|06-30-2012 01:19 PM|
What kind of rings are you running and what were the gaps set at ? Im just a little interested, are you running forged or cast pistons, what was the piston to cylinder wall clearance at their tightest points If you have no knowledge of this forget I asked! I was interested because 10 years ago it was bored honed and piston clearance was checked and ring gap set for 30 over and the type of rings and pistons installed! and now its been re honed besides 10 years of ware so those cylinders have been opened a little more! there's a formula for setting ring gaps for every inch of bore and different pistons & rings. For instance the Hastings rings I installed last: set at .0045" top ring for every inch of bore, second ring .005" for every inch of bore.
You cant pick up a repair manual and look up ring gaps and set them to those settings once you have strayed away from factory blue prints! If your bores are a little wore from being true (say .002") in some areas, cast rings are more forgiving in bores with a little ware then steal molly, and others! So I was Just a little interested in what you did during your freshening or who did it for you? Did you use .030 over file gap rings say .005 or .010 to make up for the ware and hone or just install .030 over rings?
|06-30-2012 05:39 AM|
|CNC BLOCKS NE||
Blocks that have sleeves the cylinders next to the sleeves will not be round more so once the heads are torqued on.
Plate honing is a must for good ring seal.
Here is a link on plate honing.
Values Of Torque Plate Honing - Team Camaro Tech
|06-29-2012 04:17 PM|
your not suppost to put anything on the rubber seals that go in the front or back they will blow out everytime.
i throw them in the garbage where they belong and use a thick and i mean thick bead of silicon and torque it down a.s.a.p! never had an issue and ive done it at least 50 times.
the 2 times i tried the seals leaked both times!
if you think there is a serious rise in pressure put a cheap gauge on a vac port and see if its excessive
|06-28-2012 08:07 PM|
Warm engine is better especially with forged pistons! rings and pistons expand as they warm up increasing ring tension and decreasing piston to cylinder clearance and ring gaps decrease! but cold is ok if you have burn issues If you dry test and compressions down and you add oil to the cylinder (wet check) and compression comes up you have bad rings if compression stays the same wet or dry you have bad valves or seats! A leak-down test is how long the cylinder holds compression pressures and only tells you it leaks it doesn't pin point where it could be, head gasket ,rings, valves or seats, a crack etc, etc,
|06-27-2012 09:44 PM|
|Michael 9111||I'll try to get the wet test done tomorrow and I'll let y'all know how it goes. Thanks for all the advice and pointers. Learning something new everyday.|
|06-27-2012 09:39 PM|
|68NovaSS||The ring tension is what it is, so probably not a big deal. Besides cylinder pressure you're looking for variation between cylinders, the wet/dry is to see if there's any difference. That will point you to rings or valves depending on the values you see or changes after the wet test.|
|06-27-2012 08:46 PM|
|Michael 9111||This may be a dumb question but from researching does the motor need to b warm to perform a compressiontest???I've only done the compression test when my motor hasn't been running all day. I have custom exhaust bc I have this motor in a mustang and there's no way of running a compression test on my motor while hot unless I burn my wrists to blisters????FORD TOUGH WITH CHEVY STUFF|
|06-27-2012 08:38 PM|
The wet test is squirting a couple shots of oil into the cylinder and take the test. I give a test 5 compression strokes, or until the needle stops climbing.
The throttle has to be at WOT for an accurate compression test.
|06-27-2012 08:06 PM|
|Michael 9111||And the motor only has little blow by at idle none after I rev it up. And when I plug my PVC valve back in and leave my other hole in valve cover opened the PVC sucks it all up and I don't see any then. So I'm thinking if it's got enough blow by to push a gasket out then it should b pouring out the breather hole|
|06-27-2012 08:03 PM|
|Michael 9111||I've done the compression test both ways throttle opened and closed and came up with the same numbers. How do u do a wet compression test?? Never done that b4. But one of my buds just brought me a leak down tester. Should I do the leak down or wet test?? Which is better|
|06-27-2012 06:32 PM|
|68NovaSS||You're doing the compression test with the throttle blocked open, right? Just had to ask, it's about the only thing that hasn't been mentioned.|
|06-27-2012 04:06 PM|
120 to 145 is a big differance on a freshened eng a 20 percent difference isn't except able take a wet compression check and see if pressures increase and level out, my guess is your rings are shot. And the blow by is pushing your gasket out!
|06-27-2012 02:53 PM|
The Right Stuff
The best trick i have for sealing the front and rear of the intake manifold is to use a spring loaded punch and punch about 100 or so holes throughout the length of the front and rear walls then use the Right Stuff (1/4" bead) and that seems to seal up the best and prevents blowouts. Good luck that is a weird issue.
|06-27-2012 01:00 PM|
|Michael 9111||I used permatex the last time and let it set for a day and a half. But I'm going to pull it apart again and see what happens. Yes I have bolts with washers. Wish me luck.|
|06-27-2012 12:46 PM|
Clean everything again and set the intake manifold in place with no gasket. Check the gap in the front and back. The gap should be smaller than the thickness of the gaskets. Like I said I tried glue with the rubber gaskets and they would always slip back out. I would throw them away and use Permatex. Are you torquing the bolts in sequence? Do the bolts have flat washers installed with them? Also after warm up re-torque bolts again.
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