Hi all
Has anyone taken it upon themselves to give cylinder head porting a go?
Seems a popular thing in America to do and I have some spare heads I have been porting. Just interested if there are many that give it a try on here?
Cheers all
Chris
Hi all
Has anyone taken it upon themselves to give cylinder head porting a go?
Seems a popular thing in America to do and I have some spare heads I have been porting. Just interested if there are many that give it a try on here?
Cheers all
Chris
I've ported and polished a spare intake manifold, but never had a spare head to try on.
I'd say a mild port on polish is doable DIY. For a serious job, I'd want to cut a head into cross sections so you can see how much material you have to work with.
If you give it a go remember, raise the roof, don't lower the floor!
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Yeah what I have don't is a mild port job, removal of casting marks from floor and massively change valve boss and rocker stud hump.
Have to mention it's not a nissan set of heads so alot more online about doing them.
I have done many over the years and it's worth doing if you have the time and replicate each port the same,
watch some you tube tutorial videos on basic port clean up is probs better than me typing out a long list of what to do
avoid any grinding near the valve seats, beyond casting flack removal and port casting smoothing focus on knife edge and narrow port divider
and remove material from inlet side valve guide bosses,remove less guide boss on exhaust side for heat transfer
I did a mega ported CA head years back with good results, lots of material removed still had smooth idle,haven't done an SR as hate the things,
but I do have a spare SR head that could be cut up to see how much material there is,
I've seen an SR head that was ported $hit loads to try match the VVL head port sizes/CFM flow rate, it failed as VVL ports are huge
but showed a lot can be removed from the bent cam head
ex-ctr had a head chopped up.
All the info and parts for them is in the USA or down under in OZ,near endless well priced bolt on parts for them
,but we get raped by import/customs tax unless you can find a seller doing the global shipping programe
I don't think any do decent shipping and get around import.
Even still it's cheap when buying let's say, an entire cam package springs and all.
Have been looking around and am probably going to go with a mid range cam. Don't want it to difficult to drive.
is it going into an S body with a manual gearbox? if it is imo you would have to go pretty aggressive on cam specs before it became difficult to drive
thinking lighter car and big capacity/lots of low down grunt,
if it's in a 500 kgs heavier car and auto trans with stock or near stock stall speed TC then it would be a more limiting factor
what you building the car for drift,drag,race only or still road legal (ish)
In an s13 with t56 box. Been a long term project.
Would like it road legal but want to see what it can do in a grip environment.
Most the car is fiberglass now so trying to get it close to 1000kg as possible.
Some pics of the work so far
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How inlet side did look
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looks very good mate, and I like specs of the car (lightweight + power) my CA powered 13 has a lightweight theme as well
, have you looked into bumping up the compression ratio?
can gain a fair bit of power and with a lumpy cam and the head work it all comes together and works well
swapping pistons to gain CR may cost a bit,cheaper option could get the chambers welded then smoothed and CC tested so equal
interesting build btw
Think you can also mill 0.0030 to bump compression too. Then there is possibility to need different size pushrods. Should be good for near 500 on standard compression really and restiction with the ls1 intake is the bigger deal.
I'm going to test cc anyway in a diy way but the chamber is suppose to be a really good design. Also don't want to have to open the block really or fly cut pistons. Would like to keep bottom end as is until the thing is actually built at least
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I was more into yank v8s years back ,but I have read about people using the LS1 truck intake plenum ,I guess it has a larger plenum volume
as it sits fair bit higher so bonnet clearance may be an issue,
Mill the heads is another option,I sort of forgot we was on OHV motors, skimming heads with OHC affects cam timing
Luminati do a hardened push rod possibly with a length option for decked blocks/skimmed heads
agree if the bottom end is sound leave it be and run it as is, have you had any of the caps of to check condition
It's crazy the amount of different length push rods that can be bought. Also different rocker ratios. Options are crazy. I just want a decent setup for the time with not too much lope. Will probably run it standard ( bigger primaries and performance tune) for a time to ensure its healthy first as don't want to open it yet.
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With a 2V head you'll want to shape the port to drive airflow around the chamber wall to set some charge motion up, it will help no end with low speed torque and driveability.
If you imagine taking a section at the valve guide, you want the outside of the guide to have more cross sectional area than the inside to set up the right air distribution.
You want to remove the least amount of material possible to get that sort of shape to keep air speed up. Air velocity trumps volume every time. An LS port will not be a million miles from that shape to start with, but it can be optimised further.
You want to be careful taking too much out of the port nose as well, the reason being that this causes turbulence in at higher air velocities and absolutely ruins flow distribution.
Not sure there is any putting things back anymore.
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Someone did a DIY port job on their MX5 recently, they documented all the work and stuff.
Worth a read before you start hacking your own head apart.
http://www.mx5nutz.com/forum/index.p...ead+%2Bporting