News

valve clearance 308qv

Discussion in '308/328' started by Tonksy1, Jun 22, 2017.

  1. Tonksy1

    Tonksy1 Rookie

    Jun 21, 2016
    41
    New Zealand
    Hi Ferrari chatters.
    I'm currently checking the valve clearances on my 83 qv (Euro speck).
    Info I have read tells me they should be .30-.35, also some people use .35-.40, my manual actually states .30-.35 and yet the diagram under it shows a gap of .35-.40 ....??hmmmm.
    My clearances are all ranging between .33-.38 .
    What I would like to know is, my gaps are still measuring between the two different gap ranges, do I really need to adjust them to fit between one set of gap clearances eg..30-.35?
    I know a smaller gap than .30 is not good, but what happens when a gap is a bit larger? Bearing in mind my largest gap of .38 is still within the specs of what some people are setting there clearances to.

    Any advice on this issue would be much appreciated.
    Dean
     
  2. 308nut

    308nut Formula 3
    Owner Lifetime Rossa

    Jul 22, 2002
    1,874
    NOLA/Covington
    Full Name:
    Wade
    Intake valve clearances are .20 - .25
    Exhaust valve clearances are .30 - .35


    smaller gap means faster wear, too much gap you'll get noise



    Wade
     
  3. mwr4440

    mwr4440 Three Time F1 World Champ
    Rossa Subscribed

    Jun 8, 2007
    38,989
    Bavaria, The 'Other' Germany
    Full Name:
    Mark W.R.
    The timing on the QVs is much more important than on the 2Vs.

    So it stands to reason that maintaining the valve gap within tolerance is quite important as well.

    The valve gap on my 2V was all over the place; too large and too small.

    A real monkey must have adjusted the valves the last time before I got it. Had to change-out over half the shims on my 16 valves. :(
     
  4. Tonksy1

    Tonksy1 Rookie

    Jun 21, 2016
    41
    New Zealand
    Thanks for the fast reply guys.
    wow I just finnished checking the front bank.....they are way out, as low as .15 on exhaust, every measurement on the front bank was under .30 ex and .2 intake.
    considering the back bank had plenty of clearance, I have to asume some monkey only checked/adjusted the back bank in the past... pays to check...
    I'm going to change the shims with the cams in.
    living in New Zealand makes it hard to get the correct tooling for the job, without waiting a few weeks for int post, can anyone recommend another way/tool to remove the shims? modify another tool?
    I will be ordering the shims from superformance and will get the corect tool from them to install them, but really want to get the shims out first to order the correct ones.
    Thanks
    Dean
     
  5. GordonC

    GordonC F1 Rookie
    Rossa Subscribed Owner

    Aug 28, 2005
    3,555
    Calgary, AB, Canada
    Full Name:
    Gordon
    Without meaning to get into a "while you're in there..." list of jobs to add to your task, when did you do the cam timing belts? Replace the cam seals? Cam cover gaskets? (Or, when were they done?) Any oil leaks from those items?

    The reason I ask is that changing the valve shims is ridiculously easy with the cams out, which you would do to replace the cam seals, for which you'd need to remove the cam belts, making all those easy to change in the same job. However, if you wait to measure the shims in order to order specific sized replacements, you can have a long wait for new shims to arrive.

    To make things as easy as possible, I ordered a whole set of shims from Newco Products - Newco Products - QV Shim Kit in 2014, the set of 28 different sizes of shims, 4 each size (112 shims total) was $399 US (about $3.56 US each), but you can always size the shims you take out of your engine, put them back in the kit, then re-sell the kit after you've finished.

    No waiting to measure the old shims and wait for new shims to arrive, only to find they're off by a few thousandths and you need a different size (or to find that the nominal size is not quite the same as the actual size), etc.
     
  6. Iain

    Iain F1 Rookie

    Jan 21, 2005
    3,118
    UK
    Its definitely a measure twice job. If the clearances are a long way out I'd measure again with a second gauge to be sure the first one is not misleading you. The accepted wisdom is that the owners manual for the exhaust side is wrong, it should be 35-40, not 30-35. I set mine as close to 35 as I could, none less than 34.

