Compression Ratio, Will I be able to tell the difference? Options

[Jack Standz]

Modified #2.

Bolt transmission to engine. Remove spark plugs. Make 1000% sure the fuel system and ignition system are disabled.

Hook up gauge to where the oil pressure sensor goes (use correct thread gauge). Here's one gauge kit:


https://www.harborfreight.com/engine-oil-pr...-kit-62621.html

Hopefully, you will have good oil pressure when you crank it.

[930cabman]

Have you checked crankshaft end play?

[worn]

Yep, I don't want this help. Y'all go build your own shit.

I am afraid that I have to agree. The help is valuable and the helpers are first rate. Still, simply discarding and disbelieving what you posted wasn’t fair nor was it helpful. I am only chiming in because not doing that is what makes this board great compared to some where a poster is assumed to be stupid until proven otherwise. All of the posters are people that I respect and admire.

To put my own neck on the block I would say that my experience with a 2056 has been to reduce compression. Too much heat. But I am the idiot who doesn’t torque head nuts (IMG:style_emoticons/default/headbang.gif)

[sdoolin]

Modified #2.

Bolt transmission to engine. Remove spark plugs. Make 1000% sure the fuel system and ignition system are disabled.

Hook up gauge to where the oil pressure sensor goes (use correct thread gauge). Here's one gauge kit:


https://www.harborfreight.com/engine-oil-pr...-kit-62621.html

Hopefully, you will have good oil pressure when you crank it.

Thanks for this, and the link. This will be my plan. Carbs won't be installed, no plugs. So no fuel and no spark. I'll order that gauge.

Cabman - I have checked end play, per the instructions in my 40 years old Haynes manual. Installed 2 shims, then flywheel, measured, subtracted .004 (or whatever the manual says), and then selected the third shim based on that measurement. I have not re-measured after third shim selection (flywheel not yet installed).

[sdoolin]

Yep, I don't want this help. Y'all go build your own shit.

I am afraid that I have to agree. The help is valuable and the helpers are first rate. Still, simply discarding and disbelieving what you posted wasn’t fair nor was it helpful. I am only chiming in because not doing that is what makes this board great compared to some where a poster is assumed to be stupid until proven otherwise. All of the posters are people that I respect and admire.

To put my own neck on the block I would say that my experience with a 2056 has been to reduce compression. Too much heat. But I am the idiot who doesn’t torque head nuts (IMG:style_emoticons/default/headbang.gif)

Thank you worn. The first few responses to my original question were not helpful, and in fact I think the opposite. I try to post concise questions, based on things that I really need help with.

By and large, over the years, this forum and most of the members have been greatly helpful to me and most others.

This build will have slightly reduced compression over my first build. If I solve the oil pressure problem I'll be a happy camper.

[Al Meredith]

Years ago when Len Hoffman was rebuilding heads he took a set of my 1.8 heads and welded up the stock 1.8 spark plug location and relocated it to the 2.0 location . Then he would tap the hole for a smaller motorcycle plug thus allowing more meat between the plug and the exhaust valve seat where the cracks form. The 1.8 has a combustion chamber of 52/53 CC and the 2.0 at 58/60 CC which calculates to 9.5 CR. KB 96MM pistons and a .040 squelch. The KB literature claims that the tight clearance makes the head run cooler. I'm running 44 MM carbs which tend to run rich therefor cooler. I have no cooling problems Al

[worn]

Years ago when Len Hoffman was rebuilding heads he took a set of my 1.8 heads and welded up the stock 1.8 spark plug location and relocated it to the 2.0 location . Then he would tap the hole for a smaller motorcycle plug thus allowing more meat between the plug and the exhaust valve seat where the cracks form. The 1.8 has a combustion chamber of 52/53 CC and the 2.0 at 58/60 CC which calculates to 9.5 CR. KB 96MM pistons and a .040 squelch. The KB literature claims that the tight clearance makes the head run cooler. I'm running 44 MM carbs which tend to run rich therefor cooler. I have no cooling problems Al

What a story. Thanks. Adding this to a recent post in another thread from Clay I now know that 914s can run, and run quite well, with motorcycle parts sourced from Walmart.

[sdoolin]

Have you checked crankshaft end play?

So I re-checked this today. Installed three shims (as measured for), rear main seal, and flywheel. Just trying to move the crank "for and aft" by hand, or even with an easy/gentle pry produces no discernable movement. Setting up a dial indicator to measure for and aft movement again yields no discernable movement. Spinning the crank with the dial indicator positioned as pictured below produces a maximum needle sweep in the dial of .1 mm (.0039"). Which might be right? I am not particularly comfortable with this measurement.

[Superhawk996]

No discernible crank end play is a no-go.

Redo until it is correct. Likely shims weren’t correctly measured / calculated. There is no harm in doing this several times to be sure it’s correct. When doing the mockup / measurement of shims the flywheel must be fully installed and torqued so that the flywheel s firmly seated to the crank. Personally I set and measure end play before installing the RMS since you need to remove / install flywheel several times to get the right shim selected and measured.

Disregard spinning the crank measurement that has no relevance to crank end play.

Hint #1: when you make this measurement the dial indicator must be perpendicular to the the flywheel. May just the the angle of the photo but to me it looks like it is at an angle.

Hint #2: mount your dial indicator to the engine. You want the relative measurement between the case and the flywheel only. Mounting the indicator to the engine stand adds error and uncertainty to what you are trying to measure . Alternatively you could have the magnetic base on the flywheel and the dial indicator touching off the case.

