Pulling cams without removing timing cover??

Technical info on the Pontiac Vibe and Toyota Matrix including do-it-yourself info
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TerribleTim
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Pulling cams without removing timing cover??

Post by TerribleTim »

I need to retorque the head bolts after reassembling the base engine. (ouch- don't ask). I seem to remember reading something about removing the cams with the timing cover still on and hanging the chain so it doesn't drop inside the cover.

Anyone know if it's even possible to pull the cams while leaving on the timing cover and chain inside??

While I'm in there, I got a bad valve job and the shop didn't put the correct thickness solid lifters (buckets) on at least two or three valves so it makes a lot of noise, especially when cold. I figured I could fix these buckets while the top was off.

It's a HUGE labor savings not to take off the accessories and timing cover, but the head bolts are under the cams on this engine so the cams have to come out. I'm hoping either loosening the chain tensioner and/or removing the cam sprocket(s) might let me unhook the chain.

Any ideas, input would be appreciated...
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
triz
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Re: Pulling cams without removing timing cover??

Post by triz »

It's possible. Just tie a string on the chain and tie it to the block. Don't let the chain drop! Make sure to mark the chain with a Sharpe and on the cams so that your timing is lined up. Ill try and find the write up on another board. I've done it once on my MR2.
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TerribleTim
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Joined: Fri Jun 07, 2013 4:54 pm
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Re: Pulling cams without removing timing cover??

Post by TerribleTim »

Thanks for the input. That write up would be appreciated.
I think I saw it originally in a shop manual.
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
lannvouivre
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Re: Pulling cams without removing timing cover??

Post by lannvouivre »

To take tension off the chain, you can pull the tensioner (timing cover on the back where you can't see it if you are short) and unbolt the exhaust cam sprocket bolt. The timing marks you want are the crank TDC, then the Exhaust EX o make lined up straight with the o mark on the intake sprocket (with both marks centered between the cams). That's cyl 1 TDC with the valves shut.

You then have an o o mark on the top of the exhaust sprocket and a groove on the VVT actuator of the intake cam pointed upwards I think. You count the chain links between those marks to verify proper timing on the cams.

If the chain falls off of the crank sprocket, I'm fairly sure you'll need to pull the cover to get it back on because of the oil pump. I don't know if the cover is tight enough over the front to keep the links from getting off and messing around or not, but I do know that if the cover is off, if you let it have too much slack you have to pull the bloody crank sprocket out slightly to line everything up again.

If you do have to take off the cover, you will be happy to know the power steering pump is an absolute pain to get back on with the engine in because of the sleeves for the boltholes.

You may already know all this, but just in case (and for anyone else who wants to know). I do have a picture of the timing marks, but it's not a picture you're really supposed to just give out, I don't think.
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TerribleTim
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Re: Pulling cams without removing timing cover??

Post by TerribleTim »

Thanks for the input.
I did a valve job on this car two years ago which is why I fer sure don't want to take off the timing cover again.

You are definitely correct. Unless I hang the chain under tension (like with a spring), there's enough slack for it to drop off the crank sprocket, which would ruin the whole operation.
I remember all the timing marks on the sprockets from two yrs ago and counting links.
The trick seems to be to pull the tensioner and the exhaust sprocket to gain enough slack to remove the intake cam with the vvt still on, according to your description.

Btw the reason this is needed is the head gasket is now leaking coolant and compression on the #1 cyl. This is irritating since the head was reground flat (along with a shoddy valve job) two years ago when the engine overheated big time and blew the head.
I used new Toyota head bolts and a Felpro top end gasket kit and a calibrated torque wrench and followed the exact Toyota procedure of sequence torqueing the bolts, then putting on an extra half or quarter turn (I forget). This procedure really sucks compared to the old way of retorquing the head after running it for a few hours, but when the cams are over the head bolts, there's not much to do. Of course, this procedure may only work with a genuine Toyota head gasket and I should be bitching at Felpro.

While I'm blowing off steam, it may not be the gasket at all, but a cracked head nobody noticed and I'll be wasting my time with head bolts instead of sucking down egg nog next to the xmas tree.
Guess I won't know til I try it and redo the compression test. The original compression tests two years ago were good on all four, so if it's cracked, it must have happened during driving the past two years. I consider this unlikely, but anything is possible.

Anyway, thanks again.
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
TerribleTim
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Re: Pulling cams without removing timing cover??

Post by TerribleTim »

Stumbled across this writeup on adjusting the valves on a 1ZZ-FE, which makes removing the cams look easy. Just remove the chain tensioner and tie up the chain.
As mentioned, I have a few loud valves due to a poor valve job. Nice of Toyota not to provide adjustments. At least they give a table of bucket sizes. Wonder what these suckers cost?

