Dino Engine Failure

I am in agreement with Paul that compression is not the culprit, and that it seems premature to have pulled the heads. As I mentioned earlier, bad fuel (e.g., water contamination) will lead to the same symptom. Easy and inexpensive to rull out.

Jim

 

I also think that the motor was pulled apart too soon. As you put it back together Im sure all systems will be checked and you may never know why it quit . Almost better of not having it start up so you can find out what really was wrong. Mike

 

Any more pictures?

 

Yes, never start repairs at the most expensive point when a proper root-cause diagnosis has not been completed. It could be something quite simple in one of the ancilliary systems (fuel, elect, ect)

 

If you have fuel, spark and timing, (and no physical damage) the engine must run. It has no choice! Since you have fuel and spark, it must be timing which in this case suggests the distributor. I would swap it out if possible (or rebuild it) and change the wires and plugs. Taking the head off was an extreme measure that I would have never done at this stage but the fact the last rebuild left something to be desired means at least it wasn't wasted money in case you want to get it done right.

You could have the advance stuck, or something of that nature that threw off the timing but still gives you spark.

Ken

 

Very nice. Accumulator grooves in the top ringland... shorter skirt... Are these Wiseco? With modern rings, the latest honing procedures and gapping recommended by the vendor and not Ferrari, you will have a better engine than what the factory produced.

 

why does it say mondial on the old piston?

 

Mondial is the manufacturer which is now Mahle Mondial S.p.A. since 1987. The Dino engine came with either Mondial or Borgo pistons from new. http://www.rallycars.com/Cars/Lancia/Stratos1.html

 

Might not have gotten hardened seats, and they succumbed to unleaded fuel. What ever happened to the initial diagnosis of .009" piston clearance? I would have expected that to make a fair amount of noise. And if accurate, was the clearance caused by scuffed pistons, possibly cause by overheating?
Tom B.

 

I would have thought .009 would have banged like mad, especially cold.
Cheers,
Tom B.

 

Do you think this was an honest oversight by the builder or do you think it was something more devious?

Also, the original pics above in post #11: the strange scoring has not really been explained, very odd.

 

Seats are brass, shouldn't be a problem with unleaded.

 

If I had to guess I would say the guy that rebuilt the motor set up the piston to bore clearance to factory specs-which are set for Forged pistons- not cast pistons.

I believe that the first over specs are 92.700 to 92.730 for the bore and 92.530 to 92.566 for the piston. If I did my math correct that is a loose 6-7 thousands which where not uncommon for Forged pistons in the day. You just put up with the cold piston slap.

When I got my replacement pistons back in '98 from Superformance (E-B in the US) I was surprised that even the new (at the time) forged pistons I received were sized to have this lose clearance-- I was expecting 3-4 from a more modern aluminum. Superformance told me that they had them cast in Italy by the original manufacturer so used the same aluminum mix. The cast pistons sold at the time were down to 2 thousands clearance.

If the rebuilder put in Cast pistons and set the bore to factory specifications then the piston slap would be terrible even when warmed up- which could oval out the cylinders to the 9 thousands fairly quick.

I believe that new Wisco forged pistons are set up for 3 thousands clearance.


I still have my motor on my bench as I very slowly restore the body. As an aside-I made a torque plate when I had the block bored and honed because when I torqued down the heads the bores went a bit oval--


Ok- this is my guess--- and I could be very wrong.

 

Glad to see it going back together. I also used the JE forged pistons from Superformance when I did my Dino and I don't know if they are really the 10.4 they claim since I did get away with running on pump gas, but for what its worth, compression test showed 210.

As for those bores, I've had Fiat 124 engines with blown headgaskets and discovered bores in much worse visible shape than those and just slapped the things back together and they always ran just great (though only to 6k rpm or so, not the 8k i could pull on the Dino).

 

I also put these in my Dino and ran on 91-93 octane pump gas without incident. Also made good additional HP, so I think the claim of increased compression is a fair one. We were making approx 180 RWHP with these on a US spec car, which left the factory with an optimistic 175 crank HP, right?

DM

 

Glad to see the engine running well, although I now do not think we will ever really know why it just "stopped". I know this sounds a bit silly, but did you try the emergency switch on the Dinoplex?

I also appreciate the reports on the higher compression pistons. I just put in 10.5:1 JE and will be starting it next week, so good reports about pump gas is reassuring.

Best
rt

 

Congratulations getting it all back together and running. Where is the compression now?
John