74 280 Z Engine Problem

[calliebrat]

Hello this is Stacey. Almost 3 months ago we replaced the engine in my 280 and the car ran great. Recently the car has been running rough. The compression check ran a little over 160 in all cylinders and the plugs appear to be burning about the same.

Now the compression is 120 in No. 1 cylinder and I need to find out why.

Any advise would help. Thanks, Stacey

Stacey Pike

El Cajon, CA.

'74 260 Z Coupe- 280 Block, 260 Heads, 240 Dual SU Carbs

'75 280 Z Coupe- L28 Engine

Drive Fast- Take Chances!

[MarkOS]

Sounds like it could very well be a blown head gasket.

I had my head gasket blow next to the #6 cylinder through the water jacket and had rough idle + going through a LOT of coolant (i could pour it slowly into the radiator while running the engine and it would never overflow!).

[beandip]

Hello this is Stacey. Almost 3 months ago we replaced the engine in my 280 and the car ran great. Recently the car has been running rough. The compression check ran a little over 160 in all cylinders and the plugs appear to be burning about the same.

Now the compression is 120 in No. 1 cylinder and I need to find out why.

Any advise would help. Thanks, Stacey

Stacey Pike

El Cajon, CA.

'74 260 Z Coupe- 280 Block, 260 Heads, 240 Dual SU Carbs

'75 280 Z Coupe- L28 Engine

Drive Fast- Take Chances!

I presume that you have checked the oil for coolent and the coolent for oil. Have you pulled the valve cover and checked the rocker arm and lash pad on # 1 ? If you have done these things , is the engine smoking more than usual? I am thinking head gasket, water and oil question, valve train or burned valve or something holding a valve from sealing. Did the rough idle happen all of a sudden or has it been slowly coming on ? If the engine is smoking it could be a burned piston , or a broken ring. In any event , it looks like the head will need to come off.

[calliebrat]

Hey guys thanx for getting back to me so fast. No we haven't pulled the head.

Oil & water appear to be clean. This was a used engine that we had no info on when we had to put it into the car. When idleing we put a dollar bill over the tail pipe- it sucks back in at regular intervals & the bill gets wet.

If the head is cracked what is the success of having it repaired?

Stacey

Stacey Pike

El Cajon, CA

74 260 Z 280 Block, 260 Heads, 240 Dual SU Carbs.

75 280 Z L28 Engine

Drive Fast- Take Chances!

[beandip]

Hey guys thanx for getting back to me so fast. No we haven't pulled the head.

Oil & water appear to be clean. This was a used engine that we had no info on when we had to put it into the car. When idleing we put a dollar bill over the tail pipe- it sucks back in at regular intervals & the bill gets wet.

If the head is cracked what is the success of having it repaired?

Stacey

Stacey Pike

El Cajon, CA

74 260 Z 280 Block, 260 Heads, 240 Dual SU Carbs.

75 280 Z L28 Engine

Drive Fast- Take Chances!

I would send a PM directly to phred . He works on heads daily . Pose the question to him and since he does these repairs , he is the guy. Gary