new problem with valves

[mikea]

first valve adj on BMW

when loosening the adj nut/bolt assy on No. 1 intake

rather than the nut turning, the bolt turned and broke the end of the rocker arm. = arrggghhh.

question: what is involved to replace that rcker arm- it looks like it will involve

the head coming off- some one tell me I'm wrong

mike

(this is '74 2002 carb'ed)

[Tommy]

You should be able to replace #1 without removing head. You need to take out head bolts from intake side. Remove distributor flange, timing cover, -gear and locking plate from front, remove the rocker circlips and slide the shaft towards rear. There should be just enough space and head gasket does not need to be replaced.

I say "should" because I haven't done it myself but they do this on racecars with success. I would measure the needed space behind the engine first.

Tommy

[Burleigh]

What he said, but be sure to drain your coolant. If you don't, coolant could get into your cylinder whenever you loosen the head bolts...

[kbmb02]

You should be able to replace #1 without removing head. You need to take out head bolts from intake side.Tommy

Like Tommy, I've heard it can be done but never have. Probably best to loosen all bolts to avoid stressing the head along one side. And if you go this route, pay particular attention to re-sealing the front upper timing cover... -KB

[c.d.iesel]

now - if one of the rocker adjuster screws snapped off -

presume that more will go wrong - stuff has been molested-

adjust all the other valves and check that there are

no further obvious defects

COMPRESSION TEST !!!!

if you have below nominal compression readings,

remove the head for recondition..

to replace just one rocker - without removing the head

-that assumes that the head is 'clean' and was just 'done' throughly

within the last few thousand miles and you might get away

taking the shortcut

but reality is that you don't have enough room to squeeze

just one rocker off - especially a motor with uncertain

issues with it, and a head that certainly needs more work

than you think.

With repeated over tightening, those tiny valve adjuster screws and nuts will snap off or strip.

[mikea]

C.D

I think you are correct

I should just bite the bullet and pull the head

I'll have the valves ground, and replace guides & seals

do you think I should replace all rockers?

IE sells FEBI brand for around $ 15.00

welcome any recommendations

mike

[Tommy]

Like Tommy, I've heard it can be done but never have. Probably best to loosen all bolts to avoid stressing the head along one side...

No no, then the head gasket is done! Just one side and quickly back.

But in this case if it feels that the head is in need of some refurbishment, just pull it. The trick is mostly for racers who need to get engine back running quickly or if you just put the head together and then broke a rocker.

Tommy

[c.d.iesel]

"C.D-I think you are correct

I should just bite the bullet

and pull the head I'll have

the valves ground, and replace

guides & seals do you think

I should replace all rockers? "

Wait till the head is off and striped.

Then you can examine the rocker

pads and cam lobes for scoring wear.

Look at the rocker shafts for wear - especially

where the rockers swivel. Then start ordering parts.

Stock rocker arms seem to last really well even

on tracked motors reving to REDLINE.

Your machinist will also gauge the valve stem to guide

clearance and advise you if new guides are needed.

He'll also see if the face of the valves have been machined

too thin to be reused. New head bolts are also

another low cost item not to scrimp on. One never knows

what horrors the poor car has experienced in 30 years, and

tens of thousands of miles?

[Mike Self]

As CD said, do a compression test, wet and dry. If there's a significant difference in the figures (wet testing higher) then there's a good possibility that you need rings as well as a valve job.

If you just do the valves, then the rings will become the weak point compression-wise, and instead of smoking on deceleration, you'll smoke on acceleration as oil is sucked past the rings.

Just be prepared to make the decision on how far you're gonna go before you get into it.

BTW, CD is also right about those rocker arm adjuster bolts--they are hardened and pretty strong, so a PO has really torqued 'em to have one break as yours did, so I'd start suspecting 'em all...

Good luck

mike

[mikea]

it could indeed

will try to do compression test before holiday

at this point it will be on 3 cyls, as # 1 the valve will not open at all.

what I remember from the old days- I can look at / feel the ridge at the the top of the cylinder once the heads off. we'll see. mission creep indeed!

by the way- when i yank this head, and good position to set the engine into

so re assembly is easier.

is there a timing mark on the crank pully and or cam gear that line up at TDC ?

any hints to make this easier much appreciated!

i know-I should have done a compression test before i bought the car

mike

[kbmb02]

No no, then the head gasket is done! Just one side and quickly back.

Agree that the head in this thread deserves to come off.

But man, I just don't like the idea of a fully-torqued head on just one side, even for a short amount of time (and I'd prefer to not be in a position where I'd have to find out...)

[Beaner7102]

is there a timing mark on the crank pulley and or cam gear that line up at TDC ?

When you are about to pull the head, pull the spark plugs, and rotate the engine until the pointer on the dizzy is at the #1 timing mark. There is also a mark on the timing chain sprocket. Then proceed to pull the head.

HTH Beaner7102