specific engine rebuild question

joenintiesc

Registered User
My engine guy tells me I should go with forged pistons (Diamond) on my rebuild. How necessary is this for a street perfromance engine, and where is the least expensive place to get them?

Also, how can you tell if a crank is a forged SC crank?
 
I can answer the question about the pistons... unless you decide to run NOS or pushing the envelope then get the forged pistons. I have the stock style pistons in my car and no problems. XR7Dave is still running a stock bottom end and has not had any problems.

As far as the crank goes I think it should have a code of 6302(????). I believe it will have thick line on the crank. Somebody can correct me if I am wrong.
thanks
Ken
 
Thanks Ken. The number on the crank is 6303, but it does have that wide "stripe" on it.

I am going to stick with stock oversized pistons. I've read that forged pistons tend to contract when cold and expand when hot, causing extra wear on the cylinder walls and rings. Also, I really don't need the added expense of forged rods to go with the forged pistons, as my engine budget has unfortunatley tripled as of yesterday!

Gee, that rarely ever happens, huh?
 
A steel crank has a wide line in it. While a cast crank has a narrow line. Sometimes even with casting sticking up. Also you can take a hammer and tap on them and steel has a high pitch ring to it like a tuning fork. A cast crank dosen't.
 
joenintiesc,
The cast cranks that were out there were only in the early '89 models. The problem was identified and fixed in '89, so your '90 has the forged crank.
 
Thanks. The crank was in a rebuilt engine I purchased, was supposed to be "new", and I just wanted to double check to make sure a non SC crank wasn't in there...

Now, somebody else chime in with Ken and tell me I don't really need forged pistons for my modest performance rebuild!
 
Forged pistons are only need for big HP mods, like a 150 shot of NOS or something. Forged pistons are tougher but are not used to often in minor builds due to the cost of those buggers.
 
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