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Dumb is as Dumb does (exaust valve / head gasket replacement)

Discussion in '308/328' started by bl10, Jul 16, 2020.

  1. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Sometimes I wonder about my IQ

    Managed to bend the exhaust valves on the rear bank. Happened while torquing cam pulley bolts.
    Love making work for myself!!!
    Will have the head off this weekend assuming I don't have to use a hand grenade to get it loose from the studs.

    Any ideas on a solvent / prenetrant that will help. From what I've read it might turn into a real nightmare getting the head off. I'm not a machinist and don't have correct equipment to make a head puller as illustrated on this forum. If push comes to shove I can cobble something together but am concerned about making a bad situation worse.

    So wondering about head gaskets. Anyone have experience with the Cometic MLS gaskets?

    Plan on getting exhaust valves from Superformance. Any opinions good or bad?

    Any cross reference for the valve seals or valves for that matter. I'm only planning on doing the exhaust valve seals unless the intakes are leaking and require disassembly.

    Can the rear header with heat shields in place actually be removed with the cylinder head in place and not jacking the engine up and forward. I have mine completely disconnected along with the e-brake and I can't figure a way to get it out of the car either from the top (obvious) or the bottom.

    It appears the only way to remove the heat shield is to cut it off?

    Rather than cut the heat shield off I may just replace the header the the Superformance one. Anyone have opinion on the quality. Price is pretty good.

    If I get the new header I plan on using exhaust wrap to keep the heat down. Any opinions re ceramic coating vs wrap.

    Thanks

    Barry
     
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  3. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    2,889
    Tallahassee, FL
  4. 308 milano

    308 milano F1 Rookie
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    Jan 15, 2007
    4,236
    Montana
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    Kim
    Can’t offer any advice other than to say I feel for you man. :( Hang in there.
     
  5. Mike Florio

    Mike Florio Formula Junior

    Jun 19, 2003
    575
    NW Rural Nevada
    Full Name:
    Mike Florio
    From my experience no solvent/penetrant works. The place where my head seized was in the head studs (steel) and the head bores (aluminum) even a slight amount of corrosion makes it tough to shear that connection. I tried the "rope trick" in desperation and it worked great.

    Page 2 of this thread: https://www.ferrarichat.com/forum/threads/observations-on-a-gt4-engine-pull.458208/

    I suggest using the Viton valve seals from Superperformance UK. While you're in there you might as well regrind the intake valves and seats and replace their seals as well.
     
  6. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,164
    California SF area
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    Paul
    Do you have a 2V or QV? There are people here who will probably loan you the head puller for a 2V if you need it. For a QV I don't thin there is any such tool, there is no way to get anything directly above the head studs as they are under the cam supports.

    I just did head gaskets on my QV. I think once you get that deep into it and have the head off, depending on mileage, you may want to replace the guides. Definitely replace all the seals and have a normal valve reface job done on all of them. To skip that is false economy.

    Getting the shrouded rear header out with the engine in there may not be impossible but if you can do it you're a better man than me. Cutting the shroud off took me a day and a half with it sitting on the garage floor. It's not exactly like snipping tin. I can't even imagine doing it in the car.

    Good luck, just take it a day at a time and don't cut corners. You'll be glad in the end.
     
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  8. bl10

    bl10 Karting

    Jun 8, 2011
    106
    It's a 2V. I will have the head ready to remove this weekend so I don't know what kind of problems I'll run into. Based on what I've read the solvents don't seem to do much good but they can't hurt. Another forum (Alpha) recommend Acetone and ATF so if I have trouble (likely) I'll try PB Blaster and maybe Acetone/ATF. and a dead blow mallet. If that doesn't work I'll seriously consider the "rope" method per Mike's thread. I'm aware of the potential problem of moving the sleeves and opening up a whole new barrel of snakes. I suppose the rope method could bend a rod but I doubt it as there isn't much angularity that close to TDC. I wouldn't use the starter in any case, just a long breaker bar.

    Still wondering about the quality, fit and longevity of Superformance headers. I'm not going to put the rear header back on with the heat shield in any case, can't stand the way they look and they rattle like crazy no matter what I do. It sounds like it takes a cut off wheel and snips to remove the heat shields. I hate to do that as I'm trying to save all the original parts for future restoration if desired.

