Thanks for that, but that measurement appears too small. On my cases 3 & 3/8 will not clear the oil fill/breather box and on the engine in my car the dipstick tube def clears that breather (the metal box bit, not the plastic filler neck).

I am at a full stop unfortunately as both of my new double thrust cam bearings (from Type IV Store) have locating tangs, and my case does not have a locating tang space on the right hand case (cyl 3 & 4). Very strange.

I had hoped to get it all bolted together this weekend, but no love.

One more thing you MAY want to change on that case:
If you're going to fit an oil temp sensor in the taco plate (original sensor), then check that it fits now. Some cases, and this includes some bus cases, have a lip there that needs to be removed for the long sensor to fit. Some are ok. I don't know when the change happened.
I don't have a picture right now but please check and you'll see what I'm talking about.

Here it is:
http://www.914world.com/bbs2/index.php?s=&...t&p=1558181

Checked the taco plate location on these cases. All good, long sensor oil temp will fit. Thanks for the heads-up on that.

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Finally ready to assemble cases. Don't think I'll get Ps & Cs done today, just the crank, cam, oil pump, etc.

Cases reunited. Hardest bit was the oil pickup because, well, I left it out first attempt. Realized it when I had a single M10 thoughbolt snugged up. Tried again and tightened 2 of the M10s until I remembered to "locate" the pickup with its own through bolt.

Finally all together. All bolts torqued nicely, oil pump went in without an argument and I'm not bleeding anywhere. I call this a success.

I consider this the easy bit with the rest getting more complicated. Deck height and CR must be checked and set, and then valvetrain geometry fun after that.


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Why are you using a bus case?

Because it was there?

It's in his hands. If I had a dime for every dollar I spent doing the "right thing" for my teeners, I'd have a 911 in the garage, next to the 928s and 914s (none of these are a "real" Porsche. Keep the recipts and pics and source a case later. The longer a project sits, the more likely it is a barn find. Get it back on the road.

Back in the Stone Age Mallory Unilite, grey/grey springs. Apparently sold. Now made in China. You can get one from Tangerine Racing ready to go. Otherwise call john @ aircooled.net amd get his recurved svda distributor.

Loving this thread! I have some 2.0 bus parts at the machine shop now for a 2056 build.
I was under my '73 the other day and noticed how close the engine bar comes to the 1.7 case where the bus oil fill would be. My bus engine came out of a '71, so the engine bar is smaller. I'm worried the block-off plate and studs in the bas case are going to hit the '73 engine bar, so I'm going to countersink the cover and use countersunk machine screws to hold the cover in place to try to get some clearance. Thought I'd give you a heads up about it. I saw the block-off plate in your pictures and the "1973 914" in your sig. Sounds like we're doing the same swap!

Thanks for the heads-up. If you get around to this before I do - post some pics please. My car has a running engine in it (I am still driving it) so I won't be sure if the engine mounting hardware will all bolt up until I am ready to install this thing.

Getting ready to measure Deck Height, and then set CR. Using a tool for Deck Height measurement made for Type I's. I will weld on an additional steel plate so that I will get even/appropriate clamping forces on all four studs/corners.

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The screw in center(ish) of this plate is calibrated such that 1 full turn = 1mm. So with this tool I can use the calibrated screw to take a number, I can use feeler gauges to take a number, and I can also use a dial indicator (once I weld on the additional plate) to take a number.

I just hope (pray actually) that all the numbers are the same (or very very close).

That calibrated screw is not directly over the wrist-pin I know, but I am comfortable with this approach. No shim/gasket between jug and case, and a single piston ring installed.

Having measured deck-height over the weekend I (naturally) have questions. I used the tool pictured previously with the calibrated screw. The directions indicate 1 full turn = 1mm (which I measured and verified).

On cyls 1 & 2 I get a deck height measurement of 1mm using the calibrated screw, and some stacked up feeler gauges yield the same measurement. Did not measure the other side yet. I can tell that actual deck height is just a bit less since that calibrated screw (and feeler gauges) rock the piston ever so slightly. But - I am comfortable (for now) with a repeatable measurement of 1.0 mm (.039).

Plugging bore (96mm), stroke (71mm), deck height (.039) and chamber volume (55.2) into the CB Perf. engine calculator it yields a CR of 9.3 - 1. Is that too much?

When I first began this project a couple of months ago Jake posted a quick reply that I'm using pretty much all the right bits and pieces and I should se the CR at 9.0 - 1. I tend to believe that guy.

