I have a CDA21DET in progress.
I am using a CD20 block and a CA18DET head.
I can confirm that oilpump fits, waterpump, gearbox and even engine mounts.
Im a little uncertain about the engine mounts due to the massive girdle of the CD.
Main bearings is the same , rod bearings is 5mm bigger.
I am stroking mine from 88 to 92mm.
The end result is 85.5 bore and 92mm stroke.
The CD block has an extra oilreturn where you have to add some material on the CA head to get it to seal. This is also why a CA gasket won't be an alternative.
You can use the diesel headgasket but you might want to drill some holes in it because the waterpassages are restricted.
Im using custom headgasket with CA water passages. I will also use gas/cooper rings.
The block is ~23mm higher. (corrected from 25)
With 92x85.5 you will need about -4cc on your pistons if you want 9:1 compression ratio.


Any comments, questions or maybe suggestions are welcome.

CA vs SR vs CD Piston and rod:




Diesel HG:





CA VS CD crank, CD block in the background;



CD headgasket on CA head:





I dont remember if i had to weld one or two places on the CA head, but i will try to do it soon now that my TIG is up and running.
I also have two more CD`s incoming!

Just a beautiful thing IMHO. Nothing wrong with being innovative and trying new things. Keep up the good work and just keep the progress coming.

so the CD head gasket is metal? or is this aftermarket?

TheMAN wrote:so the CD head gasket is metal? or is this aftermarket?

Its a "MLS" gasket.
Diesel engines often have metal gaskets.

All the CD20 parts look allot more tough than the CA18 parts.
Because of the block being taller,have you work out what timing belt are you going to use?
Great project you got there. Keep it up,you know i will be watching. Cheers.

Not decided on timing belt yet, but RB seems like a likely option.
Rb uses a wider belt and pulleys wich MIGHT makke som trouble with the balancer.

an-ambicious-project-t524588.html#p6165652

tommey wrote:This cda20det modification wasnt very hard, not alot had to be done.
the CDA22DET is up and running
88mm stroke and 88.5 bore, full counterweight crank.

I thought this was already up and running... I'm slightly confused now.

Anyways, could you by any chance post up a picture of the deck of the CD20? I wonder how the water passages in the block on #4 match up with the CA head.

What rods and pistons are you going with? What are your plans for surface treatment after the offset grind? Have you worked out your rod/stroke ratio?

tommey wrote:Im a little uncertain about the engine mounts due to the massive girdle of the CD.

You mean it might be too tall to fit on top of the S13 crossmember? Do you have an RWD or a FWD CD20?

RS13U wrote:All the CD20 parts look allot more tough than the CA18 parts.

Welcome to the late 80's diesels...

It was a lie, if you read on in that topic you will see it was an failed attempt to get a response from the mad scientist who claimed to have this "hybrid" figured out.

I will post a picture of the deck soon.
I have had the CA gasket on the CD block and it is almost a perfect match.
My custom gasket will have the "outer" dimensions of the CD gasket, but it will have the CA water and oil passages.

About engine mounts i don't know yet, but in worst case scenario the engine has to be lifted a little. There are some ways to avoid this if necessary.
I have an fwd CD.

I am using custom rods and pistons but i haven't drawn them yet.
Going for long rods and 22mm wristpins.

I am not planning on any surface treatment.

Finally somebody's doing this build. I've been waiting for one of these threads to come along since themadscientist (at least I think that's who it was) posted a bit of a teaser but wouldn't tell anybody what the block was.

I hope more people try this.

I came up with the idea a few years ago asked TMS if he could get me a motor if I payed for it and see if it was even possible. He did so and him and I knew that it was possible. He shipped everything but the block over here, and I was going to have the block shipped, but the economy went to crap, then Mike moved, then my oil filter failed and I had to rebuild my motor. I've been wanting to do this for years, but I'm glad that somebody's been able to do it. I'm still planning on a CA-franken-20, but it will be well into this summer before I've got the extra $1K-$1500 to spend on having a block shipped from Japan to Kansas!

so you and mike are part of a secret squirrel club and you've been holding out all this time huh? everybody in the ca18 forum slap TMS and float in the nuts. makes sense as to why TMS wouldn't respond to tommey in the other thread.

high motherfawkin' five tommey, rock n roll bay-bee.

Is $1500 what shipping costs?!
That's what it cost for a container from Japan to Norway..
You can buy one from me, but shipping is expensive FROM Norway.

I will try to take some more pictures this week, the block is probably ready to be taken out of the acid bath now after 2 months..

Thanks for comments btw!
I think i will stick to stroke after all.
I don't want to spend a lot of hours grinding the crank for 92cc more volume, its not an amusing job.

It will also make the pistons and rods i am going to make more attractive for others!

ks13: Yea, I know we suck. It wasn't supposed to be in the closet this long. Oh well, it was bound that someone else would come up with the idea.

tommey: Yea, the last time I checked (about a year ago) it was between $1k-$1500. Maybe I'm just not looking in the right places? It might also have to do with the fact that the yen:usd isn't great. If I could find a way to get it shipped her for less than $1k, I'd do it right now.

