No compression after changing head gasket?

Tiny
CLEESOUTHWICK
  • MEMBER
  • 1989 MAZDA B2200
  • 2.2L
  • 4 CYL
  • 2WD
  • MANUAL
  • 185,000 MILES
Recently replace the head gasket on my truck. Now it will not start. It has 25 PSI compression after doing compression check.
Turns over just fine. Has hydraulic lifters so no valve adjustment is necessary. Getting fuel and also has spark.
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Tuesday, January 3rd, 2023 AT 2:36 PM

15 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,005 POSTS
Hi,

Is the 25 PSI compression on all cylinders? Are you sure the timing belt/engine timing was installed correctly? If it is out of time, this will happen.

If possible, record it cranking and upload it for me to hear. Also, if the compression is 25 PSI, it won't run.

I attached some important information for the installation of the timing belt. Take a look through them and let me know if this is how you did the repair.

Let me know,

Joe

See pics below.
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Tuesday, January 3rd, 2023 AT 8:50 PM
Tiny
CLEESOUTHWICK
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Yes, 25 PSI on all 4 cylinders. And yes, we did the timing like the pictures say. We followed a Haynes manual for that truck for the specs. I am not anything but a driveway mechanic. It's my son's truck and he overheated it. We could have the timing off. We set it to TDC on 1 with both intake and exhaust Valves all the way "up" so they should have both been open. It's possible we got that wrong.
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Tuesday, January 3rd, 2023 AT 9:20 PM
Tiny
CLEESOUTHWICK
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At first, I thought when he took off the distributor it was off 180. But I checked it, and it was fine. I also have not done a leak down test to see where we are losing compression.
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Tuesday, January 3rd, 2023 AT 9:22 PM
Tiny
JACOBANDNICKOLAS
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Hi,

When you set to the dead center (TDC), both valves on cylinder one should be the furthest away from being open. Both should be closed. If you have them open, that is the problem.

Also, there is no need for a leak-down test. If they are all at 25 psi, it isn't a leak from a valve leaking, worn rings, or a head gasket. The timing is off.

Let me know if that is what you meant.

Take care,

Joe
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Wednesday, January 4th, 2023 AT 6:50 PM
Tiny
CLEESOUTHWICK
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At TDC the rocker arms on #1 cylinder were all the way up. If I understood correctly that means the valves are open?
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Wednesday, January 4th, 2023 AT 7:06 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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I'm not sure why someone would tell you that. The valves need to be closed when the cylinder is at TDC.

When timing the engine, there are marks on the crankshaft and camshaft that need to align. Take a look at the attached two pics. Pic 1 shows the camshaft and pic 2 shows the crankshaft marks. Check to see if they are aligned. If they are, the timing is correct. If they aren't, that is the likely issue.

Also, look at pic 3 below and let me know which side was all the way up.

Let me know what you find.

Joe

See pics below.
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Wednesday, January 4th, 2023 AT 8:51 PM
Tiny
CLEESOUTHWICK
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Yes, the timing marks are lined up. On Pic 3 the rocker arm is all the way up. On both the intake and exhaust.
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Wednesday, January 4th, 2023 AT 8:53 PM
Tiny
JACOBANDNICKOLAS
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Hi,

If the side that has an arrow on it is all the way up, the valves should be closed, which is what we want. However, if you are one or two teeth off with the timing, they can be in that position but open too early causing low compression.

Unless the head is leaking equally at each cylinder, the compression rings are totally faulty, we have an evenly warped head, or the valves in each cylinder are equally stuck open, timing is the only other thing that makes sense. The aforementioned possibilities are nearly impossible to happen.

Did you remove the timing belt cover to check the timing marks? Can you take a few pics of the timing marks, rocker arms, and valves so I can see what you are dealing with?

Let me know.

Joe
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Wednesday, January 4th, 2023 AT 9:49 PM
Tiny
CLEESOUTHWICK
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  • 9 POSTS
My son overheated it, ruined the head gasket. We had the head machined and clean/tested they said the Valves seat ok. I'm at work so I'll have to get pictures later tonight. We very possibly could be off a tooth or two on the timing. I am hoping he did not ruin the rings.
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Thursday, January 5th, 2023 AT 8:46 AM
Tiny
CLEESOUTHWICK
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Yes, I did remove the timing cover, the arrows do line up, as well as the mark on the crank. This is the only picture I have taken so far and saved.
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Thursday, January 5th, 2023 AT 8:48 AM
Tiny
JACOBANDNICKOLAS
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Hi,

Thanks for the update. It's hard for me to tell from that picture. Can you tell me what the white line on the belt is for? Also, the belt doesn't appear to be running true on the cam pulley. Looking at a picture, I can't be 100% sure about that, so let me know.

Joe
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Thursday, January 5th, 2023 AT 2:07 PM
Tiny
CLEESOUTHWICK
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The white line is where I had my son make his marks for putting the timing back where it belonged before he took everything apart.
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Thursday, January 5th, 2023 AT 2:09 PM
Tiny
JACOBANDNICKOLAS
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Hi,

Okay, I had a feeling it was something like that. Try to get pics of the marks when they are aligned. I've been wrong before and will be again, but I really feel we are slightly off on the timing.

Take care,

Joe
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Thursday, January 5th, 2023 AT 2:34 PM
Tiny
CLEESOUTHWICK
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Update, the timing is off the timing on the crank is off of TDC 1 mark forward. We moved the belt a tooth back and it moves it off 1 mark backwards. The timing belt tensioner pulls is also missing (must have broken) so I believe that the missing spring is not allowing for correct timing.
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Monday, January 9th, 2023 AT 10:07 AM
Tiny
JACOBANDNICKOLAS
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Hi,

Thanks for the update. The timing was my first suspect. I attached the directions for the installation of the timing belt above. Take a look through them and let me know if it helps.

Take care,

Joe
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Monday, January 9th, 2023 AT 2:14 PM

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