Oil on Spark Plug tip

Deathacus · Apr 4, 2026

Guys, i'm at a complete loss. The timing is right, she got ~180lb compression, KOEO fuel pressure is ~37lb, none of my testing tools are great but the spark plugs i did the old pull out and ground and watch for spark method showed spark, plugs are coming out wet, smelly, but she still just won't run.

I'm losing it, I'm absolutely losing it. Six months of the stupid valve stem seal job y'all talked me into and now I got a giant lawn ornament. ****, I ain't got no running car, no band, nothing better to do with my time, haven't got a good night's sleep in weeks, and if this ************* can't even make it to Colorado this year, then what's even the point?

help me....

BaySHO Performance · Apr 4, 2026

Fuel pressure is good. Should be around 38 lb. Compression is way low. Spec is 210lb. with the lowest no less than 180. Did you check all cylinders? Potential reasons: blown head gasket, valve blow by (need re-seating), worn piston rings, scored cylinder walls.

Deathacus · Apr 4, 2026

Hmm, that's interesting. I only checked the front 3 so far, too frustrated and short on time this morning. No clue if my gauge is even calibrated right, figured they can't all be holy **** can customers just **** off for like, 30 seconds? I would like to buy a starter for my Kia so I don't' have to sleep here or spend my entire day's pay on an uber again off by the same amount, so at least consistency across all the cylinders (at least the one's i've checked) was a good sign. How would I go about reseating the valves? I do I do smell a little something-something coming up the intake.

BaySHO Performance · Apr 4, 2026

Deathacus said:
How would I go about reseating the valves? I do I do smell a little something-something coming up the intake.

You would have to remove the cylinder head and take the valves out.

Valve Spring Compressor - V6SHO

wiki.wikisho.com

Check for pitting on the mating surfaces. You could start off by hand grinding them in to see if you can get rid of all the pitting.

https://www.amazon.com/Holts-Professional-Valve-grinding-Coarse/dp/B0025KMT2A?crid=2IS33SI6LVPM1&dib=eyJ2IjoiMSJ9.jEL3RCVql2njdqzvLfxfNuI5dXObbNzIcgqCe39w3jwi8i_BDVH-vNSaI4XRmXmlHwQz4Renu36ihidDzQaYp53o28gOd3v2xE8GAsBW3njtSMURzhysPk7pedj7ySlOh3lESlW5x7xvSIWyTy4gabGnFBtfpT5Pm5oT1npRYsxh3_Lk4kLhH-jpyd_fWMgfyu3DDhHdQLmxKEv4j01v5ISjstZ10wT5tw-_KwOijNiI6TRrPUvpnu6X4Z9EyLSzdYUf-5SsAD-XNS2zOtrIs-1vU1kjrXojMRP00Gn1Wm4.zb5H88wwEUjfQ2WmmjcmZ8xGnH-ZfflcLrzw8uLcdUU&dib_tag=se&keywords=valve%2Bgrinding%2Bcompound&qid=1775337868&s=automotive&sprefix=valve%2Bgrinding%2Bcompound%2Cautomotive%2C155&sr=1-8&th=1

If that doesn't work, you will have to take the head and valves to a machine shop to have them cut.

Deathacus · Apr 4, 2026

Soo......I did all that work on the car....FOR NOTHING? I have to take it all apart AFUCKINGGAIN? How could this be if everything was huny freeking dory beforehoof? Is there anyway to be sure that's the issue?

BaySHO Performance · Apr 4, 2026

Deathacus said:
Soo......I did all that work on the car....FOR NOTHING? I have to take it all apart AFUCKINGGAIN? How could this be if everything was huny freeking dory beforehoof? Is there anyway to be sure that's the issue?

Well, your compression is lousy....oil in the coolant as you initially stated points to a blown head gasket.

Deathacus · Apr 4, 2026

True, true...but why was she running fine before I did the valve stems? Like, she was running basically perfect last i drove her, I just don't see how changing valve stem seals would exasperate a head gasket. The valve seats make a little more sense.

BaySHO Performance · Apr 4, 2026

Deathacus said:
True, true...but why was she running fine before I did the valve stems? Like, she was running basically perfect last i drove her, I just don't see how changing valve stem seals would exasperate a head gasket. The valve seats make a little more sense.

You said in a previous post:
Compression test shows 190 after 5 cranks, 220 after 11 cranks. So how many cranks when you got 180???

You must have screwed something up when you did the valve stem seals, but don't have any pointers.

zak · Apr 7, 2026

Are you using compressed air to keep the valves up during the seal change? Check for play valve to guide if you can (make sure that cylinder is at TDC) without the air.

