Could it be my timing?

[badboyr6]

Hey guys I'm having a problem, I took the head off because my valve seals were bad, I had the head machines. I installed the head with a new hg and torqued it down to specs. I put my new timing belt on, lined all the marks up just like the book says, installed new water pump and all the belts. So I go to start it and she starts but the engine makes a noise like its a diesel. Could it be the timing? Please help

 

[boosted86]

not bickering, just backing up my point. and yes i agree, do a comp test, that should tell you for sure.

 

[badboyr6]

I drove the car tonight and it sounds normal. It drives really nice. I'll do a comp test tomorw to see what numbers I get. Thanks for all your help guys.

 

[thom2white]

Badboy,

I'm really glad to hear it worked out for you. Kind of as a rule of thumb, always start with the easy stuff and then move on once you've proved your tests. Hope the best for you!

Thomas

 

[JusMX141]

no your wrong, being off by one tooth WILL NOT BEND VALVES. usually when timming skips, it will jump at the crank sprocket, not the cams. your "custmers" valves probally got bent because of his cranksprocket skipping teeth. a friend of mine ran his car for 6months)off ny 2 teeth) it ran like shi* and was pulling 13lbs at vaccum. we redid his timing, and did a compression check...170 across the board, and pulled 20lbs of vaccum at idle.

I hate to refer back to a sore subject, but then again I hate to be told I'm wrong....so I'll let the pictures tell the story:

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Now unless the crank somehow spun 360*, it's still completely in time while the intake cam gear has skipped 1 TOOTH. The last photo clearly shows the open lifter and if you look deeper you'll see that the valve on the left is stuck open.

Perhaps your car skipped in some other way and still ran, but my customer's car crashed.

On a related note, I looked up "custmers" in the dictionary and found nothing, but "customer" is defined as one that purchases a commodity or service. My name isn't on the title for this car, and the owner is paying me to work on THEIR car at MY shop, so....?

 

[dsm-onster]

Why would only 4 intake valves bend? Or why would only one intake valve in the cylinder set bend.

I can certainly see aftermarket cams bending valves after being 1 tooth off. That's a shot of the number 1 cylinder, right? All my stock cams (N/T, A/T, M/T) have two rings there on the left before the 6sided lobe.

Having the cam open the valves later, by having the cam retarded 1 tooth, would mean that the valves would be less likely to bend then with the cam straight up. ??? I've had my intake cam ADVANCED one whole tooth, were the valve opens earlier and the piston is near TDC with no damage. It was driven by the PO for several hundred miles like that. And as I mentioned, I drove it 250miles home before discovering this as the cause for poor vacuum and idle.

Just some things that seam odd. I'm not negating your experience.

 

[badboyr6]

Thomas I've rebuilt my own 79 vette from top to bottom. I've never done timing though. Honestly the only reason I tackled this job was because the local mitsubishi stealership wanted 500 plus 190 for the water pump. And the head was another 750 bucks. Altogether with a new radiator I spent under 600 bucks and it took me 1 week. I'll get the comp numbers for you guys when I get a chance today.

 

[1stGenTSi]

Listen to dsm-onster. One tooth off and your not gonna bend valves! It's funny hearing everyone tell him to start ripping his motor apart. You really think it would run for a week while making piston/valve contact? (thats what 3 of you diagnosed the noise as) Anyways it appears you were defiantly off by more than one tooth. The engine will run and idle great when one tooth off though it will be much slower under acceleration.

 

[1992awdlaser]

Listen to dsm-onster. One tooth off and your not gonna bend valves! It's funny hearing everyone tell him to start ripping his motor apart. You really think it would run for a week while making piston/valve contact? (thats what 3 of you diagnosed the noise as) Anyways it appears you were defiantly off by more than one tooth. The engine will run and idle great when one tooth off though it will be much slower under acceleration.

