Not worth the effort IMO
Everyone seems to subscribe to using the head gasket as the limit to port or relieve to. IMHO this is not exactly correct especially for porting in the combustion chamber. For relieving the bore slightly should be OK for unshrouding, but in the combustion chamber you take it out real close to the gasket which can cause gasket problems. The other issue is the intake mixture hits a small ledge at the top of the bore which will cause some turbulence in a non beneficial manner. I would prefer to Dykem the cylinder head gasket surface and instal the heads on an MT block. Then scribe around the finished bores. This will give a smooth transition from combustion chamber to the cylinder, with only the small area between the difference between the diameter of the gasket fire ring and the bore.OK, the 318 has a bit of shrouding issues. But that can be elevated somewhat with a bore notch. Pick your piston first. Then at TDC measure where the top ring stops. Go about 0.100" above that and make a mark. Then using a 340 head gasket, scribe around where the intake valve will be. Then using a round carbide, angle notch the bore down to your line of the piston ring mark leaving a 1/4 radii at the bottom. Go about 2.5 inches wide. De-bure edges.
Yes this will knock the compression ratio down, as will using the 340 head gasket bore. This is why you need to do the math before hand and buy the pistons CR a bit higher.
Not worth the effort IMO
Everyone seems to subscribe to using the head gasket as the limit to port or relieve to. IMHO this is not exactly correct especially for porting in the combustion chamber. For relieving the bore slightly should be OK for unshrouding, but in the combustion chamber you take it out real close to the gasket which can cause gasket problems. The other issue is the intake mixture hits a small ledge at the top of the bore which will cause some turbulence in a non beneficial manner. I would prefer to Dykem the cylinder head gasket surface and instal the heads on an MT block. Then scribe around the finished bores. This will give a smooth transition from combustion chamber to the cylinder, with only the small area between the difference between the diameter of the gasket fire ring and the bore.
True story. For a race only engine you can chance things to their limits, but a mostly street engine is best with a little on the table for a safety factor.Maybe not to you but on a 273 or 318 its not too bad and not a hard job. Maybe 2 hours with a carbide.
A set of 360's 1.88" intakes in a super ported 273 closed chamber head, a 292 DC cam, Weiand Stelth Intake and a set of 340 A body exhuast manifolds made a 1966 Dart Wagon with a 0.060 over 318 a sleeper
You work with what you have or can afford.
I would never grind the head chamber out to the gasket bore, close but not to it. You are right about problems blowing the fire ring out as the head does move a slight amount sometimes..... Harmonic distortion.....
But to go almost to the fire ring on the block side is not as bad. And only for a small section of the diameter.
id bet my azz a 2.02 valve comes closer to 4.0 cylinder wall with a 23 degree head than it ever would in a 3.91 cylinder with 18 degree heads but you dont see chevy guys notching the cylinder bores,..shrouding is more of a myth than a reality!! alot of 23 degree chivvys use a 2.05 and 2.08 valves with no issues! it just ant needed in my opinion!
yall trying to wrench the last 20 hp outta im guessing a race motor,enginmasters and all,....ant we talking street motors here??? .090 ant that much, a good thumb nail thickness dayummmm!the guy/shop that just did my 418 with eddie heads. He showed me how shrouded the valve is even at 4.08 bore.
Said there was 20 horse in fixing it.
He is VERY smart.. won enginemasters competition with a small block Mopar.. I will take his word for it being an issue.. and a 318 has a much smaller bore
Thats right help a fellow out etc !All I hafta say about that. If we arebeing truly honest here,318s are all that's left. There was a fella on here giving one away. I almost got in mytruck and drove 4 hours for it...but I don't need it,and why be greedy? I like that folks still give them away they are drying up...
You would do this for a street engine? I don’t think you would ever feel the difference. Not worth the “STREET” effort and that’s what we’re talking about here right?Maybe not to you but on a 273 or 318 its not too bad and not a hard job. Maybe 2 hours with a carbide.
A set of 360's 1.88" intakes in a super ported 273 closed chamber head, a 292 DC cam, Weiand Stelth Intake and a set of 340 A body exhuast manifolds made a 1966 Dart Wagon with a 0.060 over 318 a sleeper.
You work with what you have or can afford.