Deathacus · Apr 7, 2026

zak said:
Are you using compressed air to keep the valves up during the seal change? Check for play valve to guide if you can (make sure that cylinder is at TDC) without the air.

I did use compressed air, although that wasn't successful on every valve. I was using my leakdown tester for that and only had 1-2% leak prior to any seal breaches.
I did wiggle the valves, probably forgot a few, and some of them did have just a smidgen of play, feelable but not visible. Within book spec, according to my cruder-than-crude measuring method.

Still wanna redo the compression test, maybe tomorrow.

Texas Marauder · Apr 7, 2026

Since you have a leakdown tester, you should check the current leakdown rate. That will tell you if there is a valve seating problem.

zak · Apr 9, 2026

ANother trick I just used, at the recommendation of a local engine rebuilder, on a different (not SDHO) DOHC engine, if you do get high leakdown rate, get a drill onto the end of the exhaust valve and spin each of them against the seat, if a chunk of carbon is holding it open it will "fix" that issue and leakup rate should decrease (mine did on a suspect cylinder in my case, had to use a drill adapter to fit in).

Deathacus · Apr 12, 2026

Okay, finally got around to this.
Leakdown at 100psi, Compression at 4 cranks and max:
Cyl. 1: 0.5% 180psi 170psi@4 - cleanest plug tip
Cyl. 2: 0.0% 180psi 200psi@9
Cyl. 3: 0.0% 195psi 215psi@8 - tip is very sooty, also leakdown actually tested negative 1 percent
Cyl. 4: 0.5% 140psi 160psi@8
Cyl. 5: 1.0% 190psi 205psi@7 - top is mildly sooty
Cyl. 6: 2.0% 190psi 200psi@9
Back: sunburnt

zak · Apr 13, 2026

Injectors or stem seals, try getting injectors cleaned first (I have an aftermarket set kicking around that no longer need).

Deathacus · Apr 16, 2026

Good news, she's starting to show some life! I left the plugs out for a few days to air out, cleaned 'em up, put another 4.5 gal of 93 octane V-power Shell super premium plus ultra deluxe or whatever. Left the belts off ~~'cause I was lazy~~ to reduce load as much as possible. Got her to start about 4 or five times. Longest she ran was like, 5 or so seconds. She really was trying on that first start.

Now, sanity check. The harmonic balancer, the 3 notches. Supposedly they were color-coded at one time, according to the book? The middle notch is the white one, which aligns with the 0 mark at cyl 1 TDC, correct? Does any of y'all know what those paint marks actually looked like? For cosmetic cleanup of course.

Deathacus · Apr 24, 2026

Now a question about the intake stays, now that I found the last bolt. The one near the right side rear, the one with the ground wire. Apparently there are a few brackets the hold wires and stuff up that I presume go there, but the prior owner had left loose. What is the proper setup for these? Like, top or bottom bolt, infront or behind the stay, etc. Also, all the documentation as well as some photos I found on the SHO Phoenix Project archive, says that stay should be slightly different than the rest, but all 4 of mine are the same.

Irish Pride · Apr 25, 2026

The bolt goes thru the intake bracket into the head to secure the bracket. Use 19mm for that. Then the wire harness bracket goes on to the stud with the ground strap and both secured with the 15mm nut.

Has your ground strap been disconnected this whole time while you've been trying to start the car?

-Chad

Deathacus · Apr 30, 2026

Irish Pride said:
Has your ground strap been disconnected this whole time while you've been trying to start the car?

I wish. So everything goes on the top bolt then? It goes intake\support\19mm bolt\big wire bracket\small...steering hose bracket, I think?\ground\15mm nut. Right?

Irish Pride · Apr 30, 2026

Install the stud thru the intake bracket and into the intake and tighten down with 19mm wrench.

Next is the black wire harness bracket(bracket is black) and then the ground strap. Secure these to the stud with the 15mm nut.

I don't know what steering hose bracket you are referring to.

-Chad

Deathacus · Apr 30, 2026

Figured it out. Yes, there is a retainer on one of the steering hoses that also bolts to the manifold stay. This one goes on the bottom bolt. And boy, the bay looks so much cleaner with all those wires hung where they should be.
No back to the main issue. Realistically, one single broken bolt on the front stay shouldn't be problematic, right? Like, I know it grounds thru those but 3/4 plus the 12 that goes on top oughta be enough to ground her, as long as that big ground wire on the back is clean and tight. right?

Oil on Spark Plug tip

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