    Quick question. Are the original headers Stainless Steel?

    The head gasket is still an open question but it sounds like the MLS type have potential compression issues due to the cylinder sleeves protruding above block which in turn could cause compression issues which as I take it could cause water leaks. I've never had any head gasket issues with the original (I think) gaskets so maybe I'll just get the standard ones from Superformance. I does make me wonder, though, why shops like Carid sell the MLS type.

    I will decide how far to go with a valve job based on intake valve leakage and if a quick lap doesn't seal the new exhaust valves.


    Barry
     
  9. ferrariowner

    ferrariowner Formula Junior

    Feb 21, 2014
    763
    Mansfield, TX
    Full Name:
    Ron
    Sounds like a good time to replace those sodium valves while your in there. Replace guides and seals as suggested. You don’t want to remove the heads again.
     
  10. derekw

    derekw Formula 3

    Sep 7, 2010
    1,308
    London, UK
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    Derek W
    Where are you Barry? I’m in the UK and have 21-4N valves (£10), viton stem seals (£1) and can give you a hand if close by. You could try some ropes wrapped under the manifold studs (back and forth) then a rope over a pulley lifting at the correct angle to keep tension on the head and aim a heater, hair drier or hot air gun at the head. Check out my blog (Derek's 308) to see where I used a scissor jack (plus hanging the engine from a head) to push the head off. Rope trick may work and heat the head first plus get PB blaster down the studs.
     
  11. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Doing it with engine in car so I'm not going to mess with front head. Compression and leak down were great, no smoke out exhaust and virtually no blow by. Passed CA smog with flying colors. Will replace exhaust valves and seals on rear bank as all four old ones are bent. (don't ask) I doubt seats or pistons are damaged as I did this myself while torquing cam pulley bolt. I will check guides but I think they are OK. Will also check liner protrusion and block and head flatness. Only reason I'm doing this to adjust valves and change cam seals due to small leak. After reading all the threads I can find my main concern is the replacement head gasket. I prefer MLS but am concerned about sleeve protrusion and block and head surface smoothness.

    Barry
     
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  13. derekw

    derekw Formula 3

    Sep 7, 2010
    1,308
    London, UK
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    Derek W
    Barry, I would not use an MLS gasket, just get the Elring gasket and add high temp RTV around the water holes. Since you are in the US (and have air injection) I would change all of the exhaust valves if you have any play in the valve guides. The guides are quite soft and the valves close eccentrically if the guides are worn which causes bending moments and fatigue at the weak area near the stem weld which is also super heated by the reaction with injected air.
    Henry Chin in CA may still have the valves I sold him as he sold his 308.
     
  14. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Derek
    I'm in California, a ways from you, however I may take you up on the valves and seals. I need 4 2V exhaust valves and seals. Are the valves OEM spec for 2V engine? Since the engine is still in the car I can't really hook up a pulley system or hang it from the rafters to pull the head off. I'll find out this weekend just how stuck it is. Who knows it may pull right off.(yeah right). As your in the UK do you have any experience with the Superformance headers and their standard replacement head gasket not the Elring one.

    Thanks

    Barry
     
  15. derekw

    derekw Formula 3

    Sep 7, 2010
    1,308
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    Derek W
    No experience with their headers but the std gasket they sell is Elring. Their seals are NBR (the ones I got) so I had some made in viton. Try rope, heat, and patience— Gently over a few days— I think it will come off. My valves are not OEM, they are solid 21-4N stainless with stellite tips and tuftrided surface.
     
  16. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Derek
    A little out of sequence here. I read the thread on the Elring gaskets and water sealing seemed to depend on liner protrusion same with the MLS type. Is Henry Chin on this site?
    I know it sounds cheap but $500.00 sounds expensive for a head gasket (unless I read the Superformance web site wrong). The cylinder pressure in the US spec engine with 8 to 1 compress (or something close) can't be high enough to cause combustion sealing problems. It sounds like most of the head gasket problems experienced have to do with water leakage again probably attributable to block / head surface finish or liner protrusion in the case of MLS gaskets or warped head or block which will probably leak no matter what kind of gasket. The engine has never been overheated so I doubt the head or block is warped but I will check.

