compression loss on 3 and 4

Rupunzell said:
One thing to consider as this cylinder head is being serviced, have the machine shop surface the head about 0.060" or just enough to remove the cylinder recess, this will increase the compression enough to make a difference in power and improve fuel economy. If the machine shop sets up the valve clearances, this will shave you an awful lot of time and frustration.
Bernice
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Shop guy frowned on the .060 suggestion. He thinks it'll just make the rings start leaking. I deferred to him. I can still request it of course if y'all think I should.
 
If Bernice says shave it .060... then DO IT~!

BTW... How far can you shave a head before it becomes and INTERFERENCE issue?
 
Oh... and another thing...

Get the new ARP bolts AND chase the threads in the block as well with a BOTTOM tap (12mm x .125... I think) then CLEAN, CLEAN, CLEAN!

Lastly, lube the bolts as well when you insert them.

I know yur spending money you don't want to but let's not be foolish by not caring for all the incidentals. You don't wanna be loosing another gasket and burning valves a few weeks from now...

All my best!
 
Shave the head.

Do it as UK heads do not have recess and are about 9.5 to 1 compression.

The stock Euro motor is built this way. As for interferance engine it will depend not only on the head being shaved but on the Camshaft being used. If the cam has higher lift this will be an issue. But... changing the timing belt every 50K or 10 years should make this a non issue. If you are running the engine hard then you can shorten the interval. I have never lost a timing belt yet and I have owned the car since 79. Not a stock engine with shaved head, 40-80 camshaft, megaSquirt, headers and porting. Just don't use the FelPro Gasket, mine only lasted 4000 KM.

TonyK.

Grimsby Ontario Canada
 
Removing this much material from the bottom of USA Fiat SOHC engine have become pretty common. Have a look at the Midwest-Bayless performance cylinder heads.. Note the lack of cylinder head ring at the combustion area.

http://www.midwest-bayless.com/stor...l.aspx?sid=1&sfid=208227&c=193056&i=250929276

If the machine shop is not comfy with 0.060" then do 0.050". Much beyond 0.060" alters the cam timing more and begins the, "not enough travel on the cam belt tensioner bearing problem."


Bernice

jvandyke said:
Shop guy frowned on the .060 suggestion. He thinks it'll just make the rings start leaking. I deferred to him. I can still request it of course if y'all think I should.
Click to expand...
 
Head done looks good. O.060 gone
Hardware store had metric studs but not 70mm long one for center manifold. Clean up some paint here and there and reassembly begins.
 
Great news. Look forward to hearing your continued exploits. We have a garage day out at Pete's in West Olive on the 28th if you want to visit.

Karl
 
kmead said:
Great news. Look forward to hearing your continued exploits. We have a garage day out at Pete's in West Olive on the 28th if you want to visit.

Karl
Click to expand...
Saw that on the calendar yesterday, of course i have to work but if anyone is still there at 4 (doubtful) I'll be there, or I'll switch days as I'd love to hang out for a while. Hopefully this thread is done by then, meaning I'm back on the road.:eyepop:

Got the head back on last night. Turning the corner I guess as the reassembly has begun. I did not get new bolts and studs. I simply can't afford anymore. From here on out it's pennywise pound foolish and fingers crossed.
I won't post here with mundane details. With any luck, within a week I'll simply come back with a ride report.

Haven't torqued yet, just cleaned the daylights out of the block, and piston tops, massaged the gasket a tad, I think it was for a slightly different model as the holes for bolts and studs where a bit smaller diameter. Laid the head down, put on cleaned, lightly oiled (and drained) the bolts/studs, put a smear of anti-sieze on where it seemed prudent, finger tight and I'll start torquing tonight, and putting it all back together over the next few days. I'm still feeling pretty overwhelmed by it all but I think I'll get there in the end. If something goes snafu, well, I just do it again.
 
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Finally got it back on the road. All done, big sigh. Goes great, runs better, at least idles better, "seems" like it has a bit more pep, could be placebo effect. And I must say I'm SO FRICK'N glad to drive it again, nothing compares. Been driving a nice Miata for a month and the Fiat has WAY more soul and is much more fun..to me anyway. Thanks for all the help.
 
I don't know how you guys do the long term stuff. I would loose heart. I need some rewarding feedback to keep me going.
 
Yep, blew out between 3&4.
Exactly why? Tired I guess. Notice the interesting top of piston 3. Ran seriously lean for a bit and considered melting down? But didn't.
blowngasket.jpg
 
Last post, I swear.
Commute in yesterday. Fine but stayed off highway.
Commute in today, highway, full speed ahead. All systems go, car runs great (at least as good as ever, not quite perfect...).
Temp gauge even after highway run stayed right at 185, climbed a tad sitting at lights, maybe 190, drops back down quick once under way again.
Seems a bit peppier too. I didn't try for top end record yet though :eye pop:
Low idle is a tad rough, no idea why, timing seems spot on according to the light but maybe my car wants it slightly somewhere else.....
Another little odyssey complete......next.
 
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