Datsun Roadster Forum-311s.org

Starting this for things I don't know, but feel free to ask your own questions!.....I am looking for answers tho......

1) IF the block will take an 89mm bore, can you still use the stock head gasket?

Standard bore is what, 87.2mm?
So the circle increases by 1.8mm diam or 0.9mm radius.
I would measure the diameter of a stock head gasket to see if at 89mm there is any gasket inside that circle.
My initial thoughts are that it will encroach into the cylinder/combustion chamber.
I used an R16 head gasket in my G15 but that was the reverse of your plan.
Custom made head gaskets are not that expensive, I checked this out when I rebuilt my engine.
The most expensive/difficult part is fitting the fire ring for the cylinders: the more cylinders the greater the expense

Hi Daryl, I just happened to have a gasket kit handy so I measured a couple new 1600 head gaskets and they measured, 3.502-3.509" with the jaws of my dial calipers, 89mm is 3.503" so the head gasket is basically 89mm at the inner diameter of the cylinder ring...Bill

The metal ring might encroach into the cylinder slightly when you torque the head. Mike

NO, I have a 89 mm bore too, and I use another gasket which works very good, it has a bore of 90, and it is a little thinner then then the original(1.2mm, more compression!), but for the R16 it works great.
It has also to do that my pistons are 0,6 mm above the block.

Thanks guys,

Peter,
I expect to have the piston above deck also, but maybe not so much.....was that a custom gasket or where did it come from? readily available? Cost?

A cheap gasket, it is the AJ100 from PAYEN.
We pay in europe 20 euro for it.
http://www.rockauto.com/dbphp/x,catalog ... AJ100.html

AJ100 is an H20 part. Being an industrial engine, maybe they are building it to handle overbores?

Why are Ford Y-block lifters sometimes used in place of the stock lifters? Head size? Availability?

What is needed to fit the U20 vibration damper? Just the U20 seal? Modify the Damper for the R16 seal?

The AJ 110 gasket is for the U20.
This is good info for the WIKI.

Linda

Anyone use the 1.55 - 1.60 - 1.65:1 roller rockers from JB Racing?

What is the MAXIMUM cam lobe lift for a reliable street R based engine?

Daryl Smith wrote:Why are Ford Y-block lifters sometimes used in place of the stock lifters? Head size? Availability?

They are basically the same as r16 lifters, a bit taller. Easily attainable. Were $8 a piece a while ago, but now are about $16. Have not compared to Nissan lately. We use the isky d-013 pushrods which are a bit shorter than stock to keep things right.

What is needed to fit the U20 vibration damper? Just the U20 seal? Modify the Damper for the R16 seal?
Need to shorten the shaft about 1/2" or so so the crank bolt goes on and chamfer. Still use the r16 seal, 5.95 at napa. Don't know how the stock belts line up, but we use the short version of a sbc wp pulley, which I think is for a long nose sbc wp

Isky Dr-99 cam might survive the street, or the dr-66. Specs are on the isky site. It's more than just cam and even more than just lift that makes streetable versus not. Haven't tried a hot street setup, so can't really say for sure. But I have driven my race car on the street, and I thought it was just fine!


Whatcha buildin'?

Thanks Steve!
"What is needed to fit the U20 vibration damper? Just the U20 seal? Modify the Damper for the R16 seal?
Need to shorten the shaft about 1/2" or so so the crank bolt goes on and chamfer."

Need to shorten the crankshaft? So a U20 crank in an R block would have to be 1/2" shorter than the R16 crank?
I thought the U20 damper was a little larger on the OD at the seal than the R pulley......?

Cam....Looking for something slightly smaller than the DR77 but bigger than the DR66. Looking in the 275*-280* advertised duration and .475" lift. So.....maybe..... about 224* @ .050"? Will settle on it after getting some flow #'s from the head and talking to a cam grinder.

Building a 2L R engine with the U20 crank. The 1.8 I have is good and healthy, but all the theory points to better results in the 2L range. Shooting for a pump gas engine @ 155+ HP with a redline around 6500. Lightened internals.

Daryl Smith wrote:Thanks Steve!
"What is needed to fit the U20 vibration damper? Just the U20 seal? Modify the Damper for the R16 seal?
Need to shorten the shaft about 1/2" or so so the crank bolt goes on and chamfer."

Need to shorten the crankshaft? So a U20 crank in an R block would have to be 1/2" shorter than the R16 crank?
I thought the U20 damper was a little larger on the OD at the seal than the R pulley......?

No, we shorten the damper. Everything else is ok. But that's on a 1600 crank. I do believe you have to shorten a u20 crank in a r block. I have a stroker laying around, and there was no chamfer on the end of the crank, and others have told me that the crank has to be shortened. No first hand experience. But lots of stroker info elsewhere here.

Cam....Looking for something slightly smaller than the DR77 but bigger than the DR66. Looking in the 275*-280* advertised duration and .475" lift. So.....maybe..... about 224* @ .050"? Will settle on it after getting some flow #'s from the head and talking to a cam grinder.

Good plan.

Building a 2L R engine with the U20 crank. The 1.8 I have is good and healthy, but all the theory points to better results in the 2L range. Shooting for a pump gas engine @ 155+ HP with a redline around 6500. Lightened internals.

LOTS of stroker info here. Sounds very do-able. You may need a few more rpm depending. You might need to get to 5,5 or even 6k for peak. But I'm no engine builder or theorist, just an assembler. Don't really know how the strokers behave.

Good luck.

There is some info on the strokers, but it seems to be short on some of the specific details which I am trying to get in this thread.
Things like the work/parts required on the head to get near .500" valve lift, which helps with 2L displacement.

I don't think too many people on here knew that the U20 vibration damper needed to be shortened, or that roller rockers were available at various ratios up to 1.65:1