Help with a cylinder head

What does this imply?

Today with the engine at normal operating temperature and accelerating from a roundabout to 70 mph the motor suddenly started pinking and there was a huge plume of smoke behind me. The smoke decreased when there was less throttle. It was diagnosed as a bad oil ring on a piston.

I've pulled the head and the sump. The cylinder bores appear unscored (thankfully) but are black and oily. The plugs were the same.

The head gasket appears to be in perfect condition.

The valves and combustion chamber also are black and oily except for the exhaust valve on #3. It is almost red. I've taken a photo, but not sure how it will show up on this post.

I'll pull the pistons out from underneath later and sort out what to do with the pistons/rings, but I'm curious why #3 exhaust is a red colour.

I'm a bit mortified...so sorry about the title of the picture. I was goofing around with my son when we downloaded the photos...I had no idea it would show up on this.

I apoligise.

Matt,

Just my opinion, but it looks as if you are pumping oil past the rings on all the cylinders. I would sure get my hands on a bore gauge and check the cylinders for being in spec. Not sure what to think of the one valve. Is it dry, rusty or heat damaged? Does it open and close like the others? Did you happen to do a compression test and or leak down test prior to taking the head off?

If the bores check out, you may get by with a ring job to resolve the oil problem. I would also inspect the rod bearings since it is all in pieces and make some decission on them as well.

Cheers,

Rob

Oil is most definately making it's way into the combustion chamber. Could be piston rings as mentioned, also look at the valve guides and seals. There would be evidence of oil running down the valve if this were the case. A valve spring compressor will be in order for such an inspection.

yep, you might get by with re-ringing in situ, but as long as you have the head off, have it checked for cracks and surfaced and valves ground and depending on the model year and fuel blend in uk, if leaded, maybe time to put hardened valve seats in head. how many miles on the engine. if you refresh the top, it may cause a failure on an unrefreshed part elsewhere in the system.

Speaking of valve spring compressors....

I miss the one I had in England. It was a relatively small one of the C-Clamp and lever type that was VERY solid and inspired confidence when removing valves. The two I have used over here seem too big, flimsy and look like they may pop off the spring at any moment.

Does anybody have a source for a GOOD valve spring compressor?

Limey Wrote:

The valve spring compressor that Eric is talking about is from UK and is made by I think "Motor Mite" could be named something different now, you can get one from Mini Mania , I used to sell them all the time when I worked there and they are great for smaller cars

see this link

http://www.minimania.com/web/SUBTYPE/SearchText/CarSearch/MINI/Search/spring%20compressor/AddedFrom/FrontPage%2DSearch/Search_Inventory.cfm

Limey Wrote:

Bugeyev8 Wrote:

Thanks for the replies.

No, I didn't do a compression or leak test first. I planned to, at a minimum, replace the rings.

I actually have a freshly built head-ironically the machine shop where this head was is one of the places I was driving to this morning when this all happened. I may use that, but I'm a bit concerned, as Mick is, about putting it on this well-used motor.

I hope the old one does check out as I'd prefer to simply clean it up and re-use. It is heavily coked up and certainly needs attention. I was told that the head was converted to unleaded. We'll see.

Thanks again.

I agree, probably bad rings.

You can take one of two courses.

1: "Refresh" the motor with rod bearings, a valve job, perhaps an oil pump, and a set of rings if the lands are not worn too much. My choice for that would be Deves rings because of their superior oil control in such instances and compliance with tapered cylinders. If the lands are shot use a set of decent quality pistons and replace the rings that come with them with the Deves.

2: Rip the whole thing apart and do a full fledged rebuild.

Jack

Jack-
Can I ask you to elaborate? You (and others here) are brilliant at providing advice tailored to the knowledge level of the enthusiast posing the question and I hope you can re-respond to help me understand.

This is the first time I have pulled a head of a car whilst it was in situ-and the oil pan as well. Actually, this is the deepest I've gotten into a car engine (not counting pulling apart a couple engines that were not in a car). I've got a great set of tools and the space to work in, and a half-dozen reference guides.

Here's what I'd like more information on:

First-on rod bearings. Does this simply involve buying new connecting rod bearings and installing them?

