1608cc rebuild

[djape1977]

hi guys

i'll be rebuilding one 1608 engine for a customer of mine during this summer. it will be installed in a 1971 spider. anything in particular i should be paying attention to?
i've rebuild a few 2 liter and 1756cc engines over the years so i kinda know my way around Lampredi twin, but since this is my first 1608 i'm sure that it will hurt less to ask first.

for one, some people say that re-grinding a crankshaft is a big no no, which is true for 1756 and 1995cc but others claim that with 1608 it's fine?
also, there are two types of crankshafts in 1608 engines, one with big and one with smaller counterweights. what would you choose?

[djape1977]

also, this particular car was originally 1438cc, which was at some point swapped for 2 liter from fiat 132 which has self-destructed due to unprofessional timing belt swap.
since we couldn't source 1438 we decided to go for 1608 from fiat 125 sedan which is locally available and i happen to have 3 of those. we'd like to get close to original spec on everything we can so any advice is welcome.

[vandor]

It will be very similar to the other TC's you've built. On crank grinding you may ask Guy Croft. I was under the impression that the 2000 cranks were hardened with a different process than all the other ones, and they were the ones that should not be ground. However, I do know of several people who have ground even 2L cranks...

If you want it to look original then you could use a block mounted distributor. The 1438 exhaust camtower did not have a provision for a distributor, so if the old 1438 engine is still available you could use that for a more original look.

Is this a Euro or US-spec car? I would love to know the VIN (chassis number) so I can put it in my list. You can email me privately if you like.

[djape1977]

euro spec, will pm VIN tomorrow, i just came home and car is in my workshop.

will be using block mounted distributor definately, since cam mounted ones are scarce around here, same with cams with distributor drive gear and cam towers.

single carb setup, probably weber 34adf-250, 124AC head, a bit of port & polish, bigest diameter intake and exaust manifolds i have (yet to dig tru my pile of parts to see what i have), have already sourced new oil pump, gaskets, valves, crank bearings (standard and undersize), set of NOS mondial pistons in standard size so engine block will likely need to be re-sleeved.

i'm also trying to persuade the owner to buy a NOS 124 abarth exaust i have sourced. it's a bit expensive, about 3 times as much as stock exaust, but i'm just dying to hear it

[djape1977]

original 1438 is long gone and we couldn't find it.

what i have is a wast stock of 1585cc, 1598cc, 1756cc and 2 liter engines and parts from 131, 132, argenta, strada, regata, croma, various lancias etc. and as i said three 1608 engines from 125s.

since i've seen several 1608 cams go south over the years, i'm thinking of replacing them with ones from later engines with wider lobes since i believe that width is the reason of failures. will this work?

[majicwrench]

I don't know one fiat crank from another, but when I disassemble a motor (of any type), if it has nice looking bearings I do not turn the crank.
Keith

[djape1977]

what do you mean by "I do not turn the crank"? you mean you don't get it re-ground to undersize?

[majicwrench]

Exactly. If it ran for xmany miles and bearings still look good, I know I have a dang nice crank.
Once it's been to the machine shop, bets are off.
YMMV
Keith

[So Cal Mark]

unless the crank needs grinding, we have them polished. The narrow cam lobes aren't the issue, it's the lack of zinc in the oil causing the flat cams

[djape1977]

oh well, sure i won't get it re-ground unless i have to. i'd be happy with undamaged crank and new standard size bearings.

@So Cal Mark - how come then 1.8 and 2 liter cams don't get damaged? diferent hardening processes used in manufacture?

[vandor]

> i'm thinking of replacing them with ones from later engines with wider lobes since i believe that width is the reason of failures. will this work?

Yes, the cams are interchangeable.

[djape1977]

started on this one finally!

NOS oil pump





decided to use engine from one of my "project" cars.
first removed the head, bores seemed to be fine so i procedeed and removed the rest of the engine




meanwhile, i managed to dig out from my warehouse a set of NOS "mondial" pistons with pins and piston rings. standard size, 80mm

[djape1977]

after some more digging, a set of NOS valves, crank nut, oil pan gasket...





took the block and crank to machine shop for a measurement. block turned out to be excellent, no need to re bore, but crank is on first undersize. bummer. i know that later models, such as 1800 and 2000 don't "like" to run on re-ground cranks, but how about this old 1608?



meanwhile decided to go all-out on a paintjob since block saved me some cash.






by the way, there's a cast "linea 5"on the right hand side of the block. any idea what it means? apart from the obvious, line 5 in italian...

[djape1977]

more NOS parts


and new valve guides. still can be bought at my local parts store. interestingly enough, they're the same as for fiat uno 1.3 diesel

[So Cal Mark]

I have a brand new 1608 crankshaft that I got when I bought the 1800 blocks. PM me if you're interested. I haven't advertised it yet, so it's still available for a really good price