dialing in cams?

[to4garret]

Yea so,

to add to my stupidity, when i installed the BC's i thought "installing them straight up" as per the instructions meant just dropping them in.

how ever, i have since learned, that means dialing them in straight up.

now i know how to find true TDC, thats easy, but apparently you cannot find the accurate valve open/close events with the stock lifters. apparently you need a solid adjustable lifter.

this is because if the lifter is partially collapsed it will alter the timming of the valve event.

i've looked into some solid lifters but damn they expensive, considering i only need two for degreeing only.

is there another way of measuring the valve events with the head on the engine.

i have almost considered attempting to measure out of phase with the opening/closing event but i dont trust my math that much


also, should you degree after the timming belt has be "run" for a few kms or before.


thanks!

 

[bazeng]

What I did was use a fake spring (get some wire, make a spring). Install it in place of the valve spring on both the intake and ex side. Remove all rockers except for the ones with the fake springs in.

Now bolt your cams in and have your piston on TDC. This is with the timing belt on of course. Now you should be able to adjust your cam gears while still being able to rotate your crank (slowly) but you will also be able to press down on the valve to see how much clearance you have. Your lifters WILL compress as you do this so you will have to press the lifter down. Ideally use a solid lifter.

We really only did this to confirm our max adjustment settings but the car will be run on 0/0. Adjustment will be made on the dyno.

But if you wanted to make a solid lifter, you could use a hydraulic lifter, remove the guts and tap the body with some thread. Find a rod that fits and machine it to the shape of the lifter top. Find a thin nut that fits or machine one if you have to and put it all together then you can pretty much adjust the lifter as you need to.

Hope that sorta makes sense. I cbf proof reading it.

 

[to4garret]

thanks baz, you just confirmed, its a **** of a job

 

[EVOCPE]

LOL.... im not gonna touch mine now... i'll leave it to a professional

 

[bazeng]

Did I mention you have to do this and also turn your crank after TDC / BTDC a few degree's to see how much clearance you have (piston to valve)..

I think you should be after 60 thou piston to valve from memory (at least).

It is a time consuming job. With V8's you have special tools that can push down the valve and actually measure with a dial. I'm not sure if anybody sells them for the 4g63 motor.

 

[to4garret]

yea i wasnt looking into finding the max adjustment, just getting them centered.

i have a dial gauge to do TDC which is hell easy. its just more the measuring lift which i dont like.

 

[to4garret]

the below link is awesome and should be tech faq'd but surely there is away to get around using the solid lifters?


http://www.dsmtuners.com/forums/cylinder-head-short-block/314111-cam-degree-degreeing-degreeing.html

 

[to4garret]

Advancing Intake and Exhaust : This will provide the car with more bottom end power, and will decrease top end. Advancing both cam gears will move overlap earlier but will not increase it.

Retarding Intake and Exhaust : This will increase the cars top end, but will decrease low end. Retarding both cam gears will move the overlap later and but will not change the amount of overlap.

Advance Exhaust Only : This will help the cars top end, and it reduces overlap.

Retard Exhaust only : This will help the cars mid range power, very useful for cars with big turbos / big cams. By increasing overlap, It decreases lag significantly. Doing this will bring the boost on all at once. Very common DSM modification.

Advance Intake only : This will increase overlap and helps the cars bottom end and mid range power. This mod will bring the turbo on all at once, although isnt a very common mod for DSMS.

 

[to4garret]

Ok, because I usually don't use a solid lifter to degree in DSM cams. I use the centerline method. Although it's not as in depth as checking 0.050 timing evens, it will tell you really quickly if your cam is where you want it at.

Example, for intake. I'll place my dial indicator on the spring retainer and zero out at TDC. I then rotate once around watching the dial and seeing what the max lift is. I noticed it was around .300. I will call this max lift (ML). I spin back to zero degrees and set everything to zero. I spin the wheel until I come to .280 before ML and I record the degrees (90). I then spin past the TL and stop at .280 and mark the degrees (110). I add the 2 numbers and divide by 2 to calculate the middle number ( 90+110=200/2=100). If i go to this degree location I will be at max intake lift and the intake centerline. I run the procedure 1 or 2 more times to make sure it is correct. I then check my my value (100) to the actual intake centerline (100). That shows i am straight up. If I got a value of 102 I would have been 2 degrees retard.

This method allows me to find out my timing without any relation to actual lift.

 

[to4garret]

^^^ stupid forum wont let me put the above in a quote

 

[bazeng]

What sort of dial indicator will you be using?

 

[to4garret]

basicailly one of these

http://cgi.ebay.com.au/RDGTOOLS-MAG...T?hash=item3c9e6dcf56&_trksid=p3286.m20.l1116

but i got one with a 6" extension so hopefully i can check TDC using it.

 

[DOUGMO]

my mate used one similar with the long extension fitted, seemed to do the job

 

[bazeng]

How are you planning to mount it to the head / engine ?

Make some sort of bracket?

 

[DOUGMO]

the one used on my engine bolted on to the head studs with a custom bracket

if the head is solidly mounted you could sit it on a metal bench with the magnet

 

[to4garret]

i was just going to use a bit of flat bar and bolt it down to the rocker covers inner (sparkplug) bolt holes then use the magnetic attachment on the flatbar.

that would be for TDC checking