[sdoolin]

No discernible crank end play is a no-go.

Redo until it is correct. Likely shims weren’t correctly measured / calculated. There is no harm in doing this several times to be sure it’s correct. When doing the mockup / measurement of shims the flywheel must be fully installed and torqued so that the flywheel s firmly seated to the crank. Personally I set and measure end play before installing the RMS since you need to remove / install flywheel several times to get the right shim selected and measured.

Disregard spinning the crank measurement that has no relevance to crank end play.

Hint #1: when you make this measurement the dial indicator must be perpendicular to the the flywheel. May just the the angle of the photo but to me it looks like it is at an angle.

Hint #2: mount your dial indicator to the engine. You want the relative measurement between the case and the flywheel only. Mounting the indicator to the engine stand adds error and uncertainty to what you are trying to measure . Alternatively you could have the magnetic base on the flywheel and the dial indicator touching off the case.

Thank you Superhawk. I only installed the RMS as I had measured for the third shim and figured (wrongly) that I'd be good to go. I will re-measure all of this, and will attach the dial indicator to the flywheel as you suggest. I had not thought of that. I have a total of 6 shims, so hopefully some combination of them will work.

[stownsen914]

Separate from the crank end play, if you are asking if .004" of longitudinal runout measured as pictured at the perimeter of the flywheel is acceptable ... personally that amount would not concern me.

[sdoolin]

Separate from the crank end play, if you are asking if .004" of longitudinal runout measured as pictured at the perimeter of the flywheel is acceptable ... personally that amount would not concern me.

Understood, thanks.

[sdoolin]

I have measured all of the shims I have on hand (6 of them). They are - .0115, .0115, .012, .012, .014 & .015. My dial indicator and I had some long conversations today about positioning as I see fit, and I believe I came out on top. Will have the magnetic base on the flywheel, dial indicator tip on the case.

I'm gonna install the 2 thinnest shims I have, bolt up the flywheel and measure (again).

After the snowstorm comes and goes...

[sdoolin]

So, I re-measured crank end play. Installed flywheel (no RMS) with two shims behind it. Measure end play with dial indicator on the flywheel tip of dial indicator on the case. I can't move the crank noticeably for and aft by hand. Prying very gently on the flywheel in the direction away from the cases I measure .43mm (.0169"). This is repeatable.

My manual says to subtract .004" from this, which yields .012". I have a shim of that thickness.

I'm not sure what value I am ultimately looking for after I install this third .012" shim?

Am I looking for .004" thrust with all three shims?

[Superhawk996]

Am I looking for .004" thrust with all three shims?

Yes

[sdoolin]

Thank you Superhawk. Installed third shim, remeasured. I am getting .14mm (.005") repeatedly. Based on my selection of shims, I am calling this good.

Now a strange question. Recall from a few posts back I am going to turn this engine over with the starter while it is on the bench. I'd like to confirm oil pressure. But, I'm not 100% certain how to do this?

Bolt up flywheel, bolt on transmission, install starter. Run the positive battery cable to the starter. Then? Do I need to ground the engine somehow? It will be sitting on an hydraulic lifting table that has a thick (1/2") sheet of delrin type material on it.

[Jack Standz]

Add a cable from the negative side of the battery to the ground strap/bolt on the transmission.

Then attach a remote starter switch like this one, make your own, or use a heavy enough gauge wire to momentarily engage the starter.

https://www.amazon.com/INNOVA-3630-Remote-S...C176&sr=8-4

[Superhawk996]

Thank you Superhawk. Installed third shim, remeasured. I am getting .14mm (.005") repeatedly. Based on my selection of shims, I am calling this good.

Agree. That is in spec. Better a smidge loose than too tight. If I recall I think Raby may have posted somewhere he runs .006” on his high HP builds.

[Superhawk996]

I’m going to ask a question that I’ve assumed you already have done.

Did you use assembly lube on all bearings and cam / cam lobes / lifters as you did final assembly? You shouldn’t be spinning dry waiting on oil pressure from the pump. Apologize I didn’t bring this up earlier

2nd - have you primed the oil pump gears with a light coat of petroleum grease? This helps ensure a quick prime and build of oil pressure. Again sorry I’m asking late but this is easy to do still.

[sdoolin]

I’m going to ask a question that I’ve assumed you already have done.

Did you use assembly lube on all bearings and cam / cam lobes / lifters as you did final assembly? You shouldn’t be spinning dry waiting on oil pressure from the pump. Apologize I didn’t bring this up earlier

2nd - have you primed the oil pump gears with a light coat of petroleum grease? This helps ensure a quick prime and build of oil pressure. Again sorry I’m asking late but this is easy to do still.

Yep, all bearing inserts (cam & crank) coated with assembly lube (Red Line). Cam lobes coated with assembly lube, same with lifters. Rockers & pushrods & valve tops lightly primed with engine oil. Cylinders coated with engine oil. Oil pump gears coated with engine oil.

Update on oil pressure - spinning the engine by hand produced oil at the oil pump output. Bolted on oil filter mount, turning the engine by hand produces oil into the filter. Installing oil filter and oil cooler and more turning by hand and I am getting oil at the oil pressure sending unit bore. So I will forego mounting the transmission and starter to spin the engine, and will install into the chassis. I still plan to use my new oil pressure gauge on first cranking when the engine is in the car (no carbs no plugs).

Thanks everyone for all the help.