Car won't idle/start after BC 264 cam swap

[87targa]

hey guys,

I swapped out my stock cams last night. I put the cams in and set everything like the stock cams, i.e. center hole on both cam and gear. crank to tdc and marks on gear pointing to the groves. Set the CPS they way it's supposed to be set following the TSRM.

Car will not start on it's own, i have to push the throttle in a little and then it starts sometimes. once it does start, i have to play with the throttle for the car to even stay running. it runs horribly, a lot of overlap. sounds, like a cammed v8. my boost gauge goes to -0.8 bar then up to -0.2 bar then back to -0.8 then to -0.2.

The car ran fine when i took out the stock cams.

I'm guessing some valves are not closing all the way? I'll be re-shimming the buckets on saturday.

I also run maft pro speed density if that bit of info helps any. When i play with the throttle so the car goes to 700 rpm, my timing on the maft pro is about 12*-20* (the numbers jump back and forth to fast to tell you what it is). i haven't checked with a timing light.

 

[IwantMKIII]

if i were you i'd just rechect everything, make sure your cams are on the right cycle and make sure your block is at the PROPER TDC point, ie take out spark plug one and make sure cylander one is at the top.

 

[p5150]

Your timing is off - ignition or mechanical

 

[bowsercake]

Don't worry about the timing, it is changing because you are on the gas and the rpm is moving up and down. There have been a few other threads on this. You need to degree the cams. I had to play around with my cam gears to get my non-BC cams to idle right.

 

[dbsupra90]

hmm. i seem to remember on the mpro you have to change a few settings when you go to bigger cams. i cant find it offhand tho. poke around on fullthrottletech.com and like was said, make sure everything is 100% correct on the install.

 

[87targa]

thanks for the info guys, i'll check again on saturday and make sure everything is in the right place, i'll try and get degreeing gear from a shop i know here locally. i'll do a post on fullthrottle

 

[MRSUPRA]

My car would not idle either with the BC264 cams. I had to set the cam gears to +4 intake and -4 exhaust to get it to idle. So obviously there must be lots of overlap with these cams. I also failed emmisions pretty bad.

I guess these cams have to be degreed like so many are talking about. I have never heard people with HKS cams having to degree them.

 

[IJ.]

Lash?

 

[MRSUPRA]

/\What?

 

[IJ.]

Too tight on the shims holding the valves open maybe?

 

[MRSUPRA]

OK. I don't think in my case since I checked all my shims for proper clearance when I installed the cams.

 

[IJ.]

Was meant for the OP

 

[MRSUPRA]

NP.

But I do think the problem he is having is the cams (with all the overlap) and not the MAFT-pro.

 

[bowsercake]

I guess these cams have to be degreed like so many are talking about. I have never heard people with HKS cams having to degree them.

Who has HKS cams and did they use cam gears to adjust them? I'm pretty sure all cams have to be adjusted more than just aligning them into the center hole.

 

[IJ.]

^ Be 100% sure

 

[MRSUPRA]

http://www.supraforums.com/forum/showthread.php?t=258259&highlight=degreeing+cams

http://www.supraforums.com/forum/showthread.php?t=176212&highlight=degreeing+cams

 

[87targa]

ok guys. i got the car to run pretty well other than idle when cold i guess.
i got it idling and adjusted timing and all that when the motor was warm. I could get the car to start when it was warm after i turned it off. I left it over night and now i can't get it to idle. i can get the car to start but not idle. in order for the car to idle at 750, i have to give it a little gas but not much.

i'm also -44 main scale on maftpro

 

[supra90mkiii]

-44 is a little scary... mainscale will affect the whole picture, so while under boost as well. It'd be a lot safer to adjust the ve table. i'm running the same cams, and 550cc injectors, and i have my mainscale set to -15. but your symptoms sound exactly the same as mine were. It'll take time to tune the idle out to run good while cold. There is a good thread on a different forum (mkiiitech.com, but it looks to be down right now) about tuning using the ve table, helped me a lot.

 

[87targa]

before the cam swap, my main scale was -20 with 750s. with the cams in it is doubled. i noticed the afrs where lean when i'm about to hit boost. i haven't started boosting yet, just cruising around off boost. the only way i feel safe messing with my idle is to drive around and then take it out of gear and let it idle while rolling. i noticed that i can't get the car started again right after i turn it off. i have to wait a about 30-40 mins before it will start again. that's why i cruise around and let it roll. my wb says 9.9-10.2 when i turn off and try to start it again (really rich). i'm just flooding the engine is my bet. some one else told me that they were running extremely rich also when they changed out the cams.

anyways, i'll look more on mkiiitech and fullthrottle's forum.

thanks for the help guys.

 

[americanjebus]

Let us know what fixed this for future reference.