[hyde888]

As I stated in my previous post, the #5 piston on my 71 has melted, seems to be caused by timing advanced too far. Since I need to replace one of the pistons, I'd like to replace them all at the same time. Now, I need help from the beginning. I have no experience with engine block. Which pistons should I use?? I have a P90 head which had been modified to be used with dished pistons. Oh, it's a n42/l28 block by the way. Any tips or advice on removing/installing pistons on a motor still in the car?? I don't have equipment nor space to remove the engine from the car. Any input will be greatly appreciated. Thanks in advance!!

Hide

 

[JT240Z]

Don't try to replace the pistons while the engine is still in the car. That's my first piece of advice. Look for any alternative to doing this. I replaced an engine in the parking space of my apartment years ago. Without a lift it's not only MUCH more difficult, but you'll have a **** of a time trying to keep the engine assembly clean and accurate while the engine is still in the car.

Second, get yourself a copy of "How to rebuild your Nissan & Datsun OHC Engine" by Tom Monroe or "How to modify your Nissan & Datsun OHC Engine" by Frank Honsowetz. A factory service manual is best. Read it!

Third, after reading your manuals, determine if the pistons are the only things that need to be done. You need to check your cylinder bores and head for damage. Sounds like you suffered from a case of preignition. If only one piston is damaged then you may only need to replace the one, but replace it with a factory part.

Fourth, solve the cause of the problem before you run the "new" engine. Make sure you don't end up having to do the whole thing over again.