Hey folks! I have the bottom-end of my 2270 assembled and spinning freely. Thanks to all who helped me get to this point!



To quickly recap: I bought the 2257 kit from AA Pistons (78mm stroke, 5.158" rods, etc.). And when I threw a P&C on for a test-fit last weekend, I immediately noticed the piston sitting proud of the deck height at TDC (negative deck) by about 2mm.



Before I overreact, or buy the wrong stuff, I thought I'd ping the community...

1. Is this normal for a stroker set-up?
2. Can you stack multiple shims when getting up into the .06 >> .09 range?
3. (If no-stack) What's the best place to have custom shims cut?
4. I recall Jake saying using large shims requires lots of advance, anyone have experience here? What am I looking to adjust for upon start-up?

Once I figure out whether or not this is normal (I.E. verifying that I don't have to backtrack), I'll get into the CR questions (just waiting on clear plastic from Amazon so that I can measure my CC volume this weekend)

Thanks!

1. It's all in the combination, what pin height on the pistons, rod length, cylinder length, etc. You might want to rethink your rod length to get a better rod ratio (rod length to stroke). But, yes you're looking at getting some proper thickness cylinder spacers.

2. Measure multiple times and get one spacer per cylinder that are the correct thickness.

3. The type iv store sells them, Blanchard ground to the thickness you pick from their website.

4. Design your motor for less compression or at least, the appropriate compression ratio. If it's too high, it will put out too much heat and you will also need to retard the ignition to prevent pre-detonation. You want maybe around 8.5 to 9.5 max and somewhat dependent upon the altitude you're running it at. You'll want good quench, a deck height probably of at least .040, so cylinder head shape and volume needs to be measured and designed to meet your goals.

Did you buy the long liners?
I’m guessing those are taller cylinders from AA??

Rich

Strokers are a lot of fun but also a lot more work to get right. Best wishes for a successful build.

BTW, I'm guessing they're not the longer liners.

Why don't you call AA and see what they have to say? Wrong pistons/cylinders or missing correct spacers

You are asking the wrong question.
Stop everything else with this build and start here:

What is your target CR? Don't make or buy anything else until you have decided this!

Once you know your target CR, do the calculations (lots of CR calculators online). You will need to know (really know) your head volume in CC for this. Easy to find, but its a little extra work.

At minimum you will need a .123 inch (3.13mm) spacer to give you a .040inch deck height. You MAY need more then that. You won't know until you have done the full CR calculations to figure out your optimal deck to secure the CR you want. If your block is square and cylinders equal all 4 spacers will be the same. Don't count on it though!
You will still need to straight edge the tops of the cylinders to make sure they are aligned flat to each other so they sit right on the head. And don't forget to measure deck on the wrist pin. Otherwise the piston rocks a little on that axis and you will get inconsistent measurements - that get worse the farther you are from the pin axis.

The good news is that once you know, you just call one of the shops above and get base spacers made for your specifications.

I built my first engine just winging it and learning as I built. I learned a LOT. I then rebuilt the engine a few months later when it failed. The second engine ran for years. It was a very expensive lesson. Start with the math and go from there.

What is your CR target. That's the math you need to do right now before going any further. Hopefully you already did the bearing clearance math and fitting!

Good luck!
Zach

Read!
Here, on Shoptalkforums, other places…
This is not an IKEA kit.
Before spending big dollars and time, READ!!

@vjb206

That looks like my motor did. It is currently apart on my welding bench waiting for my case, crank, and bearings to come back from the machinist.

I'll measure them and get back to you.

You can shim the cylinder base, use a copper gasket from the head to the cylinder, trim the top of this piston (not the full amount), use a shorter rod, or use a combination of those things.

You might want to consider using some rubber bands across the head studs and through the small end of the rod to keep them from slapping the cylinder sealing surface while you spin it.

@MikeK great idea! Don't want any scoring.

@cgnj just knowing that this is not unique to me is very helpful. If you get to it that measurement that would be great, if not, no worries. Out of curiosity - why is the motor apart? Anything inherent in the combo that I should be aware of?

@Krieger I called AA and this is normal (I.E. they didn't send me the wrong pistons).

@VaccaRabite very useful info - thank you! I'm just not there yet... Need to take more precise measurements before doing maths. I'm looking to get to an 8.5 or 9 CR (still deciding which is best).

