How difficult n/a engine rebuild?

Arizona_928 · 10:08 PM

There is a late na available locally that has a lower end knock. It's has a clean body/interior, just engine knock. I have spent most of my childhood under the the hood of my n/a. But the closest I have been to a rebuild would be the rod bearings on my 951. I have removed the engine before so that's not the big issue. I think The problem I would be having would be the ringing of the engine since of the coatings.
I would have my machine shop do all of the resurfacing, and cleaning up the crank.. Also if anyone has input on just a stock engine rebuild, and hours needed? I'm thinking 40 hours, but that usually turns into 60 really quick.

Jrboulder · 10-09-2011, 11:45 PM

I've got no input on how long it will take to do a rebuild but I'm over in Tempe at ASU if you need someone to hold a wrench for you on a weekend.

Jackson

Arizona_928 · 10-10-2011, 12:13 AM

Sure! I have the Factory workshop manuals too. I will know by this weekend if i'll get it or not...

Cocacolakidd · Cocacolakidd's Garage

If the Cylinder walls are in good shape the reconditioning of them is not all that difficult - in fact can be done in the home garage. The machine shop can get the block ready to go with checking and prep of the block (Decking, surfacing, cleaning, machine shop stuff). The cylinder walls have to be honed so the rings will re-seat. A regular 3-stone hone, Scotch Brite Pads green, and Sunen AN-30 Honing Paste for honing. Cover the three stones of the hone with the Scotch Brite Pads (the green ones are the ones to use) so the Scotch Brite Pads will not come off - never let the stone touch/hit the cylinder wall. Hone slightly until just a dullish appearance is on the cylinder walls. You can do this or the machine shop can. Otherwise it takes special diamond hones and an expert with Alumisil to do the cylinders - expensive.

Arizona_928 · 10-10-2011, 12:38 AM

Quote:

Originally Posted by Cocacolakidd

If the Cylinder walls are in good shape the reconditioning of them is not all that difficult - in fact can be done in the home garage. The machine shop can get the block ready to go with checking and prep of the block (Decking, surfacing, cleaning, machine shop stuff). The cylinder walls have to be honed so the rings will re-seat. A regular 3-stone hone, Scotch Brite Pads green, and Sunen AN-30 Honing Paste for honing. Cover the three stones of the hone with the Scotch Brite Pads (the green ones are the ones to use) so the Scotch Brite Pads will not come off - never let the stone touch/hit the cylinder wall. Hone slightly until just a dullish appearance is on the cylinder walls. You can do this or the machine shop can. Otherwise it takes special diamond hones and an expert with Alumisil to do the cylinders - expensive.

yeah I just read many944 thread about that. Doesn't seem too complicated. I just bought a new huge work bench. I think I'll give it a go.

krystar · 10-10-2011, 11:37 AM

i just put new rings in myself too. just make sure u have a feeler gauge. 0.010" - 0.018" endgap. compression ring gap facing engine forward. alternate orientation on the other rings to at least 90* although i did 180.

make sure u check/replace mains too.

and get yer crank crossdrilled #2 and #3 if u wanna splurge a little

v2rocket_aka944 · 10-10-2011, 03:01 PM

no harder than any other engine would be, really, just be careful with the cylinder walls.

944 Dream · 944 Dream's Garage

Just be careful with this "knock". I'm brand new to the porsche world but what little experience I have started with a knock.

I just recently bought a 1985.5 N/A. The PO said it had a knock and low oil pressure. When I decided to buy it I had already planned on doing a rebuild but when I pulled the head, #2 cylinder was not just scratched, it looked like someone dug their finger nails down the cylinder wall. Same thing on the opposing side of the cylinder!

I had to get a new block because this was way beyond honing and not worth the expense of sleeves or over boring.

It was a bad wrist pin that was the culprit. Hopefully you won't need a new block.

I'm still in the process of the rebuild so I don't have too much of offer on that end of it.

Let us know what you wind up doing and how it goes.