Resto - Mode L29 setup...and living in Poland

[WojTec]

Sounds cool. I would be cautious of piston to valce clearence with the ZZ502 cam. The L29 does not have much in the way of a valve relief pocket this is compounded if larger than stock valves are used. The issue is not so much total lift, but the higher lift earlier in the pistons travel due to the large duration increase. At peak lift the piston is well down the bore, it is during the overlap period where the valves are atill open and the piston is near the the top of the bore that PTV clearence can be an issue. The longer the cams duration, the longer the valve is held open and the closer the piston gets to the valve. LSA and ICL can also effect PTV clearence by altering the valve action. Advancing or retarding the same cam can add or remove clearence as well. The area you have to worry about is in the range of about 20-30° BTDC and 20-30° ATDC of the crankshafts travel when the piston is still near the top of the bore despite the crank having rotated from TDC.

FWIW, the 8100 shares a very similar piston design and guys seem to get away with the ZZ502 cam in them including Richard Holdener. Nobody has ever stated how much PTV clearence they have but I can say it has to be close, tighter than I would want it to be personally in the event of lifter pump up or mild valve float. The 454 HO and Base 502 cam in an 8100 is about as tight PTV as I would ever want to run an engine. I used checker spring and there was maybe 0.125" left on the intake valve at 15* ATDC. That was as close as either valve got. The industry accepted minimum is 0.080" intake and 0.100" exhaust but in my personal experience that is cutting it close especially in a hydraulic lifter street engine that will see higher rpms than stock and many years of abuse. At 0.080" pump up a normal travel lifter from valve float and possibly or more likely kiss both your valve and piston goodbye as well as possibly the whole engine depending on how badly it grenades. Luckily as the timing chain stretches and wears it will retard the cam and actually widen that clearence. If it had been the exhaust valve I would have been more concerned as it would have decreased that clearence with the cam retarding with chain stretch.

Ok so what could be them my alternative choices? Looking at whoe setup? Iam finding only ComaCams or Chevy Performence ?

 

[L31MaxExpress]

Ok so what could be them my alternative choices? Looking at whoe setup? Iam finding only ComaCams or Chevy Performence ?

I went on Summit Racing. Searched camshaft. Then filtered by make and engine type. Chevrolet Gen VI big block. These are the companies show to make a camshaft that will fit the GenVI engine that Summit catalogs. GenV and beyond were all factory roller engines with a step nose cam for the camshaft retaining plate.

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[L31MaxExpress]

Personally I would call clay smith, isky and howards cams. Google camshaft request form as you will need the answers to those questions for a proper recomendation.

I would not trust Comp cams to custom grind a cam for a lawn mower they were so far off on the last cam they ground for me. It had too much overlap for the engine it eventually went into much less the 350 it was ground to go in that had a lower compression ratio.

 

[Piratehunter]

@Piratehunter
Have a look on the timing set - unboxed:
Chain is 0.6inch or 16mm

that timing set will work. the double roller set shown a few replies back will not. on the cam choice something close to that comp 270 or 276 cam will be fine. other companies make them. a lot of guys used the comp 268 cam, as others said once you start increasing lift and duration over something like the 276 cam, clearances at the piston and guide become concerning, just have to check them to know for sure. I used the 270 cam, do over I might use the 276 cam.

 

[WojTec]

So I had to order ZZ502 and cancelled Jegs compcams.
Ps. Jegs has specific way of handling order- prefer calling over good customer online portal. (For me harder due to time difference and language skills)

Lets see in 3-4 weeks what will be the fit.

 

[WojTec]

Have a look on this specific build. Zz502 fitted into stock 454.

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Note that in video there is a very valid remark about valve locks comming from compcams. They do nove give proper clearance for rockers. I got other set as on video.

And a last question": who of you will help me with some BlackBox tune?
I have my HPtuners device

 

[WojTec]

Next steps (when waiting for Summit delivery) is de-rusting.
No much to be done but it will prevent the body for next 10-20years

Rock panels still in orginal paint.
Stepsides - today brushed + stoprust + 2x Epoxy primer + poliurethane painting.