Cheap Junk 1971 Build

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oprn
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Re: Cheap Junk 1971 Build

Post by oprn » Sun Dec 31, 2017 8:03 am

oprn wrote:
Sun Dec 31, 2017 8:00 am
It looks like my best option is to rig up an old valve in and old head with a cutter on it to make some clearance. There are no competent engine machinists within many hours of here. With the exception of a buddy who is a retired tool and die maker that would no doubt look over my shoulder and give advice if asked I'm sure.

I really don't want to use cylinder spacers and go big on deck height to do it. Optimum deck height is about 40 thou correct?

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Piledriver
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Re: Cheap Junk 1971 Build

Post by Piledriver » Mon Jan 01, 2018 12:05 am

oprn wrote:
Sun Dec 31, 2017 8:00 am
....
I really don't want to use cylinder spacers and go big on deck height to do it.
Absolutely. avoid like the kooties.
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oprn
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Re: Cheap Junk 1971 Build

Post by oprn » Mon Jan 01, 2018 9:49 pm

Good news! I have .o46 thou deck clearance and LOTS of valve clearance so that was not the issue. I must have been getting coil bind or something. All good now so on with the valve train geometry set up.

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Re: Cheap Junk 1971 Build

Post by Piledriver » Mon Jan 01, 2018 10:26 pm

Define "lots". Did you measure it?
rule of thumb is ~.100" clearance valve to piston and at least half that to the side (if you have valve reliefs etc)

Its not unusual for the guides to get smacked by retainers, one of the many little things...
That needs at least 2mm clearance IMHO.
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Re: Cheap Junk 1971 Build

Post by oprn » Tue Jan 02, 2018 7:35 am

My cam card says minimum of .050" intake and .080" for exhaust. I put a wad of well chewed gum on the lower edge of each valve about 1/4" high, bolted the head back on, set the valve clearance to zero and rolled it through 2 complete cycles. To my surprise the gum had not touched the piston at all!

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Re: Cheap Junk 1971 Build

Post by raygreenwood » Wed Jan 03, 2018 3:11 pm

oprn wrote:
Tue Jan 02, 2018 7:35 am
My cam card says minimum of .050" intake and .080" for exhaust. I put a wad of well chewed gum on the lower edge of each valve about 1/4" high, bolted the head back on, set the valve clearance to zero and rolled it through 2 complete cycles. To my surprise the gum had not touched the piston at all!

So...how did the gum taste when you removed it? ;-)
Ray

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Re: Cheap Junk 1971 Build

Post by oprn » Thu Jan 04, 2018 7:24 am

A bit oily but ok Ray. I hate to waste things! :lol:

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Re: Cheap Junk 1971 Build

Post by oprn » Sun Jan 07, 2018 9:09 am

I bought some elephant foot valve adjusters for this engine. Now I have come to understand that the genuine Porsche adjusters are better but I have these now so I will try them out, not a hard thing to change later. They came with 4 rocker shaft shims because they were intended for(like most everything else)a type 1 engine. I need 8.

So I says to myself "Self, what is wrong with using washers?". I got a few and started measuring them for thickness consistency. Out of 10 washers only 2 were the same thickness. So I dumped out a whole new box an went to work. Thickness varied from 0.065" to 0.100" ! How the heck do they get that much variance in the same box? Not a bad thing for me I guess as it gives me some options in setting up the rocker geometry.

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Re: Cheap Junk 1971 Build

Post by Piledriver » Sun Jan 07, 2018 10:11 pm

You may find the washers need a couple little kisses of the grinder so as not to rub on the rockers.
Strangely, I have had great luck with either tractor supply bulk grade 8 washers on the cheap, or fastenal...
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Re: Cheap Junk 1971 Build

Post by oprn » Sun Jan 07, 2018 10:22 pm

Looks like the 0.086" washers are close. I would like to go another 0.003" but there are only 3 of those in the whole box. Yes you are correct. I have found one washer so far that needs clearancing for the rocker.

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Re: Cheap Junk 1971 Build

Post by Piledriver » Sun Jan 07, 2018 10:32 pm

.003" is in the noise, the swivel feet work great (good for the valve guides) over a pretty wide range.
Just never bind them up where they can't move anymore, and never use them with hydro lifters.
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Re: Cheap Junk 1971 Build

Post by oprn » Sun Jan 07, 2018 11:42 pm

Thanks Piledriver, I hade one rocker that was backed all the way out till the swivel foot was in a bind and still no valve clearance. I swapped that rocker out to the one from the other side and presto - all was well. We shall see now if it binds up on the other side.

Now, I have not replaced the springs between the rockers with solid spacers. I am assuming that mod is for guys that plan on lots of high rpm work and is not really needed for a street/highway cruiser.

True?

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Re: Cheap Junk 1971 Build

Post by Piledriver » Mon Jan 08, 2018 10:25 pm

Something doesn't sound right.
The rockers don't vary that much.

The pushrod can end up out of the pocket in the lifter its meant to ride in, and seem a bit long.
(depends on lifter design)

If you are using used stock pushrods for some strange reason their length is going to be all over the place.
This is because they suck (technical term)

Solid spacers and hd rocker studs are always recommended, with the side play set at .003-.004.
They are sand to fit.
The stock spacer setup is really kinda junky.

The hd studs and spacer kits are cheap and will make for a quieter, lower hassle engine, esp in combination with good swivel feet. They are more work than cost, much like getting the geometry right.
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Re: Cheap Junk 1971 Build

Post by oprn » Tue Jan 09, 2018 9:39 pm

Well the tight rocker arm problem moved to the other head and there are 2 of them on that side. Not likely a pushrod issue I would say, more likely a rocker arm issue - maybe two of them are from a different production run? Thicker spacers are the fix it looks like.

So I don't recall ever having an issue with the stock spring spacers in the past but I have always respected a 4500 rpm limit and most of my previous engines have been stock. I have a lathe and could easily make my own solid spacers(when the weather warms up that is)I suppose steel would be better than aluminum for that, wear and temp expansion being the concern with aluminum.

Now, most of the rockers are not centered on the valve stems. They are slightly to the right of center. Back in the old days this was considered correct as it would encourage the valves to rotate a bit to even out valve seat wear. Is that still the case or is there an updated version of how they should make contact?

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Re: Cheap Junk 1971 Build

Post by Piledriver » Tue Jan 09, 2018 9:44 pm

It doesn't seem to hurt anything.
With good valves and seats nothing at all.

I vaguely recall looking at fixin that on a mockup and it looked like a lot of work for little>no gain.
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