Questions, block is in machine shop

[rae61]

My 200 block from a 65 falcon is in the machine shop, it will need a .30 bore done. They want to take .10 off the block deck to clean it up, will this change how much I need to take of the head to accommodate for the thicker head gasket (52cc) ?

Are the 2.3L HSC Ford tempo pistons more money than the stock ones, what are the benefits, I'm just building an engine to us as a daily driver in my Bronco.
Will the choice of pistons effect my cam choice, I want to go with a CSC-264-HSP-12?

 

[Anlushac11]

I think you mean a .030" overbore, my 200 block had to be bored that much.

.30" would be a wee bit too large

.010" to surface the block will have a very slight affect but not enough to worry about and is pretty normal. Most aftermarket pistons have a slight reduction in compression height to take that into account. My pistons measured 1.500" instead of 1.511" to take that into account.

Most stock 200 pistons are dished to lower compression. Since Ford no longer makes a replacement thin steel shim head gasket we are forced to use a modern composite gasket which is thicker. The thicker gasket causes a lowering of compression ratio.

You can raise compression one of two ways.

1) Have about .060" shaved off the head surface to reduce combustion chamber volume to make up for the lower compression. This brings about its own set of problems such as needing to use .060" shorter pushrods. Some of the guys using hydraulic cams have just let the hydraulic lifter take up the reduction with no problems.

2) Use the 2.3L HSC pistons which are flat top pistons. By not having a dish the 2.3L HSC pistons bring the compression ration back up.

 

[tony1963]

I just rebuilt my 200 using the 2.3L HSC piston. Can't really tell any difference in the performance, but it does run quite well.

You are going to have to have the entire assembly balanced if you use the 2.3L HSC pistons. They come in a matched set of 4 and then you have to buy 2 single pistons. The 2 that you buy will weigh differently from the matched set.

If you factor out the balancing, which you should do anyway, the cost of the 2.3L HSC piston is negligible over the stock piston.

 

[mugsy]

Did you measure the deck height? That's the distance from the top of the piston to the deck of the block. On my '66 block the pistons were 0.030" down the hole. I had my machine shop take the 0.030" off. With the thickness of the head gasket (0.045 or so) the pistons are still safe from hitting the head, plus it helps with the quench.

How much you can take off really needs to be measured with the piston, rod, bearing and crank installed in the engine and the piston at Top Dead Center.

 

[69.5Mav]

Is the head in the shop? Now might be a good time to get a 3 angle valve job and have the head modified for a dirrect mount Holly/Weber.

You could also pick up a few horsepower by have the crank knife edged.

 

[rae61]

To all, that is great information that will help, :thanks: I will ask the shop to check deck height with pistons @ TDC and see how much they can take off. I will have them give me the pricing options on the pistons to see which way I''l go. The head is not in the shop but I will explore the options mentioned.

And yes it's .030, I guess that's why my bankbook seems to always be short......I'm bad with decimals :mrgreen: