ohc 6 cly my rebuilt rebuild has 2to 3 cylinders not fireing properly. if my oil pressure is to high does it not over fill the lifters to the point that they do not cloapse as they should.could the 50 psi oil pressure be affecting the opperating of the lifters and valves.wts the proper oil pressure supost to be set at and running pressure set at. thnx any answers apprciated just tryin to keep it orignal.
The oil pressure in the gallery feeding the lash adjusters should be at 10-15 psi to operate correctly in the upper rpm range. That's why the restricter was installed in the head, to limit the oil pressure. Did yours survive the rebuild? At lower rpm (idle to 2500 rpm) the lash adjusters should still have time to bleed down even with 50 psi.
Are you getting 50 psi at idle when cold or hot? 1 bbl or 4 bbl? Have you checked to see if you have spark at each cylinder by pulling off the plug wires when running (insulated pliers)? Which cylinders aren't firing? Have you done a compression test? And what are you meaning when you say not firing properly; at all or intermittently?
the oil pressure is 50 at cold idle.we did a copm test and its 135 across all cylinders. then the mechanic and i did a running copmresion test and 2 cyl was 50 pounds 3 was 60 4 was 90. 1/5/6 cylinders were all within the range they should have been. as for wether the tube survived the rebuild i dont know.i was told that the exhaust vavles were burnt out when he got the motor back.now the engine burned a quart of oil on a 2 hr drive. when i pulled out #1 plug if u held it upside down it would drip 2 drops of oil. now the engine has all new valve guids new valves new rings and bearings so he has completely rebuilt his rebuilt.is the valve higthwrong since thats crustial to this engine
i just got my rebuilt rebuilt back and its got issues . ok i know i dont have any exhaust leaks and accetaline does not rev it up placed anywhere arounrd the intake or exhaust manies.when you first start it up it runs on all 6 clys ,then when the oil pressure builds up it starts to run rough like engine shaking rough.cylinders 2 and 3 have no affect when running and you pull the plug wire off theres no change in the runnng rough. i have 50 pounds oil pressure cold when it gets to bout 40 it starts to run rough. the mechanic says that the clearance is to close and when the oil pressure builds up in the lifter it hits its max and keeps the valve open . now the engine builder sayed he replaced all the valves becaused they were burnt out????.if thats the case was the valve lash or back lash on the lifters set incorectly. any answers on the topic would be appreciated on set up and oil pressures lash or any thing to run smooth thnx for any hlp
Quoted from the OHC forum
If the restrictor tube was replaced, it could still be causing issues if it doesn't seal the adjuster oil gallery properly and allows pressure to leak past and build up in the adjuster oil gallery, holding the valves open.
You can check the oil pressure in the adjuster gallery by removing one of the end plugs and installing a gauge.
ok latest is i have a spare 68 ohc, so i took the oil spring from it and installed it in my pump .started it up and ran smooth. tried to set it up and ran it at roughly2200hundred rpm and it started running rough again. now with the change of the oil spring tells me that the tube in the cylinder head is wrong. the machinist did not remove it so its stpck ,but through some research and web sites the prblems from the factory.1966-1967 all ohc had this issue the orfice that feeds the lifters is to large,therefore alowing to much oil in. so the machinist is gonna correct the prob. since he missed it the first time.now the burnt valves from last rebuild is caused from the same issue,the valves were being held open there fore burnig them out.i thank all 4 your support and hope this might hlp someone else in the future.wonder y pontiac discontinued this engine
It's not the engine's fault that mechanics rarely follow(ed) the necessary service procedures and caused premature failure, and owners failed to change the oil on the necessary maintenance schedules.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
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