How do you check if an engine is original or has been rebuilt?

[tommiman]

How do you check if an engine is original or has been rebuilt?

 

[Eagle_Summit]

carfax

 

[robvas]

Take the head off, and measure the diameter of the piston bores. If they are larger than stock, chances are the engine has been rebuit.

 

[tommiman]

Is there a way by just looking at the engine or not taking too many parts off?

I got this car a few months ago. When I recently did a compression test it reads 178 - 190 for all the cylinders. A new engine would be 178. This car has 100K miles on it. Would it still have such an excellent compression after this much mileage?

 

[amp9211]

Isn't there a VIN number somewhere on the engine?

 

[90blackdsmturbo]

i thought brand new compression was 164?

 

[David15151]

i thought brand new compression was 164?

nope.. the 2nd gen motor runs higher compression.

IF you are seeing higher compression than stock it would probably mean it was rebuilt with higher compression parts. Engines cant increase compression over stock without changing internals.

 

[Defiant]

Look for orange, black or blue gasket sealer around the edge of the oil pan and other areas. Factory was a kind of light grey. Also, from the factory the sump has no gasket, just RTV.
Look for rounded or dented bolt heads on the engine mounts and other locations. When first built, they were flawless. Grease and dirt coatings should be pretty-much uniform, or if detailed, should look untouched.

 

[rebelman]

nice post, does carfax really tell you about engine overhauls? thats cool i need to run one

 

[Darksyne]

Engines cant increase compression over stock without changing internals.

I've seen compression increase due to carbon build-up.

 

[Defiant]

nice post, does carfax really tell you about engine overhauls? thats cool i need to run one

It should if a dealer did the work, and probably won't if not. And, maybe not from the dealer- kind of depends on the circumstances. Warranty stuff should show.

 

[trbotaln]

Engines can actually build up compression without doing internals by decking the block, and decking the cylinder heads. A lot of the time if a motor has been rebuilt and the main bearing to deck height was off then they deck the top of the bock to make it straight again. This method increases compression.