Broken Camshaft?

[divemaster]

Hello all!

NO OIL PRESSURE!!!

I think I broke my camshaft....

I crank the engine over - it fires - runs rough coughs and sputters.

I removed the oil drive head and I don't see the cam shaft gear moving when the engine is cranked over - at all...

When I use a socket to spin up the oil pump drive shaft - I move lots of oil!

Any thoughts as to the accuracy of my diagnosis??

Any idea how much a camshaft costs???

Thanks in advance.

[LMP]

wow....when and how could that have happened? I thought I had understood the engine had started first but that you had noticed immediately there was no oil pressure....(I'll check your previous posts...)
If indeed the camshaft does not rotate, start investigating at the chain drive....else I understand one part of camshaft rotates, and another does not .....so it would run only on a few cylinders...
THis engine is a box full of surprises..........
Remove a valve cover and look at what moves and what does not......how many of the six valves rockers actually "rock" ? .....

[divemaster]

I am not sure!!! I will be checking but not until tomorrow - far too depressed tonight - and anyone who tells you that alcohol is not a good cure has not had their camshaft break after doing head gaskets, broken valve etc.!!

I think that the valve breaking must have broken the camshaft - or more likely visa versa - why else would the valve make contact with the piston??

Any idea how much a camshaft costs??

Good to hear from you LMP!

[LMP]

Yes linking the valve incident with the camshaft breakage as a cause makes it a logical sequence of events....if all of this makes sense at all....
I've no precise idea about price..I just checked on ebay for fun, but saw nothing for the 3.4
I wonder if scrapyards take the pain of removing the camshafts from scrapped blocks....but I bought a camshaft from an engine overhaul shop once for very cheap...however it was an overhead cam so easy to get at.

[divemaster]

i have a 3.1 sitting in my shop... think it's cam would work??

[LMP]

Indeed the 3.4 is an enlarged 3.1 which is an enlarged 2.8.....(1/8 in. inc. bore and the rest in stroke) although it is said to have an "improved" camshaft profile.....but any profile is better than no camshaft at all...... I would go for a check...in all probabilities it will fit.

[divemaster]

I called the dealership - they said the part numbers are the same.

i think it spun a bearing which blocked an oil passage causing the cam to overheat and break..

If it did spin the bearing, would the block be junk?? Or should I be able to replace the bearing and cam and carry on....

Thanks!

[LMP]

I think you will conduct that wisely. I'm just waiting to hear about rocking rockers....because I do not like first item about "camshaft removal" in the page below
www.avigex.ca/xport/camshaftremoval31.jpg
www.avigex.ca/xport/camshaftbearings31.jpg

[divemaster]

Yup -- that does sound like a nasty job. I have mitchel on demand up to 2002 and it says about the same!

I will be looking at the rockers tomorrow - have company tonight.

thanks!

[cdru]

Originally Posted by LMP

I'm just waiting to hear about rocking rockers....because I do not like first item about "camshaft removal" in the page below

Oh come on. It's only one step. How hard can one little old step be?

I don't envy your position divemaster. After dealing with two intake gaskets then a head gasket within a few months of each other, I can't imagine the work that has to be done for the cam shaft. Hopefully it's something that requires a little less then "Remove engine" as step 1.

One other possible explanation is a broken timing chain. Looking at my Haynes manual, it doesn't appear that there is a real easy way to check to see if the chain is still in 1 piece without removing the cover and everything else to get to it. But at least

[divemaster]

Thanks for the sympathy!

But - in this case I do have to remove the engine (without a hoist!) as the camshaft is too long to pull out of the side of the engine.
I know that the timing chain is not broken because I do have other valves moving - just not sure right now which ones!
I will keep you posted..

Has anyone pulled one of these engines before?? Any shortcuts??

thx!

[cdru]

I beleive I read that you essentially unbolt the engine subframe, then raise the vehicle up and pull the engine out. This is assuming you don't have a hoist to raise the entire car up and drop the subframe properly.

But.....maybe that isn't necessary. Is it required to remove the engine? The AutoZone (yeah, I know it's not exactly an authoritive source) repair procedure says it is accessable and removable through the passenger wheel well.

[LMP]

Indeed, "by the book", the wheel well provides access to crankshaft pulley and balancer, and inspection /removal for the timing chain and sprockets.
www.avigex.ca/xport/timingchain31.jpg

What is in the way of pulling the camshaft? Possibly the suspension strut, but the engine centerline is ahead of this..so since you will have to peek through that area anyway, I think you'll verify the hypothesis.....

[cdru]

Originally Posted by LMP

What is in the way of pulling the camshaft? Possibly the suspension strut, but the engine centerline is ahead of this..so since you will have to peek through that area anyway, I think you'll verify the hypothesis.....

Even if the entire strut tower has to be removed, that's still a heck of a lot easier then dropping the entire engine subframe. Just look at the right side of the page...

What size engine do you have? The instructions posted are for the 3.1. The 3.4 may be a little different. I can post the 3.4 instructions from the shop manual if you want them.

[franklipscomb]

I had a broken camshaft on my 1998 Transport at 96,000 miles and found it was ultimately caused by a failed intake manifold gasket. The 3.4l engines have a known problem with these gaskets but the cause is unknown. The symptoms are noisy lifters at first morning startup, an oilcap that is swollen and hard to remove, and a slow loss of coolant with no external signs of leaks. On mine the back half of the cam siezed and the cam broke. The engine would run on some cylinders but was not driving the oil pump so all the engine bearings were ruined. I opted to get a used engine with 35,000 miles and it developed the same symptoms before reaching 95,000 miles. I just replaced the intake gaskets and just in time by the looks of it. There was a lot of coolant goo inside from the coolant leak. The only way to work on the camshaft is to do the engine removal by dropping the subframe. I made a 4 wheeled lowrise dolly to drop the frame on so it could be rolled out from under the van when the van was jacked up. Good luck with yours! By the way the manufacturer came out with a revised gasket and bolts for the intake gasket problem but believe me they are not owning up to there being any design problem. The problem appears to be related to the Dex-Cool coolant. Other problems with the coolant is goo that clogs the radiator slowly and reduces cooling effectiveness. The goo seems to form when the coolant level is allowed to go low and if you are not aware of the gasket problem then you might have the level go low before you realize it.



thx![/quote]