    Barry
     
  17. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Derek

    Thanks for the help. I'll know more after I get the head off. Hopefully its just replacing the exhaust valves and seals. I will take a look at your blog.

    Barry
     
  18. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,164
    California SF area
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    Paul
    Not to doubt you but how did you bend all four valves when bolting the cam pulley on? I’m just having a hard time imagining how that could happen. It’s not possible for more than two pistons to be at TDC at any time.

    If it provides any hope I can say that both of my heads came right off with no fuss or struggle.

    There is no possibility of removing the header shroud in a manner that would preserve it, you have to get midaevil with it and the end result is pretty ghastly. You can do it with tin snips and a prybar but there are wide overlaps so you have to work in the spots where you’re not trying to cut or tear through two layers. The headers are not stainless. I had mine ceramic coated and have put about 5,000 miles on so far in summer weather with no apparent issues with heat. I believe the main purpose of the shrouds is to retain the heat for the Cats rather than protect anything external. I’d also suggest getting rid of the sampler port tubes. They can cause problems as they also are not stainless and tend to corrode. The air injection rail can be tough to remove without buggering it up. I had to cut mine just above the b-nuts so it wouldn’t get all twisted up and that left me with clean cuts to weld back together for reinstallation. If the rail does get messed up bear in mind that it is only used during cold start so technically, even in California, all you really need it for is the visual, a smog test won’t know if it’s completely blocked off or otherwise non-functional.
     
  19. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Bent all four valves because as I was torquing the cam pulley bolt the belt jumped a tooth. Had the cams locked with paper under the cam caps. I felt it but thought it was just rotating, it wasn't. So I did it again. Then later clicked it over with the starter as a final valve lash check which bent the valves (I had been using the starter to rotate the engine to set the lash for several days prior to this so I didn't bother to check the cam timing again, after all, all I did was tighten a bolt). I was checking the valves in the front head and when I got the the rear there was excessive lash on all four exhaust valves. I checked and sure enough the exhaust cam was out of time. I timed it again and had zero compression. As I said dumb. It surprises me that the belt jumped a tooth (at least twice) but that's what happened. Really stupid on my part but I live with what I've got.

    Yeah I figured there is no way to get the heat shield off without trashing it. I'm considering getting a replacement Superformance rear header and wrapping it with exhaust wrap as I would like to keep the original for future restoration is desired.

    Barry
     
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  20. bl10

    bl10 Karting

    Jun 8, 2011
    106
    I had already plugged two of the air sample tubes because they broke off on there own. Apparently the PO had removed some kind of bracket that holds them. (the front ones are fine) so in any case I will remove the remaining two . The air injection manifold gave me no problems once I moved the header away from the head although the header nuts were a bit of a pain. Even though the header is free of the head and disconnected from the muffler and u-tube I cannot get it out. The heat shield hits the rear firewall (for lack of a better term) and I can't get it back far enough to clear the head. I removed the e-brake assy but still no luck. Since I'm pulling the head anyway I'll just remove it then.

    Barry
     
  21. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,164
    California SF area
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    Paul
    I had to leave both headers in until I pulled the engine out. In fact I had to pull it part way out just to get on the lower flange nuts for the 5-6 header and disconnect it. As far as exhaust wrap, the earlier cars (and Euro cars) didn’t have shrouds or wrap or even ceramic coat for that matter and it seems to be no problem. Like I said the shrouds are probably just to increase the efficiency of the catalytic converters and not because of any heat concern. Plenty of people have deleted them with no ill effects. I did put a small shield around the starter though.
     
    Brian Harper likes this.
  22. 308 milano

    308 milano F1 Rookie
    Silver Subscribed

    Jan 15, 2007
    4,236
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    Kim
    Don’t you have to rotate the crank to full revolutions when coming back up on TDC for valves to be closed? ie no compression? Very early in the morning here and I’m no mechanic, just hard to believe belt jumped a tooth and bent 4 valves.
     
  23. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    10,530
    San Carlos, CA
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    Mitchell Le
    I suggest a bit more troubleshooting before you tear into it. One tooth off is not going to bend any valves. Was there something else done that led to the need to torque the big bolt on the cam pulley?
     