He first said it was off by 3 TEETH on the intake cam. He then edited his post after I posted, which I didn't even notice, and changed the 3 to a 1. 3 teeth is enough to have the valves contact the pistons, especially with the head being resurfaced. My reply was about being off 3 teeth. Read the quote in my post where it says 3. And a week means nothing. Did he drive it every day? Did he start it on a Monday and shut it off cause of the noise, then the next Monday try it again?

Intake cam 3 teeth off+ noise he was trying to describe+ won't start=internal engine damage.

 

[JusMX141]

Why would only 4 intake valves bend? Or why would only one intake valve in the cylinder set bend.

I can certainly see aftermarket cams bending valves after being 1 tooth off. That's a shot of the number 1 cylinder, right? All my stock cams (N/T, A/T, M/T) have two rings there on the left before the 6sided lobe.

You're right....cylinder #1 is pictured. Trust me, I'm quite puzzled as to why this happened as well! I wasn't with the owner when it happened, but SUPPOSEDLY it jumped while cranking the engine. Again, that's what the owner is telling me....I have no clue what actually happened.

There was definitely an auto-tensioner issue when I tore it down. The tensioner was almost the whole way out, and the belt was the most loose between the intake cam and the idler below.

When I got the car initially, I tried turning it over manually by the crank before I removed the valve cover. You could DEFINITELY hear the valves contacting the pistons, but it would still turn over.

The car is a bone-stock '90 TSi AWD- no mods to the turbo, fuel system, or intercooler at all. It has a turbo back exhaust and a K&N filter, but that's it....still has the stock boost control solenoid hooked up. I wouldn't think it was possible for this guy to pull something over on me.

I did have a non-turbo 4G63 in a car last fall that shredded the timing belt and jumped 3 teeth advanced on the intake cam, and it only smashed the valves on cylinder #1. This '90 TSi has loose rollers on cylinders 1, 3, and 4.

 

[boosted86]

On a related note, I looked up "custmers" in the dictionary and found nothing, but "customer" is defined as one that purchases a commodity or service. My name isn't on the title for this car, and the owner is paying me to work on THEIR car at MY shop, so....?

Good job on looking up that typo.


As stated before, I'm my experience (and others; stated in this thread) being off by one tooth, will not cause bent valves. Your..."customer";which was off by more then 1 tooth,had a weird accident. If you want to argue it, it's fine by me. I think my point has been proven. good luck with the job.

 

[dsm-onster]

A loose tensioner will cause the cam to "wander" forward and back as the lobes meet and leave the rocker arm rollers. It could have been advanced quite a bit when contact was made. Then when stopped, 1 tooth retarded is where it "settled".

 

[JusMX141]

Trust me- before this experience, I would've agrued that one tooth did nothing as well....the photos were taken to prove that apparently one tooth off can be a bad thing.

 

[JusMX141]

A loose tensioner will cause the cam to "wander" forward and back as the lobes meet and leave the rocker arm rollers. It could have been advanced quite a bit when contact was made, then when stopped 1 tooth retarded is where it "settled".

That's the best possible description of what actually happened. That had been going through my mind all along but I needed to hear it from someone else to actually confirm it.

Even though most of the slack is now on the idler side of the timing belt system (with the engine off), whenever the crank pulls on the belt the slack would then be on the tensioner side....like a motorcycle- when you're moving accelerating, the bottom of the chain has slack but while decelerating the top has the slack. Makes perfect sense.

 

[badboyr6]

when i first looked at my cams after the noise the cams were off by 3 teeth, so then i wrote the post, but as i turned the motor by hand they became 1 tooth off...i dont know... i honestly think that my crank was upside down or something... thats why i edited the post so quickly...and i took the car apart last thursday, took the head to the shop, then on friday i got the head back, sat i installed the head. but i broke my radiator in the process, it was brital, so i had to wait until tuesday to get a new one, so i finally got everything together by weds, and thursday i finished, so i couldnt start the car at all any of those days...until yesterday.