Hi all, I'll try & keep this as breif as I can.
I have an XF panelvan 1989 & in FEB this year I rebuilt the engine ( bearings, rings, timing kit, cam, lifters, etc) I also had the block acid dipped and new cam bearings put in.
When I rebuilt it I put my old head on it knowing that it would be replaced when I located another good one. Since the day it was finished I had just a bit of tappet noise which never cleared (I was convinced it was a head prob).
About a month ago I aquired another head which I sent down to be reco'd, it came back the same day and I was told it was near perfect.
I ripped the old one off, stuck the new one on and found I had real BAD tappet noise from No.5 cyl. Closer inspection it turned out to be a knacked lifter and a cam with most of the lobe missing.
I replaced the cam and all lifters put the engine back together and fired it up, THIS IS WHERE THE STRESS BEGINS.
When the engine is on idle it runs rough like its not timed properly & under accelleration it backfires through the carbi and then somtimes through the exhaust.

I have replaced plugs & leads, dizzy, dizzy cap & rotor button & coil, still no different. I drove it down to the place I got the head done and left it with them for the day. When I picked it up they said it must be a ridding valve, so I removed the head & took it back down to them. They checked the valve hights and the rest of the head & found nothing wrong. They could only put it down to an electrical problem with the EST module or ignition system.

Sinse then I have been to an Auto Elec they looked at it and are convinced that it is a mecanical problem. BACK TO SQUARE ONE I GO.

The only thing I can think of that was changed when I replaced the head was the cam & lifters, so I have replaced all lifters and have found no change.

The main problem with solving this dilemma is every time I drive it the problem doesn't remain constant, one time it will backfire, cough and splutter and the next time it will chugg untill it reaches about 1800 rpm and it will clear and take off like a rocket.

Please can anyone think of anything I may have missed before I fix it with 4ltrs of petrol and a match.

Thanks
Squirt

i had a coil that did this, but you've already replaced it.
have you rebuilt the carby? would you think it's too small for it?

I HAVE SOLVED IT!!!!
Most of you won't believe me when I tell you that I have found 2 DIFFERENT HYDRAULIC LIFTERS for a X-flow.

When I rebuilt my engine I bought a re-ring kit consisting of Rings, Bearings, Cam, Lifters, timing Kit, Gaskets & Welsh Plugs. I noticed a small difference in the inside of the lifters (which I'll get to in a tick) but I put it down to different manufactures. Now when I got the other head I sent it to be overhauled, BUT I didn't know the history of the head or what had been done to it in the past. The only thing I can put it down to is that it has been machined so often that the hight of the valves has exceeded the distance the lifter can allow for.
When I went back to the place I bought the re-ring kit from (to get a lifter to replace the damaged one) even they were surprised to find there was a difference.(SCARY) Anyhow it now runs great.

THE DIFFERENCE
When the 2 different lifters are stood next to each other the body heights are the same, BUT, when you measure the depth from the top edge of the lifter to the position of the push rod, the new never before seen lifters are about 3mm deeper than the standard one.
Now I have spoken to 4 different parts shops (REPCO, BURSONS, etc) and they don't believe that there are 2 types untill I show them, & then they put it down to a defect or something.

SO NOW YOU KNOW

The place I bought the lifters from can't tell me why there is a difference but I can only quess that a company has thought of a way to extend the life of an over machined head

If anyone is interested the place I purchased the lifters from was
AUSSIE AUTO'S in BEENLEIGH QLD (between Brizzy & the Gold Coast)

Hope this has got people thinkin'
Squirt

Can you tell us what brand the different lifters are?
I rebuilt my 88 xf ute in June have been trying to solve valvetrain noise ever since. The ones I fitted were federal mogul sealed power. I think they were HT900.

Sorry I don' know the brand of lifters, But it has been brought to my attention that the problem was NEW lifters are stronger than OLD valve springs.
I got this tip from a bloke that drags cars profesionaly

Can't believe I never thought of it !!!!!