The "Quick Question" Thread

[Ryan]

Ah, B6 DOHC, that will be a VICS or VRIS or whatever that model calls it, solenoid. The green you mention will be the nipple of the check valve.

If you want an explanation of how the VICS/VRIS system works, just let me know.

You can use any thick walled 1/8" ID hose to replace that hose, since its probably brittle and hard. Its cheap too, like $.80/ft.

You'll need to replace that green check valve as well, just look for a check valve designed for vacuum based systems, don't go to Mazda.

[johnmx3ze]

just did a compression test... :S

rear head is 180 all 3
front head is 160 all 3

is that ok or...?

[Ryan]

That is within service limit. Not the strongest motor, though.

standard:
KLZE -> 220ish
KLDE -> 210ish
K8 -> 190ish

Limit is ~ 150

Rule of thumb is maximum 30 difference between highest and lowest. The more even, the smoother that motor will run.

[johnmx3ze]

would a wrong timing belt placement at the front do that? cause its all the same at tge front and all the same at the back?

[Ryan]

Um, yeah, I could see that, but you'd notice it running funny.

Could also be a head gasket....

Have you tried a leakdown test?

Do a normal compression test, and then drop a tablespoon of oil down the cyl and do it again, see if it changes. If it goes up, its rings.

[johnmx3ze]

ok ill try that!

thx

[Daninski]

John did you do the test with the engine hot or cold? Secondly, did you do 1 3 and 5 first (180)?
There is a diff between a hot and cold test and even restarting the engine when going from rear to front would ensure a more accurate test. Ryan?

[Ryan]

yup, the main reason we let engines warm up before beating on them is for ensure the clearances are good (more bearing than piston/ring, but all the same)

If you managed to complete the test on all cyls within 10ish minutes on a hot motor, you should be fine.

[Daninski]

Those numbers are new engine numbers aren't they Ryan. What are realistic used engine numbers. I've seen on Ze's anything from 190 to 210/215 tops. DE's like 180. Am I wrong with these numbers. I just don't want John to be overly concerned even though his numbers a kinda low. I thought maybe he did the test on a warm/cold engine.

(Remove all the spark plugs, disconnect the disty 3 pin plug & disconnect both fuel rail connectors and the FP fuse. Do each cylinder test by cranking the motor over like 8 times with the throttle WIDE OPEN.)

John I just thought, are you sure the gauge on your tester is good. Have you calibrated it?

Ryan, I wasn't sure so I did a quick check on several other boards. 20 mins after shut down seems a reasonable time to wait before doing a CC. I wanted to double check so as not to give John a 'bum steer'.

[johnmx3ze]

the engine was cold... :S

yes dan i did 2-4-6 then reinstalled the plugs, then i did 1-3-5...

but my engine runs very strong, its a 97 DE from a probe...

what wondering is, why would 2-4-6 have the exact same numbers?

[Daninski]

If those numbers are from a cold engine then your probably going to see gains rechecking a warm engine. John, leave the plugs out and give your starter a break.

[Ryan]

Yeah, I pulled 10 mins out of my a--, shouldn't take you longer than that anyway. Of course it depends on the weather etc etc...

Operating temp (fan comes on), all plugs out all the time, disconnect disty and fuel rail connectors, WOT, and try doing them 1-2-3-4-5-6 and see. Leakdown the low ones.

180 is perfectly reasonable for a used motor. 160 is eh, but not bad. 120 is rebuild time. Mazda recommends rebuild at 143 on a K8.

[Daninski]

John redo the test will ya and do it properly this time you noob. Let us know the results oh and make sure the gauge is accurate. Maybe cross check it with the gauge on your compressor or something.

[Ryan]

Any progress yet John?

[dmac]

Does this actually work? http://www.gates.com/brochure.cfm?broch ... on_id=2742