I was tearing down a 3.4 from a '95 Camaro with 170,000 miles on the odometer. After removing the spark plugs and spinning it over I hear a metal noise in sync with the cam rotation (once every other crank revolution). Pulled the intake and rotated it and noticed the cam walks forward a bit (radically quickly) right when the noise occurs. When I dropped the oil pan two pieces of plastic fell out. One is a small cylinder a little over 1/2" in diameter and almost 1" long with a metal sleeve inside it. The other was a smallish wheel shaped device with a 1" stem sticking off of it.
1) Can anyone postulate on what the cam might be doing? I stuck a screw driver against a lobe and was able to push the cam forward a fair amount and heard what sounded like it hitting the back of the timing cover when the cam stopped.
2) Do the small parts sound like something you could ID?
I forget... Was the 3.4 DIS or did it have a distributor? (I'm thinking DIS.) It may be pieces of the dummy plug that replaces the distributor. Even thought there is no distributor, the cam still drives the oil pump, through the "dummy shaft".
So today I looked at the removed timing cover and can see fresh contact marks from the timing gear rubbing the back of the cover. So, nobody knows what is supposed to prevent the cam from walking? Is there an exploded view of the engine online where I can look at it?
Any help, please? Nobody's replaced a cam in one of these engines before?
[This message has been edited by mental floss (edited 09-03-2014).]
I looked at the 88 engine in the P22 because it's essentially the same as the 3.4. There is nothing in the crankcase that looks like what you describe. It may be possible that it's a part of the crankshaft sensor or engine block heater that was used on the 3.4. The gear on the oil pump drive is metal and a part of the drive. There may be some part of the oil pump that's come apart. A badly worn timing chain will allow camshaft walk.
I looked at the 88 engine in the P22 because it's essentially the same as the 3.4. There is nothing in the crankcase that looks like what you describe. It may be possible that it's a part of the crankshaft sensor or engine block heater that was used on the 3.4. The gear on the oil pump drive is metal and a part of the drive. There may be some part of the oil pump that's come apart. A badly worn timing chain will allow camshaft walk.
Okay, thanks. I wonder how to determine a badly worn timing chain? Is the tautness of the chain the only thing preventing cam walk, or does the gear drive on the oil pump help? Thanks for any help.
Okay, thanks. I wonder how to determine a badly worn timing chain? Is the tautness of the chain the only thing preventing cam walk, or does the gear drive on the oil pump help? Thanks for any help.
on a flat tappet cam like the 3.4 has, the primary means of thrust control is the actual camshaft lobes. Each lobe has a slight angle ground into it, opposing the next. this does two things, it causes the tappets(lifter) to rotate, reducing wear, and the opposing angles eliminate cam walk.
Okay, yeah, I saw the lifters rotating as they were actuated by the cam while I rotated the crank. I wondered how they accomplished that.
it's also why proper break in procedure is so important with modern oils on flat tappet cams. The cylindrical piece sounds like possibly part of the crankshaft position sensor, or the cam position sensor. the only reason I can think the cam would try and walk out is if the oil pump drive is getting jammed somehow.
I'm thinking the parts are part of the cam sensor. The crank sensor can still be seen. Is thr cam sensor needed for a Fiero swap?
Per the cam sliding, I removed the oil pump and the pump rod. It changed the condition by no longer making the radical movement at a ptescribed time of rotation. The cam can still be moved the same amount by grasping the gear to push and pull. But with the pump rod out it doesn't quickly slide at the exact point of rotation. It just turns and can be moved the same amount. So it makes sense what you say about pump and gear mechanics.
If you were having that much movement, You should check the condition of the cam, the bearings, lifters and the cam chain and gears and timing cover for any sign of unusual wear or damage.
The 3.4 is identical to your 2.8 in most respects. The 2.8 didn't use a crankshaft or camshaft sensor, so unless you're converting to DIS or a 7730 ECM, those sensors won't be used in your 3.4 application in a Fiero.
Today I saw that the chain tensioner has several pieces broken off of it. It has the general shape still so I didn't notice until now. I'm going to pull down the rest of the short block soon to see what the condition is. Looks like a person can't really see the rear cam bearings well even disassembled.
How do you remove the cam on a 60 degree engine? This one comes out clear until the last cam main. The last one won't clear the bearing. The gear comes through, but the cam thunks on the last main I guess. It goes through every other bearing.
ETA: The cam came out. It just took a little pushing back in to pull it back out quickly type of technique. Bearings need replacement, crank needs polishing and new bearings. Cylinders look good. I hear getting standard rings can be difficult.
[This message has been edited by mental floss (edited 09-06-2014).]
Summit shows the E629K having stainless steel oil rings, whereas the E548K has chrome-plated steel oil rings. Aside from that, they both seem identical. So either one should work.
Edit to add: the 3.4 V6 and the early 3.4TDC engine both used the same piston rings, hence the 24-valve listing.
[This message has been edited by Blacktree (edited 09-06-2014).]
The cylinders and pistons are good. The engine doesn't need high dollar/high performance parts, so something that doesn't require stiffer/larger valve springs and cut seats is the goal. Good nearly stock performance (or just a little better performance) that won't stress it to death is the goal.
[This message has been edited by mental floss (edited 09-06-2014).]
I found my list of gaskets for the 3.4 as used in the Fiero. Only thing I don't have is the head gasket numbers for the 3.4. This is based on using the 3.4 or 87-88 Fiero oil pan and timing cover and are all Fel-Pro numbers.
TCS 45828 Timing Cover Set Includes Water Pump Gasket. MS 93045 Exhaust Manifold Gasket Set VS 50077 R Valve Cover Set--Rubber Gaskets. Cork Valve Cover Gaskets also comes in the Intake Manifold Set, but aren't used with the Fiero Valve Covers. MKS 93020 Intake Manifold Set, includes lower, intermediate and upper manifold gaskets. OS 34501 R Oil Pan Set. BS 40625 Rear Main Bearing Seal.
Make sure you pull the cam sensor (or what's left of it) from the block before you knock out the old cam bearings. It blocks one of the bearings.
I used V8 cam bearings on my '95 3.4L when I swapped to the Comp Cams 260H as suggested by the Chevy 60* V6 Power Manual. They are wider than standard V6 bearings and fit the block journals better. You use 4 out of the 5 bearings. Here is my old thread: https://www.fiero.nl/forum/A...090907-2-089790.html I did not take pictures though.
I used the Cloyes double roller timing chain and a new gasket for the rear cam cover.
Cam sensor is out, and I remember reading somewhere about the V8 bearings. Thanks for explaining it to me. Is that suggested for the 3800SC engine too?
It has to have either the "dummy shaft" or distributor to run the oil pump via the oil pump shaft. Forget cam walking, you are talking no oil pressure without it.
I used V8 cam bearings on my '95 3.4L when I swapped to the Comp Cams 260H as suggested by the Chevy 60* V6 Power Manual. They are wider than standard V6 bearings and fit the block journals better. You use 4 out of the 5 bearings. Here is my old thread: https://www.fiero.nl/forum/A...090907-2-089790.html I did not take pictures though.
I used the Cloyes double roller timing chain and a new gasket for the rear cam cover.
Looking at Rock Auto as an example, there are several cam bearings listed under a 95 Camaro 5.7L. Which would fit the recommendation for the 3.4? http://www.rockauto.com/
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