Greetings All,

I recently purchased a well maintained 95 850 Turbo after selling my 244 Turbo, an upgrade the whole family enjoys. I bought the timing belt kit months ago and as the weather got colder, I put off swapping it assuming it would hold up. Big mistake, it failed on the highway commute. After a tow and breakdown, I discovered the water pump seized. It has 198000 miles and the last belt was chaned at 125000 (nothing else was documented so I assume it's the original pump, which I had purchased along with the kit to replace). My brother, the mechanic, and the wealth of knowledge around the web helped in pulling the head this past week.
Here is where I am...

I am ready to rebuild the head, new valves, seats, seals, etc. Not worried about that...My brother's friend has a shop and does excellent head work, so I can take it there to be done at a minimal cost. Not a problem.

With the head being off, the piston heads have flaky carbon build up on them. My concern is the indents from the valves on both sides (intake/exhaust) of the piston heads. He assures me we can smooth them out and it won't be a big deal. I agree. But is there a "best" way to clean off the carbon deposits and piston head without taking them out? I'd rather not risk debris falling between the head and cylinder walls.
I can post pictures later when I have them.

This is where I'm stuck...Rebuild the head, clean everything and hope for the best? Or take a chance on a new engine?

Cheers,
Herbert

p.s. I'll document my failure in the failure log eventually...and before this event, the car ran great with excellent mpg! Definitely bummed out, this is my DD.

 

Hi Herbert, welcome to the forum.

Sorry to read of your water pump failure. The pistons were manufactured with groves in them to allow a little assistance in valve clearance. I believe on the intake valve sides. If that is what you are seeing, I wouldn't worry about the groves or the carbon buildup on the pistons. You can try to clean it off, but I wouldn't hurt myself doing so.

I'm not sure if the pump seized and caused the motor to overheat or if it failed and caused the motor to jump time. If it jumped time and caused the valves to bend, I would make sure that none of the valves damaged the pistons. In that scenario the block/pistons would need to be checked out real close by a shop.

 

Oh, this is a good time to replace your PCV system and clean out your EGR if you have not done so already.

 

Hi Robert!

Thanks for the welcoming. The amount of information and time you have dedicated to the community for helping folks, like myself, is inspiring. Thank you again. It is good to hear from you.

There was no overheating. It "simply" siezed and caused the belt to jump teeth. The indents, are indeed, from the valves hitting the pistons, not just the factory spec grooves. I plan to look more into it this weekend as to how deep the valves cut in (approx. 1mm or so). Maybe not every piston is damaged, but at least a couple intake and exhaust valves made a mark. It seems that every intake valve is bent, and a majority of the exhuast valves appear to be as well.

You're right, it would be wise to have the bottom end looked over professionally. I am either investing money in a full rebuild or a JY motor. Possibly leaning towards a rebuild...

And yes, I do plan to replace the PCV system and clean the EGR. Thanks for the insight, though.

 

You can use an angle grinder and scouring pad to both smooth out any sharp edges on the piston and to clean the carbon off

 

Assuming I'll have to pull the pistons, that may be more than I'm looking to do. I'll think about it though...

After a quick search, I found a local sale of a running engine out of wrecked v70. Engine code 56. Mine is a 57...It is cheaper than I calculated the rebuild to be so far, and has lower miles. Is the 56/57 interchangable?

 

You don't have to pull the pistons. Just rotate the engine until one is at the top, clean it off, then rotate until another is at the top.

I've done plenty of head jobs for bent valves and have never had a problem cleaning them up in the engine. I even had a couple that broke valve heads off and caused quite a bit of gouging. I ground all the sharp edges smooth and never had a problem with the car.

 

Just replace the head and no the 2.3 motor is not swappable with the 2.4 or 2.5 motor without major changes. Just get a replacement head from somewhere.

 

Thanks ES6T. That is surely something I can do.

Thanks rspi. I will have to contact the seller because the information given is misleading. He says a 2.3L from a 98 XC70 with engine code 56. But I see that engine 56 is the 2.4 . If it IS, in fact, a 2.3 I CAN swap that. If it is not, I cannot.

 

I think I am going to try and find a new motor. Less expensive and less work. Any 2.3 turbo motor will work, correct?

Thanks in advance!

 

Yes, try to get one from '94 - '98a.

 

 

I am really on the fence with all of this...

As far as a top end rebuild, and considering the valve damage, are new guides necessary?

 

Cost of the top head rebuild will be real high. I would get a replacement head before rebuilding that one. Valves are pretty expensive. You can get a replacement head for $550 or less.

