Smoke on Deceleration

[KTL]

If they were wet, that would likely be oily. Fuel-soaked plugs will of course dry out when the fuel evaporates.

Just mentioned the valve seats simply because when I last had my heads done, head guy cgarr noted the cut on the valve seats was not up to snuff in terms of angles (lack thereof- didn't seem like they'd been previously cut properly) and said it's especially important to do with new valves to get them seating & sealing together right from the get-go. Also equally if not more important to have good valve-to-seat contact to ensure the valve is getting cooled by the contact with the seat. Get a valve too hot and it'll snap off the stem. Then you're in BIG trouble.

Try not to confuse seepage from the #8 crank bearing o-ring with crank snout seal leakage. Often they look like the same thing. I had a friend who kept thinking his snout seal was leaking and replaced the seal multiple times. The leakage of the o-ring around the bearing was the source. No way to fix that except for a case split.

You are correcto that rocker shaft leakage can make a huge mess and cause all sorts of assumptions as to what else could be leaking. Good indicator of rocker shaft leakage is to remove valve covers and look at the areas behind the covers that are supposed to be dry. If oily in there, it's either a head sealing issue (shouldn't be really any oil leakage from the combustion chamber!), a cam housing-to-head sealing issue, an oil return tube leak, or a rocker shaft leak. I tend to think the rocker shaft is the most common culprit.

The RSR shaft seals are a bit expensive but they do help. Hard to swallow $80 something bucks for some rubber rings. They are helpful when a shaft just doesn't want to seal. Also remember that the typical printed tightening spec for the shafts has proven to be insufficient on aged cam housings. So tightening them up more, along with the shaft seals has proven to be the solution.

"Competition Engineering - CE's war on oil leaks"

[K Sykes]

Finally got my heads to the machine shop. He confirmed my suspicions. Several valve guides were obviously shot. Cylinders look fine - cross hatching still visible, no obvious scoring. They are magnetic, so Nickies.. .

So sample of one - smoke on decel = guides

Spent the day at the Pull-A-Part junkyard getting ready for adding ignition - picked up a few EDIS modules, some throttle sensors ( if you need a throttle sensor for an SC, most BMW's have one that will work - Part # 1363-1721456 ), Crown Vic spark plug wires and EDIS coil packs.. Everything was cheaper than dirt except the coil packs.

I'll get the heads in a couple of weeks and start getting it back together.

[RD911T]

I think I'm headed down the same path. Posting to subscribe.

[K Sykes]

Minor progress - I have been working to buy as little new stuff as possible, but could't figure a way to modify the stock crank pulley. So off to Goingsupersfast.com to get one of theirs as well as a distributor plug and sensor holder. Have to admit, it looks nice and fits well. Used a Ford Focus sensor and pigtail which a drop in fit to the GSF mount. $5 at the you pull it junk yard. Have coil packs, spark plug wires, EDIS modules and a BMW throttle position sensor that is a drop in fit for the SC throttle body. Engine tin, valve covers, fan and housing back from the powder coater and looking good.



Heads are out getting rebuilt, so just rewiring and cleaning engine compartment.

[KTL]

I've got a GSF pulley, sensor wheel (60 minus 2 for use with Electromotive), distributor hole plug and sensor holder too. Nice stuff for a reasonable price. Which ignition setup are you using?

[K Sykes]

I'm using MS2 and EDIS. Mostly junkyard sourced except for the GSF kit in the pic.

Got the detailed answer on my heads. Exhaust valve guides are original, so not replaced at rebuild. Arrrgh. At least it explains a lot of symptoms. Smoke on decel, lots of oil in the throttle body from blow by pressure and very short improvement from valve adjustment.

[K Sykes]

Got my heads and cams back today!

New exhaust valves and guides all around, couple new rockers, all new rocker arm shafts, and reground cams that are a bit hotter to complement the EFI and EDIS ignition.

Will be dry assembling tomorrow to verify valve to piston clearance and then put it all back together.

[Discseven]

Great stuff Kinsley!

Pardon me for being a complete moron... but what's going on here? Is this replacing the flywheel sensor(s)?

