Engine rebuild

[phaetn]

I pulled the engine back in February and ordered a pirate's ransom in parts for a rebuild.



I'm going with 9.8:1 pistons (second oversize) and a mild performance 40/80 intake cam. Just waiting for the block back from the machinist's. I'm hoping that's happening over the next few days.

In the meantime I cleaned up the engine bay, painted it black in POR-15m, and tidied all the wiring and wrapped it in corrugated tubing. Most things are in situ now, except for the rad. I had a bunch of parts powder coated, too, which was surprisingly inexpensive.




Here's a pic with the master cylinder in place and my new brake fluid reservoir tank installed. I used a tap and die set to create a new mount in the firewall. I could have gone a little lower but wanted to make sure there was no interference with the clutch cable. I also don't think I can get that much closer to the fender as the wiring loom will interfere.

I'll replace the old blue dirty hose with brand new brown braided hose and clamp it -- this was just to test lengths.

I have also set up a cluster of new gauges under the dash up that fit me perfectly -- I was worried that my knee would interfere but it fits just right between the gauges and wheel when at rest and easily clears when depressing the clutch. It's all good and snug and visibility is just right. It took a long time to wire it all (soldering connections as two of the gauges have 2x12v and 2xgrounds, plus the sensor lead). I'm looking forward from the data from the AFR sensor to finally get jetting right.


Finally, I even managed a quick iron-on patch fix for wear on the driver's seat. Much less expensive than the quotes I received from upholsterers. I know the seat fabric is faded, but that's ok by me. It's not as noticeable when the belts are in place.


Things are finally coming together... This was at a friend's yesterday using his parts washer. Today we put the transmission together with new synchros, forks, sleeves, etc.


Cheers,
phaetn

[Nut124]

Looking good! Lot's of work!

[phaetn]

Question re. dialing in cams: I have adjustable cam pulleys but have never dialed them in precisely.

How do I go about this process? Is there a good resource/website? Do I need specialized tools (degree wheel and stands, etc. or vacuum gauges?)

The head is at the machinist's now getting the intake side ported. (I started it with a rasp on a compressor then stopped before I did anything that wasn't reversible if I took too much meat off the head or intake manifold). I also gave them my new (reground) 40/80 intake cam and so they will file the valve stems directly to suit valve clearances rather than messing about with shims.

I'd imagine they cannot degree in the pulleys/cams as they would need to be connected by the timing belt and all in situ, right? Or can they? I'm just wondering if I should ask them while it's there...

Thanks and cheers,
phaetn

[18Fiatsandcounting]

I can't help with dialing in the cams, but I appreciate seeing the pictures. Looking good!

One thought: I polish up my relay housings with a brass wire brush on a bench grinder. Makes things look so much more bright and shiny. 5 minutes per relay to remove and polish.

-Bryan

[Nut124]

Hello Phaetn, regarding cam timing. I have done a lot of it for Fiats in the last 18mos.

I would suggest doing a dry build and cam timing on a stand. The head needs to be on the block and timing belt in place.

Needed:
- Degree wheel
- Piston TDC stop plug device
- Dial indicator with long extension (fabricated, improvised)
- Dial indicator holder snake w wisegrip
- TDC pointer on the block pointing to degree wheel TDC

The biggest problems are:
- getting the degree wheel secured on the crank
- Getting the degree wheel secured on the crank where it is centered on the crank axis
- getting the dial indicator extension on the #1 valve shim

I'm not a good doc writer, or I am lazy. Could post a link to my misc Fiat pics album where there are pics about cam timing.

Let me know if you want to see the album.

I did a post mortem on my previous build before starting this last one. my old cams were off alignment by almost 10 deg.

Now they are dialed in within +/-1 deg of my spec.

Timing is checked by plotting crank degree at specific lift values at opening and closing to calculate cam C/L vs crank. Use of Excel is very helpful.

[Nut124]

I'll post a few pics here:

Never turn the crank CCW for any lift measurements. OK for the pistons stop check obviously.

[Nut124]

Piston stop plug for finding true TDC and zeroing the degree wheel.

The rod is slightly canted. I thread the plug in, when both valves are closed, in such a way that the rod is pointing down and away from the valves. The marker line is for alignment.

[wetminkey]

Yo, Nut! Where did you get your piston stop from?
I was looking for one awhile back, and never found one. Got the job done without it, but it sure would have been the PROPER tool for the job,...
Thanks, Todd.

[Nut124]

I made that piston stop from a busted up spark plug. I had actually found one on eBay, ordered it, but misplaced it somewhere.

