

should happen. thus minimising damage. the only drawback is that the valve stems on the 16v head are a lot

thinner than that of the b230.
 
Okay, but aside from 'panties-in-a-wad' timing

belt failure = engine failure.... Umm... Won't the head bolt onto the block and work like a champ internally?

(All external problems aside, tensioner, etc) Without all the machine work...?
 
Ok some of you guys are very confused or

something.
The 16v engine is an interference engine even WITH valve reliefs.
The valve releiefs are not

to make it non-interference.

The valve reliefs are ther becuase it has a pent-roof combustion chamber so

the vales do not go straight down. Without valve reliefs the valves will clash into the pistons during normal

operation.

Apparently the valves clear B230ft pistons, but it is sketchy since who knows to what rpm,

etc.

Bottom line is if you don't have the cahs to come up with a proper set of pistons for a 16v engine,

the 16v engine is out of your league.
 
Okay Cap'n

So the rumor is that the

proper clearance exists as is, internally.... Valve reliefs...okay extra margin of saftey...

My tuner is

doing this with a 16 valve volvo head...a FORD 2.3L with Chevy SB pistons and rods! He's crazy as hell!
 
Let's put an end to this

will-my-b230-pistons-eat-my-valves-if-the-Tbelt-breaks argument.

IT DEPENDS ON THE CAMSHAFT.

I

remember being told by an factory mech that all stock cammed B230F? are not interference engines. Being mindful

that quote only covers a particular _STOCK_ bottom-end&cam combo. I didn't ask what if you put a high-lift cam

into a high compression NA bottom end.

Some High-lift cams (esp aftermarket) will make your engine an

interference engine.

I do believe someone has posted a list of cams vs. interference for B230 engines. Can

someone please search of it because I'm on the road at the moment.

I can personally affirm that a

M-cammed B230F engine is NOT interference as I just broke a T-belt at about 2500rpm. And nothing but the T-Belt

and the tensoner needed replacing. And the tensoner is because of old-age. And thats an NA B230F with even higher

compression than a forced-fed B230FT
 
I have found that spinning my engine w/o tbelt

to line things up on my car with my V15 cam in place.. doesn't make anything hit.. :? i think. so far no bent

valves or anything.. and I plan on keeping it that way :wink:
 
I wonder if the 16V would

need new pistons if installed on a B21FT
block? The 7.5 cr is already great for turbo use. Is the piston

height
low enough for no machine work needed? Of course all the other
issues make it the high dollar

project anyway. But that would at least
make the internals easier to do.

Dave 82 242ti
 
Affa and own6 we are talking about 16v heads

here, none of the 8v camshaft stuff applies.
dlot, the dish in B21ft pistons is actually the same as the

B230ft, so I'm not sure it'd make much difference.
 
Thanks Kenny,
Would it work if the

difference in CR is in deck height? The CR sure is a lot lower. If the dish in the piston is the same then the CR

is made up by deck height and chamber volume. Is this correct? Just trying to see if
this could be a way to

make a B214FT.

Dave 82 242ti
 
I guess the real question is what is the

included angle of the valves, what is the distance from valve to valve on an valve plane, distance from the valve

center point to the deck, and the cam specs for a stock 1989 B234? If I am going to the trouble of making custom

pistons wouldn't I just make them non interference style at the appropriate CR for turbocharging ~8.0:1?
 
[quote:f257a45191]Would it work if the

difference in CR is in deck height? The CR sure is a lot lower. If the dish in the piston is the same then the CR

is made up by deck height and chamber volume[/quote:f257a45191]
Remember that the B21 and B23 have the same

stroke and such. This means that the B21 is effectively a B23 underbore. They are rumored to be minorly

different, but similarly the B200 is pretty much a B230 underbore (same stroke and rods I believe). This means

that with the same CC volume which all "small" heads used on anything from a B19 to a B230 have the same CC.

Deck height can't be that much different, though I have never measured, but if you made the piston sit too far

below deck on a B21 you would have #*&^ for squish. My guess is that with an underbore and the exact same

piston dish a larger percentage of the piston is taken up by the dish. This can mean some very interesting

things with regard to squish, but sadly shouldn't make any difference for 16V interference aspects.
 
I don't want to move the piston down the bore. I want to provide enough disch and relief to make a non interference engine. If I could get the angles and dimensions. I could put everything in cad and run it through some simulations. I believe the pent roof design is much lower to the deck at the valves than the 8 valve. I don't know if this is true or not because I have not bought the head yet. It is kind of pricey for just winging it.
 
pinion said:
I don't want to move the piston down the bore. I want to provide enough disch and relief to make a non interference engine.
Click to expand...

That might not work if the valve goes "through" the piston, and if not, the cut might be so deep that the piston is weakened. Take care of the belts and tensioner and it shouldn't be a problem.
 
16v DOHC head on B230 block

has anyone tried to put a DOHC 16v B234 head on a B230 Block?
Is there enough clearence for the valves?

THanks,
 
Alex Khalek said:
has anyone tried to put a DOHC 16v B234 head on a B230 Block?
Is there enough clearence for the valves?

THanks,
Click to expand...

Yes, it has been done.

It can only succeed if you use b234f pistons, or cut those same valve releifs into another set of pistons.

Its no simple head swap, you also need to get a belt tensioner.

Please search for 16v FAQ, it should have enough info to get you started.
 
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