Sr20det low compression what's next?

[Loomis112]

I recently did a compression test (dry) and had like 110 on cylinders 1-3 and like 95 on cylinder 4.

I'm not sure on what to do next I've never rebuild an engine and don't have the time or space to do it.

Should I even drive on it? It still runs fine it just feels like it has a lack of power..

Another question I have is it cheaper to just swap in a new sr20 or do an oem rebuild?

Also I found a full ka24e swap with everything included with 144k on it for $200 should I go that route I'm not sure what to do

[5280VertDET]

I would stop driving it and get a rebuild.

Another SR might be cheaper, but finding a good SR is tricky especially just a long block. (Trust me I just tried)

Don't buy the KA24e.

Hopefully the motor can be rebuilt for around $1000 and $1500 if there is no damage.

Good luck.

[Kingtal0n]

First figure out why the compression is low.

When you assume that it needs a rebuild, and it probably does, what you are really saying is you think the rings are done, and one cylinder possibly has a piece missing, physical damage somewhere, or something wrong with the head perhaps. Do a compression test with oil in the cylinder to get some data from the engine that might reveal tired rings.

[angel mkiv]

If you can't do it then I would recommend getting quotes from local rebuild shops or performance shops to see what they charge for a rebuild..then look at what sr20 long blocks or swaps are going for used in your area..then pick the cheaper option.

[Kingtal0n]

One engine, an RB25, had low compression like that. It had been sitting for years, who knows how long.
Compression was low on all 6, and the last cylinder was even lower. Looked like a bad/blown engine from this point of view.

however, we put some oil in the cylinders and noticed that compression did NOT get better. It only picked up 2-3psi each cylinder.

So we took the head off. If its not the rings... must be in the head right? Took the head off, and cleaned it up real nice. De-carbon'd all the valves using a solvent.

Put it back together and compression was back to normal, all fixed.

And more recently, we had 2jz engine with low compression on the last cylinder. I thought for sure the ring was roast, just by popular demand.
Ran the engine anyways for 2000~ miles and re-checked that cylinder... problem was gone. Must have been a sticking valve!

Moral of the story is, compression test is valuable diagnostically but does not tell the whole story, 100% of the time.

[Crazyced]

That's where the leakdown test kicks in.

[MurderedS13]

any luck on the rebuild?? what did you end up doing? having the same issue. 110 comp cylinders #3-4 and cylinder one is at 100. started to unplug harness, piping, removed intercooler and radiator, removed turbo, and everything else to remove engine. but not sure if i should open up the motor or not. i should add that the car i bought was sitting for a good while and had old fuel. the timing was super advanced, plugs were all gunked up and fuel filter wreaked. when i went to Vato Zone (auto zone) with a buddy of mine he lent me the borescope and it SEEMED like cylinder 1 was melted and it seemed dinged up as if it was detonating. im really tight on money so im trying to see what you all would recommend or if anyone here has ran into the same issue. any help or advice would greatly be appreciated.