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Just wanted to get a few opinions on my next course of action.
Background.
Bought another s2000 3 months ago. Did not do a compression test when i bought it, drove good, no smoke, no CEL but valve train was a tad noisy.
Got it home, did compression test 1-4 (180/240/210/230).
Did a valve adjustment, all very tight (.006 would not fit). Figure the crap shop that did it did not know. Valvetrain was quieter.
Ran some seafoam and blew out plenty of carbon.
Did a compression test and same numbers.
Did a leak down test 1-4 (50/90/90/85) #1 leaking from exhaust. I put gloves over the exhaust tips and they filled up. I could also hear it leaking. No bubbles in coolant/ or air flow from the dip stick or intake. This is my 2nd time doing a leak down. I did it 3 times on #1 to confirm and it was the same results. Yes it was on the compression stroke.
I put a borescope down and the valve looks fine, but my scope could not do a flip to see it super clearly.
Now the question is what to do next.
I have never done a head gasket before but after a few videos, i feel fine doing it.
1. Should i get a 2nd opinion before i decide the pull the head?
2. Pull the head myself and see if i can see anything and send it to a machine shop (i need to call around)
3. Bring it to a reputable s2000 shop and they can replace the head (reman i think) for 2200-2600.
I guess the best case scenario would be a burnt valve and i could just buy a new one, lap it and check for leaks. Since ive never done any head work, im not sure how much disassembly i need to do before it goes to the machine shop.
head is pretty easy to pull off on the car, hardest part would be removing the stuff external to the motor (header, intake manifold, injectors, fuel rail, coilpack, cam sensors, valve cover, electronics/sensors IIRC). but before removing it and doing more work than you need to, check the valve retainers on that cylinder visually. you might have a cracked retainer that's letting air through but not cracked enough to drop a valve yet (you can replace the retainer in the car). i also wouldn't trust a reman'd head unless if i knew where it came from and who worked on it. if you need a spare head, i have a couple laying around (if you're still in SF) that would be a good core.
head is pretty easy to pull off on the car, hardest part would be removing the stuff external to the motor (header, intake manifold, injectors, fuel rail, coilpack, cam sensors, valve cover, electronics/sensors IIRC). but before removing it and doing more work than you need to, check the valve retainers on that cylinder visually. you might have a cracked retainer that's letting air through but not cracked enough to drop a valve yet (you can replace the retainer in the car). i also wouldn't trust a reman'd head unless if i knew where it came from and who worked on it. if you need a spare head, i have a couple laying around (if you're still in SF) that would be a good core.
Yep, still in SF. this is on an AP2 with 125k. I didnt notice anything weird when i pulled the VC off but once again i didnt look super hard as well. My borescope view of the valves looked ok. The piston did look a tad black/dirtier than the others.
The work was going to be done by a reputable shop in the bay. They just did another guys car in 1 day as they had a head in stock.
then yeah, 2200-2600 all in is not a huge price to pay. in that scenario the only reluctance i would have is not doing preventative things while things are apart. like at that point if i could afford the downtime, i'd want rings and bearings too lol.. also probably already covered it, but did you drop oil down the cylinder and try leakdown on the other side of the stroke (turning the crank 180) to make sure? if so, i think you have most bases covered and probably looking at a valve problem. i would personally maybe pull up to dan and ask him what he thinks too
then yeah, 2200-2600 all in is not a huge price to pay. in that scenario the only reluctance i would have is not doing preventative things while things are apart. like at that point if i could afford the downtime, i'd want rings and bearings too lol.. also probably already covered it, but did you drop oil down the cylinder and try leakdown on the other side of the stroke (turning the crank 180) to make sure? if so, i think you have most bases covered and probably looking at a valve problem. i would personally maybe pull up to dan and ask him what he thinks too
Dan at rcrew?
I did the oil with the compression test and did not help.
I did not try the leak down test in any other method.
Just wanted to get a few opinions on my next course of action.
Background.