Without starting a flame war (if you are just going to bash JR, or this build don't bother posting) - how do we feel about a CR just a tad higher than 9.0 - 1? I'd love to bolt up the short block without any shims under the jugs and leave this CR alone, but am interested in experienced opinions from those who have done this (or a similar) build.

All meaningful replies much appreciated.

Whoops....that 85mm is from the flange that the tin mounts against....from the case top it's 6 inches.....152mm. That's what I used on my 2316....

Toss the VR rear main oil seal and get the Sabo seal from GoWesty as it actually seals the flywheel vs the VR seal which leaks.

More deck height and compression ratio questions (really the same one but I never got a response(?)).

I have measured and re-measured deck height on all 4 cylinders. All come up with 1mm deck height in the jug. I got sage advice from HAM that there is 1mm of step (deck height) in my cylinder heads. This gives me a total deck height of 2mm.

I am targeting 9:1 Compression ratio. Plugging the numbers into CB's engine calculator and solving for deck height it yields 1.28mm for a CR of 9:1.

So I need to remove 2.00mm - 1.28mm = 0.72mm.

I'm pretty comfortable with my measurements and with this math.

My question (finally) - can I remove 0.72mm from the jug, or do I need to remove it from the head?[i] It'd be much easier for me to remove it from the jug, so I'd prefer that, but if the conventional wisdom is against that, then I'll send the heads out.

If it is OK to remove this material from the jugs I could get it done this weekend and complete the short block...

As always - thanks in advance for all assistance.

If the heads have a 1mm lip, did you account for that in your combustion chamber number?
Or did you measure the comb. chamber volume?

You comb chamber number seems smaller than a stock head.
I had to shave my heads down significantly to get below 55 cc.

Stock is almost exactly 60 cc.

I did account for the 1mm step in the heads in my combustion chamber number, or rather Len did at HAM. I did not CC the heads myself, that was done by Len at HAM. The spec sheet that came with the heads says the chambers are 55.2 CC. I am pretty sure Len's number is accurate. Much more so than mine.

I am taking .72mm off the top of the jugs today. Should be a good time.

Ordered Sabo seal from GoWesty last night - appreciate the heads up.

Are you sure about the size of your chambers? When I did mine they were in the 59cc range. Did you do the whole clear plastic disc and burette thing. It's been a while since I did mine but I had to use spacers that I ordered from aircooled.net under the cylinders. I ended up with 9.5 : 1 compression and it runs fine on regular fuel.

I did not CC the heads myself - but have been through the process for other engines. These heads are the RS+ specification heads from HAM (Len Hoffman). They came with a spec sheet that includes the combustion chamber volume. I trust the numbers from Len.

Len did my heads too. I measured them to make sure everything matched on all 4 cylinders. My finished deck height with spacers was .014 with a combustion chamber of 59cc my exact compression ratio is 9.3 to 1.

So I did the calcs myself and got 8.37CR with a 2mm deck height which agrees pretty well with the CB calculator.

on the CBPerf website, When I plug in 96 bore, 71 stroke, comb chamber 55.2, compression ratio 9.1, and click solve for deck height I get 1.17mm.

So your target of 1.28mm will get you to 9.0:1 CR.

And sorry if I missed it, I assume you will run with no head gaskets?

Are you certain your final deck height was .014?

From what I recall from research is that you should not have a deck height of less than .025 (.65 mm Min) to allow for piston expansion.
I am sure it depends on the specific piston material, but that was a rule of thumb that you supposedly should not cross without knowing what you were doing.

I was trying to get maximum CR on my build and had the engine assembled with .024 DH, and chickened out and tore the engine back down and increased to more like .030.

No head gaskets...

The deck height of .014 was before I added a .020 spacer. And my 59cc was before I decided to send my heads to Len to have them rebuilt. He welded up the spark plug holes and changed them to 12mm. I can find my notes for the finished head combustion chamber after Len rebuilt them. I know my compression ratio is a little more than 9:3 and I was worried about it being to high at the time.

I decided I always need to know where my crank is - I mean - that's just a good idea...

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Degree wheel is an old Ducati piece. Where we say "degree wheel" the Italians turn it into a song and say "goniometro per messa in fase dei motori a 4 tempi". I mean, it says it right on there. Rough translation = "goniometer for commissioning phase of the 4-stroke engines".

"Commissioning phase" - I like that...

