February 7, 20188 yr Author he simply means replace rings if youve gone this far anyway. bent valves. Pressure test the heads or fill exhaust/intake ports with something noncorrosive and watch the leaks. Bent valves doesn’t sound surprising given accident impact, broken belt covers, damaged camshaft sprocket, damaged water pump...and all of those being on the same side with bent valve symptoms. Jumped timing from impact? Yes, Understood what GD meant about the rings.. I was getting 80% exhaust port leak on leak down test on all cylinders. Thought for sure I was going to see valves had come in contact with pistons, but they hadn't. To get an accurate pressure test do I need to loosen the cam bolts to get all the pressure off of the valves?
February 7, 20188 yr Author he simply means replace rings if youve gone this far anyway. bent valves. Pressure test the heads or fill exhaust/intake ports with something noncorrosive and watch the leaks. Bent valves doesn’t sound surprising given accident impact, broken belt covers, damaged camshaft sprocket, damaged water pump...and all of those being on the same side with bent valve symptoms. Jumped timing from impact? Yes, but I have 80% exhaust port leak from leak down on all four cylinders.
February 7, 20188 yr Thought for sure I was going to see valves had come in contact with pistons, but they hadn't. That's assuming they always make marks when bent, which I don't think is always the case.
February 7, 20188 yr Yes, but I have 80% exhaust port leak from leak down on all four cylinders. you still haven't done a proper leakdown. You rotated the engine and opened valves. Me thinks you're chasing ghosts. If the belt didn't break or slip, there is no bent valves. Edited February 7, 20188 yr by Gloyale
February 7, 20188 yr +1 a few things we're still unsure of: correct timing marks used to verify timing across D/S, P/S, and crank (dot verses arrow on the crank and veify both sprockets). gauge/test accuracy? what leakage value did you get without rotating the engine? in some ways this is simple - if none of that matters to you and you're confident in the leak down tests indicating head failure then install another set of heads or rebuild the existing ones.
February 7, 20188 yr They might just be pitted and need to be lapped. Try to lap them - you'll find the bent one's in the lap pattern if there are any. GD
February 7, 20188 yr Author +1 a few things we're still unsure of: correct timing marks used to verify timing across D/S, P/S, and crank (dot verses arrow on the crank and veify both sprockets). gauge/test accuracy? what leakage value did you get without rotating the engine? in some ways this is simple - if none of that matters to you and you're confident in the leak down tests indicating head failure then install another set of heads or rebuild the existing ones. With timing belt installed.. Drivers side cam arrow at 12 o clock, front cylinder leak down test at 100 psi..Then drivers side cam arrow at 3 o clock, rear cylinder leak down test at 100psi. Then passenger side cam arrow at 6 o clock, front cylinder leak down test at 100 psi. Then passenger side cam at 9 o clock, rear leak down test at 100 psi. I was getting 80% leakage.through exhaust port of cylinder tested.. I've only done a couple other leak down test, on a different Subaru engines..For those tests I started on the drivers side front cylinder, leak down test at 100psi . Then rotated the engine from crank bolt with long 1/2 inch ratchet wrench until I was getting air resistance in the cylinder. Then keep rotating the engine with ratchet wrench until I got to tdc of compression stroke. Then compared difference of the leak down testers two gauges. So for example, with inlet gauge at 100 psi and the second gauge at 95% psi that cylinder would have a 5% leak.. Since I've only done a few leak down tests,. Based on the results of my current leak down test, I've got to be doing the test incorrectly.
February 7, 20188 yr Author They might just be pitted and need to be lapped. Try to lap them - you'll find the bent one's in the lap pattern if there are any. GD Yes Pulling the exhaust valves looks like the next step. Is there an accurate method to test how the valves are seating while still in the heads..I've seen it done with mineral spirits poured over the valve faces and checking what leak underneath the valves?
February 7, 20188 yr Check both the intake and the exhaust valves, they both can bend if timing jumps. The exhaust is more common but I've seen both. As G.D. said Lap the valves, no doubt about it when one is bent. Pulling the valve cover and checking lash will tell you how bad it is as well. When I get a subaru in that broke or jumped the T belt I simply order ALL new valves not just the "Bent"ones. No need to wonder at that point. Replace valve seals on all at the same time ,hand surface the heads, use new subaru head gaskets and put it back together, with new timing components. Good to go.
February 7, 20188 yr Take head into dark room,shine flash light into exhaust port, do you see light coming threw? Maybe sticky valves,oil them.
February 7, 20188 yr Author Check both the intake and the exhaust valves, they both can bend if timing jumps. The exhaust is more common but I've seen both. As G.D. said Lap the valves, no doubt about it when one is bent. Pulling the valve cover and checking lash will tell you how bad it is as well. When I get a subaru in that broke or jumped the T belt I simply order ALL new valves not just the "Bent"ones. No need to wonder at that point. Replace valve seals on all at the same time ,hand surface the heads, use new subaru head gaskets and put it back together, with new timing components. Good to go. How can the valves bend, if the never came in contact with pistons?
February 7, 20188 yr Did you do what GD said, put oil in cylinders and crank a bunch,this will oil the valves and rings?
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