Isuzu G-series Twin Cam

is it ok to get a differnt set of cams and put them into my engine on the current bearings or do i need the matching bearings for the cam?

if they look alright put them in. aslong as they are the same size not oversize bearings.

Just be warned, cam bearings are one item no longer available. If you need to replace them you will be looking at modifying some alternative bearing.

found some info on cams a guy in sydney that builds rally twin cam's has a few different grinds. the problem is if you weld the cam and get it re ground it wont work with the standard buckets you end up braking the weld off so there is 3 options chrome the isuzu buckets, works sometimes. replace the buckets with toyota 18rg buckets but these are a little long so they need machining or get billets $1000 a pair but you might have trouble putting the worm gear on a billet so you might need to run a crank angle sensor instead.
the L1 grind is very mild street cam not worth spending the money on to convert. he has two larger grinds one that comes in at 3000 - 7000 and one that comes in around 4000 race only cam.
full rebuild cost between $8000 and $14000

hmm looks like im staying with the stockos then as its only a daily lol

i called wade cams today they can regrind the standard cams to any profile and you put larger shims under the buckets for $180 trade bit more for general public. sounds abit to good but ill be looking into it further.

sounds interesting and a bit cheap. let me know how u go.
i contacted tighe cams last year and they have profiles from when they backed some rally guy back in the day. they didnt mention shims etc though

yeah it sounds too cheap specially when you hear so many different stories. the one thing everyone says is dont re-weld the cams. i dont like the sound of bits of metal breaking off inside my motor especially around the cam bearing area.

reground cams seem to work in the SOHC's fine...for that price, im assuming the WADE cams are regrinds as well. Any info on what other profiles they have availible?

Also, no mention of them saying to change the buckets? Im abit dubious as to this shim - i can see it gaining more lift that way. Unless the shim goes on top to stop the bucket wearing the lobe?

Nick-

they change the whole profiloe of the lobe so even the spots whre the valve is shut it could be up to 2mm smaller. so you put a 2mm thicker shim under the bucket and on top of the spring. this is a preferd practice because your using the original metal on the original bucket so there is no compatability problem so you don't need to chrome the buckets and because there isn't any weld it wont brake off.
my engine builder said this is the go the only problem is getting the shims he's chasing a motorbike machinest in melbourne probably a few hundred dollars for a set of shims.

Excuse the ignorance, but from what i know the shim would be just like a flat washer only larger in diameter and with a small center hole to clear the valve right? If thats the case, any machinist could do something like that up easy. I have a mate whos a fitter and turner, all i need is the right material and diameter...

Nick-

that is what they are but they dont have a hole. i thought so too. any machinist cant machine them down from larger ones but for some reason i don't know they don't make them. ive got a spare one i could mail you to see if your mate can make them a coiuple mm thicker.

He should be able to do it seeing as he works at Ford in broadmeadows. Got another mate whos a leading hand at Dunlop South Pacific so i can ask him too.

Was going to say you sure they dont have a hole - then i remembered they dont run rockers and the cam is direct on the bucket lol

I thought no hole, just solid.
And was it some Yamaha shim that was close?

But it must be hardened etc (eg, shim steel). Normal washers will hammer and flatten and break, then scratch and $$$$.
And its surfaces must be parallel.
Shims are usually ground or polished down.

I know to that some type of "Ford" bucket was very close to the G-Ws (but not interchangeable), but maybe their shims...?

toyota 18rg buckets swap out there abit longer and harder material and im pretty sure the shims interchange but nothing 2mm thicker than the standard g-w

i was thinking last night about this and was wondering. if i was to get custom billet cams made up with the same profile on the closed section of the cam, the only difference is gong to be the total lift?? based on that is there any need to mess about with the shims due to the clearance being the same?

you could use the old shims but id get a few thou extra on the cam and machine the existing shims down. i swapped a pair of standard cams for standard and had to get the shims machined to get the valve clearance right. the problem with billets is getting the worm drive that turns the dizzy on the easiest way is to ran a magnetic pickup of the crank.

Shims are simply exact thickness metal wafers shaped according to the bucket inside diameter. They take up the space between the valve tip and the inside of the bucket until the specified clearance remains between the base cam lobe and the bucket contact face.

When you get an existing cam reground with taller lift they do so by reducing the base circle diameter which then requires changing all the shims till you lift the bucket approximately the same amount as is removed from the cam base circle.

It is preferable to use single shims of the exact thickness than packing two or more thinner shims to make up the required thickness.

Dummy fit the cams onto the head with buckets in place but no shims under them. Measure the clearance with the cam lobe on center base and deduct the required advised valve clearance from the figure you measure. Do this for all lobes. You will get a range of figures that you can then order some shims to suit. No reason to go buying masses of shims you won't use if you can narrow the thickness down by a simple check.