Ok so Im finishing building my VQ40(same heads as VQ35) a run down is Im running Pauter billet rods, CP forged pistons, Brian Crower cams, and springs, heads are ported and custom blower pulley for 12psi boost. My question is this, I double check all machine shop work and the FSM says the buckets marked with a U go on the intake side. The buckets marked N go on the exhaust side. They came back from the machine shop reversed, N on int. U on exh. The buckets marked U are also shorter than the N buckets. I don't believe this is a clearance issue, but maybe again for heat transfere on the exhaust with the longer N buckets improving heat transfer. I called Brian Crower, they said it doesnt matter as long as lash is correct. I don't feel confortable since I believe the N is for Nitride coating for exhaust side longevity. But looking for more info, I have already found several mistakes in the fsm and since I work on Jaguars for a living i know these mistakes arent uncommon. So any accurate info would be greatly appriciated. It would be alot better to fix it now on the stand than after I put it back in the truck.
Modified by BRUTAL05 at 6:39 PM 9/15/2009
VQ35 HEAD HELP VALVE BUCKET LOCATIONS
-
evildky
- Posts: 14225
- Joined: Sat Jan 31, 2004 9:23 pm
- Car: 71 Datsun 240ZT
87 Nissan 300ZX N/A-T
06 Nissan 350Z GT
Toyota Tundra TRD RW - Location: Louisville, KY
- Contact:
will work for ta ta's
sorry, thats my lave versin of humor, a good friend of mine worked as a rover tech when the buy out happened
buckets = lifter= hla? lash is of course the most impotant issue, but if the exhaust uses a longer cylinder I'd have to assume there is a reason, be it higher lift, increased contact area, clearance or different oil passages, I'd swap them back expecially with an aftermarket cam, most cams bor boosted application add duratin and not lift but you didn't specify
sorry, thats my lave versin of humor, a good friend of mine worked as a rover tech when the buy out happened
buckets = lifter= hla? lash is of course the most impotant issue, but if the exhaust uses a longer cylinder I'd have to assume there is a reason, be it higher lift, increased contact area, clearance or different oil passages, I'd swap them back expecially with an aftermarket cam, most cams bor boosted application add duratin and not lift but you didn't specify
Re: (evildky)
Well I have measured 1 heads cam lash last night. Based on what I have and what I need on that head I could swap 4 buckets to other correct locations out of the 12. So now multiply 8 X $18 per buckets and this adds up quick. There are no oil passages, interferance issues etc(that I can see, measure or find). So I believe that 2 things are at play as stated earlier
1) possibly nitrided to survive higher heat on exhaust side2) since the N exhaust buckets are longer they will increase heat transfere out of the spring/valve assembly on the exhaust into the head letting them run cooler.
And yes evil the cam has slightly more lift and duration that the stock VQ40 cams. Not much more since the 4.0 is even alittle bigger than the stock 3.5 cams. Theyre rated to have a slightly lopey idle on a 3.5, but with the extra .5litre may be barely if at all really noticeable, and since its in a 5500# off road truck Its not a rpm burner
Modified by BRUTAL05 at 12:30 PM 9/16/2009
1) possibly nitrided to survive higher heat on exhaust side2) since the N exhaust buckets are longer they will increase heat transfere out of the spring/valve assembly on the exhaust into the head letting them run cooler.
And yes evil the cam has slightly more lift and duration that the stock VQ40 cams. Not much more since the 4.0 is even alittle bigger than the stock 3.5 cams. Theyre rated to have a slightly lopey idle on a 3.5, but with the extra .5litre may be barely if at all really noticeable, and since its in a 5500# off road truck Its not a rpm burner
Modified by BRUTAL05 at 12:30 PM 9/16/2009