oh no....bad guides? rings...both?

degreeoff1 · 05:22 PM

well just pulled leak down numbers and as explained here.....

cold cylinder leakdown numbers

I bought the same tester.

I was pulling readings of 13% with a couple @ 17 and 21....this was on a COLD engine...I know a no no but its all I had??

two of my cylinders had a 'strange' sound from the head area....squirted alittle oil down the chute(intake) and walla bubbles around my valve....what!!???

is this an easy fix (new guides I presume?) with a small home machine shop can I do this?

Now these were sold to me as 1000 mile heads with a port job. I have only put 1000 miles on them since. My car was smoking intermittently and always on accel.

so....what do I need to do at this point aside from tear her down?

cgarr · cgarr's Garage

Normally leak down will not indicate guide condition unless they are so bad that the seats are hammered out of round so the valve will not seat. pull the top valve covers and you may be able to move the valve if they are really bad, otherwise hold pressure on that cylinder and tap the valve with a hammer so it pops a few times and see if it seals, could also be crud under the valve seat.

degreeoff1 · 06-08-2009, 06:13 PM

I did the tap and it worked on #4....not on this one however....

Do you know if my leakdown #'s were within range?

afterburn 549 · 06-11-2009, 04:17 PM

If you are getting near 20% you will hear air coming out of the intake side or exhaust side or crank case side.
If you hear air and you are @ TDC you do not need a leak dwn tester to tell you there is a problem
"IF you are @ TDC.... Huston you have a problem.

On the flip...your 1st time with a leak dwn tester I would say inconclusive as in the novice hands they are prone to error

degreeoff1 · 06-11-2009, 05:27 PM

as I was tearing the engine down lookie what I find.....I have now learned you REALLY need to drill ot the oil spray bar plugs and C L E A N them out not just spray a can or two of carb cleaner through them...a $1000 + mistake on top of using crappy deeves ring in a nikasil bore. I should be happy it ran (my first 911 engiune) and pretty quick at that for the 15-20 hrs I ran it! I will be an adept builder after this time....