T-belt slipped on 1991 164L

[Alfisto Steve]

I give up. I have been driving my 164 for 200 miles to hotel for our wine tour weekend. I am now enjoying happy hour.

I guess you are saying you bent more valves after putting on head but exhaust ones this time.

It is wine tour weekend for our Alfa club and we already have a Spider down for a fuel pump on Rt 15 near Orange, VA but Tom from IAP is going to bring a new fuel pump home with him so we can go out and fix car tonight. What a guy, huh!

[MrT]

Quote:

Originally Posted by gprocket I hate to make a federal case out of this but I am no mogul...

[ChazzyD]

Something that has to do with the oil pump drive? Forget the oil pump nut in the rear head gear? Forget the oil pump pulley, the gear in the head? I give up.
Charles

[gprocket]

When you install a 2.5L head gasket in a 3.0L motor it fits... sort of! The head gasket I used was in the box of extra parts that I got from the PO. A quick glance confirmed that it was the rear head so on it went - but it is about 15mm smaller in diameter. Enough that when the pistons come up and the valves come down the edge of the gasket becomes a valve bending wedge...

Talking to the guys at IAP, if you buy a gasket at Autozone or wherever, they will likely give you a Federal Mogul gasket. FMC only makes the 2.5L gasket but it doesn't say 2.5L on the package! In fairness it does say "turbo" and in retrospect I think that the turbo version (not available in the USA) was a 2.5L.

Lots to learn here but at least there was a root cause. Before I realized what happened I was frustrated that we were doomed to repeat the problem. At least now I can make new mistakes...


With the two gaskets together it is obvious that the top one is much smaller in diameter.


Close up of the damaged gasket which led to the bent valves.

Class dismissed!

[ChazzyD]

O' my goodness! That'll do it.
Charles

[Alfisto Steve]

That Turbo head gasket is actually for a 2.0 L V6 (even smaller pistons than 2.5L). I have four more if you want some more. I bet your PO got the set from same guy I did in Green Cove springs, FL. I bought those same turbo sets for all other gaskets which do fit 3.0L engines. Price was right. I got the correct head gaskets from IAP.

If you need more 3.0L valves call Joe at AW Import Parts in Eaton Town, NJ. He lists them on eBay if you can't find them or if you want to check out his prices.

[gprocket]

Spot on Steve:

The PO emailed me last night and said that he did indeed buy a turbo kit cheap. Just wish he had thrown out the head gaskets...

We'll be back at it Tuesday when the parts show up.

[oklaoz]

I have to pull the rear head of my 164 also (0 compression in No. 1 ) .do I have to pull the cam out or can I just pull of the pulley?
Oz

[Alfisto Steve]

Quote:

Originally Posted by oklaoz I have to pull the rear head of my 164 also (0 compression in No. 1 ) .do I have to pull the cam out or can I just pull of the pulley? Oz

[oklaoz]

Where is the oil drain port?
Oz

[MrT]

I saw that and had to think it through, too. Steve is mentioning the drain hose that goes from the oil vapor separator back to the engine. It is under this port that the oil pump drive gear lives. There is a single 6mm stud (10mm nut size) that retains the oil pump drive shaft to the aux. drive gear. Pull the nut and that will allow the head to come off without the oil pump drive shaft being damaged.

Good luck with the process....I have a head gasket job awaiting me on a 12V cart, too.

Michael

[gprocket]

That's more like it!

Got the parts in and installed the head. All timed up and she pretty quickly fired up. Best of all... no bent valves! Nice and quiet!

I finally found the root cause for the original belt slip - the mechanical tensioner. Nothing looked out of whack (springs were fine, etc) but when we went to tighten the belt the tensioner it went to it's limit and still the belt had too much slack. I watched as the rear pulley almost slipped back while we were rotating the motor by hand. Pulled another tensioner out of my seemingly endless supply of spares and that did the trick. It wound up just like the TSB video shows and the belt is nice and tight without being anywhere near the limit.

So we've got the radiator to put back in, the strut and a few odds and ends and we should be on the road.

One oddity: In the beginning we checked compression and the front head was reading 200 PSI across the board (the rear reading zero indicating damage). This time I checked compression on the rebuilt rear head and was disappointed to see 150 - 160 PSI. Then I went back to the front heads and they too were reading 150-160 PSI. Now nothing was touched with the front head so I've got to believe that it's a false reading. And that being the case and with the rears reading the same as the fronts I am of the opinion that they are in fact running around 200 PSI. This is my rationalization for not tearing the head off again. The only thing I can think of is that the gauge is off or the battery was sufficiently drained that I wasn't spinning fast enough to get a decent reading. BTW, do you take compression at WOT as we do with the Nord motors?

[MrT]

Yes, Wide Open Throttle to keep the manifold pressure approximately at atmospheric pressure. The readings you have could be impaired by slow revs, as the inevitable leakage in the engine is of greater effect when it has more time to bleed air away. 160-ish is what I got with my wife's newly rebuilt engine first time around before starting it. Maybe your rings aren't yet seated and you were reading a high value from them being oiled and sealing better the first time around? They would likely be without assembly lube by this time. Just my guesses.

Michael

[oklaoz]

please explain TSB video. Sounds like something I need!
Oz

[gprocket]

TSB = Technical Service Bulletin. In the 164 Digest is a listing of all the TSB's. Alfa 164 TSB 01.93.03 is for the mechanical tensioner. It references a video which I have from the cardisc set for 164's. I would highly recommend getting the cardiscs if you don't already have them. Alfa Romeo 164 CarDisc CD

Sorry for the cryptic language - must be too much text messaging... LOL.