I haven’t fully digested everything on this thread, but in general any chain stretch will retard the cams. I carefully set mine up with new chains and after 1000 miles I needed to tighten the chain and found the intake was off 4° and the exhaust 2°. I reset them. I don’t plan on checking them again for many miles.
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One looks advanced and the other retarded. Hopefully you put that gauge on your shop list. You want the plugs out for cam timing. It makes it way easier. Fingers crossed that your timing pointer is actually correct. The mounting holes are slotted and you’re meant to use a dial indicator to find the highest point of the front piston and then adjust the pointer to march the damper. Then you know your reference is correct.
Spark plugs are out.
This is a lousy way to see if valve timing is correct, admittedly. That said, the intake is definitely retard by a couple of degrees I’d say. The exhaust has a poor blue line. If you take a straight edge, I’m using a piece of paper, and hold it horizontal through the cent of the “8” and the center of the “1”, you’ll see a truer line. And that looks to be on center to me.
I think Bill and David have it right: it’s not far enough off to worry about now.
Everything in the motor looks new, noticeably so the chains. They have zero sludge on them and you can even feel to packing grease on them still. I have poured oil over them now, several times. They’re well lubricated and they are quite stiff (or tight perhaps). The whole engine is rather stiff. Remember the assembly lube is 25 years old and there is no oil in the sump (maybe a quart). This engine is stiff.
I do have dial indicators and I’ll use them when I get serious about cam alignment, but for the time being, if no one is advising me to fix it, I will leave it alone. Yea or Nay?
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Agreed: TDC has to be found, before anything else can occur.
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Well I got waylaid by my oil pan fiasco and now a bit behind on the cam setup. Now waiting for the oil pan so I’m back on the other stuff.
I don’t have a damper on the engine because the pan is off, but I needed to find #6 cyl TDC. I’ll mark the flywheel permanently with a punch and then some paint on the front timing cover and crank cone for convenience. To find #6 TDC, I made a simple tool from a sparkplug and a bolt and a nut. Just turned the crank one way until it hits the stop, then back the other way until it hits the stop. Split the difference between the marks and that’s TDC. For kicks I double checked it with my dial indicator in the hole. Here’s the pic of the tool.
Then I took some pics of the cam lobes at #6 TDC. Pics are just the front end of the intake and exhaust cams. Looks right to me. (Sparkplugs are just sitting in their holes.)
I’ll measure the valve clearances to start, but then I need to install those missing washers under the cam bearing studs. Then I’ll check the valves again. Should be no change. Then I’ll check the cam timing and adjust the valves if need be. Good plan? (Oh yeah Erica…I bought the cam tool!)
What do you all think about the rear cork gasket for the pan? I can only find the rubber ones like now offered by SNGB unless I buy the whole pan kit. I don’t want to do that because I want to use Cometic gaskets (no cork from them). Is the rubber version acceptable?
Scott you made the right choice in buying the tool rather than fabricating one.
The piston stop you made has got you where you need to be. Now with the engine set at #6 on TDC, you should be able to insert the cam tool in the notch on both the intake and exhaust cams. That will confirm that the cam timing is correct. Have you tried that yet?
Then I would check your valve clearances. They don’t have to be perfect, but close. And your gaps are better off being larger than smaller. That insures the valve has adequate time to seat on the head, and dissipate some of the heat. If they’re too tight the valve stays hot and you can “burn” a valve.
But as long as they’re close I’d button it up and move on to getting it running. You can always come back later and work on getting them “perfect”.
Finally if you prefer having a cork gasket I have bought cork in sheets at ACE hardware and cut my own. Quick and easy.
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Thanks Bob. Piston stop worked just fine; the dial gauge was even easier except it is hard to move the crank just a tiny bit…it jumps because of stiction. Anyway the #6TDC is right on.
On the cam tool, I have tried it. The intake appears to be advanced maybe 1 deg and the exhaust is just a bit retarded…perhap 1/4 deg, not much. I’ve also checked the valve clearance on some of the tappets that I can without rotating the crank. I don’t want to move it off #6TDC at the moment…too hard to get it back to TDC. The #6 exhaust seems to be 0.002" and so is the intake 0.002". I’ll check again when I rotate the engine to absolutely be on the base circle of the cam. #2 exhaust and #4 exhaust are both 0.006". #3 intake is at 0.006" (too large) and #5 Intake is at 0.004" (good).
But I’ve a bigger problem. Looking at the cam gears it appears I have the old style gears and the shafts (pins) do not have their retainers at their front. The Adjusting Plate is bolted and safety wired, but the pins have nothing securing them to the slotted holes in the bracket. And, the pin that is on the exhaust side wobbles. I cannot pull it out, but I can rotate it back and forth about 10 degs or so. See pics. What kind of engine builder would deliver a “finished” engine to a customer like this!? I am rather pissed and about to reveal who they were/are.
