Hello,

I have an '87 4000CSQ that has been in the family since nearly new, but this is the first time I have done any repairs myself. While replacing my valve cover gasket I decided to check my valve clearences. Being the noob that I am I only have the Haynes repair manual. The picture it has for the tappets doesn't match what I see. Do any of you have a good picture of the tappets from this engine? I wouldn't be too conerned, but when I attempted to measure the clearence I couldn't even get the 0.0015" gauge under it! Both lobes for that cylinder were up. I would just take the cam off, but I don't have a new camshaft seal. Thoughts/ideas/pictures?

Thanks,

Daniel

Why are you checking clearance on hydraulic lifters?

What engine does not require clearance in hydraulic lifters?

I do not know of one.

I gave my '84-'88 manual to my mech to do some work for me, tomorrow, just for reference, had to get my '77-'83 book for this thread.

That book gives cold clearance of .006 -.010, inlet, .014-.018 exhaust.

Newer engines, I don't know, but if you had a Chevy 6, you would still need clearance, hydraulic or no. When they pump up, they become as near as dammit to "solids". No clearance, open valves on compression stroke.

That's why on an American car, again, a Chevy 250, inline 6, you crank the adjuster down till it starts to fart, if you want to call it that, then back off, with the engine hot.

Or, you press down on the rocker arm to see if the lifter is weak, can't be pumped up.

Has to be some clearance, or it will hold the valves open when the engine warms up. Parts expanding, in length, and every other dimension, under heat, is inevitable. And, lifters are strictly hydraulic, and mechanical, they WILL lengthen under heat, and too close a cam WILL give you open valves at operating temp.

Should the OP check his book closer, he will find that the discs at each valve are replaceable, in .002 increments.

Valves DO wear themselves in, OR wear themselves out. They get a cannelure in the seating area, a groove, so the stem sticks up further, loses clearance, no longer seats if the off lift part of the cam is going past, the valve closed duration.

Cheers,

George

In '84 VW/Audi went to hydraulic lifters. Forget about discs (shims), that was on the older engines that used solid lifters with shims over bucket design. Audi lifters are direct acting there is no adjustment other than a complete head and valve job. If the lifters are noisy and don’t quiet down after 30 minutes, just replace them, one at time or all of them. There is valve clearance tolerance but it is somewhat difficult to measure, as the condition of the lifters is difficult judge. If you have rough idle and suspect valves do a compression check followed by a tune-up vacuum gauge reading.

Offramp,

Thanks for the info, don't know I never saw that in my newer Haynes.

Never needed the info, but still....

Cheers,

George

Thanks for the comments guys!

George, I have the same clearance tolerances you posted. I did have some luck measuring the clearances, but realized what has been mentioned.....I have no way of adjusting it. So, I put it all back together. Ultimately it will probably require a head job eventually. I'll look into it when I hit 300k miles (52k away).

Daniel

CSQ,

I might have to retract my disclaimer, above. There STILL has to be a way to adjust clearance, else you have a couple loud clicking valves, due to too much clearance, as well as cylinders that do not fire properly, due to insufficient clearance, ie, holding the valves open.

Gotta go pay for the last repair, get my book back, think the 84-88 book also has different shim thicknesses. Will post if it does or even if it does not.

If I screw up, I will admit it. I am not an expert.

Manana, pipple,

George

According to my OEM Bentley manual there is no valve lash adjustment for cars equipped with hydraulic lifters. If the lifters are noisy replace them. The same goes for my '87 Mitsubishi. I also checked a factory SAAB manual and it’s the same story.

Just got my '84-'88 book back, checked the valve buckets. Says the 4 cylinder is shim adjustable, but the pic of the 4 cylinder shows hydraulics with all the springs and valves in the assembly drawing.

In the text, it says the 5 cylinder uses hydraulic or "solid" tappets, BUT, it also says clearances "See 4 cylinder specifications." Shims from .118 to .167 in thickness in .002 increments.

Also, all the pics show replacing the shims when reassembling. I don't know what else to say.

You know, valves do wear in, get a groove in the sealing face, seat deeper. Not yet to the point you need a head job, but maybe shim replacement. And, if you do get a valve job done, what then, replace, rather than grind and reseat the valves, grind the stems to length?

Only one picture shows what looks like a "solid" lifter, no outline of a "shim", but it is still in the text, check and adjust clearances with shims.

I may be missing something in my perusal of the text, but...

I'll scan if you like.

Cheers,

George

I had an '84 4000S with a 4-cyl engine and it had hydraulic lifters.

The factory OEM Robert Bentley manual sucks! Plain and simple! It sucks a little less then Haynes and a lot less then Chilton’s. On my 89-91 100/200 manual and 80-87 4000, I see lots of pictures and diagrams that plainly just don't jive. Hard to believe but RB skimped on pictures and incorporate lots of photographs and diagrams from 1st generation Euro engines and models. $160, three volumes and 2000+ pages of rather worthless information. Another problem with the manual is that it doesn't contain all the service bulletins, corrections and revisions. You have to buy those separately where the cost for all of them can easily exceed the price of the manual.

I have worked for a US branch of a German scientific instruments manufacturer and discovered two things.
1st German is a very complex language and translating manuals is a major b-i-t-c-h!
2nd they are very an@l retentive about giving out or divulging any information, even if you work for the same company.