Finally and after 500,000 km I have gone to a extensive engine rebuild with some mods, as a reference we are talking about a 1989 F150 4x4 5.0 Fi, 4.56 ratio and 35x12.5R15........

The new configuration is the following:
2021 Crane compu cam centered 114 lobe center
keith black pistosn
Big valves
Ported and polished 61cc heads
roller rockers
24 lb cobra injectors
High volume high presure oil pump

After the first 120+ km the engine is making blue fumes when startingspecially at normal operating temperature, is this a normal condition till getting the rings properly seated?

So far I can not feel major differences in ponies, is there something I should chek for?

Fuel consumption has gone straight to hell, is it a good idea to keep those 24 lb injectors?

May it be the knock sensor the resposible for those arrested ponies? Maybe maf?

Need your advice since I do not wanth to damage the new engine due to something not done properly.

Kind regards
Ray

 

Do you have a chip for the computer? The computer is opening the larger injectors the same length of time as the stock 19's, and so it is likely running terribly rich. If you are making under 300 horsepower, the stock 19lb injectors should be enough. The computer needs to be reprogrammed for the larger injectors, and likely the large valve, ported heads as well. Unless you have converted to mass air, there isn't a MAF sensor on your truck. Converting over to mass air might be a good idea in your situation. I don't think the knock sensor is causing any ill effects.

 

Thanks a lot for the comments.

Does someone has info regarding this Mas air conversion? Is it something to dificult to go for? What about the blue fumes that some times happend?

Regards
Ray

 

Do a search for "MAF conversion". There are a few threads on it with lots of good information on the whole conversion process. Depending on how you choose to convert, it could be easy, or it could involve a fair amount of wiring harness work. Where are the blue flames coming from?

 

Some oil consumption is normal during break in. It should not exceed one quart per tank of fuel, and should be less than one quart per 1000km by the time you reach 1000kim or so.

Blue smoke out the tailpipe is unusual, unless you have removed the air pump and catalytic converter. The cat can usually clean up the smoke of oil burning.

Blue smoke only at startup is often a sign of valve stem seal problems. The oil pools in the valve covers, runs past the leaky seals, and accumulates in the cylinders. It is burned off at startup.

Try running the truck at 50 MPH (80kph) at high gear. Release the accellerator pedal and let the truck coast against engine braking. If you see blue smoke then, the oil is coming from leakage past the piston rings.

The larger injectors will cause the engine to be over-fueled at least until the engine warms up, and probably after that. (The oxygen sensor feedback, if installed and working, can correct for some amount of overfueling once the computer enters closed loop mode -- but maybe not this much). Too much gasoline may wash down the cylinder walls and create some of the oil burning problems.

The mods to the engine will only have be able to improve performance at full throttle and above 3000 RPM. You should not be operating the engine there for extended periods until it is fully broken in. At lower speeds and part throttle, the bigger valves and longer duration cam will slightly degrade the apparent "torquiness" of the engine.

You will not feel a bigger "boot in the rear" as you pull away from a stop treading (relatively) lightly on the gas with the mods you have done -- if anything it will be slightly less than before. The stock system has an impressive off-idle kick -- for a 302 -- but runs out of breath above 4000 RPM. That's the point where your mods would begin to do their thing.

 

If you don't have MAF EFI or upgrade your speed density system, you can't really do such drastic upgrades to your airflow. Especially the cam and heads.

I wish I had some of those parts in my motor. Without them I got a noticable gain from just a MAF conversion. Most people don't notice a big gain until they start upgrading components they couldn't upgrade before.

I'd bet a MAF would wake up some of those performance parts.

Blue smoke probably means oil in the chamber. Had an old chevy 235cid that blew smoke after it's third rebuild and it turned out to be the gaps in the rings were lined up.

 

I didn't think that a speed density ecm could compensate for any mods. I mean from my understanding basically everything is run off 3 parameters 1. engine vacuum 2. oxygen content in the exhaust and vehicle speed. In which case the new cam has messed up your engine vacuum, the larger injectors are dumping way too much fuel (ecm still thinks its using 19#ers) so the O2 sensor is giving bad reading if it hasn't burnt itself out already and the oversize tires are throwing the vehicle speed off (unless your speedo reads correctly) At any rate you definitely need to go mass air before it will run right.
SOmebody please correct me if I'm way off base.

 

blue smoke and loss of fuel econmy is those injectors. too big for stock programming. Too much gas in there... Anyways u add performance for the most part u lose gas mileage. Dont expect too much power outta that 5.0

 

The computer doesn't care how fast the vehicle is going - at least not on an '89. The main fuel mapping is done by the MAP sensor and throttle position sensor. The O2 sensor is there for the computer ot monitor how it is doing on air/fuel ratio, but since it is a narrowband O2 sensor, if it is out of the range, the computer can't correct it. A chip to account for the injectors and the increased airflow should correct the problems. To a certain extent, increasing power can decrease economy, but certain upgrades can actually improve efficiency.

I think the main problem at the moment is the larger injectors, and possibly the ported heads - the cam should be efi friendly. Do you still have the stock injectors? It might be worth swapping them back in and seeing if it would run correctly then. If not, then plan on converting to MAF or getting a chip. Keep in mind that the MAF computer would also need a chip to work with the larger injectors (recalibrated MAF meters supposedly do this too, but they fool the computer, and that's not so good).

 

Dear frieds

thanks a lot for such a valuable info.

Yes I do have the stock injectors still and will put them in the enginee withing next week.

The chosed cam is the Compu cam 2021 by Crane that they claim to be 100% EFI friendly and that was the reazon why to chose it.

So far I have found an aftermaket chip by Jet Performance products (Part number 88903) that has been purchased time ago and has not been instaled, do you think is this a good idea to give it a try? Is there another type of programing needed at the computer?

Once again thanks a lot for all your valuable info.

Regards
Ray