So disregard pretty much everything I said. I found a photo of my heads after I got them back from Len. When he finished I had a 60cc combustion chamber. Jake bored my factory jugs to 96mm and with KB flat top 96mm pistons the deck was .014 and with a .020 spacer and no head gasket that put my compression ratio at 8.8:1. My OEM cylinders must be shorter than what you are using. I used short peices of tubing and snugged the head bolts to hold the cylinders in place before I took measurements. I had to swap cylinders around and clean some minute gasket material off the registers until I got both banks to have equal pre and post spacer deck height. I also had to sand the spacers with oil and wet/dry sand paper. Both banks weren't the same but both pairs matched when I finished.

More fun finding TDC on #1. This fan from a bus (of course) so no marks on the fan itself, just a single mark on the pulley. That mark lines up at about 32 BTDC - which I think makes sense for a bus. You can barely see that mark (white dot) in the second image. Of course my pics will be rotated to appear as if I may have been standing on my head when I snapped them...

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I suppose I need to make some marks so I can time this thing from the top through the timing sight in the fan shroud....

I time my engine from the rear using the flywheel marks.
There is (should be) a machined notch with white paint at TDC #1.
I made a yellow mark 180 degrees from that.

I can time my engine with the white mark thru the hole in the top front of the trans case, and I can set my valves from underneath using the white & yellow marks alternating as I rotate for each set of valves.

You can see the white mark here:

https://www.youtube.com/watch?v=QtPd5qzyTk8

I dont use the marks on the fan for anything anymore.

First: I would try to quantify the effect on deck height measurement of rocking the piston in the bore. You might find it is significant, or you might find it is not so.

Second: Removing material from one or both ends of the cylinder will raise the compression, not reduce it.

Third: If Jake, who designed the cam profile and had input on the chamber shape and porting, says you should target 9:1, I would do what I can to get as close as possible to 9.000:1.

--DD

First - I did attempt to quantify piston movement during deck height measurement. I would raise the piston in the bore until it just kissed my calibrated screw, not enough to move/rock the piston. Then lower piston, turn screw 1/4 turn (.25mm) then raise piston again. In all instances the 1/4 turn was too far, essentially using up all available piston "rock" and stopping the piston before it reached TDC (engine would not turn any farther). So - piston rock less than .25mm and my deck height (in the jug) of 1.0mm seems accurate.

Second - agree, I am removing .72mm in an attempt to raise the compression ratio to 9.0:1.

Third - COMPLETELY agree.

Thanks for the input DD.

More progress. Have spent the better part of a week fabricating a fixture to take material (.72mm) off the top of the jugs in order to get the CR desired.

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The jugs is very nearly an interference fit onto the fixture, and slides down to a shoulder to ensure all is true. Will use the tailstock on the lathe to make things even more secure/stabil when making the cut to the jugs. There are 4 aluminum set screws on the inside of the fixture to secure the jug. Is this overkill - YES. But all will be very true, and very much the same once completed.

Never drop a brand new cylinder (or any other cylinder you might want to use). I turned down 3 of 4 cylinders using my wayoverthetop fixture, then tripped slightly on a dogs leash in my buddy's shop allowing the fourth cylinder to escape my grasp.

Damaged the skirt ever so slightly and it will not slip over my wayoverthetop fixture.

Anyone have a single 96mm cylinder laying around that they feel the need to part with?

Yep, got a box with 4 of them that may work for you just gathering dust....I'll ship them to you & you can decide to pay whatever is fair IF you can use one & you hang on to the rest for the next unlucky dude. PM me your address--

I love this place. PM sent wndsrfr.

Nice setup for trimming. I wish I had a machine shop at my disposal.

One thing keeps nagging me. Why have I NEVER seen someone else ever trim the jugs like this?

This is the first time I have ever heard mention of it.
I have 9.5:1 and didn't have to trim my jugs.

I think that lip on the heads is what killed you.

Stugray - I agree about trimming the jugs. I asked quite a few times about it in this thread, got no real response. In all of my reading/research, material was removed from the heads to raise compression, never the jug(s) - which is why I asked so many times.

I bolted the heads up and measured clearance before deciding to go this route. Head - Jug clearance with everything torqued to spec was 1.25mm, so removing .72mm from the top of the jugs should not (I pray) create an issue there. Perhaps the 1mm step in the heads is the reason, not sure.

All clearances will get very carefully measured as it goes together.

I just gotta try not to drop anything else important...

