Normal Compression Numbers for 2.0?

[73ess]

What are the typical/normal compression numbers for a healthy '74 2.0 liter motor? I'm looking at one with 85, 90, 80, 85 across 1, 2, 3 and 4 cylinders. Time for a rebuild?

[Dave at Pelican Parts]

Under 100 PSI is considered too low, generally. You have an 11% spread from lowest to highest, which is close to the edge of acceptable.

I'd say it's probably time for a top-end, at least.

Make sure the battery, starter, and so forth are all in good shape. Get the engine warm, pull all four plugs, then block the throttle open. Unplug the fuel injection (or the carb fuel pump) and test each cylinder with the same number of cranks. Note how quickly or slowly each one "pumps up". Most people go from 6 to 10 engine cycles.

If the results are still low, try a leakdown test. That will tell you what isn't sealing.

--DD

[73ess]

Thanks Dave. How much does a top end rebuild run on a 2.0 motor if I pull and install the heads, pistons and cylinders myself?

Steve

[Alfred1]

For a 2.0L, the Haynes manual says that 120 to 156 psi is normal compression pressure and 93 psi is the minimum permissible compression pressure. Maximum difference between cylinders is 21 psi.

[Bleyseng]

To rebuild the heads...weld up the cracks, new valves, new guides, deck, maybe $1000.

Pistons and Cylinders depend on the quality. Chinese 96mm are $300, 94 mm Euros $450 and 96mm good ones $550. Check out the one on Pelican.

[Scooter311]

Hey Bleyseng, what's your comp with the 2056? I just checked mine and I'm at 131 on all 4 - 2056 as well. I wonder if I'm too low?