Engine question

[Buffy]

The wife made and interesting observation. While we were doing the compression that the engine didn't knock when we were turning it over. I'll keep digging into it tomorrow and see if I can make some more progress.

[Buffy]

One thing I didn't mention from uuesterday was when I first took the timing cover off and checked the timing belt, it had a lot of play in it but after turning the motor over a few times the belt is now tight. Now I have all the covers off and here are where my timing marks are:

Left Bank (drivers side)



Right Bank (passenger side)



Crank Pulley



The belt has some play in it now. I believe I have my marks in place to start removing the timing belt. Would like to hear from someone before I take the next step.

Thanks!

[Ldub]

Would like to hear from someone before I take the next step.

Thanks!

Hello...
































I think I'm soooooo funny...

This is about the best help anyone can give you...

http://www.vehicross.info/misc/pdf_f...eplacement.pdf

This is also handy...

http://www.vehicross.info/misc/vx_manuals/IV00_01.pdf

[Ldub]

One thing I didn't mention from uuesterday was when I first took the timing cover off and checked the timing belt, it had a lot of play in it but after turning the motor over a few times the belt is now tight. Now I have all the covers off and here are where my timing marks are

The marks look like they all line up properly.

If the belt was loose before, & then somehow got tighter...

In my mind that would indicate a problem with the tensioner.

But I haven't done mine yet, so whaddoIknow...

[MSHardeman]

What Dub said....

I used Bart's (nfpgasmask) timing belt how-to to replace my timing belt about a month ago and the instructions are spot on. Bart doesn't miss a step and the instructions are well written (the pictures help out a lot too).

Looks like your timing marks are all in the right place, but I'm curious as to why the belt would get tighter too.

Good luck.

[Buffy]

I've been following Barts writeup as well and it has helped a lot. Thus far all the parts that I've removed all look in decent shape. Based on the wear on the belt I'm thinking this is the original belt. I will replace everything and hope it stops the knock.

[SilverBullet75]

You are giving me deja vu with the symptoms, etc...
I'm gonna give it a 95%-sure rating...

Of course, you'll have to make sure the marks are correct, etc, but...
Just my opinion...

[psychos2]

If the belt is loose the tensioner is bad. it is really hard to push the tensioner in ,you need a vice to do it. Replace the tensioner. shawn

[SlowPro48]

Dude you like to learn things the hard way don't you? We said in the other thread it's not the valves, check the timing belt tensioner but NO you hadda go and root around under the valve covers. Ha! Ya didn't crack that left side open though didya? Man that corner bolt above #6 looks like a PITA.

OK since you're now EXPERIENCED in the valve actuating area, I've got a couple questions for you - were any of your clearances out of spec? Also is the valve cover gasket the re-usable type that fits in a groove in the cover or is it the fiber type that sticks to the head and you have to scrape it off? I'm trying to figure out if it's worth taking the time to check valve clearance now that I'm past 100K or just let it ride...

I believe I have my marks in place to start removing the timing belt. Would like to hear from someone before I take the next step.

Cams look good but your crankshaft is off by 180 degrees. The #2 TDC notch at the back of the pulley should be lined up with the mark on the oil pump. The timing mark on the front of the pulley (shown in your pic marked with green paint) is what you align the dotted line on the new belt with. It is 180 degrees from the notch. If you look carefully you will probably see a green dot behind the pulley, opposite the mark cast in the oil pump. When the crank is oriented properly for timing belt installation, the green dot on the pulley, the dotted line on the belt and the green dot on the pump all line up - so keep all your dots in a row! That green dot painted on the pump is pretty fat though - i.e., just for information not for lining things up - so for the sake of accuracy, position the crank according to the cast mark on the pump and the #2 TDC notch on the pulley. One thing to note - you don't need to have the marks on the belt lined up for removal - they are there for proper belt installation only. You just need to have all the hard parts in their proper places - and KEEP them there during the installation. The belt is marked to make sure you've got the proper number of teeth between each component so all are properly synchronized but due to the ratio of crank to cams and the unequal number of teeth between marks for crank, left cams and right cams it takes quite a few turns before all six markers line up again. You'll see once you install a belt and crank the engine around by hand a few times to check for interference. I was going to see how many turns it took just for kix but my wimpy arm gave out after about 10 turns. You left the spark plugs out after your last compression test right? Sure makes turning the engine easier!