OK....jugs went out via Priority Mail today, prolly be there Wed....

Thanks wndsrfr. Let me know what the shipping was.

Is there an official opinion on cylinder - piston clearance? I am measuring .002 and well, that seems very tight. I have already gapped my ringset (.020 top, .015 second), but if I need to hone the jugs for more clearance I will source another set (of rings).

And I thought I'd have this thing built by now....

Was there a sheet that came with the pistons telling about p/c clearance? Are you using KB hypereutectic or J&B forged?
Here's a link to clearances--I used the "Baja aircooled" recommendation on my build.
http://www.hughesengines.com/TechArticles/...cticpistons.php
Don't sweat shipping til you know if the jugs are useable...

OK - so I had to take a break from this for a few weeks - other life priorities got in the way. I'm still not sure what I will do about the damaged jug - but should know this week. That means I will be able to finish the long block this week and then onto valve train geometry (yes, I said that back in February also).

Still no adjustable pushrod from Type IV Store, so I need to sort that out.

Some questions...

Can I set crank thrust (end play) with the long block all bolted up or do I need to do that before I get pistons, cylinders and heads installed? Crank moves very freely for/aft before everything bolted up.

For ignition timing - I have been told by someone I trust to set initial advance at 14*, and full advance at 28*. But not sure if this is BTDC or ATDC. Does this mean I should make marks on my fan at those degrees of crank rotation (I have a degree wheel on the fan/crank) for use in timing later? I think yes, but would like other opinions.

I need a distributor. Curious about opinions on what to use and where to get.

You can set the endplay with the engine finished and just before you bolt on the FW for the last time.

Timing is usually set to 5deg BTDC 'static' before you fire up the engine for cam breakin.
You wont be able to set it properly until after breakin.

I use the mark on the FW through the access hole on the top of the tranny and a variable timing light. For me it is much easier to see than through the fan housing hole.

https://www.youtube.com/watch?v=QtPd5qzyTk8

for dizzy, I use the mallory unilite, but they have been discontinued and are hard to find.

Not sure anyone else responded yet, but removing material or reducing deck height will increase your CR. If you are at 9.3 and want to go to 9.1 you need to increase deck height (meaning top of cyls). I added a .60 mm spacer under the jug to increase deck height and used NO cyl head gaskets or paper base, and with my Hoffman Rebuilt Heads am running about an 8.6:1 compression ratio. So a .55 or .50 should put you in the ballpark, but you can do the math if you want to be exact.

from Removing

Having read a little more about timing today and given this a little more thought, the 14* initial and 28* full advance numbers I was asking about must be BTDC (hence why they are referred to as "advance"). So I plan to mark my fan at 0* (true TDC), at 5* BTDC (for break in), and then also at 14* and 28* BTDC for final tuning.

Stugray - thanks for the info on crank endplay - much appreciated. I really do need to find a dizzy.

Steve Pratel - I have moved on from the CR thing, have removed .72mm from the tops of the jugs targeting a 9:1 CR.

Finally made a little more progress. My dropped cylinder was able to be repaired (don't ask - but I am comfortable with what was done). So I was able to jig it up into the lathe and remove material from the top of it. Now that all 4 cylinders are the same height, I can move forward.

WNDSRFR - I did not use any of the jugs that you gifted me. I will PayPal you the $15 shipping this week, and will store those jugs in my barn either until the end of time, or until I can pay it forward for someone else to use. You are a scholar and a gentleman (I think).

Checking ring end gap ...

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I think I mentioned earlier I set top ring at .020, second ring at .015. Piston to cylinder clearance left at .002.

Installing pistons into jugs...

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I hate (HATE) these new (to me) spiral-in wrist pin retainers. I hate them I say!

And finally on side goes together (sort of still). I mangled one of the oil scraper rails so need to make an order before I do the other side. For now this is loosely bolted up with spacers and I will return to it when I get back from a week's worth of travel for work.

I still hate the spiral-in wrist pin retainers. No one can change my mind on that.

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Have I mentioned that I hate the new spiral-in wrist pin retainers?

I saw a youtube vid where the person stretched the springs out so they looked more like a spring than a washer when sitting on the table.
Then they can go in with one finger.
You just start one end then compress the spring and they snap right in.

For getting them out, I took a tiny screwdriver and bent the tip to form a tiny hook to grab the end.

Like this one:
https://www.youtube.com/watch?v=vOYH_WICGYM