Originally Posted by K Sykes

[Henry Schmidt]

Originally Posted by K Sykes

Not trying to be critical but those seats look pretty deep. Do you know the stem height?

[Oheggem]

Originally Posted by matt demaria

Smoke on decel is classic rings; smoke on accel is guides.

Add valve stem seals. i changed of one cylinder and no more smoke on accel

[K Sykes]

Originally Posted by Discseven

Great stuff Kinsley!

Pardon me for being a complete moron... but what's going on here? Is this replacing the flywheel sensor(s)?

It's an SC, so no flywheel sensor. It's replacing the distributor, along with Megasquirt and EDIS

[K Sykes]

Originally Posted by Henry Schmidt

Not trying to be critical but those seats look pretty deep. Do you know the stem height?

Henry,

Think it's the picture. Agree it looks funky, but looks normal in person.

[trond]

I have the same configuration of ignition/fuelling parts in my 80SC
What cams did you get ?


Regards

[K Sykes]

Originally Posted by trond

I have the same configuration of ignition/fuelling parts in my 80SC
What cams did you get ?


Regards

Elgin "SC Sport" grind. It's supposed to be a step up from stock, while still idling OK and keeping reasonable valve to piston clearance. Still had to measure the clearance to be safe. That took all of Saturday. Got the left side mostly assembled on Sunday. Was missing a few head stud washers or would have both sides done up to camshafts in.

Hopefully I can get the rest next weekend.

Trond, how do you like EDIS?

[Discseven]

Originally Posted by K Sykes

It's an SC, so no flywheel sensor. It's replacing the distributor, along with Megasquirt and EDIS

Thanks ~

[trond]

Very happy with the MS/EDIS ignition. Very stable, easy to get to work and affordable.
I have struggled to get a ignition table I liked.

Be aware that the GSF toothed wheel can be configured in a number of ways and you may need to take it apart and index it to get the timing right. Then once the engine is running set ignition to 0 degrees alternatively 30 degrees in TunerStudio and use the Trigger Wizard to get the marks to line up. With mine it was 2 degrees off only after I re-configured the wheel

The Elgin SC Sport sounds like it might be similar to my DC13 grind

[K Sykes]

Engine is done. Got some friends to get it off the stand and on to the cart I use to get it back into the car. Just need to mate up the transmission and it's ready to go. Was able to use the old air pump mounting studs on the chain cover for an EDIS coilpak.

Hopefully will get a chance to do test start tomorrow.

[K Sykes]

It's running again! Lots of EDIS challenges, but most revolved around my timing light not being compatible with EDIS. Had to remove a couple jumpers on me MS2, but it runs. One little bit oil weep on the front of the drivers side valve cover, otherwise dry.

I'll post some pics later, need to catch up on a couple weekends worth of chores

[K Sykes]

Now it really runs. EDIS/MS is a chore, but once it's working, you have different car. I had one setting that caused a stumble, changed one thing on the EDIS settings and it idles smooth and goes like a scalded cat when you press the happy pedal. The new cams (964) really make a difference, particularly above 4k rpm. It just keeps pulling. I have the timing set pretty conservatively and next stop will be the dyno to get AFR and timing all dialed in. Suspect I can move the redline out a bit as well. I have it at 6,000 now so I don't hurt anything until I know it's all working well.

I was going crazy trying to figure out the problem. The MSExtra instructions allude to a "new" and "old" design for the V3.0 board. You use falling edge for one, rising for the other. I thought I had a "new" one and used rising edge to capture the ignition signal, finally tried falling edge and it was a totally different car.

Thanks for all the advice when I was tearing it down.

[K Sykes]

One last post - went to the dyno yesterday with a skilled MS Tuner - Got a nice fuel and timing map. Focused more on drivability rather than raw HP - and trying to stay a bit south of "blow the engine up" timing. Having said that got 172.5 RWHP, almost exactly the same as stock, but I think stock is measured without drivetrain loss? Also have a nice flat torque curve - think that's the impact of the 996 cams. Tuner thought there was more there with a more open intake (80 has narrow runners) and I don't have the best intake above the TB. Also would benefit from SSI's. But wallet is done for now.

Driveability is now excellent - and expect fuel economy to improve as well.