Bad Tappit RRC 1991 @ 188900 miles.

[SafariDave]

my engine started making a tapping sound about 3 weeks ago. LR mechanic checked the bearings, connector rod and crankshaft main bearings, he said they all look good that it's probably a bad tappit. He said it can still be driven like that for a while before replacing. Can I fix it myself?

[ArmyRover]

you can if you want it's just replacing a lifter.

I would check to make sure you don't have any exhaust leaks though as they are common and 90% of the time diagnosed as a bad lifter.

[TerryS]

As Army says, manifold gasket leaks will sound alot like a lifter, the bolts have a nasty habit of loosening over time. Give them all a crank with the socket wrench.
If, however, it is a lifter/cam noise, which is extremely common on high milage engines due to the lousy heat treat practice used on the cams, simply putting in new lifters is a waste of money without changing the cam. You will be shocked to see how worn the lobes are. Variations from best to worst of more than .100-.125" is not at all uncommon. Since pulling the intake (after all the garbage on top of it) is 2/3 the work of the whole job, go the extra distance, and pull the front cover. I strongly recommend changing the chain and sprockets also.

[SafariDave]

Thanks guys!
How expensive can this be & how much work is it?

[TerryS]

Originally Posted by SafariDave

Thanks guys!
How expensive can this be & how much work is it?

That depends entirely on whether you do it yourself or pay your mechanic to do it. It's only a days work, and parts will run about $500. Chances are you won't need to replace the cam bearings though theres good argument for doing so with a new cam. They don't usually wear out, but be carefull taking the old cam out and puting the new one in as Cam bearing babbitt is very soft compared to mains and rod bearings. Puting new cam bearings in requires a special tool, so if you decide you need to replace them, best let the mechanic do the whole job.

[SafariDave]

Thanks! How long can I drive with this issue before repair?

[ArmyRover]

till it breaks lol


I really have no idea.

[Green Rover]

My 92 Rover has same lifter noise in the left bank.

To be more certain of the source, buy a mechanics stethascope and (carefully/safefully) listen to different areas of the engine while it is running. If it is a lifter(s) you should be able to distinctly hear the clicking noise and pinpoint where it is coming from.

I agree with Terry S; when you go to the trouble of replacing the lifters, replace all of them and the cam.

[Series 3 guy]

My 3.9 has a lifter noise on the left bank as well and didnt think of an exhaust leak!!! I learned something new today guy's!! Thanks.

[TerryS]

To locate an exhaust leak, you can do what I do (the cheap Scotsman that I am) Take a 30" piece of half inch hose, old garden hose, whatever. Stick one end in your ear, and take the other end and move it all around each exhaust port. If and when you find the leaker, you'll know it. As an added bonus, you'll impress all your friends how clever you are.

[TerryS]

Originally Posted by SafariDave

Thanks! How long can I drive with this issue before repair?

An excessively worn cam will cause the engine to start 'coughing' back through the intake, which can, and often does, take out the air flow sensor.

The closer to the head, the more likely an exhaust leak can lead to a burned exhaust valve. (ever see how much hotter an oxy-acetylene torch gets when you turn up the oxygen?)

[SafariDave]

Thanks guys! I want to check it, but It only does the noise when it's idileing, if I put it in park, many times it stops making the tapping noise. I have to wait till it really warms up. (driving it for at least an hour) hopefully it will tapp when I put it in park.
I will get on and check for all these things and find out what area the tapping is coming from. It's hard to work around it when it's that hot.
Thanks again and I will post what happens.
Dave

[MysteryTheatre]

if it Does turn out to be a lifter, there are a few things that can quiet the noise a bit and prolong the inevitable if you want to try to drive it a while longer.Lucas oil stabilizer, in a heavy dose ,seems to quiet lifters substantially . i won't even get started on the right oil thing again... but the filter plays an important role in delivering adequate pressure to the top end. i think most filters will work but i know the fram filters are crap, and i got way less oil pressure with them, and significant dry starts and lifter noise, this was solved by simply switching to a new filter. wix or champion (ac delco or super tech) from my research have the best valve work designs in the filter to provide the best oil pressure to the top end. i hope its only an exhaust leak but if its a tappet maybe you can drive it another year or two who knows. they've taken the zddp out of almost all the oil and since then getting the right oil for flat cams is difficult. its true the zddp shortens catylytic converters and O2 sensors life, but it does provide lubrication that many consider essential for flat cams ,
in the final stages here i would give it a good high viscosity oil with a good filter and a heavy dose of lucas oil stabilizer and a treatment of zddp.

[SafariDave]

Thanks Mystery, my LR mechanic only uses LR parts on Rovers so I don't think it's the filter. I will try the Lucas oil stabilizer this week and see if it helps. Should I try the regular or heavy duty oil stabilizer?
Thanks Dave

[SafariDave]

So, I went to Strauss bought a qt of Lucas heavy Duty Oil Stabilizer $12.00. Went to the mechanic we took out 1 qt of oil (20/50) and added the Lucas heavy duty Oil Stabilizer. I drove it home with no more tapping sound even the driving felt smoother. I hope it stays that way. I was also told that the Transmission Fluid from Lucas is amazing. I will try it soon also, if this stuff keeps my tappits under control.