To build up, or not to build up?

[pertyfly]

Hey everyone...

Okay, I just got my website setup finally.

It's at pertyfly.com. I just set it up today, so it's going to be under construction for a very long time due to my car right now. However, all of my car's pics are at http://www.pertyfly.com/gallery

If you check under the 78 fiat link, there are probably about 200 pics so far. I will definitely keep that updated everytime I upload my cam pics to the computer (which is regularly due to the work I'm doing).

Anyway, back to my questions. I have been tearing my engine down, and on closer inspection it doesn't seem to be as good as it ran

I only checked a few things, as I wanted to check a few different parts for an idea, but of course I will get all specs later.

I'll list some tolerances that I've found so far:
Cyl #2:
Ring 1 (comp) - 0.035"
Ring 2 - 0.032"

Valve tappet to cam clearance:
Cyl 1: In - 0.019", Ex - 0.022"
Cyl 2: In - 0.018", Ex - 0.021"
Cyl 3: In - 0.022", Ex - 0.018"
Cyl 4: In - 0.021", Ex - 0.019"

I see that intakes are supposed to be 0.017", and exhaust 0.019", so they are definitely off. Yet there is no visible wear on the shims.
As for the cylinders, there is a ridge. I have no way of measuring the bore, but I know that to me it doesn't look that good. Obvious to see from the ring end gap. The engine is very clean inside, however. It's as if people took good care of the car, but it's just worn and never been rebuilt. I believe it has 99,000Km on it, so I think it's the original engine with no work done. There are no scores or any abnormal damage to the cylinders or any part of the engine.

Anyway, at this point I know I need all of the measurements, etc. My question is, how much can the cylinder be opened up before you can no longer put large rings with the same piston? I'm wondering if I need to get larger pistons. And when I think about getting pistons, for the price difference I don't see why I shouldn't just get some high compression ones and build it up moderately. The piston prices are not that different.

So, I would really like those answered, and also if I were to increase the power in it somewhat while keeping cost in mind, what would one do for starters? I would love to have more power, but don't want to spend much more this year. A body job and part interior is not cheap all at once. And if there are suggestions about this, could you guess-timate cost?

I.e. - what if I were to put high comp. pistons in with reground mains and big ends (these are needed, I believe) and leave the top end stock? Does this work or cause problems? Or what if I put cams in as well but keep carb, intake, exh. the same, etc? I don't know what works, and what doesn't

Thanks all. I hope I get lots of good information!

[So Cal Mark]

wow, you've asked for alot of info, probably more than can be posted here. I think first you should figure the budget you have for the rebuild and than plan. As for just re-ringing, I'd advise against it. Too much side clearance on the pistons can result in knocking, especially on startup as the pistons basically rock in the cyl. If funds are an issue, build the block properly. You can always swap cams or do headwork then without having to deal with the block
As for the valve shims, they are hardened. The wear will be on the cam lobes or valves and seats usually

[pertyfly]

Sorry for the long post with lots of questions...

I get a little bit ahead of myself sometimes.

Ahh, I understand about the wear...makes a lot more sense now, as I was wondering how they could be so off like that and look okay. Thanks!

Okay, so obviously I'm going to have to put new pistons in this, so I'd like to go to a higher compression. Do you know what stock compression is? My Haynes book says 9.8 which I'm almost positive is wrong. I saw on a website that it's 8.0:1, maybe?

A couple more simple, targeted questions now:
If I keep everything stock right now with the intent to build later, except for higher comp. pistons, will this affect anything much? (positively or negatively). And how high should I go without having to use a higher octane fuel, or any other problems?

Thanks

[YeLLoWBoAt]

factory cr is about 9.8 which is about the limit of 91, 10.5 being the limit of 93. really if you put any type of dome in there you will be in the 12 to 1 range, which is 100LL av or race gas.

If you are really want to boost up your CR I would go with

http://www.rosspistons.com they already have the forging ready and can do any thing you want. Its not going to be cheap, but you will have a set of very nice light wieght forged pistons.


I have used them on other "rare and exotic" motors from boats to racing MX bikes.


personally 9.8 is fine with me. I hate having to use av/race gas in a car that is going to be drivin on "the street".

[pertyfly]

It is 9.8?!? Hmmm... So, why does vick offer "high compression" 8.9 and 9.8 pistons? Also, in that case what would be the difference from "stock"? I guess maybe the material? I dunno....

Yeah, if it is 9.8 I'm happy with that. I just didn't believe the book. LoL

Oh well...anyone have any used pistons for sale? Heh...