The cyl head is listed at 60ccs, but I will measure them with fluid this weekend.

I'll follow-up early next week with:
• Head CC ccs as measured with fluid
• _Actual_ deck height as measured with a dial gauge (as I said, the one in the picture is just a sanity check)
• Shim / head gasket plan as a result of more detail

Appreciate everyone who weighed in!

vb

Sorry, must disagree with some of this.

A copper gasket between the head and cylinder won't fix the problem of negative deck height. You'll break the motor on start up.

A shorter rod isn't a good idea (and what size/where would you get one?) as the rod ratio is already 1.68 and going to a shorter rod would decrease it even more.

Trimming the pistons might work, but would not be the first area to consider to fix the negative deck height problem. Start with correcting the other problems and get the proper shims made.

There's more to the compression calculation and an engine build, but based on your #s, it's looking to be around 9.4. That might be high if you're looking to daily drive it and the car doesn't spend its days at high altitude.

My point was that there are several ways to get the desired result. It's unfortunate that the T4 cylinders that they are selling with their kit don't have longer cylinders like their thick wall, 92's. It's nice to have the cylinders trimmed for the correct deck height and avoid shims altogether.

I guess a shorter stroke crank would solve multiple issues, but I doubt that would be an viable option.

@vjb206
I lied somewhere. I said my chamber volume was 54cc. It is 52cc. My base cylinder shim is .140 in. I don't use a head gasket. My rods are 5.325 (vw length). I run big valve 44x38 1.8 heads with 2.0 angle 12mm plugs by Headflow Masters. Adrian was the go to guy in 2002.

Why did I take it apart. I have Dirk Wright disease. I took it out to bench run it and look for a tiny oil leak. I still had good compression and leak down above 96%. I replaced my Shadek oil pump because it was at max undersize. I installed a non stock oil pressure relief valve. The part stuck in the bore & I was running without gauges. I took it apart and found the oil pressure relief valve scored. So I decided to replace all of the bearings and rings and cylinders

You need to swap the short cylinders with the long ones from AA.
Start with that process.
Then you will have a reasonable place to begin measuring.

While you wait, learn how to CC measure your heads, build that jig, get that done

You'll need to shim bottom of cylinder to achieve correct deck height after CR target is determined. There's a online calculator. probably should stay with CR 91 or lower if for street/ available octane rating. The calculation takes in account of head dome dimension.
mark

Thats the right path.

If you measure deck height along the wrist pin, a dial indicator is overkill. It does not hurt, but your calipers are precise enough for that particular job. You WILL want that dial indicator later though when you set pushrod length. The problem for this application is that its too precise. You are going to struggle to get a repeatable measurement in the thousandths of an inch that you would not as reliably get to the hundredth with your calipers.

For CR, I'd personally target 8.6:1 for a street engine. This lets you run on regular gas. More importantly, the AA cylinders are iron and uncoated, and will struggle to shed the heat produced by a 9:1+ CR. BTDT. If you want the higher compression, you are going to want to get your pistons coated and the inside of your heads too. And then do the measurements again, as you will have added thickness to the pistons and reduced the CCs of the heads.

The important thing is to pick a CR and get precise - don't pick a range (8.5-9) pick a number and work to that. The changes from 8.5 to 9 are pretty small in terms of deck height. But it makes a big difference in power output and heat and drivability - especially for longer drives.

Zach

This is good but it doesn't tell the whole story.

Your engine parameters are decided due to expected use and EVERYTHING needs to match.
You've got a 2270 which is where I would want to start.
Pistons are sticking OUT of the cylinders. I want this as well.
It's EASY to shim.

Everyone is advising "come up with a CR and target that which is good advice.

When the engine is functional it is NOT the same compression ratio that you modified for.

Cam selection denotes when the intake valve closes during the compression stroke.
Big cams close the valve LATER than small cams and VASTLY reduce compression ratio.
What you're setting with all of the math is STATIC CR. It is a "make believe" number that doesn't actually produce the same ratio when the rest of the engine is taken into account.
What the engine runs on is DYNAMIC compression and everything plays a part.
Camshaft selection has the biggest effect. Timing of said cam is the second most important step.

Too much intake restriction REDUCES the amount of air that can get into engine.
Too much exhaust restriction REDUCES the amount of exhaust that can exit and can trap excessive heat in the system. This is worse than intake restriction in my book.

