2.8L Power? Why is my rebuilt 2.8L so slow...

['84 Bronco II]

I am not sure what you think I should have been checking for by turning the engine. I had to rotate the crank to set the valve lash and I never noticed anything abnormal. I still don't understand how I could have gotten the cam timing off? The crank and cam are each keyed to their respective gears and have timing marks that line up. There really is not a way you can install them improperly without misaligning the timing marks.

After reading about carburetor tuning for the last couple of hours, I think I will take another look at the carburetor and see if I can improve on anything.

Also, I talked to my father and he brought up distributor advance and timing curves. I don't really know much about that, so I will be doing some reading. If anyone wants to chime in on distributors, feel free.

 

[wildbill23c]

I can say this about the carburetors, just a half turn to a turn can make a huge difference. Since you did all this rebuild work, just because the carburetor worked just fine before the rebuild doesn't mean its going to run find after the rebuild. You changed the workings inside the engine, cleaned up some stuff, changes parts, etc. You have to adjust the carburetor to make up for those changes.

I just got a carburetor from a fellow member on here last week, it was cleaned and rebuilt by someone he knew and worked awesome on his rig, however I put it on mine and I had to adjust it for air/fuel mixture and idle speed. It's all in the proper adjustments of everything to get these things to run right.

If you have the computer in your rig still functioning you need to unplug the plug on the back of the carburetor before attempting to adjust it, also do your adjustments after the vehicle is up to operating temperature or you'll never get it adjusted right. I can adjust my carb all sorts of ways, and it will either effect low end power or upper end power. Its all about getting that happy medium between both LOL.

 

[bobbywalter]

I am not sure what you think I should have been checking for by turning the engine. I had to rotate the crank to set the valve lash and I never noticed anything abnormal. I still don't understand how I could have gotten the cam timing off? The crank and cam are each keyed to their respective gears and have timing marks that line up. There really is not a way you can install them improperly without misaligning the timing marks.

After reading about carburetor tuning for the last couple of hours, I think I will take another look at the carburetor and see if I can improve on anything.

Also, I talked to my father and he brought up distributor advance and timing curves. I don't really know much about that, so I will be doing some reading. If anyone wants to chime in on distributors, feel free.

hmm. well.

sometimes one can wrong side the slack on the chain and it gets a bit off. i have seen it before, but you would normally see this when setting lash as its visibly off. which is what i implied when i said visible off in the other post.


but if it was running great with the carb setup for a shit ton of blowby and uneven pulsing....

i would be suspicious of that. but curving the dizzy is another matter.

are you sure the vac advance is operating correctly??

 

[kimcrwbr1]

Get some #41 jets and put them in I guarantee you an improvment in mileage and performance. The 2.8 works best at 10 DBTDC period with my engine. I have tried every combination possible right now I am running #41 jets and still have pedal pulling a pass. Being above 4000' elevation you want smaller jets anyway. It only takes about 15 minutes to change the jets there cheap its worth a try. When pony carbs rebuild their carbs they change the power valve jet size so depending on what vacuum pressure the power valve opens will make a difference also. If you can get it on a dynamometer with a sniffer you can find the right combo for your setup maybe put some heavier springs in the dizzy for a less aggressive advance. It is kinna hard to see your tailpipe at high speeds maybe have someone follow you on the freeway and at high speeds punch it if black smoke comes out the tailpipe your running rich put in smaller jets. I started with #50 real low power pulling a long hill, #46 still puffing black smoke #43s ran alot better but still about 16 mpg running #41s up around 18mpg and alot easier on the skinny pedal. I just hauled two loads of garden dirt with the frame down on the axle with no problem I couldnt be happier. I say go by the tailpipe if it blows black smoke run smaller jets. Does you oil smell normal, if you smell fuel it is definately running rich?

 

['84 Bronco II]

Okay Bobby, now I see where the confusion is, 2.8Ls don't have timing chains, they have timing gears.

The distributor I have now is a rebuilt unit from Autozone and I don't believe it to be a very high quality rebuild. After reading up on timing curves and such, I am pretty suspicious of the distributor. I have the base timing as far advanced as it can go at idle, but I have never had the engine ping under load. If anything, it seems the timing curve may be a bit retarded.

Also, I can't say with any certainty whether or not my vacuum advance is working correctly or not. I am going to try and do a little tweaking on it this weekend if time permits.

