4age 304 deg cam issue

**xero** · 06-09-2010, 11:25 AM

Car - ae86

motor - smallport 16v

problem - the cam lobe is fouling on the head itself.

i have a tomei 304 deg 11mm lift intake cam which when trying to fit is fouling on the head itself due to the duration. i also have a 296 deg 10.5mm exhaust cam that DOES NOT foul on the head.
so it seems the issue is that extra 0.5mm lift.

options:
find smaller 10.5mm lift cam, at similar duration.

or

pull head off get machined to fit.

have to try and find another cam that will fit it my biggest issue right now. local cam providers didnt have the right profiles i wanted so bought from japan.
so at the moment looking into either getting one ground or off the shelf jobbie that will be close to what i want. rough cost $400

or i pull the head off get it machined to fit the cam, but this would mean new head gasket as well plus machining costs. last time i got something machined similarly was about $200, plus a gasket $100 plus my time.

has any one had this problem or offer any solutions?

**thechuckster** · 06-09-2010, 11:30 AM

got shimless buckets or shim-under buckets?

never done this but i'd imagine that cams that big will spit shims

**xero** · 06-09-2010, 12:03 PM

shimless, already got them sorted. was talking to takai about it a few months ago...

**oldcorollas** · 06-09-2010, 01:40 PM

if it is the cam you want, then pull the head and get it machined.
are the springs ok for that lift too?

anything else that could be done to the head at the same time to make it more worthwhile?

**allencr** · 06-09-2010, 02:45 PM

It's not wiping over the edge of the follower/lifter is it, contacting the very edge & past it???? Large lifts may require a larger diameter follower to keep the contact off its edge.

Lobe clearance in the follower bore doesn't require any special machining, measurement, angle, finish, special anything except that the edges of the new cutout in the bore be deburred & smooth, it's just gotta clear. You could do it to aluminum with a pen knife, just won't look as pretty
It's gotta be kept clean and the lifter has to move smooth & free just like it does now, that's it.

**xero** · 06-09-2010, 03:08 PM

Originally Posted by oldcorollas

if it is the cam you want, then pull the head and get it machined.
are the springs ok for that lift too?

anything else that could be done to the head at the same time to make it more worthwhile?

it is the cam i want OC, and will be best with the 12.5:1 comp i have, head work etc etc.
ive spoken to the other local cam people (camtech, kelford, wade etc etc) to try and get a slightly smaller lift cam, but they all want to sell a pair not a single and buy a pairs gonna cost similar to what the machining will be (best guestimations on other similar work) if not less.
already price new head gasket and they are in stock.

got toda upgraded springs as well to go in at the same time.

already had the head work done, this is the "last step" so to speak for final tune. i spoke to quite a few people, IPRA guys, and the engine builder, and at no point did we see a problem. not blaming anyone, i think it was just one of those things you dont think of at the time.

Originally Posted by allencr

It's not wiping over the edge of the follower/lifter is it, contacting the very edge & past it???? Large lifts may require a larger diameter follower to keep the contact off its edge.

its apparently impacting on the head just before the bucket (possibly following it too), so that section has to be machined out as well. there is a shit load of metal in there and its only going to need 1mm at best for clearence.

**oldcorollas** · 06-09-2010, 03:10 PM

oh well.. pull head off and get them clearanced

you've answered your own question

**thechuckster** · 06-09-2010, 04:58 PM

Will you get coil bind with that amount of lift? the guy with the 4AGErally car ... this guy ... resorted to new bits to cope with funky cams.

**andrew_mx83** · 06-09-2010, 05:30 PM

regrind the existing profile a bee's dick on ur 304 cam to just clear the head? should cost too much but you may sacrifice a tiny bit of lift or duration... wont need to go any lower than ur 296 obviously as that clears now

**xero** · 06-09-2010, 05:33 PM

Originally Posted by oldcorollas

oh well.. pull head off and get them clearanced

you've answered your own question

i know, thats what its coming too... if i can get a single cam ground at 10.5mm lift then its a lot less fucking around.

cheers for input anyway mate.

**Sam_Q** · 07-09-2010, 09:47 AM

now pardon for saying something so crude but seeing it's just for clearence can you fit in an attachement in a dremel style tool to take some material off without taking the valves out or head off? obviously you block the oil drains and clean up will when your done.

**thechuckster** · 07-09-2010, 12:14 PM

Originally Posted by Sam_Q

now pardon for saying something so crude but seeing it's just for clearence can you fit in an attachement in a dremel style tool to take some material off without taking the valves out or head off? obviously you block the oil drains and clean up will when your done.

you'd have potential for bits of metal everywhere - regardless of how hard you try. would be a world of fail when you discover the bits you missed have been chewed by various rapidly moving parts in the head.