North American Turbocoupe Organization



What's everyone using for valve springs?
RocketshipChair Offline
Member
#1
Hi Guys,
As many of you guys know I have an 88 Tbird. After I put everything together last year I had some small issues that I'm addressing this year. I have a Ranger roller cam in it and a t3 turbo (its at about 17 psi boost) out of an 86 tbird. I also upgraded the fuel pump to a high volume Walbro 255.

The performance issue I faced was the car would stall at WOT but only WOT not anything less. I would also seem to hit an imaginary rev limiter at like 4500-5000 rpm in second and third gear only. I never got to drive it with a vacuum gauge prior to putting
it away for the winter.

I made some discoveries this winter and here's were I'm at.

The fuel tank I used is now leaking from rust, I have a new Dorman 22 gallon tank that's going into it. I had bypassed the stock fuel damper originally has well. I put a known good fuel damper inline with the pump into the tank.

I measured the lift on the Ranger cam and it turns out I must have a 95 cam because the lift is .215" not the correct .238" of the 89-94 Ranger cam. I have one coming in the mail from Chip.

The head went through the machine shop before I installed it on the car, it is not the original head to the engine (I bought it with unknown mileage and condition). They polished the ports, decked the head, cut the valves and seats, did need valve seals, bearings
lifters, and installed the cam that I provided.

So my question is: it seems like the valve springs might be weak. Or could it be a combination of the leaking fuel tank not causing enough pressure and the incorrect camshaft not allowing the valves to be open enough to allow enough airflow?

There's springs available on RockAuto for a 94 ranger made by Qualcast ($2.71 ea), I can get performance springs from  Bo-Port (I did speak to Bo and he said go with his "drop-in" performance springs) ($80), or I have 2 other heads that never had any issues other than the cam lobes being worn that have factory springs ($0).

Which route have you guys gone with similar setups?
Andrew
88 Turbo Bird 5 spd no mods
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Jeff K Offline
Administrator
#2
I would go with the BoPort springs, Andrew. $80 for high quality springs sounds pretty good to me. Comp Cams 990 springs are also common replacement, but I think you need different keepers, etc.

Hope you guys are doing well!!!
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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