Pistons stick out

[ctomkins]

Hi,

Hope someone has the answer,

I just finished having L 28 block redone.

Aftermarket pistons installed but they stick out twenty thou.

I have a fully enhanced E31 head all the jewellery.

The head has had minor milling twice. According to the machinist the head width is 4.235.

Will this work or do I have to flycut the pistons.

Thanks,

Brain itch

[2ManyZs]

Well, this sounds like a good question for our resident engine "guru" Phred. But, he'll need to know exactly what piston you have and whether it's a flat top or not.

If Phred doesn't reply, you can send him a Private Message and ask him to respond to your question.....

[Phred]

ctomkins,

It sounds like you learned the first rule of engine assembly. Don't take anything for granted, and always do a mock-up with new pistons to determine piston to head clearance. It sounds like everythings together, unfortunately. Hopefully, those aftermarket pistons are assembled with a full floating pin. Because if they are a pressed on piston/rod assembly, its going to be a headache to press them off, machine them, and then press them back together again. Many oportunities to screw something up. The Minimum piston to head clearance you should consider is about .045. With .050/.055 prefered (small safety margin) . Which means with a stock head gasket compressed thickness of about .047, your looking to have an assembled deck height of about -.005. Meaning the piston is below the deck by .005 at TDC. The next headache you may want to avoid, is called valve to piston clr. Hereafter called V/P clr. Let me know what cam you have, and if your pistons have valve reliefs cut in them. Also, if the pistons are still in the block, Get a very good dial indicator reading on #1 & #6 pistons at TDC. Take the measurement in line with the piston pin. Take notes, and mark the underside of the pistons with there respective cyl. #. (1,2,3,etc.) Use an electric pencil, scribe, or metal stamps. If you stamp #'s, put the # on the pin boss, & do not stamp in line with the pin. Give me some more details, and we'll get you squared away.

Phred

[ctomkins]

Thanks for the input.

Sounds like you know your stuff.

I just talked to my local Z specialist and it looks like this configuration won't work.

To little clearence. To high compression.

I'm going to put the E 31 aside for a serious race setup down the road or sell it on ebay.

I have a stock N 42 that I'll give a mild work over.

I just want this engine for my 3 novice races I have to do this season. I have a second engine.I call it the (Hand grenade) engine it's ready to go for GT 2. -14.1 compression-. There's pics of it in my gallery in the white & orange 240.

The white and orange one was actually a Grassroots project car around 10 years ago. It was whit and blue then. This car is all metal no rust and came second in class Molson Indy Vancouver 2000. It will probably be for sale this year with engine I'm building right now. This car was used for GT 2 but should be configured back to ITE.

Thanks for the help.

Chris

[dogma420]

Hey, where'd that 350z kit come from for the 240sx?

That's pretty coooool

[ctomkins]

Don't know it was at the track and I just took some pics.

I think there built in California.:classic: