1.6 Volvo piston in 1.6 TD

[Nevadan]

The main purpose of this post is to make sure I can upload pictures. Once I know it'll work I'll give the whole story on this re-ring job and piston modification. I just want to make sure the thing runs before giving the whole story. I'll have it operational this weekend.

[Nevadan]

O.K., it worked.

I've been on this forum for over 2 years and have found nearly every answer without having to ask a question. Now it's time I add something and maybe ask a few questions.

J.D.

[CarlosA]

Interested to see what you have come up with.

[Quantum-man]

O.K., it worked.

I've been on this forum for over 2 years and have found nearly every answer without having to ask a question. Now it's time I add something and maybe ask a few questions.

J.D.

Go on then JD, spit it out

[Nevadan]

So I bought these Volvo pistons off eBay last year...........

I bought my first 1.6 VW (turbo) in Nov. 2010 (160,000 miles and non-operating odometer), found this site, read Haggar's Saga and started to learn. I can definitely tell you regulars on here know what your talking about...from experience. When "new" the car got about 35mpg. The prior owner had the cam timing off which I adjusted and along with using wax, putting new nozzles in the injectors and "hillbilly tuning" I got it up to 39mpg. My mileage is mostly 70mph freeway driving, mountain travel on I-80 and a little bit around town. (Also, the engine always runs hot, especially climbing mountains or going 75mph in the summer with the AC on. The temp needle is about 3cm from the top white line. But it NEVER overheats.) I did a compression test in Nov 2011 and was surprised the car even ran.

Cyl Compression Dry Compression after squirting oil in cyl

1 250 320
2 280 360
3 230 280
4 190 280

So, after reading on this site and others, mainly this site, gathering parts & tools I decided to see what was going on in there. (For future reference I'm much more in agreement with Quantum-Mans methods, chiefly represented by his soda bottle hone job!!)

After pulling the head and removing the pistons this is what I found: broken 2nd rings on pistons 1, 3 and 4. Heavily scarred piston #3 on the injector side.



Fairly large ridges at the top of the bores.



I decided to replace the scarred piston with my Volvo piston but the cutout for the oil squirter was in the wrong position.



You can see in the picture how I just filed a cutout in the piston in the correct place.



I only did the one piston thinking that would maintain the crank/piston balancing since pistons 2 & 3 are side by side. (Now I wish I had replace all 4 pistons since the original 3 were heavily carboned on the sides above the rings.) Any thoughts on removing that amount of mass from the piston skirt?

I borrowed a ridge reamer from Kragen O'Riely's and did an adequate job of removing the ridges, stone honed the cylinders with a Harbor Freight item and measured the bores. I didn't take any after pictures but it came out o.k. The bores were over the wear limit but seemed o.k. My theory being: it ran before so it should run now!!!!!

Last night I got it all put together and it started right up without the block heater!!!!!!! (it was 35 degrees...still winter here in Reno) I've got to finish putting all the little things back together and will drive it today with an update later today or tomorrow.

Addt'l info: I did put on a new water pump with the steel blades.

When doing this I corrected many small problems from prior owners: stripped lower injection pump bolt (the one that's below the pump on the timing belt side); missing thick washer on one of the other injection pump bolts (causing binding when trying to adj. the pump. Now it rotates perfectly!!); two broken exhaust studs on cyl #2 (looking for better boost now since gas is going out the exhaust pipe now; etc., etc, etc.

My purpose for doing this the way I did was to improve smileage, better power, lower operating temperature and get experience for doing another engine that's currently sitting on my stand. I didn't want to spend much money and I didn't (well.....except for all the tools I bought, and all the "little" parts, you know $10 here, $20 there, $60 over there. Oh, and the $400 1.8 '88 Jetta as a backup car!!!!)

I'm convinced if these engines were taken care of from the beginning they would last forever.

[Quantum-man]

Sounds like you are striding along with confidence .
Re the carbon buildup above the rings, assuming its evenly deposited, I'd leave it there as it improves compression, and new rings will prevent bore scoring.

Remember for best chance of setting rings to highest compression, set compression rings 180 deg apart and not 120 as per all books that merely plagerize each other

[CarlosA]

If you want to balance the pistons that you notched, just weigh each and remove a small amount of material until they are all very close or identical. Can use a kitchen style digital scale with .1 gram increments ideally.

I did this with my connecting rods when I had everything apart.

[Nevadan]

If you want to balance the pistons that you notched, just weigh each and remove a small amount of material until they are all very close or identical. Can use a kitchen style digital scale with .1 gram increments ideally.

I did this with my connecting rods when I had everything apart.

CarlosA,

Thanks for the reply. That's a great idea on the connecting rods also!!

I was more concerned about the piston to crank balance. ie. the weight of the piston -vs- the opposing weight of the crank opposite the piston. I'm no engineer so that small amount may be immaterial. When I do my next engine I will do that with the rods and pistons.....and my next engine is on the stand now, and will probably start it in May. I had good experience working on this one.

[Nevadan]

Sounds like you are striding along with confidence .
Re the carbon buildup above the rings, assuming its evenly deposited, I'd leave it there as it improves compression, and new rings will prevent bore scoring.

Remember for best chance of setting rings to highest compression, set compression rings 180 deg apart and not 120 as per all books that merely plagerize each other

I read one of your earlier posts about the 180 degree offset and already did that. Thanks for the tip! It never made sense to me to offset them 120.

I left the carbon there, mainly because I didn't want to do the "oven cleaner" routine and wanted to get the car back on the road so I'm glad you suggest leaving it there. I'll stick with that reasoning when I'm discussing this in the future.

I ran the car hard yesterday and today by doing a mountain run from 4000ft up to a ski area at 8000ft (50 miles round trip) and another run today from 4000 up to 7000 (90 mile trip). I read somewhere that it's best to seat the rings under a load than just letting the engine idle. It makes sense since the compression will force out the upper, and possibly second, ring.

The engine runs totally different, a lot quiter, a lot smoother and it starts much easier. I'm not sure about the smileage yet but will know once I fill the tank. It doesn't seem to be much improved based on my trips yesterday and today but I don't want to jump to any conclusions. I base my mileage on fill ups, usually when the tank is near empty.

A comment on the wax in the fuel. Despite the age and non-care of this car prior to my purchase there was almost no carbon on the pistons. I'm speculating the wax takes care of the buildup by burning it off?? or maybe something else??

Now for a few more questions, open to all for replies. I have not tested the internal pump pressure so that is an unknown variable. There is significant difference in pull resistance using the cold start advance test suggested by Hager and there are no major leaks from the pump, none from the front seal.

!. Since I live at 4000 feet should, as a general rule, the timing be a little more advanced?

2. My engine still ran hot on the mountain runs!!! I don't have an actual temp gage and am just basing it on the stock gage. I thought for sure the temp would go down since the engine should be running more efficient. The radiator is 1 year old, new water pump with this job, thermostat is 1 year old and still works properly. I didn't do any head work and the valve guides were a bit sloppy, would that affect coolant temp? Any other ideas?

3. The power is different!! It seems fine in the sweet spot between 2800 and 3500 rpm's but not much before 2800. It seems like it was less than before. Any ideas? It may be because I was driving the '88 gas 1.8 Jetta and I'm adjusting back to the diesel.

4. I have not adjusted my injectors to 130 bar (or whatever it's supposed to be for the TD's) I just replaced the injector nozzles about 9 months ago. Since I have better compression now (not sure what but I will test them this week) it may be that I need to set them to spec. Does that make sense even though I was averaging 39 mpg with them as they are and with the lower compression? How much do the internal springs "sag" over time? 1985 until now...could be a bit.

5. The return line from the "outbolt" leaks. It's a new tight fitting line with a good clamp. It's as if there's something plugging it further down the line, at the tank or somewhere back there. Any experience with plugging problems back there? This has happened as long as I've had the car but was hoping it would just go away!!!

6. Is it necessary to torque the headbolts the final 1/4 turn as shown in the Bentley? It says to do the procedure after about 1000 miles. I'm a little spooked about cranking them another 1/4 since the previous torquing seemed VERY tight. I need some experience in this area.

I'm headed back to the garage to replace the gauge cluster lights. No questions on that procedure!!!

[Fatmobile]

An EGT gauge would give a better idea of what the combustion temps are doing,
compared to your coolant temp.
Retarded timing will cause the EGTs to run hotter.

I think 155 is the breaking pressure for TD injectors.
I has alot to do with where the timing will need to be set to run right.
Higher breaking pressure requires more advanced timing.

#5 There's a check valve in the return line, back by the fuel level sender.
That can get plugged.

Final torque on headbolts.
I've been using a torque wrench and watching the needle.
Let's me see when it's in the stretch zone because the needle stays steady, doesn't increase in value. Seems like that's somewhere near 100lbft

[Nevadan]

#5 There's a check valve in the return line, back by the fuel level sender.
That can get plugged.

Thanks for the tip. Is it inside the tank, on top of the tank or somewhere by the fuel/water separator? I haven't looked in the Bentley yet.

[Nevadan]

Final torque on headbolts.
I've been using a torque wrench and watching the needle.
Let's me see when it's in the stretch zone because the needle stays steady, doesn't increase in value. Seems like that's somewhere near 100lbft

I thought about doing that but didn't, I just used a breaker bar for the final 180 degrees, 90 degrees at a time.

So, any input on turning the headbolts the final 1/4 turn?

[Quantum-man]

1000 miles is too long. Bentley transcribed 1000km to 1000miles when plagerising
I believe in about 500 miles revisiting the head. Unlike the 'new' poilicy of not undoing bolts first.., I still use the contrary method.

This, for me shows up those bolts that have worked surprisingly loose, be it from actual bolt loosening or probably variation in the gasket spread. It will also prevent those nasty bolt creaks. I loosen, then retighten each bolt individually. As per Fats, which I believe is as per me; I peer down onto a torque gauge, and I personally stop when plastic position reached.

RE the injector pressures, 130 to 155 is quite workable, with adjusted timing, but clustering the break pressures tightly really helps remove injectors from the equasion when trying to get the engine to run 'smoothly'.

[Fatmobile]

Right Quantum man, I learned that from you.
Instead of grabbing the breaker bar last few times, I grabbed the 1/2" drive torque wrench and watched for the torque to quit rising.
I'll do the same as you subscribe on the final retorque.