Mech Q

[Teddy]

Hey All

 

Well, Ive been thinking about compression's / Heads etc lately, and Ive come across lots of different pieces of advice, facts - etc.

 

First up i need some good Samaritan(s) to fill in the following...

 

Stock 3k Head...

 

Compression Ratio:

Standard Port Size - Inlet :

Standard Port Size - Exhaust :

Maximum porting size - Inlet :

Maximum porting size - Exhaust :

 

 

Big Port 3k Head...

 

Compression Ratio:

Standard Port Size - Inlet :

Standard Port Size - Exhaust :

Maximum porting size - Inlet :

Maximum porting size - Exhaust :

 

 

Stock 4k Head...

 

Compression Ratio:

Standard Port Size - Inlet :

Standard Port Size - Exhaust :

Maximum porting size - Inlet :

Maximum porting size - Exhaust :

 

 

Stock 5k Head...

 

Compression Ratio:

Standard Port Size - Inlet :

Standard Port Size - Exhaust :

Maximum porting size - Inlet :

Maximum porting size - Exhaust :

 

Now, no need to get upset if you don't understand why i am asking for this info... even if u just say "look @ this page.. www.3kheads.com - etc"

 

thanks in advance people :)

[Felix]

Stock 3k Head...

 

Compression Ratio: 9.0:1

Standard Port Size - Inlet : ~25mm

Standard Port Size - Exhaust : 21/26 mm W/H

 

 

Big Port 3k Head...

 

Compression Ratio: 9.0:1

Standard Port Size - Inlet : ~30mm

Standard Port Size - Exhaust : 21/26 mm W/H

 

 

3K-B head (not 3k bigport, has 2 water galleries leading to inlet manifold, very very rare)

 

Compression Ratio: 10.0:1

Standard Port Size - Inlet : ~30mm

Standard Port Size - Exhaust : 21/26 mm W/H

 

 

Stock 4k Head...

 

Compression Ratio: 9.0:1

Standard Port Size - Inlet : ~25mm

Standard Port Size - Exhaust : 21/26 mm W/H

 

 

4K-E dished piston head (small combustion chamber)

 

Compression Ratio: 9.5.0:1

Standard Port Size - Inlet : ~27mm

Standard Port Size - Exhaust : 21/26 mm W/H

 

 

Stock 5k Head... (small combustion chamber, dished pistons)

 

Compression Ratio: 9.0:1

Standard Port Size - Inlet : ~25

Standard Port Size - Exhaust : 21/26 mm W/H

 

 

all the heads had pretty much the same size exhaust ports. valve size is the same except on early K (1100 cc) heads which had slightly smaller valves.

 

how far you can port them has alot to do with how neatly they were cast. some were done neatly, some not so well. note bigger ports are more suited to engines developing topend power, small ports for low end torque. if anything the earlier bigport heads have ports to big for the valve size.

Edited August 31, 2004 by Felix

[irokin]

Edit: Felix beat me to it :)

[Teddy]

Wow

 

Thanks!

 

can't talk now, g2g 2 school - when i get back ill post my thinking :)

[Teddy]

Wow, thanks for the offer nick - ill talk 2 u on msn about it ok :P

 

Ok, Well - thankyou felix (and ben) for all that info :P

 

Now, come some 1 help me fill in the missing bits here..

 

 

3K Block (stock)

 

Bore & Stroke : 75 x 66

Displacment : 1166 cc

 

 

4K Block (stock)

 

Bore & Stroke : 75 x 73

Displacment : 1290 cc

 

 

5K Block (stock)

 

Bore & Stroke : (fill me in)

Displacment : (fill me in ) - 1490 ?

 

thanks in advance, again

[Teddy]

Ok, So now that all that info, here are a few Q's i need anwsered...

 

- Ive been doing research, and you can apparently put a 3k crank into a 4k..are there any / many modifications needed to do this ?

 

- How hard is it to "shave" the head & is it very expensive?

 

- When you get your head re-done / reconditioned - (assuming they do a dam good pro job, and a bit of $ is spent on the head) - i know they can make the valves bigger, and install bigger valve springs, but can they actually slightly change the position / angle of the valve ? (is it called the valve seat..i think i have got my tong around it!?! lol)

 

- ive been told that a 3k revs much more because of its shorter stroke compared to a 4k or 5k. Can you apply the same principal and make a 4k or 5k rev a bit higher by making the stroke shorter?.. => can you get slightly longer conrods for a 4k or 5k?

 

- To my knowledge so far, a "quick" way to gain a bit of power is to put a 3k head onto a 5k (for example) - But after talking to lots of different people, and reading stuff, it seams to be better to put a 4k head onto the 5k and port it out...can some one explain to me in great detail why it would be better to do this...i have herd snippets of why its better to do it, but nothing in great detail...

 

- Does any 1 know the following compression figgures... (or close too)

- 4k Block + 3k Head (assuming nothing else has been changed)

- 4k Block + 3k Biport Head (assuming nothing else has been changed)

- 5k Block + 3k Head (assuming nothing else has been changed)

- 5k Block + 3k Bigport Head (assuming nothing else has been changed)

- 5k Block + 4k Head (assuming nothing else has been changed)

- 5k Block + 4ke Head (assuming nothing else has been changed)

 

 

Thankyou, again in advance !!!!!!!!

