Belt Skipped a Few Teeth

[CharlieB]

Oh man, I forgot there were different types. Thanks AJ...sorry Bryan.
I'll track down one of those in the next few days.
Don't know what I'd do without you guys.
Thanks
Charlie

[18Fiatsandcounting]

No worries Charlie, we're here to help. As for the valve spring compressor, I used to have a spring compressor like what you showed in the picture, but I could never really get it to work on the Fiat setup. Here's what I use (or something similar):
https://www.summitracing.com/parts/wmr- ... gJZbvD_BwE
One end goes around the collar at the end of the valve stem, and one end pushes against the valve head. When you compress the tool, the collar at the end of the valve stem is released, and the two collets slip out. Put in a new valve, do the reverse, and you're good to go.

But, if you're friendly with a machine shop, they could probably get your old valve out for $20. Or less. If you're not friendly with them, maybe more.

-Bryan

[CharlieB]

I was in South Carolina to see the family but I'm finally back. Ok, I got the correct tool and it worked like a champ.


I should have the gaskets, timing belt and valve in the next couple of days. I ordered a valve guide, just in case. I have valve seals already.
I checked the head with a straight edge and it's dead flat.
Can I reuse the valve seal and guide, or should I replace them?
If they need to be replaced, is that something I can do or should I have a machine shop do it and install the new valve?
Thanks,
Charlie

[18Fiatsandcounting]

Awesome progress Charlie! Well, since I think you said previously that you didn't want to dump a lot of money down this project, here's what I would do:

EDIT: I see you said you've got new valve stem seals. I'd just go ahead and install them.

1. Get a new valve. Make sure it's right for your engine.
2. Put the new valve in the old valve guide and wiggle it side to side. If it moves only very slightly, your existing guide is probably fine. Or, remove another valve and use that to check the valve guide of the broken valve cylinder.
3. As for the valve stem seal (the turquoise part), if it seems fairly supple if you squeeze it between your fingers, it might be just fine for now. If you do want to replace it, you should just buy a set of all 8 valve stem seals, and that would require removing all your valves to install them. Maybe not necessary, but on the other hand, your combustion chambers did look a bit oily which could be leaking valve stem seals (or leaking piston rings).

If it were me, I'd replace all 8 valve stem seals and buy some valve grinding (lapping) compound and touch up the valve seats by hand. As for removing the old valve stem seals, a pair of vise-grips will get them off but don't get too carried away with the clamping force as you can damage the valve guide. To install the new ones, clean up the top of the valve guide, lay the seal on the top of the valve guide and use an appropriately sized socket to gently pound the new seals on. I think the socket is about 11 mm, and it should clear the top rubber and spring part of the seal, and rest against the metal "frame" of the seal. Try a few different sizes, both English and metric, to see what works best.

-Bryan

[CharlieB]

Thanks Bryan,
A few years ago a member of the forum gave me a seized engine from a car he lost in the divorce. I've been using the head from that engine to practice on, that has been very helpful in determining how much force is too much force.
I have parts coming in the next day or so, so hopefully this weekend I can start getting things back together.
I have seen a few different methods for lapping the valves, some more involved than others.
What is your method for lapping the valves?
Also, I assume replacing piston rings is not a task I should attempt on my own...correct?
I don't even know how to remove the piston.
Charlie

[18Fiatsandcounting]

As for lapping the valves, what I have done may not be very professional, but it works. As long as there isn't severe damage to the valve seating area, either in the head side or the valve side, you can buy some valve grinding (or polishing) compound at most auto parts stores and have a go at it. You're not really grinding into the valve seat with this stuff, just abrading off any minor imperfections like discoloration, scratches, very slight pitting, etc. I just put some of this stuff around the valve seat, insert the valve, and then use a hand drill on the valve stem to slowly turn the valve while gently pulling on the drill. Don't get carried away with too high a speed or too much pulling; just go slow and steady and check the valve seats every 10 seconds or so.

As for piston rings, the best way to do this is to pull the engine out and take it to a shop. You can do it with the engine in the car, but it's tricky and you'll need some specialized tools. And, while it might be do-able, you're not going to get as professional a job and you won't be able to change some other parts like bearings and seals and such. But, if you really, really want to attempt it yourself in the car, I can give you the process. However, unless your car was burning a lot of oil (blue smoke out the tailpipe when you drive, need to frequently add a quart of oil, etc.), my suggestion would be to leave it be for the time being.

-Bryan

[dinghyguy]

as much as it hurts me i agree with Bryan re lapping the valves, you have the head off, you have the tool to remove the valves. Now is the time! If you use the drill, alternate directions as well. Many people do it by hand using a stick with a suction cup on the end. Stick it to the valve and rotate the stick back and forth like a caveman trying to make primitive fire. Takes a while, but works fine.
Do not mix them up, i would suggest you do one at a time just to be sure.

Silly question, if you have the spare engine why didn't you just steal a valve from it?

