BC264 cams in 7MGTE - overlap?

[BLACKCAT]

Installed a pair of BC 264 cams in a 7MGTE recently.
According to the cam card they have 36 degrees of overlap.
It certainly does not like that much & I had to reduce it to 32 in order to get a decent idle & prevent occasional stalling.

I can easily reduce it further but am concerned at bumping up dynamic pressure too much.

Is that still too much overlap for the 7MGTE & if anyone else has installed the same cams what adjustment to cam timing was made?

PS: Lost 10-15 psi static compression from the original Toyota cams but goes MUCH better now.

 

[edmonton]

installing these this week, let you know how it goes

 

[MRSUPRA]

My BC264 cams never idled good at 0,0 cam gear settings on the stock ECU. With the AEM, I have the idle set to 950rpms. I have the cam gears clocked for the most power now but I cannot remember what the settings are off of the top of my head.

 

[shaeff]

Heh, 0,0* on these things idle like a bag of rocks with the stock ECU. I've been working on a car that has these cams.

He needs to get some adjustable cam gears, at the minimum. There's only like 10in/hg of vacuum at idle, too. Not so good.

 

[BLACKCAT]

Running a Microtech MTX-8 standalone.
Idles at around 750 rpm (15-16) in neutral & 680 in Drive (14) when warm.
Adjustable cam gears certainly come in handy with these cams.
Needs to be warmed up a bit when dead cold not like my N/A which could be driven immediately with these cams.
Not having the cold start injector wired up does not help things.

 

[IJ.]

My 280's idled like a kitten you could barely tell it had cams at all.

 

[BLACKCAT]

Forgot to mention that I did not degree them just installed straight up as I finished working on them at midnight & was stuffed.

IJ is right about taking the time to degree them properly.

Will probably do that this weekend just to see how much they are out & what the difference in idle quality will be.

 

[Mo87NA]

Issues like these are what makes me hesistant to purchase the BC cams. I have adjustable cam gears, I just haven't read enough positive feedback to warrant spending the money and dealing with the headaches....


-Mo

 

[MRSUPRA]

/\I don't blame you. My first set of BC264's would not allow the engine to idle at all at 0,0 setting, not even close. I sent them back to BC to get checked out and they said they were fine. So I told them to give me a different set and they did and my car idled again. It was a major hassle with the hours and hours of me troubleshooting my new motor. Anyway, I'm making very good power now with the BC264's.

 

[BLACKCAT]

Time for an update.

Degreed the cams & yes they were both out a bit.
According to the cam card info, ie @ 0.050" lift I opens at 0 (TDC) & E at 48 BBDC, my ideal setting should be I +4 1/2 & E + 3 1/2.
Well at those settings it wont idle cleanly as the vaccum is crap & stalls pretty easy, even in neutral.

After a lot of stuffing around trying different combinations I ended up setting my cam timing at I +2 & E +3.

Goes good now & has no trouble pulling redline in second, only 5psi boost, wonder how the valve springs & bottom end is coping?:aigo:
Now I need to get it dyno tuned to see the difference these cams have made.

For anyone trying to tune these cams this is what I did:

Ended up setting the exhaust at +3 adjusted timing to 10 degrees & dialing the intake to -1.
Progressively advanced the intake cam by one degree increments & at the same time increased the idle speed (turning clockwise) with the adjustment screw. If you dont alter the screw setting it will idle too low & stall every time.
Any higher than 3 & I could not get a decent idle, too much overlap starting to creep in I suppose.
You must tune it with the engine at operating temperature, take it for a drive & then make minor adjustment to idle speed if required.