[Felix]

5K Block (stock)

 

Bore & Stroke : 80.5 x 73

Displacment : (fill me in ) - 1486

[Felix]

- Does any 1 know the following compression figgures... (or close too)

- 4k Block + 3k Head ~10.0:1

- 4k Block + 3k Biport Head ~10.0:1

- 5k Block + 3k Head ~7.5:1

- 5k Block + 3k Bigport Head ~7.5:1

- 5k Block + 4k Head ~8.5:1

- 5k Block + 4ke Head ~10.0:1

 

above is approx. you could fine tune it by working it all out mathematically from the original compression ratios, to work out the heads original combustion chamber volumes. check back through yahoo oldcorollas archives for more definite numbers.

 

 

you don't want to shave a head to much, it weakens the deck face and makes it way more prone to warpage if it overheats. say 60thou max. costs about $50 to deck a head. you should always use a burette or syringe to check your combustion chamber volumes, and work out your compression ratio. you could get the valves reangled as you say, expect to pay for it. a machinist will do anything you ask, so long as you have the $$.

 

if you put a 3k crank in a 4k you will sit the piston 3.5mm down the block at TDC (top dead center). easy way to decompress an engine, not ideal though. it will only be a 1200 cc 4k after. think it gave something like 7.0:1 when i did the calcs ages ago.

 

if you put longer rods in a 4k/5k you will need pistons with a different pin height so they don't poke out of the top of the block at TDC. lotsa $$ if you start going to these sorts of lengths. consider engine conversion as better value for money.

 

alternatively you could put a 4k crank in a 3k like redwarf (gives 1290 cc+ depending on bore size). this is something you would only do to comply with motorsport class regulations, where you need to run the original block. the above applys in that you need pistons with a different pin height.l

 

if you put a 3k or 4k head on a 5k you will lose power (through lower compression, ideal for forced induction) unless you go to flat top pistons or deck the head until the combustion chamber has only about half the original volume (normally the piston dish makes up half the combustion chamber volume). note as i said above if you deck a head to much you weaken it, and potentially make it more unreliable in the long term.

 

from memory a 4k-e head on a normal flat top 4k would give near a 16:1 CR. almost be able to run it on diesel :P not

Edited September 1, 2004 by Felix

[irokin]

from memory a 4k-e head on a normal flat top 4k would give near a 16:1 CR. almost be able to run it on diesel :P not

Methanol goodness :P

[Teddy]

Ahhh damnit ure good !!!!

 

Wow!

 

Thanks a Chunk!!!!!

 

How long would a 4k last if u have a 4k-e head on a normal flat top 4k?!

 

16:1 CR is pretty crazy... :P

 

So, for a high compression motor, you would need a 4ke head ey... :P

Any idea how much they are worth? (no, I'm not going to be getting 1 any time soon!)

 

(ill post more after my HW, need to stop thinking about motors and start focusing on homework (hw) ! !

[Felix]

How long would a 4k last if u have a 4k-e head on a normal flat top 4k?!

 

not very long, would probably ping and detonate itself to death on pump fuel, and overheat like mad. the only way it could be of use is maybe with methanol on a drag engine, like ben said. the CR would probably still be too high.

 

you really don't want any more than 10.5:1 with pump fuel, otherwise you may have problems with pinging and overheating. CR and cam selection work together. the higher the overlap the higher the CR needed to get the most from the cam.

 

 

So, for a high compression motor, you would need a 4ke head ey...

 

no. i'd only use one on a dished piston 4k, or on a dished piston 5k. otherwise you end up with way to much compression.

 

teddy, i would recommend you read the book "tuning new generation engines for power and economy" by A. Graham Bell, or one of his 4 stroke tuning books. also try to read books by David Vizard, he is a tuning wizard. these guys are definitely the two best authors of engine tuning books i have ever read. very educational!!!

[Teddy]

How long would a 4k last if u have a 4k-e head on a normal flat top 4k?!

 

not very long, would probably ping and detonate itself to death on pump fuel, and overheat like mad. the only way it could be of use is maybe with methanol on a drag engine, like ben said. the CR would probably still be too high.

 

you really don't want any more than 10.5:1 with pump fuel, otherwise you may have problems with pinging and overheating. CR and cam selection work together. the higher the overlap the higher the CR needed to get the most from the cam.

 

 

So, for a high compression motor, you would need a 4ke head ey...

 

no. i'd only use one on a dished piston 4k, or on a dished piston 5k. otherwise you end up with way to much compression.

 

teddy, i would recommend you read the book "tuning new generation engines for power and economy" by A. Graham Bell, or one of his 4 stroke tuning books. also try to read books by David Vizard, he is a tuning wizard. these guys are definitely the two best authors of engine tuning books i have ever read. very educational!!!

ill look for those books !

 

Thanks for that, id love to learn some more stuff !

 

- just reading your posts are good enough !