And i assume you know that the shims for all the valves will need to be checked after you get everything back together....and you didn't mix those up. Oh measure all of them with a micrometer before you reinstall them and record the values for each valve for your use in mixing and matching when needed.

glad you are having fun.
dinghyguy

[18Fiatsandcounting]

Excellent suggestions from DinghyGuy, and it's a good thing we have him here to keep me honest!

-Bryan, who will soon be surpassed by dinghyguy in terms of garage space, and a better looking dash.

[CharlieB]

Not a silly question Dinghyguy. The valves from the spare head are in pretty rough shape for the most part. 1 or 2 of the exhaust valves might be ok but I figured a new valve would be safer.
I'll try the drill technique on the valves first.
Yeah those shims are what got me in this trouble in the first place, but I'll certainly take my time with that this time and order the ones I need. I have some spares from the "donor" engine if anyone needs some. I'll measure them.
2 questions:
(1) How do you know when you are done with lapping the valves?
(2) Whats the best way to clean the carbon buildup on the other valves?
Thanks guys
Charlie

[dinghyguy]

when lapping the valves you will see a polished band appear on the seat and on the valve. In a perfect world you lap until the bad is even and more or less the width of the "flat" but that takes a while (too long). so I would expect if you get 50% of the flat lapped you are doing better than most and will be more than fine.

I am sure there are products which will dissolve the carbon, but i would just use a dremal and wire wheel, being careful not to scratch the seat area where all your lapping will be.
Now wait and Bryan will tell us actually how to do it...….

cheers
dinghyguy

[18Fiatsandcounting]

As if on cue from Dinghyguy, heeeeeeere's Bryan!!! [applause] Thank ya. Thank ya very much.

My thoughts are similar to Dinghyguy's. The baked on carbon and grime is pretty tenacious, and about the only method that really cleans it up is mechanical abrasion. Chuck the valve stem in your favorite drill and use a stout wire brush, medium grit (150) sandpaper, and a Scotchbrite pad (in that order) to remove the buildup. Valves are pretty tough, so you won't damage them. If you want to make them look really pretty, finish up by wetsanding with 600 grit or higher emery paper, depending on how much shine you want. (the engine doesn't really care)

As for the valve seat, as Dinghy mentions, the goal is to have the seating area to be an even band all the way around, with no narrower or wider regions. If there are, the axis of the valve guide is not totally perpendicular to the plane of the valve seat, and that would definitely take a machine shop to fix (if it's serious enough to warrant fixing).

The band of contact should be roughly in the center of the cone-shaped contact area of the valve, and about 3 mm wide.

There is a Fiat spec for this, and for a non-Fiat example, see: https://johnmaherracing.com/tech-talk/3 ... valve-job/

-Bryan

[CharlieB]

Thanks guys, that sounds simple enough. The compressor tool I bought off of Amazon bent last night while I was removing a valve from the spare head. It's being returned today and I ordered a much better tool last night, like the tool you showed me Bryan. I'll have it tomorrow.
The parts I ordered should be here by saturday so hopefully I can get this process started soon.
Thanks for all the tips guys,
Charlie
(Side bar) Dinghyguy you gave me some priceless carb info a while back. I just wanted to thank you again for that.

[CharlieB]

I just wanted to give a quick 'progress report'. More travel delays, but I'm back on track now.
All the valves are out. I've cleaned them up and they look ok for the most part.
One of the exhaust valves is not exactly straight, there is a slight 'wobble' if I roll it on the edge of a flat table. I think I may have bent it when I was using the spring compressor.
So, since I have 4 extra exhaust valves (from the donor engine), I was going to use one of those. The donor valves cleaned up better than I thought they would and all are straight.
All of the other valves have been lapped (using Bryan's method), that seems to have worked well. However, I'm still not 100% sure that I have lapped them enough. I'll check them again tonight.
So, I guess the next step, after lapping, is to reinstall the valves.
Anyway, that's where I am.
Thanks again for all of the advice.
Charlie

[18Fiatsandcounting]

Thanks for the update, Charlie. I'm always curious how things work out for the people who pose questions on this forum, and sometimes we never find out whether it was resolved or not. Please keep us posted.

Anyway, yes, if you can see your valve wobble as you roll it around on a flat surface, you can discard that valve. Valves are very strong when the pressure on them is equal on all sides (such as in an operating engine), but they really are quite weak when they get knocked from one side, like being hit with a piston or even dropping the head onto a workbench with the valve extended.

One simple sealing test that you can do it to turn the head upside down with the valves installed (and all closed), spark plugs installed, and fill each combustion chamber up to the very brim with some sort of fluid. Perhaps not water so as to avoid rust issues, but something like rubbing alcohol or the like. If you see the fluid level drop over a few hours (beyond what you would expect from evaporation), then your valves aren't sealing. And if you see fluid dripping out of your exhaust or intake ports, then you definitely have a big leak...! It's not a foolproof test because it isn't pressurized, but if you do see fluid leakage, it's not right.

-Bryan

[CharlieB]

Great idea Bryan. Could I use motor oil as the liquid? Might get a bit messy, but my garage is a disaster anyway.
EDIT:
Nevermind..rubbing alcohol it is.