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Joe Craven
11-18-2002, 04:56 PM
I've just got my new motor installed and running in my 71 Capri and I have a few questions. Unfortunately, my usual race crank had too much clearance so I installed a used crank that was still at standard clearances. My mains are at 1.5 to 2 thou and rods are about 1 thou.

Motor is running fine with Unocal 20-50w dino oil but oil pressure after running the engine for 30 minutes and water at 200 deg F is 55psi at 1000 rpm. My last motor was closer to 25ish psi at idle.

I'm wondering if I should run thinner oil?

2nd question, has anyone run synthetic oils in the 2.0 or 2.3 motors? I've read in several places that syn oils weren't recommended due to the cam and follower setup.

joeg
11-19-2002, 09:26 AM
Joe--55 LB hot at idle is crazy high. I doubt it is the oil's viscosity causing this.

Check the gauge and then see if the pressure relief valve in the oil pump is sticking.

Synthetic oil tales are for the most part fiction. The only two that may have some truth is to use dino oil for break-in (ring seating) and not to switch over to a synthetic on a worn leaky engine because the leaks will get bigger. Apparantly, there is even now some questions about the former.

Joe Craven
11-19-2002, 03:20 PM
Thanks Joe. I'll eventually put synthetic oil in it. In the meantime, I'll probably drain a couple of quarts of oil out of it and mix in some 10-40 since I plan to run it this weekend at Infineon raceway to break it in during mid 60s weather.

In regards to the oil pressure, this is the same oil pressure gauge, same oil pump, same head as my former engine. I just tested my water temp gauge last night and found out that it reads about 40 degrees high, so it was actually only about 160 degrees. In this motor, I gutted the thermostat so it is no longer temperature controlled. I was running the motor at about 3000rpm for 30 minutes to break in the cam and spraying water into the radiator to control the temperature. I'll need to order a new temperature gauge as it probably got damaged when I pegged it out (260 deg F) when the crank shaft pulley broke earlier this year and the water pump belt fell off.

CFRRaceBoard
11-19-2002, 10:47 PM
Joe,

I raced a 71 Capri competitively in GT3 for many years in the SEDiv and in ITB also. The high oil pressure you are experiencing is caused by inadequate side clearance on the rods.

Are you running IT or GT? I've moved on to a Mazda but have many years of experience building and racing the Capri. I even have some left over competition parts laying around if you're interested. If you need help or advice please feel free to contact me at [email protected].

Robin

Joe Craven
11-22-2002, 03:31 AM
Robin, thanks for the advice and I will be contacting you off list.
Hmmm, I fear that you might be correct about the rod clearance issue. I had several sets of rod bearings, and rods for that matter and they were all ever so slightly different. For example, I had what appeared to be two sets of identical rod bearings but one set gave .003 clearance while the other set was closer to .001 thou. I didn't even think to check the side clearance.

I'm going to run it Saturday during a NASA driving school to test out the car and break it in. Hopefully, the break in won't be literally broke!

I've just corner weighted it with my new "circle track tool" and got 560 and 570 lbs on the fronts and 470 lbs on each of the rears w/o a driver. Of course, I should corner weight with driver but I did this by myself.

My car has new shocks all the way around, (concerned that rear rebound will be too stiff though) and I found numerous problems during the service including, loose and bent front sway bar mounts, elongated cross member holes allowing the TCA to move in and out affecting camber.

I have installed a couple of EGT gauges so I can use them to tune my fuel mixtures.

I'm optimistic that I and this car will be a front runner in '03 ITB.

Joe Craven
11-25-2002, 01:13 AM
What would be the minimum valve lash measurement that can safely be used in
a racing ITB 2000 cc motor? Everything is pretty much stock, valves,
springs, retainers, followers and I will probably wind this motor until the
power tails off or 7000rpm, which ever is lower. The manual specifies .008
and .010 thousandth clearance for the intake and exhaust respectively. Of
course, I'm willing to check the clearances as often as is needed. The
motor will probably be run for about 30 minutes at a time, and I will be
using leaded gas which will reduce valve recession.

71 ITB Car report

I finally got my 71 ITB Capri back together with new/old parts, rebuilt
engine and I drove it yesterday at Sears Point Raceway to test and break the
engine in. I ran the engine at my house for a total of about 2 hours to
break the cam in and pre driving break-in. I drove the car very easily for
two 20 minute driving sessions running up to about 4500rpm 1/2 throttle. I wound it up to close to 6000rpm at full throttle later in the day and the car pulls very well.

All in all, motor is running good, car is now handling quite well although
it still oversteers in turn 2 and through the Esses (turns 8,8a) at Sears
Point. It understeers a bit through 4. I'll have to do some more testing,
I'm experimenting with tire pressures and I'm already down to 20psi cold in
the rears which significantly improved things with the BF
Goodrich R1 tires How much lower
can I go? I might try stiffening up the front sway bar (it's a slightly
ground 1 1/8") if I can't get close enough with tire pressures alone. I
shouldn't complain too much, I'm sure that the car is already fast enough to
break a couple of track records next year.

Oh, I might also mention that I installed a couple of EGT (exhaust gas
temperature gauges) on cylinders 3 and 4. If you recall on the carbed 4
cylinders, cyls 1 and 4 and fed from one side of the manifold while 2 and 3
are fed from the other side. I wanted a way to determine if one side was
running richer or leaner as compared to the other side. Adjusting the
primary or secondary main jets in the Weber carb should affect each side a
little differently.

Here is what I saw.
During my part throttle runs, I was getting higher temps in cyl 3 than cyl
4.

Cyl 3 ~1250 deg F
Cyl 4 ~1300 deg F

During my full throttle runs, I was getting significantly higher temps in
Cyl 4 than 3.

Cyl 3 ~1375+ deg F
Cyl 4 ~1450 deg F and it was still rising before I had to lift for
turn 2.

I'll have to look how my carb is orientated to see which cylinders is fed by
the primary of the carb which was fully open in both of these tests.