Simple Stroker?

[DDS]

I know it isn't simple, but here's the scenario - I have a tired 2.0 that I'm rebuilding. I don't want to spend huge bucks on a 4 (my car is prepped for a six) but may be living with this engine for a few years and I can't help but tinker.
I was lucky enough to buy a few cartons of new parts from someone else's abandoned project, all from FAT including 96mm P&C, 440hp cam, lifters, gear, all but main bearings, a spare crank and rods (used) and some other stuff.
I have already rebuilt the heads with 44X38 mm valves and porting.

You know how it goes - I'm in this far, what about increasing the stroke?
I've heard plenty about 5.5 and 5.35" rods with chev journal sizes and T1 wrist pin diameters - I assume this is due to parts availability.

As I already have bearings and pistons, is there a stoke length that will work well using the stock rods, or at least the pistons I have with the T4 wrist pin dia?

Many thanks as always to those who know.

Dave

TIA! Dave

[This message has been edited by DDS (edited 09-01-2001).]

[Jake Raby]

That cam is definately gonna be a large factor on the crank you decide to run.

With stock rods, 74 stroke is max and they need clearance work...

If you change cams, and get a custom base circle, you can go to 78 stroke with stock rods, for some awesome torque, but a high rod ratio..The 2270 (78 X 96) is our best engine,and hard to beat..If you go to type 1 journals, and 5.4 rods with JE pistons it will lessen the ratio and add midrange..

You could have bought our entire kit, and saved all this guesswork....Too late now...LOL

[DDS]

Thanks for the advice Jake, (you salesman you ), but please don't laugh too loud. - Your 2270 kit would cost about $6500 Canadian landed, PLUS INDUCTION for about 150hp. While I do really like and seriously considered your kits, my car is prepped for a six already and I decided to make that my ultimate objective. The reason? 180-200 hp, a more sophisticated engine than even the best prepped type 4 and higher resale value to boot. I can install a 3 litre six (yes, used) for about the same price as completing a 2270 install once the cost of the induction and proceeds from the sale of the type four are factored in. Once I did the math, the decision was clear.

WRT my current 2.0 four, I got very lucky and paid a great price for pistons, cylinders, cam, valve springs, bearings, etc..., and as you may remember, I already have the heads. My exercise now is to maximize the performance of what will be an interim engine. I want to do it very well but at a modest cost and if that means that it ends up barely more powerful than stock, so be it.

I do appreciate the help as I investigate what my options are and I find that the guesswork and learning is part of the fun.

Your reputation speaks for itself, and its never too late, but I think your 2270 will have to wait for my Spyder replica some day. I'll probably just order a completed engine.

Regards, Dave

[DDS]

Hey Jake:
the 74mm stroke looks interesting and I'll also get the higher CR as a bounus. I have to calculate that one to be sure its OK.
I take it that at that stroke, interference with a 'standard' cam won't be an issue.

Though this will be clear on trial assy, what part of the rods needs to be clearanced? Any other parts a'gonna whack?

I'll obviously need 1.5 mm longer pushrods and 1.5 mm spacers too.
Many thanks for your assistance.

Dave

[SteveStromberg]

You could use Type1 pistons as they have a PCH that is about 3mm lower than Type4 pistons.Also when the rods are rebushed there is a 2mms of adjustment to play with. Have one rod rebushed then assemble it in the case mount the cylinder check the deck height then you can figure out the deck height and have the rods rebushed and redrilled to set the deck height. Steve

[DDS]

I worked out the CR for a 2150cc (96 X 71) and found that with 1.5 mm base shims and stock rods, the CR is around 8.24:1, not including the increase in CC area at TDC contributed by the 2mm bore increase. vs 7.6: for a stock motor, this should be good for a few hp in addition to the displacement increase.
Steve - Thanks for the tips - I can see why T1 stuff is used a lot for these things and didn't know that you could stretch or shrink a rod by non-concentrically boring a WP bushing. In this case though, I'm trying to use the T4 96mm big bore kit that I got so inexpensively, so I have to work within those limitations. Other than clearancing the rods and possibly the prohibitive cost of having the crank done, I may be ready to make some decisions on induction/ignition.


[This message has been edited by DDS (edited 09-03-2001).]