engine rebuild advice please

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john tynan

engine rebuild advice please

Unread post by john tynan »

Hi.
Looking for some opinions. Brief history......No compression on No.3 cylinder. took head off, scoring on bore.Broken ring. Debated whether to get an engine or rebuild. Sourced an engine, but when I washed off the muck and grime, discovered that the block had been repaired with some sort of putty/epoxy. Gave it a tap of a screwdriver, and out it popped, leaving a nasty crack. So, back to square 1. Ordered 1mm oversize pistons from cavalito, and block off to be rebored. Now, after stripping head for decoke and valve regrind, noticed that there are no valve stem oil seals on the exhaust valves, and there are 2 broken outer valve springs. So questions are, Do I replace all springs with brand new ones, or do I recycle some from my spare engine. Are they prone to failure or was I just unlucky. Also, Are there supposed to be oil seals on all the valves, or just on the inlets
Huib

Re: engine rebuild advice please

Unread post by Huib »

At the time stem seals did not exist.
During an earlier repair someone may have put seals on the inlet valves only to save cost.
I would replace all valve guides with new ones with seals. I have been replacing them for a number of years simply because I always regretted it when I did not replace them even if they measured ok. It does not cost much.
Neither do new valve springs cost much.
Usually the seats do not have to be replaced, just recut.

I also throw away the pistons rings supplied with the pistons an replace them with state of the art ones. I use 5W40 Shell Helix full synthetic and leave it in for 12.000 km. It is then still light brown and still at max on the dipstick. Oil level has not dropped a micron.

You should also clean the inside of the crankshaft and measure it. Also check rocker shafts and oil pump. And of course all the obvious things as camshafts, rockers etc.
Paul de R. Leclercq

Re: engine rebuild advice please

Unread post by Paul de R. Leclercq »

I have never fitted valve stem oil seals to exhaust valves (but always on the inlets). I have always taken the view that any oil that manages to get down the exhaust valve guides is probably a good thing.

As Huib says, S1 Fulias were not fitted with oil seals on the guides. I ilagine that the guides were reamed to a closer tolerance in those days.

Paul
john tynan

Re: engine rebuild advice please

Unread post by john tynan »

I have got to the point where I just want the thing back running, so the valve guides are in good condition and I got 8 oil seals, so I put them in. I am a bit dubious about re-using the springs, but by the time a new set are delivered, I could be another 2 weeks behind. I was just curious if the springs were prone to failure. Should get the block back by the end of the week. A few days should see it back together. Looking forward to running it in.....easy does it.
Huib

Re: engine rebuild advice please

Unread post by Huib »

Don't rush it. Take your time and do a proper job. If not chances are that you will have to do it all over again within 5000 km if you do not do it right now. Remember that a standard Fulvia engine is in fact already a tuned engine. I can't remember any other car from those days which produced 90 hp from 1300 cc. Most needed 1600 cc.
Peter Cripps

Many horses, few ccs

Unread post by Peter Cripps »

Huib, I think you're right about 90 hp from 1300 cc being about the best hp/litre for a high volume production engine. The original Fiat twin-cam came pretty close, though, at 96 hp from 1438cc, with just a single Weber carb.

Peter
ecoangel

Re: Many horses, few ccs

Unread post by ecoangel »

My old 127 Sport had 1049cc and on rolling road with standard weber dmtr 34 pas putting out over 80bhp (Fiat quoted 70BHP) Later I fitted the1301cc from the later 127GT model along with 5 speed box - that was over 100bhp (Fiat quoted 75 bhp).

It seems the 1584cc Fulvia engine is harder to develop. A good UK S2 1600HF as featured in the book "Lancia's Sporting Coupes" put out 95bhp on the rolling road running Solex 42s (against quoted 115 bhp).
Paul de R. Leclercq

Re: Many horses, few ccs

Unread post by Paul de R. Leclercq »

My first visit to a rolling road was with a 1600 Fulvia that was entirely standard.

It showed 83hp at 6300 rpm, which Peter Gerrish told me was typical for a good 1600. To this you have to add the transmission losses which, with the Fulvia's hypoid final drive under load (sadly not spiral bevel) amount to 30hp minimum. So this time Lancia wasn' far out.

Remember that Rolling roads that measure transmission loss on the over-run do not allow for the sliding load of a hypoid when being driven.

Paul
Paul de R. Leclercq

Re: engine rebuild advice please

Unread post by Paul de R. Leclercq »

Yes, Huib, quite so.

The high specific output, plus the unconventional architecture are two of the reasons why extracting greater power from a Fulvia is such hard work.

As for John's question about the valve springs, I have never seen a broken one, BUT I have seen many ones that were weak, so replacement is worth it after so many years - a weak spring can cause a number of problems. It might be possible to find someone with a test rig to evaluate them but it's not a great expense to renew them.

I was told the story of how an English Lancia specialist gave a pair of 1600 springs to a manaufacturer so that reproductions might be made. After a long interval, he chased them up and on asking for a progress report, received the question "Er, yes, um, what are they made of exactly?"!

Paul
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