Rebuilding my 1.7 8v

[streamz]

Here are some pics hopefully showing the comparison. You are right, the valves are slightly longer in the 1500 head by about 1mil.

It looks as though someone has had a go at opening the intake ports on my 1700 head. he have a slightly more radius on the lip where they meet the inlet manifold and another strange additional opening that doesn't match the gasket or inlet ports. Not sure what the point was.

[rsfruitbat]

Is the strange opening for use with injectors???
rsfruitbat

[streamz]

That could make sense. The engine came complete with carbs when I got it but it may have had parts swapped at some point.

[bobkelso]

I think all 8v heads (1.3/1.5 and 1.7) from '89,
and all heads 1.7 (from some years before)
were produced with the predisposition for iniectors
also if they were used also on carbs model..

it seams there is a unique alfa code for 1700 head,
so a recent (90-94) alfa 33 1700 head could be
a possible spare for a 1700 Sprint for example..

in 90-94 heads the slightly more radius on the lip where
they meet the inlet manifold (about 2-3mm at 45 degree enlarged)
is standard, is done by alfa,
it helps to have carbs intakes duct mounted on the in-let port
without steps and without being worried about the precision
of the mounting screw/holes of the inlet manifoild,
mounting screw were positioned in the head "by hand"
and sometimes are positioned wrong about
1-1,5mm from one head to another..

Thanks really for the images, this comparaison
helps with many small doubs about boxer engine versions!

From photo it seams the 1500 head is not "inferior" to the modern 1700 head,
so a possible direct swap to mech tappets..

More, it seams that your 1500 head have bigger intakes
(non considering the initial enlarged lip on 1700) ??,
if it is original it could means it was a quite extreme head
(for higt rev, according with the more revvy camshaft the 1500 had),
and instead the 1700 head intakes was slightly reduced for more torque
al lov revs.

[streamz]

that is interesting about the hand positioning of the inlet manifold studs.

i forgot to attach the pic of exhaust ports

[streamz]

that is interesting about the hand positioning of the inlet manifold studs.

i forgot to attach the pic of exhaust ports

[bobkelso]

Incredible, with these engines it's like a Lego,
many possible swaps/combinations..

Positioned "by hand" I mean, they surely used
a mask-tool to have the 3 stud in the right relative position,
but the head position during the process was not so precise
(and it was not thinked to be necessary probably), for example
if you see in your photos you see the 3 intake stud in the 1700 head
are slightly (0,8mm??) decentrered to the right respect the ideal position,
..in one 1991 1.3 head I repaired I found also a bigger (1,2mm)
intake studs position "error"..but still it was not a problem,
inlet manifold diameter is a bit smaller than the diameter
of the enlarged lip on heads inlet..

Ps.: also the height of the heads you have is spot-on equal?

[streamz]

quite right they are ever so slightly out. Perhaps I should take the sharp edge off the 1500 head's inlet ports like the 1700 has.

Yes the heads are identical in height.

[streamz]

The single lobe camshafts are looking a little tired in my mech tappet cam boxs. Are the hydraulic tappet camshafts a direct replacement? My single carb motor has the dual lobe camshafts.

[bobkelso]

Hi,
I'm not very expert with older boxer engines, what I read here and there is that
1500 mech 105cv version had camshaft with the most aggressive cam's contour,
it was used also in the very few first 1700 with mech tappets;
this camshaft have valve lift increased about 0,5mm respect other boxer camshafts
and aggressive phase angles for higt rev; this give a sharp edge at cams so
if one of these camshaft were a little defective in the surface hardening
it could be more easilly "tired" after some years of use.

The camshafts used after this one are a little less aggressive but a bit more clever
for not tuned boxer, generally people like them, the newer version of camshafts
have few less "high revs" power, only 2 or 4 cv less at high revs, but a better
drive at low and middle revs (and lower gas consumption and emissions);
these newer camshafts are used in the most 1700 with hydraulic tappets
and also in every 1.3/1.5 with hydraulic tappets (engines after '90),
carb or iniected, so are a lot easier to find in good condition.

One thing you have to check it is the shape of the camshaft
and of his aluminium camshaft housing at the end
(the rear end, opposite at the end with the pulley):
in the hydraulic heads at some point (about '92??) alfa changed
it from one shape to another to use a different rear oil seal system
(from paper seal to o-ring seal, if you check on Eper online
catalogue it is the "C 0312- D 0312" change) so camshafts
after 92 are surely not compatible with prior camshaft housing.

Instead not sure if camshaft from hydraulic heads between '90 and '92
can be fittet or not in the 105CV mech head,
you have to compair in particular the shape of the end
(the rear end opposite at the end with the pulley) between
the two camshaft type (or between the two aluminium camshaft housing).

May be on this forum someone more expert have already tried it
--
Edit: sorry my english is basic, I corrected the text hope it is more clear

[Marlow Sud]

Hello Streamz,
Are you going to fit tougher shell bearings for your track day activities?
I am advised that the standard ones are a bit soft. I am just having some fitted to my Racing SC.

