Now that i've got your attention,

i got my head back on friday

 

time for some PICCYS

 

 

 

Some specs..

 

32mm intake ports, 25mm exhuast,

 

37mm intake valves, 30mm exhaust....

 

ENJOY!!!! :D

Edited February 3, 200521 yr by Xany

Looking nice, whens that going in?

Mmm, newly done heads always look cool :D SuperJamie's is preeeety too :D

 

SuperJamie's photo page

it looks like a reconditioned stock bigport. what does it CC at? has any work been done on the guides or bowls? how many angles on the valve seat? what are the springs?

 

why use the early 3k retainers and seals? you can run higher lift with the later 4k stuff. however this is probably a pain in the ass now, i think you need to fit 4k valve guides too. i don't think your valve measurements are exactly right, they have larger than 37mm inlet valve stock

 

i think your intake ports are a tad too big, but mine are the same :D i like your exhaust ports alot, they're better than mine

 

it's a good start. many of us dream of owning such a fresh bigport head. throw some more money at it. get the valves deshrouded better in the chamber, fit bigger valves with thinner stems, use iron 4k rocker posts not 3k alloy ones, 4k guides and retainers, polish the chambers and the exhaust ports, 3 angle valve job, then get your manifolds matched and the entire intake manifold runner enlarged to match. 600 plus dollars later...

 

what bottom end are you running? what cam?

A 5K I believe hes trying to run....

 

and hes not quite sure what compression hes gonna end up with.

i think the k-line valve guides i've just had put in would be better than 4k ones. also i have a bigport inlet manifold so no dramas there. my measurements are prolly wrong........the chambers have been polished and the extractors i'm putting on will suffice. my camera flash was too bright for the glistening head....thats why they look dull. also i don't really want to have my car idle at 1500rpm because i've got a really high lift and duration....thats why i left them.

 

 

thanks for the input though.

k-liners aren't guides, they are like, guide inserts. they make it easier to recondition the valve guide seal when they wear (usually quickly, ie in a drag/race motor) beacuse you don't have to move the guide at all, and hence don't have to recut the valve seat. some people say not to use them, some people do. i personally think they are the bees knees, until your valve guides wear out in 2 million miles, head recos are going to be a heap cheaper

 

stock valves are 37.36mm and 28.98mm

 

this head on a stock 5k bottom end will give you like... 9:1 compression, maybe a little lower depending on what your chambers CC at. go to the chemists and score a few cheap syringes, say a 50cc and 5 or 10cc. measure each chamber as accurately as you can. within 0.3cc is accurate enough (within 0.1cc if you have a medical burette). use petrol or thin oil or inox or something like that, not water

 

that's with a normal head gasket too, not a graphite one like mine (that would make it lower, but be better for heat expansion differential between iron and aluminium, which is what high compression alloy head motors do). you can shave these heads a f@$kload before you hit water jackets, the exact maximum spec is in the tosco manual, which is on stewart ford's website http://drive.to/oldcorollas

 

i have a fairly big (270 degree) cam and my shit idles quite nicely at 800rpm :D ok well its just tough and sorta lumpy sounding, but it smoothes out by 1000. i'm sure you could run 0.400 valvelift with those retainers, that's respectable

 

hmm, 5k with that head, would be one quick little corolla. nice to drive too cos of the torque, even with a stage 2/3 cam. man it needs bigger valves, if you can get decent carbs on the thing (twin downdrafts or twin SUs or twin sidedrafts. whatever they are, you need two of them), the valves are your next big restriction point. i reckon you're robbing yourself of a good 10-15hp with the stock ones

i have a fairly big (270 degree) cam and my shit idles quite nicely at 800rpm :D ok well its just tough and sorta lumpy sounding, but it smoothes out by 1000.

I would have though you would want to open the exhaust valve at about 185 degrees. going to 270 i recon your loosing power...the piston has to come half way back up..compressing expanding gasses :D same with intake...but in reverse.

that would actually lose power with my setup, and i think in general anyway as you'd be sucking out too much intake charge. my exhaust valve opens at 205 degrees, the advertised duration of the cam is 270 degrees. the timing itself is the best grind anyone has found yet for a fast street motor, probably the best there is cos there's not that many left to try after 30 odd years. its torquey down low (20nm more than any other cam i can find) and powerful up high too

 

exhaust valve closing is relative to compression ratio, there would be no point my running a stock cam with 10.1:1 CR in a motor designed for top end power, it would make killer torque though, you could tow a heavy trailer with it!

 

this is also the reason nick could safely run 13:1 in his 4k IF he can design a combustion chamber that doesn't pre-ignite (stock piston shape wouldnt let you run this CR anyway, but its an interesting theory)

gees......thanks for the info....i would really like to pick your brains over an instant message convo.....i have looked at that tosco manual, its a good read...i'm going to get the crankshaft balanced and linished, also the cam will be reground.....to what i'm not sure yet.

 

i will also be boring the block out to 40 thou over, however the pistons i have at the moment are majorly dished and i'm not sure about compression issues. i will be prolly be putting a weber on it for now, until i can get my hands on some twins.

 

these are the pistons i prolly will be using unless i can get different ones.

 

 

any other things that you can think of that i might have trouble with....??

 

again.....thanks for the info....

I have twin 40mm SUs for sale. $150 for the carbs alone. $170 with the L20 manifold (not QUITE the same as a corollas...but you could weld it up to match.)

 

I have seen new 5K pistons with a SLIGHT dish...nowhere near as deep as that. Infact that one almost looks stupid.

hence why i think my compression will be low if i use these pistons.....

 

i'll give the carbies a miss for a bit and see how this weber goes...

how bout $100 the lot?

 

have you had a look at 7K pistons for a dish? The bore is the same.

i had a quick look at the ACL catalogue and realised they don't make any 7k pistons....???.....i was told today that my 5K block and crank is rooted and i need some others......i guy has offered a standard 5k block and crank for $200.....thinking about buying that....also my brother has told me that the engine rebuilder is regrinding my cam to a 450 thou lift, with lots of overlap.....those valve springs on that head should be good up to at least 8000 rpm.....also getting everything balanced and buying some ACL duralite shallow dish pistons.....

 

crossing fingers that nothing else goes wrong.......

So, what excatly are u using from ur 5k engine at the moment in ur new 1?