Piston Removal - Two Questions
 

Two quick questions regarding removing pistons from the bores on my ‘87NA:

First - do I need to “ridge-ream” the cylinders first - or can I simply (carefully) use a bit of emery or some other cloth (possibly saturated with WD-40 or engine oil) to clean up the bit of carbon which may otherwise make a mess of things?

(170K miles on a very well cared for car, and the cylinder “ridges” seem to consist mainly of a bit of carbon buildup).

The reason I ask is because I recently watched a video of a guy who used some sort of cloth (no narration so did not specify) to clean the rim deposits prior to pushing the pistons out. This would seem much less “invasive” than using a ridge reamer - plus this would be one less thing for me to purchase or rent, to say nothing of the time to properly set up.

Second question: as I will be removing the crank (want to look over/measure the mains and crank bearing surfaces) - would it be possible to simply push the pistons out the bottoms of their bores?

At any rate…just thought I’d ask!

ive never touched the ridge, even "big" ones, and ive disassembled a lot of 944 engines.
just a good push from the "bottom up" and a hand to catch them on the way out.

you cant push pistons out the bottom, the block structure is in the way.

WD40 and a clean rag will clean up all the carbon pretty fast. the underlying "aluminum" ridge is the remnant of the original bore size, below which the piston rings have worn the bore.

I would not recommend doing any main bearing work with the engine still in the car. The girdle must be glued back into place afterwards, making sure that the oil channels are completely sealed so that you actually can prime the oil pump at startup.

Do NOT use a ridge reamer on an Alusil block. You should only have a small carbon build up that can be cleaned up with a rag as Spencer says.

Thanks for the quick replies!

Engine is out and on a stand. Cam and head are off. My plan is to move all the engine components down to my basement shop so I can work on them over the winter (in relative warmth/comfort) as time permits - and re-assemble in the early spring.

kd
I pulled the girdle off the block with the badly scoured cyls. seemed to lift right off and don't recall seeing any residue.

I have not dug into engine build threads for the assembly phase yet. do you have a link/links to that part of a 951 engine rebuild? I have Wayne's book for my 930 engine.

thanks.

the glue is loctite 574.
it gets applied very thin and gets squeezed hard by the girdle being torqued down, but it's still there to seal the oil passages up.

no need to clean it as the fresh coat you apply at reassembly will dissolve the old original layer.

Get the shop manual for the 944. It's all in there. You also need to glue the oil pump to the block in a similar fashion, as well as the balance shaft covers.

Now is the time for an engine swap!

https://www.motorwerksracing.com/porsche-944-engine-conversion-18t-swap/

thanks, I have the WSM. I do not tend to think of loctite as glue....