After I measure the clearances, I can pull the cams, torque the head bolts and hopefully fix the coolant leak. Luckily, I see no evidence of coolant geting into the oil pan.

http://testroete.com/car/Toyota/celica/ ... stment.pdf" onclick="window.open(this.href);return false;

Here's some useful info right here-

http://forums.genvibe.com/files/importe ... lation.pdf" onclick="window.open(this.href);return false;

Even AZ gets their 2 cents in-
http://www.autozone.com/repairguides/To ... 3f8038244b" onclick="window.open(this.href);return false;


Last issue. If the timing cover bolts to the head (don't recall, but there are a lot of bolts), I'll have to loosen the ones to the head before retorquing the head bolts, otherwise it won't squeeze the head gasket without distorting something.

Sigh...
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
lannvouivre
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Re: Pulling cams without removing timing cover??

Post by lannvouivre »

MWR sells used heads from the Celica (larger intake valves) for $150 or so. You may try just finding a used head and re-checking the levelness of the cylinder block. Did you buy new head bolts? These ones stretch and lose clamping strength if reused (torque-to-yield).
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TerribleTim
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Re: Pulling cams without removing timing cover??

Post by TerribleTim »

New Toyota head bolts since the process is torque to yield.
I checked the block with a straight edge and it looked ok. My machinist claimed they seldom warp, but I have no confidence in him anymore.

I'm trying to fix this coolant leak without removing the head. If retorquing the head doesn't work, my next step will be a "liquid mechanic" wonder chemical into the radiator to seal the block, but I hate that stuff.

"in the old days", we used to spray Permatex Hi-Tack on the gasket just for this reason. Felpro dry coats their gaskets with a sealer which apparently is marginal.
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
lannvouivre
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Re: Pulling cams without removing timing cover??

Post by lannvouivre »

Not to be nosy, but is there a particular reason you won't consider a used head? I'd hesitate to try anything mechanic in a bottle.
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TerribleTim
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Re: Pulling cams without removing timing cover??

Post by TerribleTim »

No problemo.
I would put a used head on in an instant if I thought it needed it, i.e. mine is cracked.
In fact, I"'m intrigued by your comment on a Celica head with bigger valves. Something interesting to consider.

Really, I hate repairing repair jobs, especially my repair jobs.
I'm hoping to get this car going again with minimal effort, with minimal being the operative word.
I'd like to fix it without pulling the head or the timing cover, i.e. retorque the head bolts.

While I'm in there, fix the valve lash since it's all open anyway. This would fall in the category of repairing someone elses repair job which I paid good money for them to do right.

If I retorque the head and it's a bust, the decision becomes a used head or the bottle mechanic.
The big mystery is why it happened (compression leak on the new head gasket after two years) to begin with.
I'd hate to put on a used head and have the same thing, or worse, happen again.
I would probably go with a genuine Toyota head gasket if I did it again, although I've never heard anyone say anything bad about Felpro and have used them for years.

I'll let you know & thanks for the help.

Btw I just drove this car back from Tucson a few hrs ago and had to stop about every 30 miles to topoff the radiator. All the coolant is being pushed into and out of the reserve tank by the compression leak.
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
TerribleTim
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Re: Pulling cams without removing timing cover??

Post by TerribleTim »

Update-
Pulled the cams. Very easy. Everyone says tie up the chain, but the chain can't drop. There's a big piece of metal under the timing cover keeping it up within reach. I tied it up anyway to make sure it didn't jump a tooth on the crank sprocket and mess up my timing. About six valves were out of spec on lash from a bad previous valve job. Many others were at their limits. By playing soduku with the lifters in there and buying three at $15 a pop, I got most of the valves close to nominal lash. Makes a big diff in cold noise and pep. Toyota only sells lifters with even numbers, but my oem set had even and odd?? Each number is 0.01mm (.004inch).

Anyway, with the cams out, I could retorque the head bolts. The question is how much? I still have the set of used ones from the valve job two years ago, so I broke a few with a torque wrench and got around 120ftlbs. I figured 75 ft-lbs would be safe and most of the bolts moved a bit. Test drove it and the valve adjust made a big diff.

Surprisingly, the hot compression on all four cyl is around 175psi. Checked the cooling system with a pump and gauge and got no leak down but the pressure rises while running. FML FML.
Coolant still being blown into reserve tank but much much less.

Conclusion- probably a small crack somewhere in #1 cyl ( steam still coming out during compression test).
Driving it back to Tucson this morning so I will see how bad. FML

next step - when the car returns in May I will pull the head and find the damage and probably end up replacing the head. I plan on keeping the car, so I really don't want to gum up the cooling system with block sealer chemicals.

Lesson- pretty easy to do valve adjustment on this motor and access head bolts & FML. (next time it will be a Honda)
04 Vibe base - A/T, moon & tunes, pwr pkg, white, hvy tint
Daily driver - bought new
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