Here are a few pics of my 1.8L engine coming back together finally, after a blown head gasket in November last year. I'm using a stronger heavy-duty head gasket this time (the Guy Croft heavy duty gasket). It is about 25mm thicker than the standard gasket, which should drop my compression ration down from 10.6 to a more manageable 10.1 - 10.2 or so. Also using the GC grade 12 head bolts, and changed the valve springs out for the GC triples, and am using total seal piston rings this time.
Buttoning up the oil pan, cylinder head ready to go:
Using the clutch pressure plate to lock the flywheel from rotating while tightening the flywheel bolts, and all the front pulley bolts:
Another peak at the flywheel :
Adjusting the timing of the cam wheel pulleys. For starters I have the intakes at 108° and the exhausts at 111°. I may play with these adjustments a little bit during the upcoming Dyno Day the Mark is planning:
Next: rebuild the carbs and the distributor, then drop everything in the engine bay.
Beautiful engine Ace. I always love seeing it, but in the car is better. I'm surprised, I thought a 25mm thick head gasket would lower your compression more than just a few points.
manoa matt wrote:Beautiful engine Ace. I always love seeing it, but in the car is better. I'm surprised, I thought a 25mm thick head gasket would lower your compression more than just a few points.
The heavy duty GC gasket is about .075” thick, or about .025” thicker than the .050” thick standard gasket that I used previously. I figure it will probably compress somewhat when torqued down, for a net thickness gain of about .020”, or about .05 cc’s. This equates to a gain of about 2.9cc’s for the 85mm ID of the head gasket.
Compression Ratio = (combustion volume + swept volume) / (combustion volume)
With standard gasket: ~ (47 + 450) / (47) = ~10.6
With heavy duty gasket: ~ (49.9 + 450) / (49.9) = ~10.0
great looking motor. one thing i am wondering, how much hp are you predicting? and shouldnt you pin your pressure plate. im sure the hp is enough that the stock straps might fail. just an idea
Automotive Service Technology Instructor (34 year Fiat mechanic)
75 spider , 6 Lancia Scorpions, 2018 Abarth Spider, 500X wifes, 500L 3 82 Zagatos. 82 spider 34k original miles, 83 pininfarina, 8 fiat spider parts cars
son has 78 spider
Alvon:
If you want to know your actual CR I have access to a Whistler, which is a tool that measures the actual CR with the engine assembled. You just have to turn the engine to TDC. When is the engine going back in the car? Let me know I could bring it up most anytime.
Hal
The flywheel is the stock 1438cc flywheel that came with the car (1970), though it has been lightened, and the 6 mounting holes opened up to accomodate 12 mm bolts for the 1.8L crankshaft. I had the wear surface touched up, and it needed the outer diameter touched up a bit also to get the proper step dimension (.020", if I remember correctly). The other holes you see in the picture are for balancing.
a whistler, are you a tech inspector for a race series
Automotive Service Technology Instructor (34 year Fiat mechanic)
75 spider , 6 Lancia Scorpions, 2018 Abarth Spider, 500X wifes, 500L 3 82 Zagatos. 82 spider 34k original miles, 83 pininfarina, 8 fiat spider parts cars
son has 78 spider
BEEK wrote:a whistler, are you a tech inspector for a race series
Thank you <I think??>
No, not a tech inspector. I just enjoy figuring out what makes these things tick. I learn more each time I tear into one. Unfortunately, as I get older, I find that I forget more than I learn each year!
Bernie,
I'm putting back mostly the same that I took out, with little improvements along the way: (the engine had 25K miles on it when the head gasket blew)
40 IDF 30,15 carburetors, waffle manifold and domed sponge filters. Looking to replace the 32 chokes with 34's.
1.8L block, 85mm bores.
8mm dome pistons, total seal rings (improvement????)
New main bearings, and new connecting rod bearings, though the old ones didn't show much wear
New pilot bearing, the old one was grumbly already!
New Valve springs, the Guy Croft Triples (improvement). I had springs in there that were way too strong.
Heavy duty head gasket and new head bolts. (improvement)
New rubber (seals, gaskets, belts, some hoses) and new tensioner bearing.
New grind on the valves, and new bronze valve guides (improvement).
40-80 camshaft on the Intake, 70-30 on the exhaust, with adjustable cam pulleys,
Rebuilt distributor with new bearings and seals, and will experiment with springs to adjust the advance curve.
Crane 700 electronic conversion on the distributor.
Lightened 1438cc flywheel.
Standard 4-2-1 exhaust with stock pipes and muffler, but considering modifying to open up the exhaust.
Electric fuel pump in the trunk.
Marelli 55A alternator w/ internal regulator.
Also, changed out some leaky gaskets and seals on the transmission, and a rear wheel seal that was leaking.
And, had the driveshaft balanced.
