Single Cylinder Misfire - intake valve spring
Thread Starter
Member
Joined: 08-10-2016
Posts: 61
From: PA
Is there something like the seafoam spray that cleans up the intake valves could do the cleaning for exhaust valve?
If I have to go with a rebuilt header, I guess I am not good at diy for the replacement. What is the rough estimation of the labor hours/cost if the garage does it?
If I have to go with a rebuilt header, I guess I am not good at diy for the replacement. What is the rough estimation of the labor hours/cost if the garage does it?
Thread Starter
Member
Joined: 08-10-2016
Posts: 61
From: PA
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Joined: 05-01-2014
Posts: 8,512
From: California
Yeah, it was much lower on #3. Adding engine oil brought the compression from 120 to 150-170 psi while other 3 cylinders showed 210 psi. The leakdown testing I did was more about figuring out where the leakage was instead of which cylinder had the leakage. The percentage gauge is not that much useful to my case since I am pretty sure the #3 has an issue.
I just don't want you to spend money on a new head, without being sure. And your engine is VVT. Variable Valve Timing.
See, I've got 4-5% leakage in #4, cylinder wall and/or rings. Adding oil only brought my compression up by about 5%. When you added oil, you gained about 20%. I also had leakage past gunked up intake valves, so there were other factors at play in my engine.
This is a very important diagnostic, make sure it's done right.
You may want to price shop for a new or used engine, you may need it, it may be the same cost as a new head.
Thread Starter
Member
Joined: 08-10-2016
Posts: 61
From: PA
This is what has me concerned, the oil helped quite a bit. That means the cylinder wall and/or rings are worn. I'm still not sure you were at true TDC, so I'm not sure there is a valve problem. #3 is at true TDC 1/2 crank rotation after #1 is at true TDC. True TDC is not just when the piston is at the top of it's stroke, but at the top of it's compression stroke, right before it starts the power stroke.
I just don't want you to spend money on a new head, without being sure. And your engine is VVT. Variable Valve Timing.
See, I've got 4-5% leakage in #4, cylinder wall and/or rings. Adding oil only brought my compression up by about 5%. When you added oil, you gained about 20%. I also had leakage past gunked up intake valves, so there were other factors at play in my engine.
This is a very important diagnostic, make sure it's done right.
You may want to price shop for a new or used engine, you may need it, it may be the same cost as a new head.
I just don't want you to spend money on a new head, without being sure. And your engine is VVT. Variable Valve Timing.
See, I've got 4-5% leakage in #4, cylinder wall and/or rings. Adding oil only brought my compression up by about 5%. When you added oil, you gained about 20%. I also had leakage past gunked up intake valves, so there were other factors at play in my engine.
This is a very important diagnostic, make sure it's done right.
You may want to price shop for a new or used engine, you may need it, it may be the same cost as a new head.
Thank you so much, RJ_RS_SS_350. I will rerun the compression test and leakdown test again today. I will rotate the crankshaft pulley based on #1 being at TDC since I know #1 is in good shape.
Platinum Member
Joined: 12-06-2009
Posts: 11,721
From: Alabama
Back in my mechanic days (80's-90's) I have run numerous leakdown tests.
I would always pull the valve cover(s) so I was sure the valves were closed on the cylinder I was testing.
I would think the same principle should apply when doing a leakdown on the HHR engine.
I would always pull the valve cover(s) so I was sure the valves were closed on the cylinder I was testing.
I would think the same principle should apply when doing a leakdown on the HHR engine.
Thread Starter
Member
Joined: 08-10-2016
Posts: 61
From: PA
Back in my mechanic days (80's-90's) I have run numerous leakdown tests.
I would always pull the valve cover(s) so I was sure the valves were closed on the cylinder I was testing.
I would think the same principle should apply when doing a leakdown on the HHR engine.
I would always pull the valve cover(s) so I was sure the valves were closed on the cylinder I was testing.
I would think the same principle should apply when doing a leakdown on the HHR engine.
Senior Member
Joined: 08-03-2010
Posts: 3,564
From: Lake Ronkonkoma, N.Y.
You should hold the engine from rotating too when you charge the cylinder with air when at TDC.
Knowing that 1&4 and 2&3 are companion cylinders you could mark the crank pulley and front cover with paint when say #1 is at TDC. Rotate the engine 360* and now your on #4 TDC. The same can be done for #2&3.
