whats wrong with my Xr
- DPDISXR4Ti
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Definitely do a compression test before pulling the head, but here's what is probably going on...
You've got a valve guide and/or seal which has failed, letting a bunch of cold (relatively) oil onto the back of the hot valve. That's why your first valve failed, and your replacement will likely do the same unless you fix the problem.
Always remember, parts don't fail for no reason. Look beyond the symptom of the failed part and fix the root cause problem, rather than just replacing the symptomatic part failure.
You've got a valve guide and/or seal which has failed, letting a bunch of cold (relatively) oil onto the back of the hot valve. That's why your first valve failed, and your replacement will likely do the same unless you fix the problem.
Always remember, parts don't fail for no reason. Look beyond the symptom of the failed part and fix the root cause problem, rather than just replacing the symptomatic part failure.
Brad
- NC89merkur
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vac.
was speaking in terms of the quality of the valve seat. seeing if it would hold vac would be something youd do to test the seat with the head off the engine.
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- Newbie
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So just a quick update on my Xr.....
Got head back out of the shop. Head was milled, 2 burnt exhaust seats replaced, New Valve Seals, and cam bearings..... Installed, timing set dead on, smokes like a train still...... Ran great, then fouled out and misses... Oil on spark plug in cylinder 3.... What else could be wrong with my car?
Only thing i can think of would be piston rings.
My question is.... is it easier to do pulling the motor?
Or just dropping center brace and oil pan?
Did a comprerssion test and i did not have any leak down.... My theory is one of the 3 rings is broke, thus on a downstroke picking up oil and dumping into the combustion chamber on the upstroke.
Thoughts? Ideas?
Got head back out of the shop. Head was milled, 2 burnt exhaust seats replaced, New Valve Seals, and cam bearings..... Installed, timing set dead on, smokes like a train still...... Ran great, then fouled out and misses... Oil on spark plug in cylinder 3.... What else could be wrong with my car?
Only thing i can think of would be piston rings.
My question is.... is it easier to do pulling the motor?
Or just dropping center brace and oil pan?
Did a comprerssion test and i did not have any leak down.... My theory is one of the 3 rings is broke, thus on a downstroke picking up oil and dumping into the combustion chamber on the upstroke.
Thoughts? Ideas?
88 Xr4ti In the process of being built.
Steven
Steven
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- 86XR4Ti5SPD
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You might try this question over at Merkur Sport too, just to get another range of opinion.
Ed, Nashville
98 SVT Cobra, 1-owner 33K-mile convertible bought 8/15
86 5-spd, Solid Roof, sold 9/15 with 62K miles
03 SVTF #1965 of 3985, sold 9/15 with 68K miles
http://www.86xr4ti5spd.homestead.com
98 SVT Cobra, 1-owner 33K-mile convertible bought 8/15
86 5-spd, Solid Roof, sold 9/15 with 62K miles
03 SVTF #1965 of 3985, sold 9/15 with 68K miles
http://www.86xr4ti5spd.homestead.com
Did you change the oil after the head rebuild? does the oil smell of contamination from gasoline? this can cause smoking if not checked, also merkur dipsticks are not the most accurate, if you do drain the oil put no more than 5 quarts in.scubba.steve wrote:So just a quick update on my Xr.....
Got head back out of the shop. Head was milled, 2 burnt exhaust seats replaced, New Valve Seals, and cam bearings..... Installed, timing set dead on, smokes like a train still...... Ran great, then fouled out and misses... Oil on spark plug in cylinder 3.... What else could be wrong with my car?
Only thing i can think of would be piston rings.
My question is.... is it easier to do pulling the motor?
Or just dropping center brace and oil pan?
Did a comprerssion test and i did not have any leak down.... My theory is one of the 3 rings is broke, thus on a downstroke picking up oil and dumping into the combustion chamber on the upstroke.
Thoughts? Ideas?
Russ
Stable is vacant..
Stable is vacant..
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No, i did not change the oil, i was waiting to see if the headwork fixed the issue b4 dumping new oil in it, and ruining it.
Im just going to pull the motor and do new rings, and rod bearings....
Its only leaking in cylinder 3, and compression is very nice all the way across..... i just didnt know if i was easier doing this pulling the motor... or dropping the oil pan and cross member
Im just going to pull the motor and do new rings, and rod bearings....
Its only leaking in cylinder 3, and compression is very nice all the way across..... i just didnt know if i was easier doing this pulling the motor... or dropping the oil pan and cross member
88 Xr4ti In the process of being built.
Steven
Steven