cam shafts are out....got some questions

[bgambino]

96 2.5 DOHC automatic—136K very clean condition---head gasket job

Cams and lifters are now out—tomorrow, heads come off

Okay

1)--1st thing: I was still a little worried about the drivers side cam shafts rotating and causing damage when I took the lower passenger side idler off. When the belt became loose, a few seconds later the top driver side cam turn abrubtly counter clockwise…the bottom one remained still==I rotated it clockwise by hand……this still does not seem to be a safe way to do it…should I have done something differently?

2)—one of the idler pulleys has a little more play in it than I think it should so I will replace it. The T belt tensioner pulley is hard to figure out since the bolt is set-up to keep things loose (right?). As for the other 2, I can feel a hint of movement, but maybe this is okay…?

3)I have labeled and bagged everything. Is it okay for the hydraulic lifters to sit for 2-3 weeks OUT of an oil bath?

4) I read where some have smoothed the areas where oil seals rub (cam shaft area, inside where front and rear crank seals go)with 600 or 800 grit paper. Which grit and is it done wet or dry? Cam shaft looks like it could use a little

5) Why have people posted 14 and 7 foot pounds for the cam cap bolts (7 for the front I think)? ALL the bolts look identical (I thought the reason might have been because the front bolts were smaller—they are not)

6) I really could not see any sealant under the front cam caps as I’ve read there should be. Are you supposed to smear a tiny bit under them upon reassembly?

7) Tensioner….what’s the consensus….replace or no?

Unfortunately I am an idiot…I did not do a comp test before starting this

Car drove okay but lacked power up grades and engine light was on too….idiot…!

[nipper]

96 2.5 DOHC automatic—136K very clean condition---head gasket job

Cams and lifters are now out—tomorrow, heads come off

Okay

1)--1st thing: I was still a little worried about the drivers side cam shafts rotating and causing damage when I took the lower passenger side idler off. When the belt became loose, a few seconds later the top driver side cam turn abrubtly counter clockwise…the bottom one remained still==I rotated it clockwise by hand……this still does not seem to be a safe way to do it…should I have done something differently?

2)—one of the idler pulleys has a little more play in it than I think it should so I will replace it. The T belt tensioner pulley is hard to figure out since the bolt is set-up to keep things loose (right?). As for the other 2, I can feel a hint of movement, but maybe this is okay…?

3)I have labeled and bagged everything. Is it okay for the hydraulic lifters to sit for 2-3 weeks OUT of an oil bath?

4) I read where some have smoothed the areas where oil seals rub (cam shaft area, inside where front and rear crank seals go)with 600 or 800 grit paper. Which grit and is it done wet or dry? Cam shaft looks like it could use a little

5) Why have people posted 14 and 7 foot pounds for the cam cap bolts (7 for the front I think)? ALL the bolts look identical (I thought the reason might have been because the front bolts were smaller—they are not)

6) I really could not see any sealant under the front cam caps as I’ve read there should be. Are you supposed to smear a tiny bit under them upon reassembly?

7) Tensioner….what’s the consensus….replace or no?

 

Unfortunately I am an idiot…I did not do a comp test before starting this

Car drove okay but lacked power up grades and engine light was on too….idiot…!

 

1- not sure what the problkem is.

2- when in doubt replace

3- as long as the coated with oil they will be fine. If you cleaned them wipe them with oil and put them in a bag. They should go back to their original locations.

4- When sanding anything on a machined surface, you go with the finest grit possible (higher number) and dont over sand. Sand by going around the surface 360 degrees. i dont really recall seeing this anywhere

5- book says 70-90 INCH pounds

6- haynes manual has a great pic of where to appy the sealant. They stress to NOT use too much.

7- when in doubt, replace it. Its buried and you dont want to do it again if you dont have too.

 

hope this helps

 

nipper

[bgambino]

1- not sure what the problkem is.

2- when in doubt replace

3- as long as the coated with oil they will be fine. If you cleaned them wipe them with oil and put them in a bag. They should go back to their original locations.