  24. bl10

    bl10 Karting

    Jun 8, 2011
    106
    The belt actually jumped 3 teeth. Since I didn't realize it was jumping a tooth each time but I stopped each time I felt it move (thought whole engine was rotating). There is definitely no compression on the rear bank cylinders and more than 60 thou clearance on the rear exhaust valves. It just never occurred to me that the belt would jump a tooth. What apparently happened was that I didn't have the exhaust cam locked tight enough and it moved one tooth each time. I'll know better next time. What actually bent the valves was using the starter to do a final lash check before putting the cam covers back on.
    I'm wondering if it cracked the timing belt pulley which might in turn cause the pulley to jump a tooth. I was torqued the bolt to 80ft lbs. I've probably built a couple of hundred drag racing engines all the way to top fuel and never had anything like this happen. Not much I can do about it except give up (never) or fix it.
    At least this gives me the chance to really clean and detail the diff and rear of engine as well as the back of the engine compartment.

    Barry
     
  25. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    San Carlos, CA
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    Mitchell Le
    3 teeth would bend valves. Head off time.
     
  26. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,164
    California SF area
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    Paul
    I don't know about you but I bought my 308 as much to tinker with as to drive and you sound like a bonafied gearhead so maybe you should at least consider just pulling the motor out and doing it right. I hate to think of the torture your back is going to endure trying to pull a head in-situ when you could be sitting in a chair will full unfettered access to everything. The list of other chores that can be easily accomplished with the engine out is nearly endless especially when you start contemplating "clean and detail" stuff. Honestly, it's not that hard to pull it in comparison to what you're about to face and the car is at least 38 years old so maybe it's about time?

    But that's just my way of thinking...
     
  27. Nuvolari

    Nuvolari F1 Veteran
    Sponsor Owner

    Sep 3, 2002
    5,591
    Toronto / SoCal
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    Rob C.
    Unless you are very lucky the head will be near on impossible to remove in situ especially without a puller. The above advice to pull the engine is wise and will allow you to tackle a multitude of other tasks / cleaning. Also what you are proposing is a half rebuild which introduces all kinds of buyer doubts should you look to re-sell down the line. Pulling the motor you can do both heads with fresh exhaust valves forever taking away the sodium valve worry. The extra cost difference is not much but has a lot of personal and resale perks to doing it.

    To answer your other questions, the rear exhaust header with USA wrap can be removed with the engine in place however you do need to unbolt the 4 engine mounts and rock the engine out of the way to gain clearance. It was a long time ago but I remember removing the exhaust from the bottom but I may be wrong. For sure I took the USA shrouded manifolds out without removing the engine or head.

    As for the header itself, unless damaged or rotten use the original header. Once you peel away the USA shrouding you will find a very nicely made piece underneath. I peeled my shrouding away and had the header ceramic coated. Looks much nicer than header wrap and the under hood temperatures were noticeably cooler than even with the USA shrouding. The Superformance headers are nice pieces but no real advantage over what you will find under the USA shrouds. Save your money unless the headers are damaged.
     
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  28. bl10

    bl10 Karting

    Jun 8, 2011
    106
    Yeah your probably right. Just didn't want to get that far into it right now. I do like to drive it since I got it running again and don't mind (to much) the patina that comes with a unrestored 42 year old car. It's all original except the paint which is only 35 years old. I'm afraid if I rip it apart one thing will lead to another and I'll end up with a garage queen 5 years later. This was my daily driver for 10 or 12 years and we drove it everywhere. You would of thought it was a 4x4 off road jeep. Belly pan and front valance looks like they've been through a war and the paint has it's share of rock chips and a couple of creases low down where I hit boulders or something. Once in Yellowstone had a grisly bear stand up and rest his paws on the top (no damage). Long days and nights in parking lots cleaning filters and carbs due to bad gas in some out of way burg as well as changing points and such. Even spent some time in a bank parking lot (for the shade) tightening all the suspension bushings which shrunk to the point they clunked due to four 110 degree days in Arizona. Had to actually loosen the belly pan once or twice to get the gravel out. Kinda sounds like ROADKILL now that I think about it.

    Until this happened I planned on a slow march through a long list of things to fix and cleanup. But nothing that would keep if off the road more than a week. That's kinda out the window now.

    Barry
     
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