311 heads vs 040 heads

[nicolas]

some time ago, Udo spoke off picking up every 311 head he could find for his engines.
my question is what is the difference between the two?

i have a dualport type3 engine but the heads were (are) a bit troublesome right now. i have 11 CR (measured with a hella CR tester) and haev found out that this is the cause off many troubles with the stockish 1600 engine i have in the squareback at the moment.

i had the heads cut 1mm deeper to come to a CR off 8.5 in spirit off the older 64S engines and to add a bit off extra hp. seems that plan went all wrong and i end up with an engine only 48IDA's can feed and cool 
so i go to the shop and ask for type3 heads and they don't have a set off them, but sell me some 040 heads insted and they say they are the same. is that so? or are there differences?

[Bruce]

The 040 is the universal replacement head.  It incorporates most of the unique features of all the different types of heads.  Just like there's only one stock engine case now.

[nicolas]

The 040 is the universal replacement head.  It incorporates most of the unique features of all the different types of heads.  Just like there's only one stock engine case now.

thanks.

[richie]

Nicolas,why not do a little diy chamber work and get some ccs in there so you can use them again,maybe some mild port work as well,if they are junk anyway the worse that can happen is you make a mess everywhere

cheers richie

[Peter]

hi nicolas,
how did you measure compression ratio?
you dont measure compression ratio with a compression tester?
the tester just gives you a value of the pressure, no?µ$
compression ratio is calculated is what i thought,
or am i totally wrong? could be

[nicolas]

Nicolas,why not do a little diy chamber work and get some ccs in there so you can use them again,maybe some mild port work as well,if they are junk anyway the worse that can happen is you make a mess everywhere

cheers richie

thinking about that!

i have been reading the chapter off the Fisher book a million times and i have been cleaning up the inlets off the 'new'  040 heads. nothing serious, just smoothing the casting with a mild file.
the 311 heads will be used to work/wreck a bit more and see what can be done. i have thought off buying a rotary file, but the walls always look thin... i am not sure how thin they really are, but i will go steady. should be fun to learn to do that.
so if someone wants to share the mods they did on original non-welded heads or show the tools they use for all the steps they do that would be great.

one more question regarding these heads. could it be they don't have the 3 angle valvejob from the factory? it seems they don't have the stepped angles, but i could be wrong.

hi nicolas,
how did you measure compression ratio?
you dont measure compression ratio with a compression tester?
the tester just gives you a value of the pressure, no?µ$
compression ratio is calculated is what i thought,
or am i totally wrong? could be

the CR was measured using a hella CR tester.
i have heard that the measured CR is a bit higher then the calculated one... don't get the point why this should be that way, but i measured 11 on three cylinders and 8 on the one with the helicoil (which was put in wrong), but i calculated the CR would be around 8.5, so that is a big difference between the two. can't remember the exact measurements, but i think the cambers were 53cc in stock form and CR would have been 7.4, so i thought a 1mm flycut would put me in the ballpark.
anyway i have taken the engine out and will be doing it all over again, with some added attention to the lifteradjustment and rocker geometry.

[alex d]

didn't you cc the heads after flycutting them? 

[nicolas]

didn't you cc the heads after flycutting them? 

to be honest, i didn't 

i did all the calculations and we had to lose 1mm, so cutting the step/ridge one mm deeper in the heads seemed logic to me. guess something went wrong. i will measure things 1,000,000 times now 
i do have a tendency to learn things the hard way. good thing is i still learn things, anyway that is what i tell myself after these fµc£ups

[alex d]

didn't you cc the heads after flycutting them? 

to be honest, i didn't 

i did all the calculations and we had to lose 1mm, so cutting the step/ridge one mm deeper in the heads seemed logic to me. guess something went wrong. i will measure things 1,000,000 times now 
i do have a tendency to learn things the hard way. good thing is i still learn things, anyway that is what i tell myself after these fµc£ups

don't worry your not the only one 

[Udo]

The 311 heads have better casting , so there can get more air though the heads and they have a bigger guide boss in the exaust ports that can be ported better for more flow.  this is what found out .

