Motors How I wanted to be like GOO, and then became more awesome

Yes, and I have since run the tank to about 1/2 and refilled with 93, hoping for a ~89 blend. As I drive that down, I will keep up with the 93 until I'm sure it all that is in the tank. In general: 87, 89 and 93 are commonly available with 10% ethanol. There are a few exceptions, like California and in the mountains. 100 octane is occasionally available, usually close to a race track. There was one place in Atlanta, in the middle of a suburb strangely enough. and (illegally) av gas can be found at small airstrips. But then you run into tax issues if you're caught. Non ethanol blends are available, you have to hunt them down. There are 2 here in town and I'm aiming for them on my next refuel.

I am hoping to build it for an 89 octane diet. The factory compression is listed as 10.5:1 and I'm told that was often over stated. I'd like to see 9.5 or 9:1.

I haven't messed with the carb at all. It runs now and carburettors are something I don't really know anything about. That will, of course, change over the winter. But that relationship between mixture and timing, carbs and distributors.....Well that's sort of the point of doing all this.

The ZDDP additive isn't an additive for anything other then lubricating the flat tappets. It's to replace the zinc that the engines were designed to use, which was removed in the late '80s due to catalytic converters. I agree with you on the other additives, I was very careful about letting it idle a long time and listening for any indication of a problem. I'm always very skeptical of claims made by additives for oil or fuel. The only exceptions are fuel stabilisers for my lawn mower and the zinc to keep older engines from excessive wear.

 

For a "leaded" engine, isn't lead replacement available?
It sure is here, I've had to use it on one or two of my cars.


Ehhhm, I'm actually embarrased here. I (very shortly) worked as a technical interpreter for a car company, but I've never come across the word "tappet", The "Oxford" doesn't know it. I don't have my american dictionary at hand (and funk and wagnalls isn't online appearently)
What is that, the lobe of a cam? The top of the valve head?

Edit: forget it, I mistyped in the Oxford
It's a "Stößelstange", why didn't you say so

 

Yes, there are lead replacements available. I think that for a garage queen it might be an option, but I would prefer to not have to dump an additive into the tank every time I fill her up. I want to drive this car a lot. Also, a proper lead additive is quite toxic. It seems silly to say this aloud considering it's a 6.6L V8, but Tetraethyl lead is just bad stuff. I'm trying to keep as many toxic things out of my garage as possible. The dogs simply spend too much time out there with me.

Since the motor is being broken down and refurbished, it seems more logical to just build it for modern fuel.

My German in general is rusty, and I really never had any use for technical automotive German. I suppose if my wife ever becomes head of Opel, I might have to change that, lol.

 

You're right, when you rebuild the engine, you adjust it for modern fuels.
Shouldn't be much more than replacing the valve seats and these "tappets".

For our engines it's just the valve seats, but thats because pushrods haven't been seen since before my birth

If your wife ever becomes head of Opel tell her three things:
Don't use american managers. (Hasn't worked for decades, should be a sign)
Don't rebrand american cars as opels. (What americans expect of cars just isn't the same...sorry)
Sell them outside of europe. (or they'll go bust in the long run)

 

What's all this about tappets and zinc in what I presume is the petrol as there's mention of cats?

Tappets as far as I'm aware are the bits that sit between a camshaft lobe and a pushrod, therefore shouldn't be anywhere near the petrol?
Never heard of anyone putting zinc in any of the older cars over here, my Dads never put any additives in any TVRs he's owned (or other cars) going right back to the 70s.

As above, unleaded conversion is just having some hardened exhaust valve seats installed.

 

The zinc additive goes in the oil, not the fuel. The zinc content of modern oils was lowered because it was clogging catalytic converters when then were introduced in the late 70s/early 80s. There are some oils that have more and some that have less. Heavy racing oils here can be as high as 1000ppm. But are expensive when your car takes 7 quarts. Even the 10w-30 I used was $70 for the oil and filter.

As a rule, I don't use it. I won't after the rebuild since the cam and the tappets will be of modern materials. I only used it in this oil change because they are still original and I didn't want to grenade the engine. I *will* use a cam shaft break in additive for the first 500 miles, which you need to do even with modern tappets. But the zinc additive is needed for older flat tappets to reduce wear and keep the proper lobe profile.

 

Xir - the American for tappet is "Valve Lifter".

 

I see.

Wouldn't it have been better for them to just have stopped the oil from being burnt, .

That oil cost isn't too monstrous. The Millers Mini oil I put in my, wait for it, mini, , is £35ish for 5 litres, add a filter at a few quid, and the other 3-4 litres to take it up to 7 quarts and it's probably not far off $70.

My Dads T350 is even more expensive, it takes 6 litres at £60 at a service, but the actual capacity is 12-14 litres due to being dry sumped.

 

so the tappet is not the pushrod but the rocker? or is it something between pushrod and rocker?

 

Between the pushrod and the camshaft.

The tappet sits on the cam lobes, the pushrods then sit on the tappets, and the other ends of the pushrod pushes on the rocker.


Although a quick google would suggest that when the cam is overhead, the tappet sits between the cam lobe and the rocker, when no pushrod is required. Finger followers are also used here in some engines.

 

Obviously the left hand one is applicable in my car.

 

Indeed, so there are two tappets in the pushrod design, both needing their clearances adjusting occasionally.

In an overhead cam design there's only one tappet, which can either be adjustable or (as in the picture on the right) a hydraulic self-adjuster. The self-adjusting type fill with oil under use, occasionally if they get blocked that's when you get a noisy/stuck tappet on modern vehicles.

 

By two I presume you mean inlet and exhaust?

*edit*
not wait, there's inlet and exhaust on the other one too.

So where's the second tappet? There's only one per valve on my engine, and in the kent crossflow engine and essex v6.

I think that pic is slightly misleading with the "Tappet clearance" label, as I would call that valve clearance.


And just to add another configuration,

This engine has no tappets technically. Cam lobe interfaces with the finger follower, which then presses down on the valve. Clearances are acheived with different thickness shims on the top of the valve stems. And it's a bloody awkward job to adjust some of them, as you have to lift the camshafts to change some of the shims.

 

Yours is a DOHC single-tappet design Cerb, no pushrods to complicate things!

The pushrod design has one at the cam end of the pushrod and the valve end of the rocker arm.

 

No tappets, just finger followers, unless the shims could called tappets.

But on our crossflow engine, there's a tappet sits on each cam lobe in the block, pushrod then goes onto that, the other end of the push rod sits in the rocker arm (ball in cup style), the rocker arm then presses directly on the top of the valve stem. So one tappet.

 

in SOHC designs you often have the rocker arm in direct contact with the cam lobe....
In modern motorcycle engines these contacts are sometimes bearings or rollers for lower friction.

 

Sorry, I glanced at that image above without counting the spark plugs/cylinders!

Yes to all the above, plenty of alternate design ideas out there, but in JJ's case it's a two-tappet system.

 

Think I get it now that I've looked for some pics.
It uses both normal tappets on the cam lobes and then the bucket tappets on the valve end?

Although I can't for the life of me find any bucket tappets, pictures or listings, for a pontiac v8.

Only picture I can find that I think shows the bucket tappets.



Sorry for making a mess of your thread JJ,

 

Nah, this isn't a mess. This is sort of the point of the thread.

 

So, did your wife become head of GM?