My Lancia Delta Integrale 8V restoration project

[samo]

Thank you for your tips!


#1 With the blue and the red lines I have a small problem! The valve seats have already been done. They were 3-angle cut by a proffesional workshop so i tried to awoid damaging the seats. This "edge" is in fact not an edge but a indentation. So in fact there is a narrow hole between the valve seat and CC. I think to get rid if it I'd have to give the seats a "back cut" (not sure if i used the right term) to lower them and blend them in propperly. The edge that was there originally (approx. 1mm higher than seat insert) was removed so this is now flush with the seat.

#2 & #3 I was planing to do the things you pointed to with yellow and green but after I finish the exhaust side ports.

#4 I will have to get the resurfacing done by a specialist and if he'll decide there is enoug space (i think it's around 0,5mm) I'll resurface the head only and if not the valve seat will have to bo top ground which will also solve problem #1 :) But cause multiple new problems sutch as dropping the valves lower, new shimms or valve tip grinding...

[Guy Croft]

I know what the ridge is!

OK - re # 4 - ask the machine shop to set the head at a slight angle so the cutter misses the seat insert.

G

[samo]

I know what the ridge is!
G

I am just over-explaining because I am sometimes not to sure if I am using the correct terms. The exhaust valve seats actually protrude into the CC a lot and it doesnt look good. If I could afford the time and money I really would make it perfect...

[Guy Croft]

If you top-cut the ex seat to remove the material above the chamber on these heads you could have problems shimming as it will drop the valves way deeper into the head. Probably best left alone.

G

[samo]

Today I managed to measure the capacity of the CCs. After final shaping they stand at:

#1: 51,5 ccm
#2: 51,6 ccm
#3: 51,4 ccm
#4: 51,3 ccm

They are all within 0,3 cc which I think is OK. They will not be changed anymore shape wise, but I will try to polish them a bit better. I have till next week to play with it till I receive my heli-coil tool wich i need to repair the threads for the manifold bolts. After that the head will just go for re-skimming and finaly I'll have my engine together.

I tried to measure the vertical distance between the valve seat and head surface and it seems I still have around 0,6mm of clearance so skimming shouldn't be a problem.

[samo]

I finished all the ports today. They came out quite good I belive. It would be even better if the guides were out.

I also deburred all the water and oil channels and chamfered all the sharp edges all-round! Sadly couldn't finish the chambers because of a failed cable on the grinder.

[Guy Croft]

Coming together, well done!

If you can get your hands on a Bosch orbital sanding machine, 120 grade abrasive with some WD40 or light oil will make a nice job of your cyl head in/ex manifold faces, get rid of all the scratches eg: where the porting tool slipped across the face.

G

[samo]

I forgot to mention that I have to helicoil the manifold threads because they are more or less all gone (I belive an ape tried to cure a leaking exhaust with more torque). That's why the mating surfaces have not yet been resurfaced. Will do it last in case I have another slip up.

Will a 8mm helicoil insert be enoug or should I stack up two coils one on top of the other?

[Guy Croft]

Don't use Helicoil there. Try and get hold of Wurth 'Timesert' - it's better at M8 and certainly makes cutting a new thread easier because the kit contains a special drill (which is actually designed to be turned by hand with a tap wrench) that cuts the old damaged thread out.

G

[Guy Croft]

some of the missing parts of this thread retrieved:

Samo:

"I tried to get the Wurth system but could not get it in a reasonable time and price so I had to settle for second best... I don't think it's gonna be a problem, I've even seen helicoils used on sparkplug threads and I haven't seen one fail yet. But I will use Loctite to bond them in... Just hope I'm not gonna run over my own turbocharger. I forgot to add that some of the threads have already been helicoiled prior to me getting the head and they are the only ones I haven't had problems with..."


GC

"I was not referring to the holding strength Samo - merely the ease of use. I will just point out (before anyone accuses me of saying they are no use) that a Helicoil thread repair will never fail per-se - under normal preload/loading and there are reasons for this, firstly that the thread major diameter of the joint is now some 10% bigger so the thread shear stress is commensurately lower in the parent material. Installing Helicoils makes the joint stronger not weaker, the old Lancias had them in all threads. After significant test and research I introduced an important programme of Helicoil threading on new units at Napier Turbochargers when I worked there as a Chief Engineer, both to enhance joint strength and (because the inserts are stainless steel) to reduce the risk of seizure. BUT! To the point about installing a Helicoil is that the tap tool that cuts the thread for the insert has to follow the old thread, which is the very thing that is damaged and the risk of runout during tapping is as high as the old thread is damaged. This can be a real problem when doing spark plug threads (they may end up off-line) - though for compactness they have no equal in that application. Whereas - with Wurth Timesert the first tool is a drill which removes ALL the old thread so the tap goes into a virgin hole. Of course alignment is important but you cannot drill out the old thread with a Helicoil repair. Much depends on the engaged length and setup height of the Helicoil whereas the Timesert has a flange to set the position and a hand-driven counterbore tool to cut the region for that. Timeserts are aval in different lengths too. I write for the benefit of all readers, capitals are for emphasis (not shouting), I trust you understand my points. The only exception I must make clear is that I have long since ceased to use Timesert for spark plugs of any size as for a time I found them coming out with the sparkplug on removal. Whether the design has now changed (as I urged Wurth UK to do for some years and then gave up) I don't know but don't care frankly. For the reasons stated and as I have said in my book I use Timesert on M6 and M8 predominantly."


