[AZ_SVT]

Is there a way to verify the VCT is activating correctly? Four years ago I had the head off and rebuilt due to a broken timing belt. Referenced the cam timing threads here extensively. In the four years since I put it back together it has remained my daily driver and it hasn't thrown a single code. No over/under advanced, nadda. HOWEVER, ever since putting it back together, I thought the car lacked the top end power it had before it was apart. Part of the personality of the car was that it really came alive above 4000 RPM, you could feel it open up and pull harder as it revved. On some of my very first test drives after the repair I noted that the power band now felt perfectly linear from idle to red-line, no distinctive top end surge like before. I chalked it up to my imagination and decided that I should drive it awhile. Well, I did. Maybe I shouldn't be complaining about a completely reliable car, but I got walked by a 2012ish standard focus on the freeway entrance ramp a few days ago. I was wide open in 3rd and he pulled me. Just doesn't seem right. Plus this perceived power loss has been nagging at me for four years.

Oh, also relevant, IMRC function was verified yesterday by revving the engine while watching the IMRC lever at the intake and verifying movement. I put the billet lever on when the engine was apart.

Other SVTF owners have anything anecdotal or specific regarding seat of the pants feel of the powerband? Am I crazy? I just really remember it pulling harder the more it revved. Since 4 yrs ago it just seems flat. I've had the car since '09 and driven it about 60k, probably about 30k before the timing belt broke. VCT solenoid is to much $$$ to replace on a whim. Considering just unplugging it and seeing if the car runs any differently. Should answer the question pretty decisively. If it runs like a dog unplugged then it's working. If it runs the same...

 

[1turbofocus]

If you unhook the VCT it should be down about 60-70hp and you should get a CEL for the 1381/1383 CEL , My guess is your solenoid is fine and you have the cam timing off and or need a Tune

Tom

 

[AZ_SVT]

Unplugged the solenoid and drove around for about 10 minutes. Definitely slower and absolutely piggish throttle response. Didn't throw a scanner on it, but it didn't trip any dash lights, so I don't think it threw a CEL. Maybe if I drove it around unplugged longer. I guess the next step is to pull the valve cover and recheck the cam timing.

 

[G-forces]

Agree, your cam timing must be a bit off. Unless the 2012 has an aftermarket turbo, or your compression is low on a couple cylinders, your power to weight ratio is better than his... no way he could have walked you. May as well verify cam timing first, then check compression, just to be sure the rebuild addressed all the damage.

 

[AZ_SVT]

Did a compression test. Engine was up to normal operating temperature no more than an hour before I finished the test more or less. In order, 1-4 read 100,115,105,110.

Also pulled the valve cover and checked the cam timing. TDC was located using only the timing pin. I have the factory manuals and see nothing resembling the timing mark on the crank pulley or a pointer on the oil pan. In any case, with the crank on the timing pin the timing bar slid in perfectly. Is there any way #1 is not at TDC when the crank is on the timing pin?

 

[G-forces]

Well SVTs can be tricky, especially due to VCT oil pressure. There seems to be a bit too much variation, especially between 1 and 2. I think you should do it again to be sure what you're seeing. Warm it up again, pull all the plugs, pull the fuel pump fuse, have somebody hold the TB open while you check, and make sure you have a good seal for each plug... can be a problem down in those deep wells. Check in the opposite direction this time... 1 > 4, or 4 > 1. Once you hit 3, 4, or 5 turns, you're done, so inside guy can stop the motor, just count the same every time.

Anyway, which cylinder(s) had the bent valves? Did you get a complete valve job across the board, or just repair the bad ones?

 

[AZ_SVT]

I should say I did 1-4 and then 1 again. The 100 on #1 is essentially the fifth measurement. The first time I did #1 I didn't crank it over enough times. It was the first time I've actually done a compression check. We did do it WOT. Did not pull the fuel pump relay though. I don't remember which cylinders had bent valves. I think all of them. I believe it was nine valves, but not 100% sure. Head was completely redone, hot tanked, all new valves, valve stem seals, seats where needed, valve job, etc.. Put it back on using ARP studs.

 

[AZ_SVT]

Another thought. When the belt broke, I was in the middle of doing a compression test to verify bent valves. I think we got to the second cylinder when it knocked a valve head off and locked up completely. I didn't take the bottom end apart. Is it possible to bend a connecting rod just cranking it with the starter? Seems like the fact that it has been running reliably for 30K since would indicate the bottom end was fine but I dunno... stranger things have happened I guess. Multiple oil analysis have come back good as well.

 

[G-forces]

Something isn't right about piston 1 then. If all numbers were closer to each other and just over 100, that would be acceptable, just lower than you'd want.

Don't worry about a bent connecting rod, they are forged and a lot stronger than the rest of the rotating/reciprocating assembly... the rod bearings or wrist-pin bushings could have been hurt, though, but you should be able to hear a problem with a pin bushing (doubt that happened, the valve stems are weaker than all that). It is possible that one or more compression rings got abused.

At this point, I suggest carefully checking the valve lash. It's possible that you may need to swap around your buckets and replace a couple. After a complete valve job, it very possible that the lash hasn't been set properly on all valves. Maybe too tight on one, and too loose on 2. Maybe not in spec on several valves either side.

 

[AZ_SVT]

I think I'll check the compression one more time since I'll have to pull the valve cover to do this anyway. Might be onto something with the lash though. Also, I took a picture of the position of the cams when on the timing pin. When on the timing pin, the peak of the lobe on both cams is horizontal to the ground. The exhaust cam is pointing towards the front of the car, and the intake cam is pointing towards the back of the car. At TDC shouldn't they be on the base circle? I ask because the picture for checking lash says to put it at TDC and the picture shows the cam with the peak of the lobe pointing up.

Is it possible the engine is not at TDC on #1 when the crank hits the timing pin, or is that the ONLY place the pin makes contact?

 

[AZ_SVT]

I am referring to cam position on #1

 

[G-forces]

You can do the chop-stick (or pencil) trick to decide when you are at TDC. Stick a long wooden dowel in piston 1, through the plug hole, and turn the crank by hand until the dowel is as far up/out as it can go... then go back or forth a tiny bit to find the "home spot" for the pin.

The intake cam lobe should be elevated, pointing to the side and up, about a quarter turn behind the position of the exhaust cam lobe on the same cylinder (peak compression).

 

[AZ_SVT]

Soooo long overdue update here. Found myself with a lot of time on my hands recently. Needed to drive the car, and, other than being down on power, it has been reliable, so I never got around to checking the lash, despite a strong suspicion that was the problem. Finally did that today. I was hoping one or two were out of spec. NOPE. Shop that did the head appears to have set (kind of) stock ZETEC lash. They are ALL way too tight. Range from .080 - .152 INT and .130 - .254 exh. Now the question is, do I have to pull the head to grind valve stems, or can I find buckets to get it back in spec. Anyone know aftermarket sources? I checked Kent Cams catalog, and they list some mechanical followers for ZETEC silver tops, PN CF57. I plan on contacting them directly, unless someone here knows another definitive source.