Exhaust and intake selection also play a huge part on CR and cam selection.

All of Jake's engines say "must have Billy Badass exhaust". There are really good reasons for this.

Try to run that engine through a normal set of SSI Heat exchangers INSTEAD of a dedicated serious exhaust and you need less compression and less cam.
You will accordingly make less power.

Jake always posted about "balance" and he wasn't talking about stuff the machine shop does. He was talking about having all the parts "matched" for the engines intended use.

I'm prone to build to the outer edge of "streetable" and use the highest-octane fuel that I can easily acquire.

The range of 8.5-9.5 should work OK for a street engine. The higher CR needs a different cam than the lower CR.

What it boils down to is EVERYTHING is important at this level of engine.

You should have had an entire plan before the build.

Another thing that Jake stressed was that he had more money and time in the heads than in the entire short block.

Port flow is stupid important in the above engine. That's the biggest sticking point in my build. A 2270 needs heads that can flow 30-50% more air than a 1.7-2.0l engine.

Good heads get expensive fast...

The current crop of heads are Chinese and can have failures.
Jake says he only uses the bare casting and everything he puts in the heads are "bespoke" parts special to him. This says MUCH!
AA offers the heads BARE for just this reason...

Almost 1/4" of shims, isn't that a lot? I would look for longer cylinders.

+1

Yes, agree with post #18 from the ninja above.

An example is the 2615 we are starting to build. Some of the particulars are: coated pistons, DFL on skirts, starting with brand new bare heads with modified & coated exhaust ports & combustionchambers/valves, special/custom valve train components (including cryogenic treatments), "nickies" cylinders, custom dual pattern "big" cam with more exhaust duration, etc, etc. Lots of time invested in researching and developing the plan before starting to acquire the parts and starting to machine parts.

As already mentioned, stroker motors are a lot of fun, but lots more work to get right.

I'm planning on re-using the original Mahle cylinders and having them bored due to the posts I've seen on here.

The original German stuff is BETTER quality than what is available now. (with the exception of Nickies).

It will actually be MORE expensive to have my cylinders bored out than to just purchase new but I will be able to control P-B clearance better and will end up with a plateau honed surface.

The biggest area that the new cylinders seem to have trouble with is length.
The original German stuff looks to have a variation in length under .001" and the Chinese junk seems to run =/- .005.

On an engine with P to CYL head clearance above .065 this will not matter at all.

I build engines with as tight a quench number (p-cyl or "deck") as I can get away with.

I'll be under .040 on cast and .045 on forged and a .005 variation means DESTRUCTION of engine.

So I'm starting with used parts that will cost more to prepare than just buying new.

Did some measurements this weekend!


My combustion chambers are 60ccs. Measured with fluid as well as called the manufacturer. Double confirmed.


Deck height is -0.090. Got that with a dial indicator.

@cgnj LMK if this is in your range if you recall...

@VaccaRabite great to know re: CR range (and thank you for the details, really)

So here's what I'm thinking, would love opinions...
• Base shim of 0.090
• Copper head shim of 0.08
That'll get an 8.6 CR

...a 0.060 copper shim would have gotten me to an 8.9CR. I would have run with that prior to reading this thread, but maybe not?

Have you fully researched the use of head gaskets? If not, do so then make your own decision.

I don’t want to rehash the topic which is contentious.

The thermal linear coefficients of expansion for aluminium, copper, and steel per degree centigrade are:

Copper 17∙10E-6
Aluminium 23∙10E-6
Steel 12•10E-6

@Superhawk996 Looking into this now... Thank you for the heads-up.

You need a base shim of 0.135 and NO fire ring (Head shim) at all to achieve .045 deck height. This is for forged pistons.

Base shim of 0.130 for cast stuff.

Few use a head shim (fire ring) today due to what Superhawk referred too.

If you create a deck height clearance LARGER than .060 you eliminate the quench action which VASTLY increases the tendency to detonate and reduces your compression ratio.
Bad in two ways...

Less power AND an increased requirement for higher octane fuel.

I built a 2056 a couple years ago and was on the fence with regards to the use/no use of a head gasket. I checked and double checked everything including Plastigage at quarter points at the cylinder/head mating surface after torquing everything together. I was pleased with the results and learned mating the heads to the cylinders without any sealing product works well.