4- When sanding anything on a machined surface, you go with the finest grit possible (higher number) and dont over sand. Sand by going around the surface 360 degrees. i dont really recall seeing this anywhere

5- book says 70-90 INCH pounds

6- haynes manual has a great pic of where to appy the sealant. They stress to NOT use too much.

7- when in doubt, replace it. Its buried and you dont want to do it again if you dont have too.

 

hope this helps

 

nipper

Nipper....

1--the problem as I saw it is that both the drivers side cams were in tension and could have sprung in the wrong directions and possibly had valves collide...no? Isn't this why they have that special tool? How would you have done it without the tool?

2--the idler pulleys.....are they going to be 100% free of any play or is it normal to have ever so slight movement?

7)not in doubt about the tensioner as I have no real way to check it...it's got 136K on it--that's all

 

8)---when sending heads to get checked...what do they do?....check for flatness....do some kind of leak test? shouldn't they lap the valves to smooth out the seats even if it pressure tests okay? I was thinking of getting the gasket overhaul kit which I read has new valve seals and keepers.....

[a97obw]

DANGER Will Robinson! Personally, I don't know why the Haynes manual attempts to freak you out when it comes to the camshafts turning....IF you lined up the crank mark and the cam marks to their respective locations before you remove the timing belt. Ok, here is a picture of where the pistons are located with the crankshaft mark lined up in the correct position. This is the passengers side. Drivers side is same. The valve train can not possibly crash into a piston!

 

And you are correct, the drivers side upper cam (the intake cam) will definitely spin abrubtly on its own. Lucky for you, you didn't have your hand on the cam pulley because it will remove several layers of skin from your hand when it does spin. Yeouch!!

 

 

 

The bolts that hold the front camshaft caps that hold the seals are definitely smaller than the other camshaft cap bolts, at least on a 97 2.5----and I don't see why they would have changed that from the 96 models. IIRC they both use a 10mm ATF (across the flats) wrench to remove/install, but the shoulder of the bolts is much larger in diameter for the middle and rear camshaft caps than the front. Should you attempt to tighten the front ones to 14 ft. lbs. rest assured you will shear the bolts and then you are in search for bolt extractor tool.....that is if it doesn't strip the aluminum threads in the cylinder head before it shears!

 

Cleaning the old seal material that has formed a ring of crud on the camshafts right where the new seals are going to "ride"--- I'd forego the sandpaper. Instead, find some of the red Scotchbright pads at the auto parts store...maybe even a body shop supply store. Use the red Scotchbright after moistoning it with a bit of spray carb cleaner to easily and lightly remove the crud. Somebody above mentioned using the sandpaper to clean a machine surfaced by going around it as if you hold the paper and rotate the shaft. Thats good advice....and I'd suggest you follow it with one added modification....hold the scotchbright pad, rotate the cam in the pad and go backwards and forwards with the cam or the pad while you rotate it. Now you've got more of a "honed" surface as the result. You'll need the pads and the carb cleaner to clean the sealing surface of the engine case where the head gasket fits anyway. I think the photo above is after cleaning with the Scotchbright and carb cleaner.

[nipper]

Nipper....

1--the problem as I saw it is that both the drivers side cams were in tension and could have sprung in the wrong directions and possibly had valves collide...no? Isn't this why they have that special tool? How would you have done it without the tool?

2--the idler pulleys.....are they going to be 100% free of any play or is it normal to have ever so slight movement?

7)not in doubt about the tensioner as I have no real way to check it...it's got 136K on it--that's all

 

8)---when sending heads to get checked...what do they do?....check for flatness....do some kind of leak test? shouldn't they lap the valves to smooth out the seats even if it pressure tests okay? I was thinking of getting the gasket overhaul kit which I read has new valve seals and keepers.....

 

1- no, and i would just remove the heads. There isnt enogh force there to damage the valves. Valve damage comes from hittin the pistons when the belt jumps or goes.

7- replace

8, where in heck did 8 come from?