[bandit]

The stock CR on a 1800/1756cc TC Bore size 84mm Stroke 79.2 mm
is 8 to 1 not 9.8 and most of the time the ratings on pistons are
according to what head your using the 1800 or 2000 they are 9.8
on a 1800 then it will be 8.9 on a 2000 head .

There's a few ways to tackle the performance issue's your looking
for if you just install HC pistons your not going to notice much of
a gain yes the engine will be fresh and have more power then it
had before but next to a brand new stock engine it would be very
close hardly much of a gain .
If you plan on adding the other upgrades down the road then I
would do the HC Pistons ( Cam's , Larger Carb or IDF's , Header
Ignition ) That will bring the TC to life

Bolt on parts will be more cost effective like the bigger carb and
header If your not interested in a large investment in the Fiat .

You shouldn't need to regrind your crank unless it needs it Fiat
Cranks are very tough they can handle some abuse .
Upgradding the Dizzy is a smart move the stock 1977 duel point
Dizzy has to much advance on it the curve is to wide .

Are you doing the work your self ?

Dan

[pertyfly]

Yeah, I'm doing it myself. As stupid as I may sound, I've done rebuilds before. And I've done them properly, I've just never cared to upgrade it (which I plan in the future with this) or anything like that.

So....the CR is definitely 8.0:1, then?? LoL, this is confusing. So for a couple extra bucks I can put in 9.8s...

This will work fine with stock everything else for now? I plan on doing the rest next year, but want to make sure it's very driveable this summer. As long as that's the case, I'll be willing to do it. If you think leaving them stock, and next year just putting in cams and a header and maybe ignition would not make much difference than having HC pistons, then I obviously won't waste my money.

With just cams and a header and ignition, would there be much of a difference if I put in stock pistons vs. HC (about 9.8 )?

Thanks guys

[Danno]

btw, that coppermine gallery looks good, that's exactly what Evan needs to get going here!

[pertyfly]

Ahh, thanks

Obviously I'm still working on it, but I am very happy with it so far.

hey, if anyone wants to be able to post some pics on it, I would have no problems with allowing that. I disabled registrations so I wouldn't get tons of e-mails from strangers who want to post random pics, but I would add a username for you guys if you just PM me or something. Lemme know

[So Cal Mark]

with the gas situation hitting $3 for regular again and probably staying there, I'd suggest flat top pistons. But, you may have trouble finding them. The recent shipments into the US have been the domed pistons, and the price was less than the flat tops. Seems there has been more demand for the hc units, so that's what the vendors ordered.

[bandit]

" If you think leaving them stock, and next year just putting in cams and a header and maybe ignition would not make much difference than having HC pistons, then I obviously won't waste my time "


What i am saying is your going to waste your time and money
on HC pistons if every thing else remains stock .
If you upgrade the carb , header, cams and pistons the whole
engine will breath better so HC pistons would be an add bonus
and yes you would see a differnce in power vs stock pistons .
If you did the same mods on this project but stock pistons
the results would be less of an improvement when you start
allowing the engine to breath more it also helps to increase
the CR every thing go's hand in hand .


Dan

[spiderrey]

the hc pistons are not a waste of money. itll just be thr first step in raising the performance of this motor. with the other mods that come later, it will all pay off.

[pertyfly]

That's the type of information I was trying to get. I thought I conveyed my needs okay, but maybe not. I'm trying to build the bottom now, pretty much so that it can be ready for the top next year. HC pistons with stock everything else won't hurt anything? I may do this. Now, I need to know if it's definitely 8.0:1, as I've had varied responses, and my book says 9.8 which I disagree with. If it is 8.0, I'll probably only go to 8.9 or something *shrugz*

With a 9.8 would I be able to run 87 gas, or will this definitely cause a problem? jsut curious

Chris

[YeLLoWBoAt]

If you run normal pump gas with that high of cr you will create alot of heat. Now you "can" do it, but your hurting your motor. Alot of nasty things can happen: detonation, burn the oil off the top ring, over heat a piston and ......

I mean hell its not that much more to run high grade, its a 4 banger it gets good gas milage.

[bandit]

9.8 is going to need 91 octane fuel, 87 will cause detonation
and over heating not a lot but just enough over time will cause
problems so bump up the octane you'll be fine . If you want to
drive the car daily and keep it simple just go with the 8.9 to 1
your not giving up much for a street car .
Remember to tell your parts supplier it's a 1800 .

Daniel