[DeTomaso] Cam problems

[Thomas Tornblom]

steve meausette wrote:
> Hi all,
> 
> I need some major advice..........  I have just had my second Comp Cam go flat in my Pantera.  The first one went in about five mins of break-in time and the second in about ten mins of break-in time.  Both times never below 2000 rpm.  Both times  new cams (560 lift hydraulic),  the first time I used Comp Cams lifters (hydraulic) and the second time Crame lifters (hydraulic).  Push rods were measured and were the right length,  double valve springs (old and weak) when tripple are reccommended for this grind of cam,  Comp Cams break-in lube the first time and Crane break-in lube the second time.  I used an oil accumulator (3qt) and the oil pressure started off at 60lbs and gradually went down to below 20lbs (new guage) and that's when I shut it off.  Both times.  New oil pump both times.  I use an engine oil cooler.  Pete Jackson gear drive that has plenty of clearance, (new).  I pre-lubed the engine before I put the weber manifold back on (could'nt get anything in the distr
ibutor hole after as the webers were in the way) and the oil pumped up through everything including the new lifters and pushrods (Comp Cams 3/8 pushrods).
> 
> I am now thinking of using a hydraulic roller cam and lifters.  I understand that they require no break-in time.  Is this true?  I don't know what lift and duration etc to use when ordering.  The engine is bored 30 over with Kieth Black pistons and reworked rods, windage tray, large oil pan, completely balanced,  Webers and 180 degree headers.  I am after a rough sounding idle.  The car will not be raced but street driven.  I have never used a roller cam before.  Are special valve springs, pushrods etc needed?  Any suggestions on cam manufacturer and lift, duration etc?  Are any modifications required in the lifter valley etc?  
> 
> Any and all help would be greatly appreciated.  This is driving me nuts not knowing what's causing the problem.  

My "new" engine is going in to morrow, I hope.

I rebuilt my stock engine in 2002, and installed a hydraulic flat tappet 
Crane cam. I installed just the outer springs for cam break-in, and I 
used the Crane break-in additive.

We went to France just a couple of weeks after the initial break-in, and 
it ran fine and strong, still with only the outer springs, but as I'm 
using titanium valves, the valve train is quite light, so I had no 
problems with valve float.

During the winter I had hard seats installed, and I installed the inner 
springs while I had the heads apart.

It ran fine the season after, and in 2004, during the trip to Austria 
and Italy, it decided to wipe a lobe (#5 intake) on the way out of Italy.

Except for the cam and ring break-in, I have always used Mobil 1 synthetic.

The new engine has a Crane hydraulic roller, and I hope I won't suffer 
from any wiped cam lobes again.

The roller does not need any break-in, and there is no modification 
needed to the block. It does need shorter push-rods though, due to the 
longer lifters.

> 
> Thanks in advance,
> 
> Steve

Cheers,
Thomas

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-- 
Real life:      Thomas Törnblom             Email:  Thomas.Tornblom at Hax.SE
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