Second-on the oil pump. My pressure was, even when this happened, well within specs (65 at motorway speeds and just under 50 at warm idle). Do you think that is necessary?

Third-on the rings. The Haynes manual references using stepped piston rings when you have worn cylinder bores (as I do where there is a thin bit of a lip at the top of the bores). Is that what you mean by the Deves rings?

Last-a valve job. I just spent 226 quid on a professional machine shop rebuild of a late B model head. Actually it was closer to 250 because I bought new springs and intake valves as well. That money got me (on a head I provided) the inspection, new valve seats and seals, three-way machined valves, a skimmed head, and paint.

I can disassemble, reassemble, lap valves, and of course, I'd have the machine shop inspect it, but how much is involved in a "valve job"?

Rod bearings: Its not simply a case of old bearings out and new bearings in (if you want to keep the car) Measure the crank journals to determine size and roundness (for want of a better word) If your crank is ok and there is no damage to the big end journals and when you have determined the size bearing shells that you need then you can fit the new ones.
Oil Pump: Whilst you have access it's probably not a bad idea to open it up. It's just 3 nutsand 6 washers and it should pull off the crankcase. Two more bolts will pull it apart. check for damage on the gears, to the housings and also check your clearances. refitment is just the reverse. Make sure you select the correct oil pump gasket. I got the wrong one and the oil pump wouldn't suck.
Valve grind: If you are going to take the head apart then you will need to measure the valve stems and valve guides. Also hardened valve seats are quite popular these days. As well as carrying out a crack check on the head you may want to get the head skimmed. Your machinist could do a lot of that for you.
Rings: some one more knowledgeable than me will be able to tell you all about them as well as correct any of the above.

Good luck

Russ

Thanks Russco.

Pistons 1 and 3 had broken rings.

Broken rings are a good sign of worn piston ring lands and and a worn cylinder bores, at this point I vote for a bottom end rebuild, and for sure a cylinder overbore to get everything back to the clearences it should be. This is probably not what you want to hear, but no way would I stick a new set of rings on those old pistons and hope for the best.

No mate...that's certainly what I'm not wanting to do.

I think I'm going to do this:

Ream and hone the cylinders-great excuse to get a couple new tools!
New rings (assuming the pistons are ok, if not, new pistons as well)
New oil seals on the head
Clean and de-carbon everything
New gaskets
Oil pump rebuild if needed

If it all goes back together and runs ok for another year or two I'll be quite chuffed with myself.

If the worst happens-as in this doesn't work-then I'll chalk it up to a learning experience and then build up the bottom end of the spare motor I have (the same one the head came off of).

Many, many thanks and I may be posting again asking for some guidance as I put this back together next week.

In the meantime I'll get to drive the scooby van to work!

Back in my younger days....

We couldn't afford rebores and new pistons, so we typically would hone the bores and put in new rings. On the ring sets we used to buy, the top ring was what we called a "ridge dodger" - it had an "L" shaped cutout around the upper, outer, edge of the top ring to dodge the ridge! They worked great provided the bore wasn't too bad but I have never seen them over here.

Are they still available?

the piston rings I just put in a TR6 had the l shaped top ring, they were deevs rings

Hap,
I used to work at Mini Mania West, in late 1997 Sean Murphy from Mini Mania east and I started the repair shop at Mini Mania West(milpitas) I only knew of Paul through the friend networks we all shared then, don't talk to Don much if at all anymore unless he wants to buy some parts, saw him at the Monterey Historics did not get a chance to talk to him

after all the free help working on his french cars before the races never even a thank you from Don

we had a parting of ways...I quit when I saw an ad in the Grass Valley times for my job, I was going to move there but he found someone to do my job for 10$ per hour..so in anwser to your question earlier....I do know how hard it is to get anything from Don he likes to save a dollar any way he can

I worked at Mini Mania from late 97-2001 and it was a lot of fun, great crew then, shop was always busy

I know the feeling, I got a little fed up with MM, when Don quit the Mini bucks racing program, I won a championship with his decals all over my car just to find out the program was now disolved, I did however get my stuff for that year. Don only offers me a 15% discount as shop owner, which at his prices is not much of a discount, so I seldomly buy from MM anymore.