Methods for reducing compression ratios

[TCJBOLDIE]

IMHO the article is a bit misleading and needs redrafting for the following reasons.

1 "use shorter rods' Yes it will with stock height pistons as the piston crown will be below the top of the block BUT it will alter the rod ratio as the shorter rods will place more side thrust on the piston skirts particularly after BDC

http://victorylibrary.com/mopar/rod-tech-c.htmhttp://victorylibrary.com/mopar/rod-tech-c.htm

2 " skimming the cylinder head " one needs to tread with caution as the valve to piston clearance will need to be checked especially in an "interference engine " design. Careful attention also needs to be paid to the oil flow to the DOHC heads as skimming may reduce the passage into the head and some machining/grinding may be needed to ensure the cams etc still get the right amount of lubrication.

3 "reducing the stroke" also reduces the cubic capacity of any motor and I would only advise this IF one needed to reduce the CC's to get into a particular class of racing.

4 "head work increases the volume of the cylinder " Not if it is just skimmed as that will result in a smaller combustion chamber along with a slight increase in the CR and if the combustion chamber has been altered by removal of metal this will only increase the combustion chamber volume and not the cylinder volume as that can only be altered by varying the stroke or over-boring.

More than happy to stand corrected if need be

 

[old-git]

Seems pretty good to me Rad. I would add that skimming the head will raise the compression ratio.

 

[HDi fun]

This is why engine swept volume is not relevant now.

 

[TCJBOLDIE]

Seems pretty good to me Rad. I would add that skimming the head will raise the compression ratio.

Steve are you referring to the original article OR my post

I mentioned the slight CR increase in my No 4 paragraph

It appears that link to the rod ratio article I posted earlier may not show so here is another .

http://www.strokerengine.com/RodStroke.html

 

[SLEEPER]

having read the stroker article it seems to me that firstly its mainly about american v8s and reducing the stress on the rods when stoking them especially when revving higher than 5500 ??
why not just fit forged rods and pistons ?

 

[HDi fun]

I prefer real rods and pistons.