Udo

[nicolas]

The 311 heads have better casting , so there can get more air though the heads and they have a bigger guide boss in the exaust ports that can be ported better for more flow.  this is what found out .

Udo

so i will go carefully with the 311's then.

any tips to make a helcoil fit tight? i think welding up the hole would be the right answer, but can't pay for that right now...

[Lee.C]

The 311 heads have better casting , so there can get more air though the heads and they have a bigger guide boss in the exaust ports that can be ported better for more flow.  this is what found out .

Udo

so i will go carefully with the 311's then.

any tips to make a helcoil fit tight? i think welding up the hole would be the right answer, but can't pay for that right now...

Its funny dude - reading this thread ours "heads" are very similar - Mine were stock 040 heads with some minor port work just to smooth things out a little and they were stock CR/chamber size with a deck height of 0.060/1.5mm so I worked out 42cc will give me 9.057:1 and thats what the formula Vee guys are doing for me, I do not know how deep they will have to cut the heads I just asked for 42cc chambers 

I also talked to them about fitting 125 rockers and they said they would be able to gain that extra "hp" with the port work alone plus alot more - They HAVE to work with stock valve sizes in the race cars so they KNOW about gitting flow with the smaller valve - I also gave them my shortened Race trim manifolds and they think I should be looking at around 100bhp (very roughly) with this new sett up/head work 

[Jon]

the CR was measured using a hella CR tester.

I would not base any upgrades on such a test, if this works its the first time in my 19 years working with cars I have heard of it.
The numbers they give are depending how fast the starter motor turns the motor and more....

[Lee.C]

the CR was measured using a hella CR tester.

I would not base any upgrades on such a test, if this works its the first time in my 19 years working with cars I have heard of it.
The numbers they give are depending how fast the starter motor turns the motor and more....

I have used those "screw in the spark plug hole" type in the past - we used to use them when I was at Vauxhall/opel but only to check that all the cylinders gave a similar figure in PSI, mainly to check that there of no mayjor faults 

[nicolas]

the CR was measured using a hella CR tester.

I would not base any upgrades on such a test, if this works its the first time in my 19 years working with cars I have heard of it.
The numbers they give are depending how fast the starter motor turns the motor and more....

probally you are right. but the engine did 'funny' things. it wouldn't run good enough and like Lee mentioned it allowed me to determin the fact that one cylinder was way down on CR. so i did find out the heads had to be taken off.

so far i have been working my 'magic' (read first attempt at opening up the intakes and outlets) on the replacement 040 heads and i will indeed CC those and put everything in a calculator and find out what that gives.
for now i have found that the 1641 has a deckhight off exactly 1mm ( i used both feelergages and measuringtool to come to the same result). so i put that in the calculator and no where near do i come to 11 CR.
i can't really draw conclusions at this point as i haven't got the tools to cc the heads properly, but i do recall now that the original ones measured 53cc and that the guy offered me a opened up set off 1300 heads which i measured and gave 43 cc. i didn't like the idea off that, so wanted my heads to be cut 1mm deeper and get a cc off 46-47.

no cutting will be done on these heads, just made sure that they are the same cc's and everything is set up correctly.

[vaughn bros]

Great thread, kinda old. I just wanted to add a photo to it.  I have a pair of NOS 1967 Dual Port 311-101-376G Heads I found in the shop attic . Must have put them up there over 30 years ago.

[vaughn bros]

Just a few more.

[Udo]

Nice pictures . there you can see why these are the best for street use . If you have aftermarket heads the air can not get through the head , They get hotter and the the fan needs more power .

Udo

[Type1/DVK]

way more holes than those new castings. I opend much of them on the 044 head on my own engine. Nicely visible on the pictures above.