Compression numbers

These threads might help:

http://www.ferrarichat.com/forum/348-355-sponsored-bradan/164207-compression-test.html

http://www.ferrarichat.com/forum/348-355-sponsored-bradan/465036-best-way-disable-ignition-system-compression-test.html

 

should be 210 is across the board ish

 

haha on a brand new ringed motor..

Anything 160 or above.. And its really not the number..it the percent that the cly are difference then each other..

There are several ways to do it, so how ever they do it on the first one, that's how they need to do it though out the test.. You can get all the number within specs if you keep turning the motor over for a period of time.

He is my comp test and results.. 355 will be somewhat similar.. http://www.ferrarichat.com/forum/348-355-sponsored-bradan/459555-joshtownsends-1992-348-engine-out-service-maintenance-thread.html

 

See chart in this pdf. http://www.healey6.com/Technical/Nominal%20compression%20pressure.pdf Pressures should be close to each other but if you have a 355 with 160 psi it's either a bad test of a bad engine.

EDIT: FYI, on my 355 all cylinders were over 200 psi.

 

Also reference this link: F355 Compression tests - PistonHeads

 

Compression test should be done with engine warm, no oil, throttle wide open. If numbers are low or inconsistent a little oil can be added to cylinders. If results come out the same this would indicate a probably valve problem. If numbers get better with oil the problem is typically with rings.

 

If all are 150 at least they r consistent and makes me think the gauge is bad. But how bad. All we know they r consistent but would a good gauge show 200 or 175 consistently? Invest the $ and go get a good gauge either snap on or napa I would not use hb for this job. U r already on location

 

it is not the gauge. The motor has one or two bad cylinders. Likely valves.

 

The Harbor fright compression tool has NO shrader valve the connection that goes into the spark plug, it is upstream at the guage. This will give a lower reading 150-165 normal for a good motor
A proper compression guage will read 225
I have almost every make model design compression and leakdown tester and have compared them

Snap on leakdown 35% is not good at all, car needs valve guides at mimimum, Leakdown should be less then 10%

These are common numbers for a engine that needs guides and possibly new valves @ 30K miles


If they said it passed a compression leakdown 1500 miles ago I would says it BS, sorry

Would you have the last smog test results? I can see from that how healthy the motor is also

Hope this helps

Are you in LA? I can stop by if you are

 

I just saw you are in Texas

Average cost to do that fix on the car 7-10K negotiate a price accordingly Also please post the serial number so no one gets scammed if you pass on the car

 

Tim is RIGHT ON in his comments about the leak down tests. I just had a leakdown test on my car and they were all within 1-3%. 35 % is way off. Be careful.

 

$1,500 is very steep for a PPI

 

$1500 and not the proper tool??

 

I think he said trip and PPI (hopefully).

 

Hete is a close up off the snapon guage I marked off with blue tape 10% which is max. Unless he did not calibrate it properly
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PPI portion normally runs $350 to $550 with test. Thoughts on what others have paid?

I try to arrange PPI first remotely, and then fly out if all checks out. No real wrong answer though. Just what has worked for me.

A lot of good knowledge here.

Fingers crossed for you.

Robb

 

Get back on the plane and go home.. a $1500 ticket is a lot better then a $15000 mistake.. or more

 

I hope..

 

If the compression numbers are good at 160 and two cylinders much lower, at least 2 cylinders have some serious problems. But you need to also find out why the other 6 are at 160. That is too low for a correctly done test on a decent engine. Was the test done with the throttle plates closed? Was the gage off? As for the leak down, 35% is like a fist size hole in a bucket. You state maybe it was 3.5%. Well, that also seems unlikely as 3.5% would be a number that would be representative of a freshly built engine after the rings were seated.

In summary, either the guy doing the compression and leak down tests doesn't know what he is doing or the engine needs work.

What did the guy doing the PPI say?

 

Even a bad 355 sounds good. They will even fool owners until they get a taste of a really good 355. That motor does not run strong at all if those numbers are right.