Wondering if speedfactory no notch rods would affect the TDC where I could not connect them to YCP high compression pistons. I’ve heard so many conflicting theories on what longer throw pistons do to the actual valve clearance. And if this combination is possible what would be the necessary supporting mods? I’ve heard cams are not necessary but increase performance but I’m not sure what else would be needed. I’ve searched extensively and cannot find information on it. Thanks.

 

It will depend on the install height of the pistons. The no notch rods are over 50 thousandths longer than a stock rod, and "D" series pistons have different installation heights, so the combination that you choose could stick out of the block quite a bit and thus, make contact with the combustion chamber and require much larger diameter valve reliefs because of where the centerline of the valves will land on the piston dome. I suggest you use the Zeal calculator and plug in the components that you intend to use... and IF the piston sticks up out of the block/deck, add the amount to the thickness of a custom head gasket from Cometic. This will drop the compression quite a bit, but it will work and you can run the engine safely this way.

The only fixes you will have then are an adjustable cam gear to get the cam back in proper relation with the crankshaft... and just for your information, more camshaft compliments more compression. You will pick up some power with higher compression... but the engine needs more camshaft when you increase compression.

 

As stated by JRCivic1, it can be done, but there are also high compression rod/piston combos that are made to go together readily available, which would likely be a much easier path.

Don't forget to make sure you have a way to get the car tuned, and to get it dyno tuned once you do the modifications.

 

If I were building a single-jingle, I would use the longer "no notch" rods and order a custom set of pistons from JE or CP. This way I get the better rod ratio, don't have to chop on the block to make the rods clear, and get a piston EXACTLY like I want it (both the compression ratio and install height)... still sitting 12 to 15 thousandths down inside the bores for proper quench and valve clearance.

But what do I know...

 

This is good info too... and this would certainly be a slightly cheaper option than I suggested. DaX, I don't know if you have noticed lately, but the selection of "off the shelf" forged piston choices for the "D" series seems to be dwindling, and compression ratios seem to be either right about 9:1 or 11.5 - 12.5:1... and with Forced Induction, I would prefer to be in the 10 - 10.5:1 range... as in a Flat Top piston design over a dished piston... and this is why I suggested a custom piston.

 

You're right - and I don't think custom pistons are THAT much more expensive than shelf pistons...maybe just a few more weeks of waiting time. I haven't looked at what shelf piston availability looks like for D-series lately, but honestly I wouldn't be surprised if what you said was true since it seems like 95% of folks building D-series engines just want to run Vitara spec pistons. Next time my bottom end comes apart I want to go with a low/mid 10 CR piston.