I missed a critical point!

Check deck height on ALL pistons, don't assume they will be all the same height, they seldom are.

Choose your shims for the cylinder with the most piston height!

I'd also make damn sure the height of the jugs matches per bank.

Detail in the grand scheme of things in the current state of discussion, but I don’t see where you have measured the volume of the pockets in the pistons.

I maintain my previous comments. This is not an IKEA kit.

Need to read a lot on building a strocker high power type 4 engine before starting to put parts together!!!!

Good luck with your project!

I think you need the longer cylinders from AA.

Might want to check the deck height for all cylinders, don't assume they're the same.

In addition, you might want to skip the copper head gasket, unless you're racing the car and will re-torque the heads regularly. And using your numbers, you're aiming for zero deck height? If you use a head gasket and zero deck height and you've measured even a little off (again, check the deck heightfor all cylinders), you might end up hitting the piston crown on the head gasket, if it encroaches into the cylinder. Might get away with it, might not. Better to figure it out now before the mock-up. No matter what, plan to mock things up a bunch of times before the final assembly.

AA Pistons only lists longer cylinders for 103, 104 and 105mm cylinders.

Also don't forget:
Pushrods will not be stock. Buy cut to length and determine the valve geometry.
Since the head spacing will be further apart, there might be some fitment issues depending on the induction system used.
Pushrod tubes will need to be either modified or spaced out slightly for the additional length.
Rod/case/cam clearance will need to be checked and verified.
Not too major, just a lot of "this" will change "that"

Definitely planning on getting deep into the valvetrain geometry, but want/need to install the heads 1st.

If I'm 90 under and get a 90 shim I'll be at 0. Then the head gasket = my deck height. based on the thread above, I might not want to go that route in the end (still doing some reading per @superhawk's recco).

Can / should multiple cyl base shims be stacked to achieve desired deck height (rather than doing a cyl shim + head gasket)?

My vote goes to NO head gasket

Can they be stacked - yes

Should multiple shims be stacked - no.

Each time you add a head gasket or stack shims you are creating potential leak paths by adding unnecessary interfaces between parts.

Just going to do some more reading before pulling the trigger on the Type 4 store .150 Blanch Ground Cylinder Shims. Soon. This will get me me an 8.9 : 1 CR. Type 4 Store 2270 page says, "Target compression ratio is 9.0:1 using pump 91 octane or 9.5:1 using pump 93 octane (R+M)/2." So that's just giving me pause that perhaps I need .140. Either way, single shim. No fire ring. I'm in NJ (no altitude, and not mountain climbs) and will run 93 octane at all times.

Also will measure my valve pockets, and factor that into the CR calculations / internal debate.

While I'm mulling that over the plan is to take apart my feeler gauge to set the deck height approximating a big .150 shim. While the deck is mocked up, I'll start playing with the valvetrain geometry. I have an adjustable pushrod so I can start to get the feel. This is the 1s time I'm doing this so I want to have time to explore....

Thanks again for all who have weighed in!

Proper quench distance is far more important than staying under a specific compression ratio number.

You take an engine with no quench that requires 93 and INCREASE the compression ration by decking the block (adjusting shim size on a T4) to achieve optimal quench and the engine can now run regular without detonation.
The really wild thing is the higher compression engine will also require 5-7 degrees LESS timing to achieve MBT.

MBT stands for Mean Best Torque and is how a steady state dyno tunes.
You continue to add timing (at a specific rpm) until either the engine detonates (detonated limited timing) or you see no further increases in torque for additional timing.

Also, your compression ratio is low enough already that a decrease of 1-2cc in compressed volume is only worth .1-.2 increase in compression. IE you end up with a 9.0 or 9.1 engine instead of an 8.9...

Do some reading involving "quench".
IMO it's the MOST important clearance to get right.
Getting this wrong can be worth 10% less power and a requirement for higher octane fuel.

For a customer job on a sub 4" bore with decent rods (h-beams) and forged pistons I want to hit .045.

On my personal stuff I might go a tiny bit tighter. I'd run as tight as .041-.042.

This clearance must be verified for all cylinders and the tightest used as the reference point for shim selection.

