Greetings, I am tearing down a 1981 GTSi engine and keep finding interesting conditions of which I do not have a good feel for regarding the "serviceability" of these items if they are re-used. Of latest are the cylinder liners. They were cleaned by wire brushing and brake cleaning solvent.Removal of the soot revealed some corrosion and pitting as shown in the attached photos. It appears that the pitting is outside the head gasket sealing diameter. Are there concerns with re-using as is? What is the cause and will it it get worst or can it be arrested? I had them honed ,and according to the shop measurements, they are 81.026 mm in diameter . Like many others have experienced, overhauling one of these Ferrari "jewels" will eat up some pennies. Although I plan on doing it "right",I also do not want to replace parts unnecessarily. Any thoughts would be appreciated. Thanks, Mike Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
If that's the worst of it my personal opinion is the head gaskets will seal on the firing ring (don't know if that's really the term?) ... do you have the .001"-.002" sleeve protrusion above the deck? I did make an engine stand to fire up the engines and re-tq the heads ... I'd blown a head gasket and I had a few pits in the fire ring area but nothing as bad as in your pic outside the fire area. The aluminum must be really corroded if the steel looks like that. You might have to put some kinda stop leak in there to stop water seeping ... the F1 fix is to deck the block and sleeves ... send it to Steve and then you can run the less expensive and superior (opinon ) Cometic gaskets without sleeve protrusion ... if you want to re-create the .001-.002 sleeve protrusion after decking so you can use the stock head gaskets that will get spendy if you actually want it right . If you are getting paid for this you should not try and run it . cheers
Sean, Who is steve and I am not familiar with using a different head gasket and decking block and liners flat with no protrusion. Has that non-ferrari way worked out well?
You can re-use the Cometic head gaskets and if you're not okay with that less expensive. He's a Chevy wet sleeve guru ... like makes them into wet sleeve ... aren't you playing with one of them now? cheers
Sean / Tim, Thanks for the input. I appreciate the help. I attached a few photos of the block and one cylinder head. Overall, the aluminum looks good, except for one or two pitted areas as shown. Thoughts? Regarding the 0.01 - 0.05 mm protrusion, I have not checked it yet . Finally....if I were getting paid for this, I would be homeless and pretty hungry ! Thanks again. Mike Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Thanks for help. New pistons are coming Tuesday, so I should start putting the engine back together during Thanksgiving break. Regards, Mike
I have not had a 308 apart in 20+ years. I forget what their gasket looks like. IIRC is does not use a cometic MLS gasket right? When I took them apart I just did what the wsm told me to do and used OE ferrari gaskets. And well playing yes but it is so bullet proof I'll probably sell the car before I have to rebuild it and if I did have to rebuild it crate motors are $5k for the Z06! You can barely get a Ferrari major service for that. Hope to see you at the track soon. Checkout speedventures.com for casual trackdays. Often they run cal speedway and an interior autox at the sametime. Bring the P out and have some fun throwing the car around. All working on the cars and no play make sean a dull boy.
The aluminum surfaces look excellent. How do the sleeves slide in and out of the block? You really want to avoid any inteference 'cause it distorts them. I was measuring the "out of round" and if there was any inteference as in I had to tap the sleeves in with a tiny rubber mallet the sleeve would distort a few thou, so I cleaned the surfaces that "capture" the top of the sleeve (no inteference in the bottom on every motor I've tore down) really good with a piece of scotchbrite or emery ... you basically want a "net" fit ... which means zero clearance but no inteference. If there's inteference tap the sleeve in and you will see a witness mark where the inteference is happening ... polish only that spot ... repeat .... repeat. Anyone else have any thoughts/advice about fitting the sleeves in the block? cheers
That's right I was just giving that advice if someone had to go thru the grief of decking one of these blocks. Oh I've been having plenty of fun ... you should bring the sled down early one morning and take a drive in the local mountains with me . I really keep it safe on the public roads but have a frickin' blast! Yeah I do need another track day but I'm really at the point where they're becoming more test days than just driving around seeing how close I can get to the edge. I've been out enough that if I go to the trouble of going to the track, I want to be pushing all the way to the limit which is dangerous without a cage and I'm not doing any development (which is what I enjoy) on the 911 .. it's really been my driving trainer/benchmark for Ferrari performance (1:32 @ Big Willow). cheers
Right on!! Smear a bit of Hylomar on the pitted areas before you seat the head gaskets, and don't look back --- you are good to go
Trial fitting the sleeves went pretty well.... after a few scraped knuckles and several scotch brite pads. However, I'm struggling a bit with the protrusion measurement. Using a vernier caliper body as a straight edge across the cylinder and dragging a 0.03 mm feeler blade between the block surface and it. Some cylinders have clearance indicating the high point being the sleeve. On a few,it appears that the top of the cylinder sleeve flush, or at least within the shim thickness. Also tried .02 mm . How critical is this measurement ? How much tolerance can the gasket accommodate? Short of the Ferrari tool, any recommendations on measurement techniques? How does one measure 0.01 mm (minimum value) with hand tools in a an area such as this? Also,does something like Hondabond work as well as Holymar in filling the pits? Thanks, Mike
Are you kidding? Hylomar is an old material that only worked marginally well when it was new and would never do anything for this situation.
Never put Hylomar on a head gasket (maybe a water pump). The gaskets are probably okay dry but you could spray each side with Copper Coat. I've used it many times on head gaskets.
Don't like Hylomar on critical engine parts, huh...? Next time you guys take a seat on a passenger jet with Pratt & Whitney, GE, or Rolls Royce engines on board, you'd better cross your fingers and order some strong cocktails ---- cause you're in for a long flight thinking about how well all the Hylomar is holding up !!
BTW, the reason for the Hylomar isn't for a combustion-side pressure seal (it can't withstand those forces) ---- it's for sealing the pits and prevention against further corrosion from the trapped moisture (condensation) and the coolant that's been migrating between the block / gasket / head which has caused the pitting.
Who is this guy?? What is he up to?? And, what is that "blue stuff" smeared on that block and that head gasket?? Image Unavailable, Please Login
And they quit using it about 30 years ago because it wasn't working any better then than it does now.
The pitting is caused by not changing the coolant often enough. Corrosion or more likely electrolisis especially since this is occuring at the meeting point between an aluminum head and a steel liner. the several thousandths of a gap work very much like a battery plate and eat up the steel in the process. This also degrades rubber hoses as they begin to work a conductors to get rid of the charge. I have seen several volts being generated within the cooling system. Several manufactures have found the need to add additional ground straps to eliminate this concern. Generally replacing coolant at aminimum of every 24 months will prevent the concern. There are several good addatives to assist. Once of the best is made by Ford and the part number in PM-8. If this is the only concern with the liners I would reuse them as the pitting appears to be outside the gasket sealing surface. Best of luck
