fresh head reshim?

[s13drob]

ok heres my situation. i just got my SR cylinder head fresh from the machine shop last week (valve job) and i decided 2 put my cams back on. Thing is that it doesnt sit right in the journals/bearings. Seems like 1 rocker arm is pushing the cam up from the middle. its the same on the other cam too.

should i just tighten the bearing caps down and just force it level? i dont want 2 cause damage 2 the cams via crack/bend it. or does this means it need 2 get a reshim?

thank you for ur time

[blu808]

Interesting. There is nothing that having a head freshened up could really cause this. Unless the people that did the work did the following.

Cut the valve seals way to far which would cause the top of the valve to sit higher. Keep in mind you would have to be really dumb to machine valve seats that far.

2nd.

They somehow used the wrong valves???

3rd.

The remark you made about shims is prob not the cause. The shims. really rocker shims from what i remember are more or less just a surface for them to ride against. they are not like say a 3sgte where it is a bucket with a shim on top of the valve, and you order new shims once the old ones get worn down.


I would say a picture what you are seeing would be worth a thousand words.

Thanks.
Luke

[s13drob]

ok let me find my cam and ill post it up. thanx so far i appreciate it blu

[RedtopTech]

First off one lobe will always be pointing down. That is why there is a VERY important torque sequence which is performed in several steps.
Also the shims that sit on each valve stem are crucial. There are 36 different thicknesses from the factory all in .0001 increments. The reason for this is that the shims determine how level the rocker arms are sitting on each pair. Many people make the mistake of performing valve jobs and simply tossing the old shims back in. The problem is that each of these shims may be of different thickness as well as the valve stem height has now changed from the valve job. Each guide (the left shim with the ears) are all exactly 3mm thick. Now you must use a tool that fits in the lifter bore and measure the difference between the height of the shim guide and the corresponding valve stem. The difference will be the thickness of the required shim for that pair.
The factory gives a tolerance of .0001 b/w the guide and the shim. To much of a difference will lead to the rocker arm wobbling, making noise, and potentialy being thrown which will negate all the money and time youve put into your build. Take the time and do it right. Your biggest issue will be finding a tool that fits the lifter bores and gives a mounting location for a dial indicator. PM me if you want to buy mine.

[blu808]

RedtopTech:

Wow. Good reply. posi rep for you.

[s13drob]

yea very nice reply thanx 4 ur info. i put the valve guide and shims back in place and i had them all marked off in seperate bags wen i pulled them. so i gess the main problem would be the valve stem height after the valve job. would the valve height be that much of a difference that i would need 2 reshim if i put the originall guides/shims back?

once again thanx 4 both of ur input. its greatly appreciated and acknowledged

[RedtopTech]

yes sir, the valve stem height will change considerably after a valve job, at least enough to warrant you to measure.

[90KAcoupe]

yep i ran into the same problem with my ka24.. except intstead of changing shims i measured the gap with a set of filler gauges and ground off what was need on an old valve grinder i got for free.

so for me i couldnt afford all new shims (they get pricey) so this was cheaper but not easier..lol

[s13drob]

ah ic. thank u all.. if i was 2 reshim myself i would use the feeler gauge method. now does any1 know a good machine shop in so cal 562 area thatll do it cheap?:naughty:

[s13drob]

ok well i contacted the machine shop about the reshim. they originally did my valve job and they are engine head specialist since that what they do at "The Head Exchange". they said that its not necessary since i have hydraulic lifters it self adjusts. thats kinda wat i thought in the 1st place which is y i was just gonna force the cam dwn on the journals/bearings. again i would like your opinions.