Gotta Pay to Play
 

You may have read, in my post from yesterday, I did some 1/4 mile time trials using a Blackberry. Well, I went out last night to the same spot for some late night drag racing and made one run. One run and one cylinder less, my night was over.

I pulled the plugs today and checked compression.

Cylinder 1--- 95psi
Cylinder 2--- 0psi
Cylinder 3--- 85psi
Cylinder 4--- 100psi
Cylinder 5--- 90psi

Needless to say, this engine was a bit weak. A turbo engine' compression should be no lower than 135-140psi. This explains why oil persisted to blow out the oil cap(even after the pcv overhaul) and why it took 1.5-3 seconds for it to start. I did a Stage 0 but never did do a compression test.

I pulled the head and was very relieved to see the damaged exhaust valve on cylinder 2. The last thing I wanted to find was a hole in the piston or cracked ring lands. Both of which could have destroyed the cylinder wall.

http://schigara.smugmug.com/Other/Vo...55_5Kwqb-L.jpg

So, she's due for a rebuild so I'll pull the block tomorrow and inspect the condition of the rod and main bearings and measure the bores and then start searching for pistons and rings. Might call Pauter and see if they have already designed some rods for this engine.

Anybody know if ARP has head studs for our beloved 5 cyl?

That sucks. Oh well, could have been worse. Are you going to do a full rebuild? Rods, pistons, etc? Or just do rings and bearings?

Yup. Full rebuild.

That looks like it hurt. If you need anything for your rebuild that you do not see on our sight, just give us a call. There is a lot of stuff that we have that has not made it on the website because we are in the process of upgrading our website. Also, we can get any Volvo part that you need regardless.

Compression's low on all the cylinders. you should have 155-180, according to Volvo. Yes... even the Turbo cars should be that high. My S70 puts out about 170 on all cylinders.

Also, that engine's been worked on before. Those are aftermarket intake valves... I wonder if there was a broken timing belt in that engine's past...

that is low compression.

stock rebuild or aftermarket internals?

Aftermarket internals! :D

Well, I got the block out, apart and to the machine shop and had the block hot tanked and the bores measured. The bores measure within specs. The bores still had visible crosshatch patterns. The rings were mostly stuck in their grooves from carbon and sludge.

The bearings look pretty good and the journals look fine.

I'm going to replace the bearings and and re-ring the pistons with the first oversize rings and cut the gap myself for each ring.

Oh, so no rods or pistons? No big power? :(

Na, no BIG power. I thought about but I really need to put all my extra money into my TR7 project that has been going on for more than 5 years.

Fair enough. How about some pics of the other project? :D

I had a website set up for the TR7 up on Geocities until yahoo shut down Geocities a couple months ago. I'll upload some pics to my Smugmug account in a few.

http://schigara.smugmug.com/Other/TR...58087699_eG4jA

I just uploaded all the pics but they are out of proper order.

Damn...Schigara nice job on that TR7! or is it an RX7:D

yeah, no kidding, now that's a project.

Thanks Bobec,

Actually it's a bit of a few different cars.

TR7 ...................body
RX7 TurboII.... .....Engine, trans and harness
Jaguar XJS...........Posi-loc differential @ 2.87:1 ratio
260Z.............. ....front struts
300Z Turbo...........front hubs & rotors
Toyota 4 Runner.... Front 4 piston calipers
Celica GTS............Seats

that is going to be one fun ride!

Good luck on both builds.

Well, I got to stripping the valves out of the head today and found the real culprit of the low compression and what caused the valve damage. Before I pulled the valves, I poured water in the intake and exhaust ports to see if they would hold water. The intake valves all held water just fine but every exhaust valve leaked.

Once I pulled the valves, I could see major carbon build up on the exhaust valves. So much so that it was preventing a seal.

I'm still amazed how well the engine ran on such low compression but it was evenly low.

Anyway, the rod and main bearings have virtually no wear and will be re-used. Even the machinist commented and said there was no way these bearings had 160+k miles. They look like they have less than 10k miles.

There is no wear on even the piston skirts.


The head was cleaned and surfaced and I just finished cleaning the carbon out of the chambers and ports. I cleaned the valves and checked the side play of the valve guides and all was very good. The machinist checked the valve springs and height and tension was right on.

I ordered the rings, head bolts, head gasket set, 1 exhaust valve and all the lower end seals. The total money spent on parts and machine work to get the engine back to spec will come in at less than $600.

Turns out I didn't do the damage to the engine after all. Well........I did but a solid engine would not have burned a valve like this one did. Ofcourse I could have kept driving it with low compression and leaky valves for quite a while but what fun would that be. I'll end up with a very new engine and be able to start some mods without worry.

Is there a thread on how to do a compression test?

Does seafoam treatment clean all that motor carbon stuff out?

Hey Schigara

Any chance you can send me info on where you get the OS1 rings? What type will you use?