|
Title: Red motor freshing up Post by: hsv-001 on October 25, 2017, 12:02:55 PM My old FC van has had the same bored 173 in it since the 80's and I am thinking its time to pull it apart and have a look . I have replaced the rings and bearings once over the years as it had an extremely light flywheel and full XU1 cam . So removing these item[cam shaft was second hand] ,I thought it best to hone bores and replace rings ,and bearings just for good measure . Now years down the track I realize that the head didn't have hardened exhaust seats and although no real obvious symptoms have appeared I would like to take a look and remedy this . I do have a intermittent tappet rattle that seems to move up and down the rockers at idle and on two occasions have bent push rods while revving a little too much . I will get the head skimmed and hardened seats in . I am thinking of putting in a new close to stock cam ,lifters and push rods and maybe a new oil pump. What I am wondering is ,should I retain the double valve springs ? My thoughts are that the double valve springs help at high revs but have contributed to the wear on the cam lifters and maybe even the bent push rods and intermittent tappet rattle[ but this could be explained by the soft valve seats] .There is some maintenance to be done on suspension and steering but any ideas on this motor would be greatly appreciated . I am not looking for high speed anymore just a nice running little red that breaths properly [forgot to say it has x2 headers ,some headwork ,twin barrel and a 2 1/2 inch sports exhaust] and run economically with the 5 speed Borg Warner .
Title: Re: Red motor freshing up Post by: Errol62 on October 25, 2017, 12:44:15 PM You haven’t told us much about the valve train. The common setup has a spring and internal damper which is a lighter spring and shouldn’t impose much extra load on the valve train. If you plan to rev even with a stock cam you will have valve bounce without the dampers.
Cheers Clay Sent from my iPhone using Tapatalk Title: Re: Red motor freshing up Post by: hsv-001 on October 26, 2017, 12:33:45 PM Yeah , that what I meant by double valve springs . A bit of work done to the head over 30 years ago [double valve springs ,port and polish ] .A while back a mechanic friend rang me with an engine problem he couldn't diagnose . Continually changing valve lash and compression readings and it turned out to be damaged exhaust valve seats [not replaced with hardened seats when leaded fuel was phased out ] same as I suspect in the old van . Anyway I will know soon enough . Cheers Haydn
Title: Re: Red motor freshing up Post by: ardiesse on October 26, 2017, 05:57:09 PM Haydn,
You could always do the "kero-in-exhaust-port" trick, if the manifolds are off, to determine how well the valves are (or not) seating. Turn the motor over by hand, and as each cylinder begins the compression stroke, squirt a couple of teaspoons of kero into the exhaust ports. Leaking valves will make a nice bubbling sound. Or, if you have a spark plug adaptor to fit a compressor, put each cylinder at its firing instant with the car in top gear, and pressurise each cylinder in turn. You'll be able to hear leaking valves by listening to the exhaust or the air intake. Just a thought. Rob Title: Re: Red motor freshing up Post by: hsv-001 on October 27, 2017, 08:41:47 AM Thanks Rob, can do that when I start to pull it down . I was more concerned that the exhaust valves may have been slammed home into soft valve seat so many times that they maybe sticking a little . If that were so it could bend push rods and could it also bleed the lifter enough to alter valve clearance .Time will tell. Haydn
|