About cams, valves and timing positions...... Help?

[Grizz1963]

Paul Y also came over early to supervise (well, he did all the work as he has built a few engines and knows his way around) he also tried along with Martin to teach me stuff, I think I make a good cuppa tea though.

No smiles today......



I took photos of stuff in position and also the progress, that is my job.



I did help find some nuts n bolts and made a few bits up.



Ohhhh, and another useful tool....... Keeps stuff in position. Simple.



Moving stuff about.



Very good news.... It's a four bolt main.

And the oil pump has been upgraded.





Then when the front end got opened.... Timing chain good.

But note the position of the timing marks......... Way out it seems.



With the camel hump heads off, it was found that most of the exhaust valves were missing their valve stem seals.



The engine has definitely been rebuilt previously, block has been decked, it has a +30 overbore with the cross hatching very visible, new brass freeze plugs, new oil plugs, oil pump, you get the picture.

In the truck the engine was running fine, and the reason for the tear down was that is was using a lot of oil and low compression on No 1 (both wet and dry). Think we have found the problem for the excessive oil use, lack of valve stem oil seals on exhausts, and a build up of carbon under the exhaust valve on No.1 giving a bad seal against valve seat. Upon disassembly the whole engine smelt of burnt oil and the heads and pistons had a heavy coating of oily carbon. Maybe because it has a broken valve spring, that valve has a mushroomed valve stem (and may possibly be bent)

The cam itself is undamaged, the lifters are good and the pushrods are straight.

So, the need to identify it is to ensure that the correct valve springs are procured and the mystery of the off timing marks can be solved.

What are the markings on the cam then ?

Glad you asked - This is what is cast into the cam

EP6
30
D8
C8
C5
CWC

There is also Blue and Purple paint on the distributor drive end of the cam and a 2 white spots half way down.

On the distributor end there is also an A punched into the shaft. Other than that there are no marking or casting number.

I 'think' that it is a Chevy cam rather than an after market item but happy to be proved wrong.

Spring has sprung.







So that then was the fun for today.

Seems the motor needs a few bits to get it back together.

A valve, springs, clean up and some info as tow hat motor this may be, so that I know what springs to buy.

Thanks as always to helping friends, Paul and Martin.

Back to normal tomorrow.

[geezer#99]

Timing marks aren't off!
Crank the motor around until the keyway in the crank sprocket is at 2 oclock and if the dot on the cam gear is at 12 oclock you're on #6 tdc. To get to #1 tdc and the dots to line up, just rotate the crank one turn.
Then the cam dot will be at 6 oclock and the crank gear will be at 12 oclock.
Never assume the timing chain is good. I can see slack in it. Get a new one.
Also never re-use an old cam unless you're dirt poor.

Nice pics though!!

[PGSigns]

On these older engines the exhaust valves used what looks like an oring with square sides at the retainer and not an unbrella seal like was on the intake. There is not any suction on the exhaust like on the intake so that type of seal was fine. If it is using oil I would rebuild the engine and for all means put a cam and lifters in it. Looks like your lower timing gear has a few key slots and that will have more than one mark on it to line up based on advancing or retarding the cam.

Jimmy

[Grizz1963]

Thanks a lot guys.

Remember, you are speaking to me which means I know verrrry little so all learning is great.

Here's a reply from Garage Journal.

Originally Posted by Bob Heine

Rian, I think the crank sprocket has multiple timing marks because I see a second keyway (there should be a third as well). Pretty sure those sprockets can be installed 4 degrees advanced, straight up and 4 degrees retarded (should that be "challenged" rather than "retarded"?). There should be 3 timing marks on that kind of sprocket.


I'm not that familiar with small-block issues but my '87 Corvette 350ci (5.7L) with 85,000 miles belched blue smoke when it started up. I pulled the valve covers and removed the valve springs, one cylinder at a time. The intake valve seals looked fine but I replaced them anyway, along with the springs (they do weaken over time from the heat cycles). I found this on the exhaust valve -- nothing.


I carefully removed the exhaust valve spring and chunks of black stuff fell out. I believe its the remains of the exhaust valve seals.


I replaced the seals with Teflon pieces so maybe they'll hold up better.

[vince1]

How many miles will you be driving? I bet less than 5000 per year. Looks like it is a nice hobby for you, as of course it is with most of us. IMO it doesn't need to be built to go 200,000 miles.

If it were mine and me always on a budget; clean it up, replace broken parts, rings, bearings and gaskets. Chain looks OK to me (replace if you want), replace lifters.
Happy motoring.