They will check the heads for latness and any cracks, and machine the surfaces. If you are going to have them do a valve job, they will do the lapping and grinding and stuff. They will not automatically do lapping.

er um, what do you mean by pressure test? You said that you did not do a compression test on the car. A pressure check (that i know of) of the cylinder heads involves checking for cracks in the water jacket, and has nothing to do with the valves. The big mistake here was no compression test before taking things apart. me personally, on a sooby engine, i would have them do a valve job too. On a non sooby engine i would hesitate. Doing a valve job on a high mileage engine may raise the compression and cause the piston rings to leak and you get blow-by. Soobies are fairly robust and dont seem to be affected by this. i am sure somone else will chime in to agree or say im nits, but i would do the valve job.

What caused you to do a HG job in the first place?

 

nipper

[bgambino]

thanks a97obw and nipper

 

a97obw-I like the idea of the scotchbrite..I also have the grey which is even finer

Now this is interesting.....I went out and measured my cam bolts just to make sure I wasn't going crazy....they are ALL identical...10mm, shoulders are all .250" dia and shoulders are same length....what do you think the torque should be???

 

nipper

 

#8 was an additional question.....LOL

I thouht I read somewhere that the machine shop could do some kind of pressure test on the heads (guess I misread somethiing)

 

Any other thoughts about whether a valve job is a good or bad idea?

 

Bought car for 400 ...was overheating and had bubbles in radiator...I know now that it was very dumb not to do the comp test....car has a like-new interior (lady owned)..body very good except for some of the silver tape of lower half of body chipped of in numerous places

[nipper]

Bought car for 400 ...was overheating and had bubbles in radiator...I know now that it was very dumb not to do the comp test....car has a like-new interior (lady owned)..body very good except for some of the silver tape of lower half of body chipped of in numerous places

 

no need for a compression test at that point. If you can budget the valve job go ahead and do it, especially since you dont know what history of the car.

On the torque its 70-90 inch lbs. In inch lbs it sounds like a huge spread in the book, but its actually 5.8ft/lb to 7.5 ft lbs. At this torque foot/lb torque wrenches are very inacurate, so inch lbs are used. I am very comfotable with what the book says.

 

nipper

[cookie]

A valve job is always a good idea if it is done correctly and the clearances are set. The clearance changes a lot when you cut the valves so you really have to start over, bit of a pain.

If you can afford it you avoid the instance of having a valve burn later or finding out a vlave is already burnt after reinstalling the heads.

[bgambino]

A valve job is always a good idea if it is done correctly and the clearances are set. The clearance changes a lot when you cut the valves so you really have to start over, bit of a pain.

If you can afford it you avoid the instance of having a valve burn later or finding out a vlave is already burnt after reinstalling the heads.

 

Cookie

This engine (06 Legacy CJ25 has hydraulic lifters)---so there is no adjustment

BTW...I read a post tonight which talked about bleeding lifters...would this apply to any hydr lifter? How/why is it done?

[nipper]

Cookie

This engine (06 Legacy CJ25 has hydraulic lifters)---so there is no adjustment

BTW...I read a post tonight which talked about bleeding lifters...would this apply to any hydr lifter? How/why is it done?

 

Bleeding lifters/pumpin up lifters. The lifters are hydraulic, they get filled with engine oil when running.. Normaly one way of avoiding doing this is when you remove the lifters you submerge them in oil, to keep air from getting in. Hydraulic lifters are like little cylinders that have to be filled. i assumed that since you had everything apart and bagged, it was too late to do that.

Its not that hard to do. Follow the procedure in the haynes manual (you DO have one dont you). The other option (which i dont like all that much) is to just put them in thier bores. Remove all the plug wires and crank the engine untill the oil starts circulating, and the valve train quiets down.

Now there is no such thing as too much lubricant when you put the engine back together. Make sure the heads are completly clean. Use camshaft lubricant when reinstalling the cams.

 

nipper

[cookie]

you learn someting every day. I thought all DOHCs had shim tappets,