You just need to cut off the ground electrode, bust up the glass on the underside and hollow it out and then epoxi in place the stopper rod.

[rjkoop]

Wow. Nice work. Never had the guts to pull the engine.

Glad to see some of these Ottawa Spiders still around.

Richard

[ORFORD2004]

I'm not Guy Croft but that's the way I did it:

I don't see the need for timing marks on the pulley. For timing my cams i have to find the lobe center of the cam and be shure that the crank was at 110 degrees. you need a dial indicator and a degree Wheel for that job.

The way i did it is you find the real TDC. The way to do it is to use the infamous screwdriver method to find TDC.
Then you install your degree wheel on the flywheel and put a piece of wire attach to the engine to 0 degree.

Next is to put the dial indicator in the plug hole. Not much of steel in that area for my magnetic base so i made a steel bracket that use the valve cover bolts to old steady. So you install your dial indicator so you have some pressure on the dial. Set to 0 and turn the crank clockwwise. When you read let's say .002, note the number on the degree Wheel. Continue turning and when you are .002 before the 0 you set, note the number on the degree Wheel. For example if you read 355 and 3. You have to move your pointer 1 degree up to 4 so the reading will be 356 and 4. Equal from the zero. From now the pointer or the degree wheel can't move. Retest to be shure. Now you have your true TDC.

Now you have to find the lobe center of the cam. For that you have to install the dial indicator 90 degrees from the valve tappet and clear the lobe rotation. The trick i found, sorry for the purist was to use electric tape and a piece of steel wire at the end of my dial indicator because my needle was to big to fit on the side of the cam and clearing the lobe. When there is full pressure to the tappet, you install your dial indicator whit some pressure on it. Set to 0 and turn the crank clockwise. when the valve start closing let's say .002, note the number on the degree Wheel. Continue turning and when the valve is .002 before the 0 you set, note the number on the degree Wheel. For example if you read 84 and 134, you take 134-84=50/2=25. So 25+84=109. Your lobe center is at 109 degree and you want 110. If you move to 85 you will read 135 also. So 135-85=50/2=25. So 85+25=110. So you set your degree wheel to 85 degree and using the adjustable pulley turn back the dial indicator to .002 when the crank is at 85 degree. Retest and you should read 85 and 135. Now your lobe center is at 110 degree.
Same thing for the other side.

That's the way i did it.

[phaetn]

Thanks so much folks, that's very helpful!!

Orford2000, thanks for the description of how-to and Nut124 for the pics so I can visualize it all.

I'll ask Dan, with whom I am reassembling the engine, if he has a degree pointer. I have also asked a buddy with whom I used to wrench on old Vespas. He's probably still got one if he's willing to lend it.

I think I might get this from Summit Racing: it's a degree wheel and dial pointer. Wish I could find one here in Canada but we can't compete with US supply and prices.
https://www.summitracing.com/int/parts/sum-g1056-16
I can't see using it more than once or twice, though...

Cheers,
phaetn

[ORFORD2004]

Print one a put it on cardboard. The dial indicator can be found locally.
https://www.blocklayer.com/degree-wheel.aspx

[Nut124]

Here are a few pics of my degree wheel. It needs to be cut to allow a socket on crack for turning the crank.

I ended up putting bolts that center the wheel on the crank pulley. This made it easier to get the wheel positioned correctly.

I would get a dial indicator with a visegrip and flex arm. To get the indication on the bucket properly, you will need to extend the probe as shown in my other pictures.

[phaetn]

Thanks for the pics. That's a lot more work than I thought -- I was hoping it would plug (bolt?) n' play. As an aside, I used a 35mm (or is it 34?) oil filter socket that lets me turn the crank with the engine in-situ without having to remove the rad. Very handy. Before that, when I was adjusting cam shims, I had to rock the car in 4th gear. Much easier with the socket. I'm also blessed with a fair amount of space in the engine bay since on a '74 there isn't any the the FI plumbing and all the emissions stuff has been removed.

Thanks for the link, too, Orford2000. I've used a paper cutout in the past but the site you sent me too is much better as one can more easily size the degree wheels. A great resource!

I've been eying a a vice-grip style dial guage on Amazon but will wait to see if the friend who is helping me has ab appropriate tool. I know he has a dial gauge, but he's probably used to just measuring TDC, not the valves as he always used stock Fiat cam pulleys back in the day. But he does have a lot of really specialty original Fiat tools, so we'll see.

I think the pistons are in so I will head over in the next day or so to see what's what and hopefully I can put the head on. Fingers crossed, I might be on the road by this weekend. Certainty within the next two weeks!

Cheers,
phaetn