Scott, that’s actually the way those are supposed to be. It looks odd I know, but the pins are just free floating in their bracket. If you think about it, having the gear bolted to the cam shaft, it has no where to go, so being secured to the bracket is not only not necessary, it could prove problematic.
If you were to take the cams out, you’d need to disconnect the cam gears. It is then that the bracket serves its purpose, holding the gear and chain in relative position, but allowing required wiggle room to realign the gears when you want to reconnect the cam shaft.
If you look at the parts drawing, you’ll see item #4, the pin, set to engage the bracket, item #7, with nothing on the end of the pin to retain it.
Make sense?
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That is an awful and essentially a useless job of safety wiring.
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There’s not much to stop the pins from rotating, they’re only secured the other end with a snapring anyway. There’s also no reason to secure them to the slots until it’s required to remove the cylinder head. In that case, one would use a jamb nut on the pin to hold the sprockets out of the way while the head is lifted.
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Well thank you Gentlemen. Once again I have shown how woefully ignorant of this engine I am. But, in this case, happily so. Bob, I did note that on the diagram, but as its from the later engine, I thought the “missing nuts” showed up elsewhere. So I get it, the cam bearings bearing the support of the chain drive. And I see that the pins don’t really support anything in normal operating mode. So it does make sense, but it sure scared me. And like Clive there’s not much holding the pins in place. Perhaps that is why they refer to them as pins vs. shafts. Anyway, thankyou All. I guess I hold my tongue on the builder from 30 years ago!
On the safety wire I did look closely at them. They would never pass Mil Spec MS20995 and note that the wire is not stainless steel. Definitely not the way I was taught. That said, the lock wire as installed will prevent the bolts from turning out, messy as it is. So I’ll leave it until I have to time the cams.
So that is the question. with the Exhaust almost TDC aligned and the Intake being 1 deg advanced, should I redo this now or wait until the engine runs a bit? I am going to have to set the tappets some time.
And thank you folks for the knowledge you have and are willing to share.
If the cams are that close, it should run fine.
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Wait until you have to adjust the shims, the engine will be perfectly happy with where they are now.
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Agree. A ‘few tablespoons’ in 50 ml plus and depending on CR is getting uncomfortably close to hydraulic lock and possibly a blown gasket. A few teaspoons is plenty for a vertical bore.
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Scott, Definitely wait. This is not a problem. It’s more like perfectionism. 
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Couldn’t agree more. And not for a New York minute do I believe Scott has accurately measured the cam timing to 1/4 or even 1 degree without a heap of equipment and experience we’re not seeing here. No offence Scott. And which degrees were you referring to? There are two different measures when checking cam timing.
The lock-wire isn’t pretty but I see an above-average rebuild (not perfect) and good prep if it’s still that good after 30 years standing.
The double-stop TDC method is pretty much the only time I read some thing reassuring. Get the thing running and enjoy it.
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Thanks Everyone. This is encouraging. Especially from Peter where I definitely have not measured to 1/4 deg. It is just my eyeball. Cam degrees of course. The cam alignment tool almost fits in to the Exhaust side. The Intake side it is off enough to not go into the slot. So I look/feel on the one side and say, “that’s a degree too far,” and I look/feel at the other side and, “it’s almost spot on” hence, 1/4 deg so says I. It helps with the confidence of how this car was built so many years ago. I am not looking for perfection, but level of confidence that I can move forward to the next task. See, it is not just the engine, it is the whole car that has these anomalies and I am, admittedly, gun-shy. Now is the time to make things right and I hope to do so. Thank you…all of you.
I’d call you prudent and practical: the cost of failure, of unknown quality of prior, undocumented work is too high.
I had a customer who “got a good deal” on an early 911 engine, which had been rebuilt by a “professional” rebuilder on the east coast: long story, greatly shortened, was I ended up disassembling the entire engine, to rebuild it properly.
His good deal barely cost him more than had we just rebuilt his OE engine.
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I hear that. And I’ve learned not to let me kids drive my hot rods that do not have electronic distributors and they overrev to destruction. Gee dad, I didn’t know it didn’t have a rev limiter. Thank you very much!
Slight detour to pull the carbs and make them ready to ship after the holidays.
Here are the measured tappet clearances:
| Intake (factory Clearance 0.004") | Exhaust (factory Clearance 0.006") | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cylinder Number | Clearance | Difference from Spec | Existing Shim Thickness | New Shim Thickness | Clearance | Difference from Spec | Existing Shim Thickness | New Shim Thickness | ||
| 1 | 0.003" | -.0001" | 0.005" | -0.001 | ||||||
| 2 | 0.002" | -0.002" | 0.006" | = | ||||||
| 3 | 0.006" | +0.002" | 0.004" | -0.002" | ||||||
| 4 | 0.002" | -0.002" | 0.006" | = | ||||||
| 5 | 0.004" | = | 0.006" | = | ||||||
| 6 | 0.002" | -0.002" | 0.002" | -0.004" | ||||||
What do you all think? I’m thinking that these are okay for startup except that #6 Exhaust that only has a 0.002" lash. Opinions please?