SAMO

"Very interesting! I didn't know that helicolil uses the old thread! The system i am using is in fact a generic German brand that uses an improved approach. In the kit you get a 8,3mm drill to firstly remove any residue of the old thread and this way you start with a vigin hole which you then tap with a M10 x 1,25mm hand tap. I think I will use an old bushing over the hole for tapping to keep the tap vertical. I did a test yesterday and I taped a M8 thread in a 15mm thick aluminium plate and then striped the thread with a bolt and a long bar. It really didn't offer much resistance. Then I coiled the thread and tried again and found it's much stronger. Of course as you wrote if the bolt thread doesn't let go then the coil which is harder surley won't let go and the outer thread is bigger which means it's stronger! TO ALL: After spending another couple of hours polishing the combustion chambers and comparing my pictures to the pictures in Guys book. All I have to say is my hat's off to you sir. Even the most irelevant thing like taking a good ilustrative photo that shows what you wanted to show isn't easy. Let alone all the work. The major work of shaping, deburring etc. isn't that hard with some guide and help but as soon as you think you've got the hang of it your burr slips and skids across the head plane... And if I managed to get the port's looking at least half decent I had to admit defeat with the CC's! It's just not possible for an amateur to achive this kind of results without guidance from stage one...
Very interesting! The major work of shaping, deburring etc. isn't that hard with some guide and help but as soon as you think you've got the hang of it your burr slips and skids across the head plane...
Just a comment on porting and chamber work. Always protect the head deck and manifold faces with old gaskets or tape. Very maddening to do all of the work just to run a groove across the nice machined surface."

[samo]

Today I got the head resurfaced. No problem there is still around 0,5mm clearance to the valve seats. I managed to coil the threads on the exhaust side, and I used a block of wood, sandpaper and had a go at mating surfaces to clean off the scratch marks. Just to be on the safe side I used some really fine cutting paste on the valves and I gently lapped them all to check if they mate nicely with the seats.

I promiss you after this I will not be boring you with pictres of the bare head. After refacing I also removed all the sharp edges on all the water/oil channels and holes. I then washed the head with a power washer, detergent and hot water. I used an airline to dry the head and I even remembered to oil the guides and seats. So if all goes to plan tommorow is assembly day :)

I have already bought myself a Spesso performance head gasket and some non-strech stronger head bolts. With these I recived instructions for using that go something like this:
#1 tighten all bolts to 40 Nm
#2 tighten all bolts to 60 Nm
#3 tighten all bolts to 80 Nm
#4 wait 15 minutes to settle after that loosen and re-tighten to 90Nm each bolt seperatly.

Does this make sense?

[Guy Croft]

Tightening regime looks OK, though I would do the final tightening (after very fractional loosening) to 84Nm (62lbf ft) not 90Nm and then give them a final pull-down 1/16-1/8 of a turn by hand 'to equalise'. A skilled hand is safer for this than a torque wrench.

That is what I do. The trouble with torque settings is that even with a good lubrication regime (oil underheads of bolts, copper-based lubricant on male AND female threads) the variance in preload is still about 20%+/- which means that if you go straight to 90Nm you could well go over the safe working stress in the block threads (the weakest link..)

G

[samo]

A skilled hand is safer for this than a torque wrench.

Hmm my hand isn't really skilled. Can I use an angle tightening load for the last step or would this again defeat the purpose of "feeling" the equalization?

[Guy Croft]

Just give it a try, you will easily get the 'feel' for it.

Main thing is to only turn the bolts a small amount each in turn - applying the same 'arm power' each time and see how much they move.

G

[samo]

Today I measured the piston to valve clearance. I did wan't to make sure it's gonna work out ok as it might be a bit expencive to just cross fingers that non OE camshaft and non OE pistons will not clash.

So I assembled the head using a spare set of cam boxes (as mine are in a process of beeing eloxated) and I used an old head gasket to avoid destroying a new one. After 2 full crank revolutions I dismanteled everything and I tried measuring the clearance.

On the intake side the vertical clearance is 4 mm and the minimal clearance is 3mm. On the exhaust side its around 4,5mm vertical and 3,5mm minimal.