Bought another s2000 3 months ago. Did not do a compression test when i bought it, drove good, no smoke, no CEL but valve train was a tad noisy.
Got it home, did compression test 1-4 (180/240/210/230).
Did a valve adjustment, all very tight (.006 would not fit). Figure the crap shop that did it did not know. Valvetrain was quieter.
Ran some seafoam and blew out plenty of carbon.
Did a compression test and same numbers.
Did a leak down test 1-4 (50/90/90/85) #1 leaking from exhaust. I put gloves over the exhaust tips and they filled up. I could also hear it leaking. No bubbles in coolant/ or air flow from the dip stick or intake. This is my 2nd time doing a leak down. I did it 3 times on #1 to confirm and it was the same results. Yes it was on the compression stroke.
I put a borescope down and the valve looks fine, but my scope could not do a flip to see it super clearly.
Now the question is what to do next.
I have never done a head gasket before but after a few videos, i feel fine doing it.
1. Should i get a 2nd opinion before i decide the pull the head?
2. Pull the head myself and see if i can see anything and send it to a machine shop (i need to call around)
3. Bring it to a reputable s2000 shop and they can replace the head (reman i think) for 2200-2600.
I guess the best case scenario would be a burnt valve and i could just buy a new one, lap it and check for leaks. Since ive never done any head work, im not sure how much disassembly i need to do before it goes to the machine shop.
Any suggestions are welcome.
I had some funky compression numbers just like yours and mine turned out to be the exhaust valve seats in the head. I pulled the head and took it to a local machine shop (they build a ton of V8s and are very knowledgeable about everything), and during their testing they found that the exhaust valves were leaking due to someone previously not keeping up with valve adjustments. Some of my exhaust valves were tighter than .005"! Apparently when the valves are this tight, the beat the crap out of the seats and eventually wear them out. If you're mechanically inclined, you can remove and reinstall the head, it isn't all that hard. I'd take the head to a reputable machine shop and have it checked out. The valve seats can be removed from the head and replaced. They will have to do a valve job during this repair. If your car has a lot of hard miles on it, you may also want to replace the valve springs at a minimum.
One other major important thing to know about he S2000 cylinder head, DO NOT have the head machined or "shaved." This will throw off your valve timing. If they need to flatten the head, they will have to remove the absolute minimum amount of material otherwise the head might have to be replaced. Feel free to ask more questions too! Old damaged exhaust valve seats removed from the head. New valve seats installed. Head fully rebuilt with Ferrea components.
yeap, he's earned plenty of my money over the years and is pretty much the only reliable mechanic for my s2. aside from minor differences in styles of doing things, i really enjoy him and ryan's workmanship. i actually plan to go there once i get a replacement block together lol... if that doesn't pan out, joey at westborough arco and ariel salazar at wrentch can do the head too... though their backlog might be even bigger than rcrew's
I had some funky compression numbers just like yours and mine turned out to be the exhaust valve seats in the head. I pulled the head and took it to a local machine shop (they build a ton of V8s and are very knowledgeable about everything), and during their testing they found that the exhaust valves were leaking due to someone previously not keeping up with valve adjustments. Some of my exhaust valves were tighter than .005"! Apparently when the valves are this tight, the beat the crap out of the seats and eventually wear them out. If you're mechanically inclined, you can remove and reinstall the head, it isn't all that hard. I'd take the head to a reputable machine shop and have it checked out. The valve seats can be removed from the head and replaced. They will have to do a valve job during this repair. If your car has a lot of hard miles on it, you may also want to replace the valve springs at a minimum.
One other major important thing to know about he S2000 cylinder head, DO NOT have the head machined or "shaved." This will throw off your valve timing. If they need to flatten the head, they will have to remove the absolute minimum amount of material otherwise the head might have to be replaced. Feel free to ask more questions too! Old damaged exhaust valve seats removed from the head. New valve seats installed. Head fully rebuilt with Ferrea components.
when you sent your head to the machine shop, what was still on it? Valves and spring?
06-23-2021, 12:41 PM
Low compression and head work suggestion
