The Top Mitsubishi Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

this is tdc

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
Now am I off a tooth or is the cam timing just this far off from machine work?


Edit: just checked the cam card. Exhaustcenterline is out 6 and intake is out 1.5 degrees. What's a full tooth?
 
Last edited:

prove_it

Well-known member
Joined
Jul 3, 2008
Messages
4,201
Location
Sioux Falls, SD
It looks like normal machined head to me. Your maybe 1/4 tooth off, or about 3 degrees. My stock gears line up like that with a machined head. You had the block decked didn't you?
 

prove_it

Well-known member
Joined
Jul 3, 2008
Messages
4,201
Location
Sioux Falls, SD
In reality, if you were doing a timing belt with stock gears, you would just rotate the crank CW a tiny tiny bit and the cam marks would line up fine and the crank lines would be just barely off to the side.

Double check all your measurements to be safe though. Also I'd like to see what Evan has to say.
 

CutlassJim

Well-known member
Joined
Jul 17, 2006
Messages
1,699
Location
Manchester, NH
This is the exact reason for adjustable cam gears and degreeing.
 

prove_it

Well-known member
Joined
Jul 3, 2008
Messages
4,201
Location
Sioux Falls, SD
Wait?, We agree? /ubbthreads/images/graemlins/jawdrop.gif


jk
 

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
I'm having a difficult time getting my open and close events to match the numbers on the card. I found it easier to match the center lines with the spot I found peak lift. Is that good enough? I'm tring to measure open and close at .04".

Also when I'm done are the timing marks on the cam supposed to line up again?
 

donniekak

Well-known member
Joined
Jan 1, 2009
Messages
748
Location
surprise az
It's pretty rare for the opening and closing events to match with most cams. Use the centerline method. And not peak lift, the center of the opening and closing events.
 

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
So target the calculated centerline with the one on the card. Don't measure centerline. Don't worry about opening and closing events in relation to the card, but insted just use to find actual centerline.

Ok ill try again. That seems easier.
 

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
Ok.. . Now I forgot to take into account that I'm degreeing a stroked engine.

How should I adjust my target centerline while using a 94mm stroke crank?

I guess I should call GSC and see what they have to say. I'll report back.

Repoprt: I Talked to Gregg over at GSC, he's a super nice guy! Foremost he assured me that all his cams are sent out measured to the 5th decimal place in metric, and that any irregularity I'm getting is due to the equipment I'm using. If you saw my equipment you would agree with him too. He mentioned that a solid belt tentioner needs to be used and that his company made special flat top spring retainers so a perfect 90 degree angle can be maintained on the shaft of the dial indicator. Two things I have thus far overlooked.

So after all that he said I should concentrate on aligning my opening events to the numbers on the card. He also stated the stroke should have nothing to do with the targets.
 
Last edited:

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
I did this to death. I got the exhaust cam exactly where it is on the card. The intake cam doesn't match the card though. It opens 1* BTDC and supposed to close 35* ABDC when in actuality it closes at 42* ABDC. I measured many times. The card for GSC S1 cams is wrong.

After all this Exhaust cam 2* R Intake cam .75* Advanced. Complete waste of time money and and effort. One of my cam caps had a heli coil holding it in. Now it does not... Destroyed the set pin for that cap too. Going to try to stud it today. Trowing the nt engine back with a 14b is looking better and better.
 
Last edited:

EHmotorsports

Well-known member
Joined
Sep 25, 2012
Messages
1,278
Location
Beaverton
Making the cam timing perfect is never a waste of time.
 

prove_it

Well-known member
Joined
Jul 3, 2008
Messages
4,201
Location
Sioux Falls, SD
It's not a waste. You'd be surprised to know that 1-2* cam change in the right direction can yield up to 20whp. Getting them set to where they need to be at will make the whole engine happier.

I'll be going down the same path you did. I'll be throwing on some gears and adjusting them to spec, your not alone!
 

tektic

Well-known member
Joined
Dec 19, 2012
Messages
1,497
Location
ronkonkoma, ny
My intake cam seems to have 7* of extra duration not accounted for on the cam card. did you find anything like that?

This could be from my crap tools however the exhaust cam numbers all worked out perfect.
My machinist told me that small cam company hand index things and accidents happen constantly.
I know there's many other variables like valve installed height.

What I know for sure is that in my setup I have 7 extra crank degrees of intake cycle over the specified duration on the card provided. I indexed the opening event with that on the card and thats where it going to stay unless it gets dyno tuned.
 
Support Vendors who Support the GVR-4 Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications RixRacing RockAuto RTM Racing STM Tuned

Recent Forum Posts

Recent Classifieds Listings

Top