[Buffy]

I tend to learn things the hardway sometimes, besides I like to see what makes things tick.... quite literally in this case. I haven't checked any of the clearances yet.... probably because I didn't think to do it. The valve cover gaskets are the re-usable type. I can attest that the # 6 cover bolt is a serious pain the the . That was the only bolt that was tough though. Also, taking the power packs out really makes removing the valve cover easy. After that brain fad I decided it was time for a sammich and a Gatoraide!.

I was following Bart's wright up on the timing belt install and his instructions were 180 degrees from your instructions. Bart's instructions have you to align the green mark on the pully with the mark on the oil pump and the dotted line with the notch on the back of the pulley.

[nfpgasmask]

Yeah, its been a while, but as far as I remember it, the GREEN LINES on the pulleys line up with the NOTCHES on the housing. You DO NOT need to line up the marks on the OLD belt to check for correct timing. The marks on the belt are ONLY for reinstallation of a new belt.

Now, from looking at your photos, I would almost say you might be a tooth off here:



But everything else looks correct from what I can see. For every full manual turn of the crankshaft pulley, your tick marks should line up the same every time. And again, I am talking about the marks on the pulleys with the marks on the housing. Only during new belt installation do you pay attention to the marks on the belt. This is to ensure you install the belt correctly and are not a single tooth off.

I think my instructions are a little easier to navigate here:
http://www.nofuture.com/myvx/how-tos/tb/tbelt.htm

Keep us posted.

Bart

[nfpgasmask]

Here's the diagram from the manual, it shows the dotted line on the left and the tick mark on the right lined up with the housing.



So like I said, it looks like you have things correct. I would certainly take this opportunity to change out the tensioner.

Bart

[Marlin]

I have what I thought was the valve ticking also, but I am going to go ahead and replace the tensioner, looks like that can be done without removing the timing belt? I just had the belt put in about 6K miles ago(last Jan).

[SilverBullet75]

Yes, that is correct. You just need to use something to keep the belt in place when you remove the tensioner. A helper with a prybar pushing/lifting the roller arm helps.

[SlowPro48]

Ahh, so you DID tackle the left side valve cover! You're the man! Thanks for the info on the gasket. If you check your valve lash how about letting us know if you've got any out of spec or close to it. It's something that doesn't get checked very often so it would be good info to see what the results are for an example like yours with close to 100K on the clock. I haven't checked mine for three reasons - #6 bolt, not sure about gasket ( i hate scraping/cleaning!) and the #1 reason - what to do if I find one out of spec? I've got shims but that bucket depressor tool is big bucks for something that gets used once every ten years! You blew my first two excuses out of the water so maybe it's time to fab up a tool and dive on in...

RE: timing belt instructions - yes, I was faced with that dilemma because I went by Bart's excellently documented timing belt replacement (except for the radiator removal - I just yanked the hoses and upper fan shroud out of the way and left the rad in - there was still plenty of room to work) but when I got to the part about installing the belt on the crankshaft pulley I saw his instructions didn't jibe with the shop manual, the bulletin or the videos put out by Isuzu - so I went with what the manufacturer said. Bart sorry man but you got outvoted! Take a close look at the figure you just posted. #8 in the illustration shows a closeup of the dots on the belt lined up with tick mark on the FRONT of the pulley - #7 shows the notch at the BACK of the pulley lined up with the mark that is cast in the oil pump housing. Note that the notch lines up with the keyway on the crankshaft. Note that in the illustration, the keyway is 180 degrees from the dotted line on the belt. Now check out the pic of the crank pulley in your instructions and note where the keyway is in relation to the dotted line on the belt.

It obviously works with the crank turned 180 degrees from how Isuzu said to line it up though - so that must be one of the "valid" combinations - i.e., if you line it up the way Isuzu says to do it, then spin it a bunch of times, it eventually ends up with solid belt lines, cam sprocket lines, and head lines all matched up but dotted belt line 180 degrees from point of beginning on the crank sprocket. That's my guess anyway. It could be figured out mathematically but that would require someone with a lot more smarts than me!