Brgds
Simon

[streamz]

I am going to order copper lead bearings. Not sure what the standard ones are

[Veesix75]

The mechanical cams are not the same as the hydraulic cams. I'm not sure of the exact difference but was once told it was lift. Not sure if you can swap them over.

Tougher bearing shells are hard to come by for standard boxer sizes.

ACL racing seem to have gone bust or similar, King bearings do a race quality bearing for nord twin cams.

Simon - what are you fitting in the SC, I never had issues on AE standard shells if keeping to 6800rpm cut out. I use a machined down version of the Nord King race bearing in the sprint. Dave Ashford at Brunswick machines and fits them for me.

[Marlow Sud]

Hi Tim,

Tom Shrubb fits tougher bearings for me.

Brgds
Simon

[streamz]

Couple of questions regarding assembly.

I am going to plastiguage the crank and conrod bearings before permanently bolting things up to make sure clearances are correct. Can I also plastiguage the end float of the crank?

Should I use threadlocker on the conrod bolts and/or main bolts? What strength?

[Marlow Sud]

In the thread titled "cross drilled crank" you can find a lot of helpful information.
902a recommends ARP big end bolts - ARP 216-6301.

Brgds,
Simon

[streamz]

thanks Simon. I've had a read through that thread.

The costs are starting to add up and I'm not sure if i'll see any value in ARP bolts. I'm only going to use the car for very occasional track days and In future I wont be taking it over 7k rpm. With a baffled sump I should be ok.

[streamz]

I've changed my mind. I may as well spend the extra $80 on the ARP bolts. I want to make a reliable motor that will last me a long time.

I'm going to take the heads into the cylinder head shop and get them crack and pressure tested and skimmed.

I have removed the camshafts from the hydralic tappet cam boxes and compared with the mech tappet cams and they are almost identical ion fitment but obviously with different lift specs which I havnt the tools to measure. The only difference I noticed was the mech tappet cams have a groove around the circumference of the front main bearing for oiling where as the hydraulic ones do not. Should still be ok to swap them I hope as the hydraulic ones are in much better shape.

I cant seem to figure out how to remove the valve stem seals from the head. Is there a special tool or do they just require quite a bit of force? I dont want to damage the valve guides.

[KevJTD]

good choice on spending a few extra quid to ensure against it happening again. a little spend now should help prevent it happening again

for the valve seal removal I bought one of these cheap tools. helps grip the seal tightly and they pull off quite easily, even when old and baked on.
bonus is you also get a handy seal fitting tool which is much better than using an old socket as I used to

http://www.ebay.co.uk/itm/11pcs-Valve-S ... Sw7ehXSASs

[streamz]

Yes my thoughts exactly.

Thanks Kev that tool looks perfect.

[streamz]

Is this Piston ok to reuse? Its quite pitted in one spot. It looks like its been that way for some time. Im a bit apprehensive about putting it back in.

[KevJTD]

more experienced guys will no doubt have a better idea but I'd say not, the little pockets are probably caused by detonation and being still there they'll promote further wear in that area and may cause damage to the bores

[streamz]

I thought as much. I don't really want to risk reusing it. Unfortunately 87mm Pistons are not easy to find though.

[Sud 145]

Saw a piston comparison chart today while browzing, seems Nissan Z22 is a match but as you state probably just as hard to source.

[streamz]

I have sent off a message to Justsuds and Alfasud parts hoping one of them has an 87mm piston.

With the conrods. I have taken one out of my 1.5 motor and they are the same visually as the 1.7 rods but 10 grams heavier. Can I grind 10 grams off the cap or is this best left to professionals?

[bobkelso]

hope this can help:

http://www.ebay.co.uk/itm/ALFA-ROMEO-NO ... GRmSISh50w

[streamz]

Thanks Bob, they dont ship internationally though. I think I may have found one on a Spanish site though.

[bobkelso]

With the conrods,
I think you should weight and mach with other conrods
eich side of the conrod (small end and big end, and so also total weight),

https://lh5.googleusercontent.com/-j_u6 ... AG1746.jpg
http://www.ciaocrossclub.it/root/discor ... biella.JPG
http://i57.tinypic.com/jj9pav.jpg
https://www.google.it/imgres?imgurl=x-r ... mrc&uact=8

this will give a more complete compensation of the vibration,
pace of mind expecially if you are planning to rev higt..

..but also 0 approssimation
(macht the total weight grinding only one side)
shold be better than no match at all..

[streamz]

hmm I dont think my kitchen scales quite have the same accuracy as that setup. I might take them down to the engine shop and see what they can do.

[streamz]

I have had my pistons and rods balanced and the heads resurfaced and the crank is in the block just setting up my piston rings and I am getting a gap of .024 out of the box. Trying to track down a piston ring file tool.

Are the piston ring gap settings of .03 - .05 correct for the 1.7? I only have a workshop manual that covers the 1.5 engines and wanted to make sure it was the same.