Diesel Crank in a 3B?

[Paul McCleary]

As a few of you know, I am in the process of building an S2 powered 90. I had a Cancer scare last year and the project was shelved while I healed after my surgery. Now I have the all clear, I'm gagging to get stuck into it again.

Can anyone give me some advice on the up's and down's of throwing an oilburner crank into my 3B?
So far I have a crank(Given to me by Tim of RT Sport bless him) and a set of new standard size uprated rods. Aside from tweaking the block for clearance, the only non standard parts I will need are pistons. Does this sound correct?
I'm told the engine will come out just shy of a 2.6 when built and the extra torque is worth all the effort?

Thanks in advance.

Paul.

[Rusty]

back, glad things are on the up for you.

There are a few ways of doing it, using stock block with the 95.5 doesn't give a great rod ratio but getting diesel block in can also be hard work, you'll need pistons, rods or some block work at some point. There are lots of stroker projects on here, have a search and a read (Jamo, AndyP spring to mind, there are several others).

[Jamo]

I wouldn't use a 95.5mm crank in a 220mm block for a couple of reasons:

a) Rod ratio
b) You compression height on the custom pistons has to be woefully small
c) Piston rings wear very quickly
d) Rev limit will be about 6500 rpm to save on engine wear

However if you can live with the above torque will be greatly increased. There's a few threads on the 220mm conversion on here and on motorgeek ( for instance the Red Baron ) http://www.motorgeek.com/phpBB2/viewtopic.php?t=15035

The engine will be 2.5 litres with 82mm and 2.6 with 83mm pistons.

I wouldn't go 83mm from the off as this is the largest you can bore the 20v block to before scraping it.

If it's a track toy then it's possible but remember the engine will need looking after. The proper route is to use the diesel block and crank.

If you want to do a stroker in a 220mm block I'd advise to use the 92.8 stroker crank

Available from CR enterprises and 034. Reference Flat on my back for details

[Paul McCleary]

Thaks for the replies.

To be fair, the rod ratio does worry me as my driving style suits revier engines and a 6500rpm limit is lower than I am used to in a performance car.

What is the best model and year of Diesel block to look for? If I find and use a Diesel block, does that mean my uprated S2 rods would be incorrect for this setup? Also, what sort of rev limit is the oilburner block good for?

Sorry for all the n00b questions.

Paul.

[Jamo]

Do remember strokers are about torque, you will find your powerband is lower down negating the need to rev the nuts of it.

The AAT block is the best one to use, there are a few other variants such as the AET but they require extra machining.

The S2 rods are the wrong length for the diesel block they are 144mm you would need either 155mm or 159mm rods depending on.

Diesel block you can use the stock limit of 7300rpm, Repo has said you can take them to 7600rpm when he did the tuning on mine but the OEM rev limit is fine for me.

Reference http://www.s2forum.com/forum/showthread.php?t=6797 this is the engine in my car except I rebuilt it with 82mm pistons and larger turbo

[Jonnybravo]

Thats a very interesting thread ^

I am sure you have seen what Martin Hadland did with his Yb engine to increase the stroke without sacrficing the revs ?

Its the same as Os Giken do for the RB26 Skyline engine, not a cheap route of doing things and I would imagine there isn't much room for the increased engine height but it would be interesting to see the results.