Ford DOHC Tappets

[cameronfurnival]

Im posting this on the Cabrio/HUnter thread as there are more DOHCs here than elsewhere.
After starting my engine (it was lying in a garage for about ten years) - I spun it over to get oil pressure first etc - I find that one of the tappets is very rattly. It did quieten down momentarily but is now back to its rattly old self. Has anyone experience of freeing them off or can suggest a remedy? My thoughts at the moment are to strip the top, soak the tappets in parafin/degreaser, resoak them in clean oil and refit them... and replace the timing chain tensioner at the same time. Am I barking up the wrong tree???DSCF0612.jpg

[chris_cussen]

Re: Ford DOHC Tappets

Hi Cameron.
I rebuilt my DOHC engine during the summer, including having the valve guides refurbished and a light skim. When I put the engine together and fired it up it sounded like a cement mixer full of bolts.

I took my car to a friendly mechanic who I use occasionally and he recommend some Wynns tappet additive. So I nipped next door to a motor factors, bought a bottle (about £6 if I remember rightly) poured it in, and fired up. Within seconds the tappets became a lot quieter, and in a couple of minutes it was running as sweet as you like. I've done about 2kmiles since, and it still seems OK.

I'd keep away from taking the head off or taking off the cam shafts. Its not easy to re-assemble and get the timing right, and the timing tensioner costs about £50, and if you accidentally un-latch it you have to buy another, as I found out to my cost. The Haynes manual isn't much help and there is a website devoted to the Granada which has more info on re-building the engine (I can't remember where it site is, as its not in my bookmarks at work),this info is from the Ford manual but even that isn't too helpful.

Chris

[cameronfurnival]

Re: Ford DOHC Tappets

wow £50 for a tensioner! will get some of that tappet additive though - many thanks Chris..

[cameronfurnival]

Re: Ford DOHC Tappets

just to follow this up - I added about 1/4 litre of atf fluid to the oil and ran it up to temp. the tapping stopped almost immediately and hasnt come back. Fresh oil in and still no tapping so well worth a try before stripping the thing down.

[CompoSimmonite]

Re: Ford DOHC Tappets

With my old Golf I knew when getting near an oil change as the tappets got noisy. I always used the engine flush additive for 100miles, as per the instructions, before changing the oil to clean out the oil ways. Hydraulic tappets work on oil pressure and if there is a build up of sludge etc in the tiny holes in the tappets they don't properly "expand" and hence the noise. With my old V8 Range Rover I read you change the oil based on how many times you open the car door rather than mileage. ie cold starts are what causes the worse problems for hydraulic tappets. Not sure if that is true but heard it several times so there must be some basis to the advice.

Paul H

[djj_engineer]

Re: Ford DOHC Tappets

I had a conversation with some racing types who said they changed the oil and filter at frequent intervals. They added it didn't seem to matter what oil, they used the cheapest they could find. They said the most important fact was that it cut down the 'glazing' seen when you have extended oil change miles.
I change the oil and filter in FMB every 2500 miles and when I heard a tappet rattle, in Brough, on one of the Lakes runs. I immediately turned the engine off. The oil pressure sender had been leaking and a lot of the oil was gone.
FMB came home on the big yellow truck with the flashing lights but a new gallon of GTX and a blank plug in place of the sender unit and the V8 bellowed into life much the same as it always did!

If you use Wynns or STP I think the engine then requires them and if you stop using either you can hear the difference. Whether you get used to the 'quietness' of your engine when you use the additive is not clear.
I can remember using STP and the biggest difficulty was getting it out of the tin, leaving it to flow out for a number of hours seemed to be the only way.
Derek