    If you have the tools I'd take every shim out & measure them all & then see what you can achieve in terms of correct clearances by swapping shims around. That should leave you with a much smaller number of shims that you actually need to buy. It is however quite difficult to do that without a spare shim or two. You can't just take all the shims out at the same time with the cams still in.

    Might well be easiest to take the cams out this time. Once you know what shims are in your engine & where they are then it will make the job much easier for next time. Measure them all with a micrometer because what is stamped on them might not reflect what a micrometer tells you either!
     
  7. moysiuan

    moysiuan Formula 3
    Silver Subscribed

    Nov 1, 2005
    1,535
    Toronto, Canada
    Full Name:
    Andy
    Is the QV shim kit usable for the 3.2 as well? If one was to set the clearance for each valve to be identical, within the ranges what would one choose as the optimal clearance I presume the higher end of the range (manual specs aside, do the seasoned mechanics use the same optimal ranges as noted for the 3.2?) would be best and allow the clearances to likely remain in spec for the longest period of time?
     
  8. jdamon

    jdamon Formula Junior

    Jul 6, 2015
    288
    Boston
    Full Name:
    Jeff
    Another tip for your original question on what the clearance should be, there is a sticker to the left of the engine (standing at the back of the car), that has the recommended specs for valve clearance ( for your car specifically). My understanding from researching this topic myself prior to checking and replacing shims, is that the USA spec cars had the .35-.40 spec due to the cats and running a bit hotter, and the euro cars maintained the .30-.35 exhaust valve clearance because they don't have cats. But, you can eliminate the ambiguity by just looking at the sticker located in your engine bay.

    I also agree with Gordon, it's much easier to deal with the shims with the cams out, and it sounds like the front bank on your car may need attention as the clearances were so different from the rear, they may have skipped the seals on that bank too. Good luck!
     
  9. Tonksy1

    Tonksy1 Rookie

    Jun 21, 2016
    41
    New Zealand
    Thanks for the tips guys. I have made my own tools and had the shims out for a measure.
    alot of the shims will be re used, so I don't actually have to buy many, but the newco shim set is very tempting.
    I will leave the cams in for now as I have already done the belts less than a year ago, next belt change I will do the cam seals. I'm taking on just one job at a time as I learn all about this engine.
    Thanks again for the advice.
    Dean
     
  10. mwr4440

    mwr4440 Three Time F1 World Champ
    Rossa Subscribed

    Jun 8, 2007
    38,989
    Bavaria, The 'Other' Germany
    Full Name:
    Mark W.R.
  11. pshoejberg

    pshoejberg Formula 3
    Silver Subscribed

    Dec 22, 2007
    1,083
    Denmark
    Full Name:
    Peter H
    #11 pshoejberg, Jun 25, 2017
    Last edited by a moderator: Sep 7, 2017
    You are on the right track. You don't need a complete set of shims unless you run a shop. Re-use the old shims if they are ok and add new shims as needed. Taking cams out also comes with a price such as wear and tear on threads, seals etc. and mistakes. Just use the special shim removing tool and compressed air and your shims will be canged in minutes. Calculate your new exhaust shims as per the 0.30-0.35 mm specification and you will be fine. What ever you do, don't get them too tight! Not much different from fixing an old Volvo. Good luck.

    Peter

    P.s. Attached fyi is my actual valve settings from engine overhaul 5 years ago.
    Image Unavailable, Please Login
     
  12. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,387
    Texas
    Full Name:
    Steve Magnusson
    They can be reused in other positions, but best to only use each surface once in contact with the cam lobe (IMO, a requirement to use each surface only once).
     
  13. Iain

    Iain F1 Rookie

    Jan 21, 2005
    3,118
    UK
    I thought they were one side use only with the dimension stamped on the underneath?
     
