I just installed:

Coswoth m-2 cams (mivec)
ARP headstuds
Supertech single springs and retainers

Drove the car for about a week or two under 5psi at most, really easy driving. Noticed on warmup (before at op temp) car was really hesitating and popping out the exhaust. After warmup it would be really dead below 3-3500 rpm.
I figured it just needed a tune.

I had the car on the dyno for an English racing dyno day and the car was deemed "untunable" as it was showing 36 ounts of knock and they couldn't safely tune it out since tehre was obviusly something wrong. We re-checked timing on the car and it was timed right. I pulled the valve cover for an inspection of anything obvious..nothing.
We ran the car a bit and thought we heard something come open, like a valve open up just under normal revving.
Decided to re-bleed the lifters again and follow procedures to fill them back up as in thehow-to section.
Still the same drivability issues. Car is still showing knock.

I checked the t belt after it had cooled down to notice about an inch of play up and down on it. So the tbelt didn't tighten back up right.
I just took the timing components apart and retensioned the hydralic tensioner as it was loose.

Still driving the same as before. Popping and sputtering during warmup, slow to make boost, and hesitating.

Not sure at this point whats going on with it. My plan of attack now it to do a leak down test to see if it will point me in the right direction. I'm going to try to eet up with someone tonight/tomorrow who can datalog it and tell me if it's still knocking.

I did all the springs/retainers/cams/etc in car. no head removal. no weird noises and the car started right up afterwards. It seems to be idling alright, it might dip down to 800 or so here and there and sound like it's going to die. i don't have a wideband hooked up to monitor the warmup enrihments to see if it's just running lean and sputtering on startup/warmup.

Any ideas? Where should I go from here. Aside from leakdown test, I will probably have to take it into a shop to have it looked over. Anyone experience this before?

Rob

 

just logged it, showing same knock as before. up to 36 counts on slow acceleration. the car is not showing physical signs of knock. No noises, no face dives.

 

Very odd, so much knock at slow accel. If you're really determined, loosen up the belt and keep it ziptied on the gears (to not lose your timing), swap stock cams back in and try it.

I might say your balance shaft is out of phase, but you'd feel some real vibrations as you're getting into higher rpm, so that's probly not it.

Did you buy the cams from a reputable place?

 

Where in Washington state are you?

 

did you mod anything with fuel?

this is deff a diff one if it truly is in time correct. You sure the crank wasnt out of time when you did all this? 1st cyl at TDC?
I know it sounds stupid, but thats the only logical thing i can think to be honest.

 

Yeah, positive its all in time. I actually just pulled apart all the timing components and re-timed the motor perfectly. Gears, main, oil and balance are all fine. t belt has good tension on it now too.

no fuel adjustments.

I'm in the renton/kent area in WA

The cams were picked up used with 3k miles on them. They were origionally from turbotrix and all the work was done by turbotrix for the previous owner. I've thought about swapping cams out and putting in some stocker to see what it does.

 

bump
any other ideas?

I'm doing a compresion test tonight

 

I've been thinking about this... the only thing I can think of is that the car is indeed out of time. I know you say everything looks perfect but that is just my thoughts. Redo the cam swap and degree the cams and see how that goes. This is only my thoughts and guesses.

Good luck.

 

Just did compression test:

#1 170
#2 162
#3 159
#4 165

All within a few psi not too much to be worried about yet.
Did a quick leakdown test minus the pressure gauge. So I basically hooked my compressor up to each cylinder and filled them with air up to 60-80 psi to listen for leaks. I set the timing marks at timed which would mean #1 and #3 are tdc. Did those two cylinders, then switched to the other two and rotated the crank 180 degrees to put them at tdc.

All this was done while the motor was still warm from a previous running as to expand the metal a little to make a better seal.

here's what this told me...
#1 and #4 had virtually no to very quiet leaking of air, both from neither the intake or the tailpipe. I stuck my ear to both of them. Sounded like real subtle from the valve cover.

#2 was leaking from the intake. Pretty loud, defenitly could tell something was not sealed right.
#3 was the worst by far, leaking very loud from intake and a little coming out the tail pipe.

So, these also were the two cylinders that had the lower numbers. Next aproach is to pull valve cover and inspect valvetrain in #2 and #3. I'm thinking its collapsed lifter, or a valve seal needing replaced.

Timing is still good and tbelt still has some decent tension. Thought about balance shaft being outta phase, but tbelt was never fully removed from car when the work was done, so this would have had to fully slip 180, and there isn't any weird vibrations.

Any other thoughts on these?

 

bump... anyone?