S50 Compression Numbers

[CBRSTi]

Hi guys

Sorry if this is a noob question, but i did a search and couldn't find anything. Basically, my buddy is offering me a 132k miles s50 with a transmission and all the accessories (alternator, AC, etc) for 2k.

The compression on cylinders 1-6 is 175, 175, 180, 175, 180, 165 respectively.

Now what i want to know is are those numbers low for an s50, and is the slightly lower compression on the 6th cylinder something to be worried about?

This is going to be swapped into a DD and im looking for something reliable as well as fun.

Thanks

[ck_taft325is]

Yeah, I'd be worried about the 6th at 165. I like to see 180-185 across the board. The sixth cylinder can get a bit warm as it's the last on the block to receive cooling. I just rebuilt the top end of my S50 and my compression numbers with a very minor blow in the HG (no overheating, literally happened while idling) was about 124 on the sixth. And that's right where the head gasket blew.

What's the build date of your S50?

[CBRSTi]

The build date on the s50 is 01/1995. Yeah i figured that the numbers seemed a little bit low, but i wanted some outside opinions.

Would there be any way to refresh the engine into a reliable s50? Or would it not be very cost effective?

[ck_taft325is]

Pull the head. Have it pressure tested and stripped. Then replace your valve retainers, split collets, valve guide oil seals... it'll save you in the long run. The worst that can happen is that you put it in, drive it and at around 5,500rpm + you'll drop a valve due to a fucked up valve retainers (10/95 is the "safe" retainer zone) and grenade your engine pretty hard.

[CBRSTi]

Ok cool. And doing all that and replacing the head gasket should give me a fairly bullet proof motor?

Also, how much do you think it would cost to replace everything you listed? I'm not trying to skimp on it, just trying to adjust my budget to accomodate it.

Thanks for all of your help.

[ck_taft325is]

No worries.

I got a FANTASTIC deal at a machine shop that I'll recommend and use from here until they close. They pressure tested, lapped the valves, installed valve seals and the valve retainers for about $200. If you can find something similar, it'll run you substantially cheaper. SHOP AROUND. I got quotes of anywhere from $500-$2100 from shops in the area. Finally found this one on many a local CCA recommendations.

The parts alone I sourced entirely through Blunt on the forums. I believe my total cost (head gasket KIT which came with the valve seals, guides, ect... and the retainers which where separate) came to $298 + $200 for the machine shop costs. So, for $600.00 you've got a really sturdy motor that wont grenade itself due to the retainers. Peace of mind costs sometimes, but it's worth it ;) While I was in there I rebuilt the VANOS unit which I highly recommend. It's $65.00 total from Beisensystems.com. VANOS oil seal, VANOS aluminum ring (inside the unit itself) and the 18mm modified socket which YOU WILL need. Ask me how I know? ;)

Inspect any and everything while you have it apart. Replace anything worn or tired looking such as vacuum lines. Should also mention some of the "special tools" you'll need such as cam locks, VANOS timing sprocket tool and cam installation/removal tools. You don't NEED the cam installation/removal tools but, be VERY careful when removing and installing to give each cam cap only 1/8th of a turn and move very carefully down the line.

[CBRSTi]

Awesome. Thank you very much for all your input. 600-800 dollars is well within my budget, to refurbish the motor so i'll definitely be doing it for peace of mind.