  14. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,387
    Texas
    Full Name:
    Steve Magnusson
    I've never seen that restriction in any F documentation -- but, if you follow that rule, you'll never violate my rule ;)
     
  15. mike996

    mike996 F1 Veteran

    Jun 14, 2008
    5,229
    TX//Mexico/UK
    Full Name:
    Mike 996
    Personally, I do not like removing cams to install shims. To me it's much easier to do it with everything in place and, IMO less prone to an error. You check the clearance, change the shim if necessary, re check the clearance and move on. I also don't like reusing shims UNLESS they are going back in the same location.

    Removing the cams means you have to check/notate all clearances, make the necessary calculations, insert all the shims, reinstall the cams, then check all the clearances again, correcting anything that may not be right. It's too easy to make an error in all that writing of clearance figures/moving shims around. ALSO, when you check the clearance initially, you may find that when you remove/reinstall the cam, a clearance/shim that measured correctly before removing the cam, does not when you reinstall.
     
  16. mwr4440

    mwr4440 Three Time F1 World Champ
    Rossa Subscribed

    Jun 8, 2007
    38,989
    Bavaria, The 'Other' Germany
    Full Name:
    Mark W.R.
    Mike,

    My spreadsheet does all the math for you. Plug-in the gap and shim thickness and it gives you the MIN and MAX new shim thickness and the 'dead center' thickness. It also calculates the shims required for cam timing IAW the Shop Manuals (2V & QV)

    Then I take my micrometer and go 'shim hunting' at my nearest BMW or Volvo dealer (for 2V shims). Easy Peasy. No mistakes.



    If someone wants my spreadsheet for the 2V motors (Imperial & Metric), let me know and Ill post it.
     
  17. Freddie328

    Freddie328 Karting

    Jul 29, 2013
    149
    Herts, UK
    Full Name:
    Richard
    Hi All
    Is the consensus of opinion still that exhaust valve clearances should be 0.30mm to 0.35mm, not 0.35mm to 0.40mm as stated in the owners manual?
    My car is a 328 UK spec.
    Thanks in advance for any advice
     
  18. Brian A

    Brian A Formula 3

    Dec 21, 2012
    2,053
    SanFrancisco BayArea
    Full Name:
    1983 US 308 GTS QV
    I recently regapped my valves without removing the cam shafts. I found it perfectly fine way to do it.

    I offer these observations:
    - I bought and used the Hill Engineering tool from Superformance. Its a reproduction of the OEM tool. I had to reshape the taper on the holding tool as it didn't hold open my intake valves.
    - Yeah, new shims vary in thickness from their claimed thickness; they need to be measured just like old ones.
    - Use a spreadsheet. I built my own. There are just so much to keep track of.
    - I reused many of my shims but I still had to buy 8 or so. I have 3 friends who recently redid their valves; none of their spare shims were ones that I needed.
    - There are OEM factory shims which are very expensive. They are no different from the cheapies (Volvo etc) available Superformance, TRutlands etc.
    - On my car, any exhaust valve that was off-spec was tight and any off-spec intake was loose. I gapped them toward the appropriate end of the spec range under the belief that they would drift the same way.
    - One ideal exhaust shim needed to be exactly between the two 0.05 mm spec shims. I bought 4 of the same spec, measured and selected the best.
     
  19. Squirrelmonkey

    Squirrelmonkey Karting

    Dec 27, 2010
    126
    Manitoba ,Canada
    Full Name:
    Tom Thieme
    That is correct. They are one sided. The shims actually have a very slight crown. This causes the shim/buckets to rotate as the cam lobes contact the lifters/buckets
     
  20. derekw

    derekw Formula Junior
    Silver Subscribed

    Sep 7, 2010
    999
    London, UK
    Full Name:
    Derek W
    Where are you in NZ Dean? I may be able to get what you need here in the UK and send them with a friend from Auckland.
     
  21. ferrariowner

    ferrariowner Formula Junior

    Feb 21, 2014
    495
    Mansfield, TX
    Full Name:
    Ron
    As the valve seats wear the valves clearances become closer. To maintain the correct clearances you use thinner and thinner shims until you reach the limit of available shims. Then it's time for a valve job and new valve seats.
     

Share This Page