I would contact someone who imports cars from japan, they could probably help you out.
A little CD block in the back of a car should not cost much.

tommey wrote:Thanks for comments btw!
I think i will stick to stroke after all.
I don't want to spend a lot of hours grinding the crank for 92cc more volume, its not an amusing job.

It will also make the pistons and rods i am going to make more attractive for others!

Sounds good.
132mm stock rod length (CA18DET)
+25mm deck height difference (according to you)
-2.2 mm half stroke difference
+14.3mm compression height difference (CD20-CA18DET)

You can have a maximum of 169mm rod length for an R/S of 1.92...
That rod length is big block V8 territory. In sets of 8, sometimes they come cheaper per piece, than in 4cyl sets. You may not need to have custom rods made.

Yep, thanks for the tip!

Looks like the CD deck height is almost 228mm (227.75 - 227.85) VS almost 205mm (204.75 - 204.85) on the CA block

With 1.5 mm gasket, wich i need to have if i am going to use gas rings the compression will be just over 9 with 88mm stroke and flat top pistons.
If i am not totally mistaken ofcourse.

the crank on the cd20 is a 8CW so....where the CD17 is a 4CW as CA18DET one.

interesting thing

Yes, but CD17 also uses the same rod bearings as the CA18.
So the "downsides" of the CD build is heavier internals but that is not really a big issue.
You can compensate with lighter flywheel and we are not building a NA engine here.
I looked into rods and Chevy big block rods that are 6.635 in length are pretty close, lenghtwise that is.
Still need to see if it matches the crank diameter.
If the Chevy rods are an option i will have to use 25mm wristpins.

If i make custom rods i will go for 22 or 23mm wristpins.
Stock CA18 uses 20mm.
I use 22mm 9310 pins in my custom CA "setups".



Notice the amount of "playrooom" between rod and piston, 1.5 mm on each side to reduce wristpin load.

I will make something like this for the CD also if the Chevy rods are unusable.

float_6969 wrote:ks13: Yea, I know we suck. It wasn't supposed to be in the closet this long. Oh well, it was bound that someone else would come up with the idea.

tommey: Yea, the last time I checked (about a year ago) it was between $1k-$1500. Maybe I'm just not looking in the right places? It might also have to do with the fact that the yen:usd isn't great. If I could find a way to get it shipped her for less than $1k, I'd do it right now.

Call an engine importer who fills up large shipping containers with motorsets and rims (Venus Auto, , maybe they can source one and bring it over for you in their container. Also could try emailing this guy nissan-cd20-diesel-engine-for-sale-t457085.html and see if he still has it.

Block fresh out of the acid bath!
I have rinsed it ofcourse

Nice pics!

The water passages in the block seem somewhat narrow, and somewhat few compared to the CA18DET. (RBxx/RD28 blocks are the same, guess it's a diesel thing). Are the passages so narrow down in the block, too, or only at the deck level? I'd be afraid of cooling issues, but I guess we'll see in practice, anyway. Do you have an oil temp sensor planned?

That main girdle seems quite tall, indeed.

I have no worries about cooling.
There is no reason to either, just look at blocks that are filled almost completely with concrete and are used in different motorsports that see much more heat than any street driven car.
Or new engines, they have very shallow water passages in the block.

Yes i will have an oiltemp sensor. : )

ks13 wrote:so you and mike are part of a secret squirrel club and you've been holding out all this time huh? everybody in the ca18 forum slap TMS and float in the nuts. makes sense as to why TMS wouldn't respond to tommey in the other thread.

The first rule of secret squirrel....


It's a shame things got all messed up and I could never get the machine work done and rods made. This is going to work and this dude is doing all the right things to make it happen IMO.

tommey wrote:It was a lie, if you read on in that topic you will see it was an failed attempt to get a response from the mad scientist who claimed to have this "hybrid" figured out.

So in addition to being abrasive you tried dishonesty? Not good and you probably understand better now why I ignored you then.

At any rate, I don't have to like you, and I don't, to applaud your hard work, and you are definitely busting your a**. Keep working on it; it will be sweet if you pull it off.

I havent forgot this project yet, i am just busy with finishing my car and some other projects that takes time.
I will replace the photos of the block, i have an beta build on my phone with a camera bug.

I have borrowed RB25 balancer, camsprockets, cranksprocket and timingbelt.
Next up is to assemble the engine with just the crank and cylinder head to see what i should do with the timing belt.
I also need to order the CD headbolts or some other bolts that could hold the head while i mock things up.

RB belt ain't gonna work. You might want to check the length on those CD headbolts too, but hey, what do I know?

themadscientist wrote:RB belt ain't gonna work. You might want to check the length on those CD headbolts too, but hey, what do I know?

Why wont the RB belt work? I guess it might be too long.
I havent checked if i can get the CA belt to work either, if it does it would be great and i could still use the RB25 balancer.

I remembered that SR has M12 bolts, and i have aot of SR ARP studs.
I wont use ARP but it will work for now.