 

As far as the work needed on the head it's best to leave it up to the machine shop to recommend it to you. If you are serious about getting it rebuilt take it in and get an estimate. If it needs guides they will surely tell you before they get too far into it.

Any reputable shop wants to make sure your word of mouth recommendation isn't a negative one from poor work.

As for cleaning up an engine, I always used pads to do intakes until I read why not to.

"NEVER USE SCOTCH BRITE TO CLEAN UP GASKET SURFACES OF AN ENGINE.

NEVER, EVER, EVER USE SCOTCH BRITE ON AN ENGINE. At least not one you want to run again for a long time."
Came from: Scotchbrite--------NEVER !! | Mechanical /Maintenance Forum | Bob Is The Oil Guy

That would include pistons. They are handy, easy and do a great job but when you do some research and reading you'll see it isn't the right way to get the job done. There are numerous articles on the perils of using them and the danger of what gets into your engine from them.

 

We send the heads out for any machine work, so they do the cleaning.

To clean the head gasket off the block, I use a razor blade for any big parts. But I do clean it up with a scotchbrite on an angle grinder. I also clean the tops of the pistons.

However, I also open the drain on the block and flush out the coolant channels with water and blow them out. Then, I clean each cylinder with brake clean while the piston is at BDC, so any dust is washed into the pan. I coat the cylinders with fresh oil. Then I drain the oil in the pan.

Never had one come back with any issues.

 

Thanks for the info fellas. A few days ago I decided to go for the rebuild. My brothers friend who does head work will hook me up on a rebuild, so parts+labor will be less than a new head. And I couldn't find an engine for less either. Plus, I am already halfway there...

So this weekend I will tackle cleaning the pistons. I've read about the scotchbrite pad issue before. It is definitely what I was initally worried about and want to avoid. I think I will take my time and file by hand the burrs on the pistons, vacuum the shavings out, and then soak and clean with a solvent. Using ES6Ts method for cleaning and flushing sounds pretty thorough to me. So, I will do my best and report back.

 

I should also say I have seen plenty of guys who flat rate the job and don't do as thorough of a cleanup as me, and still haven't had problems. I just do it because I prefer not to take my chances... it doesn't take that long. If a customer is paying as much as they pay to do a headgasket or a head, I feel I should give them value and clean out whatever I can while I'm in there.

 

Almost two months later...and it purrrrs again!

Many days/nights in a cold garage...then every night this past week and the MOT yesterday proved successful.

It goes to show that the right tools, shared knowledge, and a helping hand go a long way in getting a job done...

I took care of many items that needed attention while the head was off getting reworked. Vaccuum lines, radiator hoses, gaskets, orings. full stage zero...

I'll sahre a little bit of the problems I came across, though nothing was a big deal. First, when the head was finished and I picked it up, I had ordered new exhaust studs (since most were in poor shape). Thought I got a deal from JCW but they were the wrong size. I was refunded and got the right ones from our trusted OEM dealers ...Studs, check.

Another BIG frustration was the tensioner roller, that dang T45...I was able to get a shallow drive to fit it in but wasn't able to get nearly enough torque on it...So my simple solution was to tightly vicegrip the outermost housing around the T45...A couple mallet smacks later, and it was loose...replaced all the TBelt components and torqued to spec...

The MAJOR work I did was the piston heads. It took me about 3 hours by hand. I decided to do it by hand in order to have a nice, flush, resurfacing with no worry about little bits getting into places they aren't supposed to be...I didn't take any pictures, but EACH pistion had multiple indents on both the intake and exhaust side. no cracking, but burred aluminum. I used a razor blade and carefully smoothed everything out, shopvaccing frequently...the carbon build up came off nicely with acetone also. It wasn't spotless, nor did it have to be, but all the buildups were taken care of...Done...

These weeknights were spent putting everything back together...torquing the head, cam cover, etc...with everything in it's right place and a full coolant system, I turned it over...All five cylinders were chugging away in time!

There was a slight tap at first, i suppose the lifters, but after about 10 minutes or so at idle it went away...

Thanks everyone! especially RSPI and ES6T...

Feel free to ask any questions...I DIDNT take any pictures but can do my best to remember things...

CHEERS!

 

Very nice to read that you saved that car and did a lot of the work yourself. I know you now appreciate why some shops charge what they do.

TO ALL: I'm in the process of rebuilding a few heads. What is the best thing to use to get that tough carbon build up, off of the bottom of the valves?