Just noticed the baby syringe in the video. A real burette is far more accurate!
I use a cow syringe in a pinch. They are really handy for chambers at or under 60cc as the cattle syringe is a 60cc unit.
The cow syringe is also not as accurate as a burette but getting the measurement in a single syringe load helps accuracy and if you use the same syringe for each cylinder measurement you will be fairly balanced between cylinders when you are finished.



What cam will you be using?

Induction?

Exhaust?

@vjb206

I used a .140 shim. No head gasket. I lapped the cylinders to the head. Rods were machined as described in #5 in attached Tech Bulletin. I used Manton CrMo pushrods. Buy n extra pushrod and make your own adjustable push rod. The tips on the adjustable push rod that I used were not the same and caused measurement error. It is possible to stack washers in the pushrod tube bore to space out stock pushrods. EMS sells stroker tubes.

Click to view attachment

+1

We use a 100 ml burette with a three finger clamp for accuracy and repeatability. BTW you can fly cut the heads to reduce chamber volume and increase compression ratio among other ways.

I'd say that if you got 60cc measuring with your little syringe and your machinist got 60cc, then 60cc is probably right. Move to the next task. :-)

Pay attention to @cgnj 's post. You will need the stroker tubes and you will need to make your own pushrods. You will likely need shims between the rockers and the heads. EMS sells the shims. In the dark ages I just used a washer as a spacer too though. I did measure the thickness of the washers though so I could get them the same size.

When you use the the spacers you may need to shorten the adjuster stem a tad or it will tap against the valve cover and scare the bejesus out of you!

Zach

I honestly never thought about the pushrod tube length. Great call-out to start to prep for that step (not there yet). Thank you.

Where can I obtain a set for my specific additional length (either 0.14 or 0.15)?

Re: all the valvetrain stuff: I am going to follow Ian Karr's pushrod and valvetrain geometry guidance. To that end, I contacted Tabari and am investigating all that needs to happen to go from my stock 1.7 set-up, to what I need.

EMS? Link me?

Rubber bands were mentioned found this picture to add

If you haven't figured it out yet.
https://www.europeanmotorworks.com/vw/type-4-engine-parts

This list is really good as well. Stickyed at the top of the "garage" page.
http://www.914world.com/bbs2/index.php?showtopic=361087

I LIKE the rubber band idea!
Best "rod holder" I've seen yet...

Amazing! Thank you so much.

Yes! thank you!

This is REALLY REALLY valuable. Thank you for adding this.

FYI I'm running a WebCam #163/86b and carbs. Exhaust I'm still working out. Finances may require me to re-use my existing exhaust. The dream is the Tangerine Racing w/ heater; but $$$$$ ¯\_(ツ)_/¯

Just to close the loop here, I ordered a few shims just to start measuring with a non-proud deck-height and am taking more measurements around different areas of the piston.



Right now with a .150 shim I have .064-.068 deck height depending on where on the piston I measure. A few folks have guided me towards a .045 deck height as optimal for quench ( @cgnj , @technicalninja , etc.) so I'll need to wait for 0.13 shims to come in.

Then I'll find time and do this for each I guess since I've been told I can't assume all cylinders will be equal. Lots of measuring and trial-and-erroring until I get as close to .045 as possible; taking as many readings as possible from various points along the surface of the piston.

The 2270 recipe I'm following calls for 9.5:1 with 93 octane (which we have here in NJ), so I'll be a little under with an estimated CR of 9.2 (averaging out my various readings along the surface of the piston). I was originally thinking 9.0:1 "just to be safe," but I do realize now that's not the way to approach this.

Thanks again for all of your help!

I'd run 9.5-10 on that cam.

It's a good street cam for that engine (with the proper heads).

cgnj is running that same cam on 10.3!

AS long as he doesn't detonate that will be STRONG in the mid range.

Too small a cam for compression makes more torque down low.

At 9.0-1 that cam will be opposite for you. Screamer up top and less meat down low.

Yours will be less prone to detonate than cgnj's IMO.

It's all about dynamic compression, your engine at 9.0 versus his engine at 10.3 static will have a different dynamic compression ratio. His will be 2 whole points higher than yours with the same cam.

I want to run AS MUCH dynamic compression as I can WITHOUT detonation!

His engine may be iffy on 93, yours should work fine!

I am VERY interested in how cgnj's set up works for him.

The way he's going is the way I want too...