Agreed, not on the street or even mile strip cars. If it was a race only deal chasing the money on a big scale, sure!id bet my azz a 2.02 valve comes closer to 4.0 cylinder wall with a 23 degree head than it ever would in a 3.91 cylinder with 18 degree heads but you dont see chevy guys notching the cylinder bores,..shrouding is more of a myth than a reality!! alot of 23 degree chivvys use a 2.05 and 2.08 valves with no issues! it just ant needed in my opinion!
Did you “Fix it” or just run it?the guy/shop that just did my 418 with eddie heads. He showed me how shrouded the valve is even at 4.08 bore.
Said there was 20 horse in fixing it.
He is VERY smart.. won enginemasters competition with a small block Mopar.. I will take his word for it being an issue.. and a 318 has a much smaller bore
Well now dirty boy, you also do not see Chubby guys stuffing 2.05 or 2.08 valves in a 305 engine. Their just is no room. Now could they notch the bore for valve clearance and shrouding? Of course.id bet my azz a 2.02 valve comes closer to 4.0 cylinder wall with a 23 degree head than it ever would in a 3.91 cylinder with 18 degree heads but you dont see chevy guys notching the cylinder bores,..shrouding is more of a myth than a reality!! alot of 23 degree chivvys use a 2.05 and 2.08 valves with no issues! it just ant needed in my opinion!
there you go posting enginemasters/max effert tech in a street/grocery getter build thread again!! and you wanta suggest who might get hurt by ignorance, bless ya hart mann...Well now dirty boy, you also do not see Chubby guys stuffing 2.05 or 2.08 valves in a 305 engine. Their just is no room. Now could they notch the bore for valve clearance and shrouding? Of course.
Being as you are a "shrouding doubter" mebe you is needin to get copies of David Visard's books; How to Port and Flow Test Cylinder Heads and How to Build Horse Power. It may be an idea to also watch some of his PowerTec videos. You may just learn sumat before ignorance hurts you.
I can only like or agree but not both…. Darn shame.there you go posting enginemasters/max effert tech in a street/grocery getter build thread again!! and you wanta suggest who might get hurt by ignorance, bless ya hart mann...
yall trying to wrench the last 20 hp outta im guessing a race motor,enginmasters and all,....ant we talking street motors here??? .090 ant that much, a good thumb nail thickness dayummmm!
i agree with most of this but i disagree theres 20 hp in notching a cylinder bore half a fingernail bigger less than .300 below deck to stay above the ring! that lil bit would be un noticeable on a dyno and mean dittly chit above .300 valve lift!! hell then again might help the grocery gitter a lil bit under the curve....just my humble whitetrash opinion....Find 20hp in 5 places and all of a sudden you found yourself 100hp,or 10hp in 10places is also 100 total or why not an easy 5 hp in 20places?
The difference adds up quite quick when you start paying attention to stuff and is the reason why some poeple are engine builders while others are just (in best case scenarios) assemblers.
If we are going to ignore all the small stuff just because its not a raceengine we start to leave a whole lot on the table,a whole lot of "free" power,power that wont screw up your drivability,fuelconsumption or lifespan of the eninge.
An engine with a ton of very nice and expensive parts on it can be beat regarding power,durability,fuelmilage,performance and drivablitily by something built from much "simpler" parts if the builder has payed attention.
Not saying everyone has to pul out every trick in the book,sometime something simple will do just fine and sometimes one wants to assemble a bunch of very fine parts ignoring the fine details and the owner will be just happy about the result but the whole "ohh its just a streetengine and not a raceengine" is not the best argument for it looking at a much bigger picture.
Actually dirty white boy, I try to see all sides. If you have been watching, I just had a difference of opinion with yellowrose over big bore. I was trying to explain there are other interests beside racing, and that even in racing there are things to consider with respect to bore and stroke for different tracks or applications. My interest is more toward strong running street engines that run cleanly. The engine masters is supposed to be a showcase of engine builders talents, supposedly aimed at street use. I doubt anyone would argue their engines are more race oriented with 0.8" valve lift and 2:1 rocker ratios.there you go posting enginemasters/max effert tech in a street/grocery getter build thread again!! and you wanta suggest who might get hurt by ignorance, bless ya hart mann...
Did you “Fix it” or just run it?
I can certainly see that type of power gain and better. Build dependent of course.
Cool man. This is the mill you reported on a little while ago at the track?fixed it. And to be clear, this involved clearanceing the bowls to unshroud the intake valves on eddy heads
Cool man. This is the mill you reported on a little while ago at the track?
No argument there.yes. The heads have very minor porting, but my guy thought doing this work was worthwhile cost to benefit