[DeTomaso] Dyno Trip #1 and Roller Lifters.....

[steven.liebenow at att.net]

All,

Had a very interesting trip with the Goose to the dyno yesterday, to see what my 
new collection of bits and pieces would do!

Short story is "TO BE CONTINUED"  but we saw +300HP with some break up starting 
at 5700-5800 or so......  This represented about a 100HP increase from my old 
(poorly implemented) tired Boss 302 engine!!!      No wonder I kept sliding out 
of my pants when I would nail the throttle!!!  This thing is an absolute HOOT to 
drive in the Goose!  Actually, it can be a bit much!!!  It has sooo much pickup 
and is so quick to rev, that you really need to be on top of the whole steer, 
shift, clutch, hang on, thing!!! This thing really does throw your head and you 
back into the seat!!!     It has changed the dynamics of driving the car, and I 
need to learn how to do it all over again!!!

The basis for this Mangusta engine is a 92 Ford roller 5.0 block 
(Thunderbird/Mustang etc), with a 331 stroker bottom end.  Flat top pistons (two 
reliefs), Y303 Motorsport aluminum heads, F303 cam, Ford roller lifters, 1.73 
Ford full roller rockers, RPM Edelbrock intake port matched to heads, and a 570 
Holley carb (street avenger?).  Duraspark ignition system.  Aluminum flywheel. 


After talking with the owner who was running the dyno, he asked me what my lash 
was set at for the lifters.....or "how tight" are you running your hydraulic 
lifters(?) is what he really meant!

I told him that I was at 1/2 turn from zero lash.   

He then asked about my oil pump....high volume or stock?    My answer was high 
volume...... at that point he went hmmmmm!  I see.   "You need to readjust your 
valves to no more than 1/4 turn tight from zero lash!

Apparently the high volume pumps still cause some pressure increase at speeds, 
with Ford lifters (and perhaps others!) and that you can then lose performance 
due to the valves staying open....

Which could also explain my very low idle vacuum figures.....which I attributed 
to dropping my vacuum gauge one too many times.....  I think I was around 12-14  
inches, but rock steady....

I had jetted my carb over rich for the break-in of this engine...until I could 
get to the dyno and dial it in.    The readings for the air/fuel ratio never 
even made it onto the scale at first.  So we dropped the secondary size down 4 
and due to a lack of jets, only brought the primary down one size.....and it 
barely made a difference at all.....pretty much none...which my guy is saying is 
pointing to something else amiss!   Fix the valves first...then chase 
mixture....with a bigger pile of jets!!! ( I neglected to bring my baggie full 
of jets.....duh!)

Anyway, with so many guys starting to build roller cam'ed engines, I thought I 
may throw this out for you to try or bounce off of your builder in the event 
that they have not done a roller cam motor yet.... This "could" be an issue.....

I'll readjust the lifters, and see what happens!    ...and then find out where 
my fans went..... came home after a little impromptu weekly car gathering, to 
grab the wife to go for a hotdog run (Mark's Hotdogs- San Jose landmark 
thing...) and on the way there, about 6 blocks away, I noticed my fan lamp was 
not lit!!!   Of course we had caught EVERY freaking stop light on the way there 
after we got off the freeway (about a mile or so).....(7:30 at night? Whus up 
with that???)  Got there with my pucker factor up about as high as the temp 
guage went....and shut down, had dinner....   After eating....quickly checked 
and found the fuse is good...., swapped out the relay....clicks and does all it 
should, but no fans.....  Car was cooler by the time we got done eating, so 
hopped on the freeway this time and cruised at speed all the way 
home.....thankfully it was a much cooler evening!!!

Knowing this car, it has a relay feeding a relay........and the first relay gave 
it up..... we'll see!