 

['84 Bronco II]

Also, I will try and take a look to see what size jets are currently in my carburetor.

 

[kimcrwbr1]

Do not attempt to time it by earball use a timing light and set it at 10 degrees btdc with the advance disconnected and plugged. Then adjust the idle air needles for the highest rpms or vacuum pressure. You should have 10 degrees advance when you hook manifold vacuum up to the dizzy. Use the pointer not the round thing to set the timing. with a flashlight and a socket get under the front of the engine and rotated the crank clockwise until you see the timing marks the wide groove marked TC is TDC the next numbers are twelve. with a yellow crayon mark it one line back toward TC that is !0 degrees. Allways adjust the idle air needles after you change the timing. Before you pull the float to check the jets check your wet float setting you want 3/4 inch center of the fuel in the bowl to the top of the float bowl. Pull the float to bend the arm and then soak up some fuel with a rag. Disconnect the coil wire and crank on it unitl the fuel stops and check your level again. Do not try to adjust the float in the carb you will damage the needle and seat. If your careful you can run the motor with the top off the carb to check the wet float. If you do these thing in order I can almost guarantee you will bring that engine to life.
1-Put smaller jets in #43 to begin with
2-confirm 3/4 inch wet float setting
3-turn the idle air needles out 3 1/2 turns pre adjust
4-Start motor and bring up to temp then adjust idle to around 700 rpms
5-adjust base timing at 10 degrees (DBTDC)
6-Set idle air screws for the highest lean vacuum pressure (where vacuum drops as soon as you turn them in)
7-Connect the vacuum advance to ported vacuum on the carb.
8-Take it for a beat
I do this for every tuneup except check wet float with great results the base timing has not moved in four years I run autolite single platinum plugs and the stock TFI coil it jumps a gap around 7/8 inch with a wicked snap. I was messing with the vacuum for my tranny and knocked a plug wire up and my whole arm went numb in a split second.

 

[bobbywalter]

i forget about the lil backwards fawkers having gears sometimes...

some of the high power modified 2.8s i have been around have had belt drives and custom cams for tuning and adjustment, 12 to 1 screamers making nearly 250 hp. whoop my fresh 5.0 out of the hole to 80 mph easily..but that was also its top speed. the truck (stock class race 2wd) i am referring to run up at bark river years and years ago. it was a 10 year old build back then...would be a 25 year old rig now.

go to the store and look at a few more dizzies. i have had gear problems with the dizzies to and have had them slip and just fail at the teeth as well with these.

i have had the advance on the wrong port, or the port was blocked ect....

one step at a time...all part of the fun.

Do not attempt to time it by earball use a timing light and set it at 10 degrees btdc with the advance disconnected and plugged. Then adjust the idle air needles for the highest rpms or vacuum pressure. You should have 10 degrees advance when you hook manifold vacuum up to the dizzy. Use the pointer not the round thing to set the timing. with a flashlight and a socket get under the front of the engine and rotated the crank clockwise until you see the timing marks the wide groove marked TC is TDC the next numbers are twelve. with a yellow crayon mark it one line back toward TC that is !0 degrees. Allways adjust the idle air needles after you change the timing. Before you pull the float to check the jets check your wet float setting you want 3/4 inch center of the fuel in the bowl to the top of the float bowl. Pull the float to bend the arm and then soak up some fuel with a rag. Disconnect the coil wire and crank on it unitl the fuel stops and check your level again. Do not try to adjust the float in the carb you will damage the needle and seat. If your careful you can run the motor with the top off the carb to check the wet float. If you do these thing in order I can almost guarantee you will bring that engine to life.
1-Put smaller jets in #43 to begin with
2-confirm 3/4 inch wet float setting
3-turn the idle air needles out 3 1/2 turns pre adjust
4-Start motor and bring up to temp then adjust idle to around 700 rpms
5-adjust base timing at 10 degrees (DBTDC)
6-Set idle air screws for the highest lean vacuum pressure (where vacuum drops as soon as you turn them in)
7-Connect the vacuum advance to ported vacuum on the carb.
8-Take it for a beat
I do this for every tuneup except check wet float with great results the base timing has not moved in four years I run autolite single platinum plugs and the stock TFI coil it jumps a gap around 7/8 inch with a wicked snap. I was messing with the vacuum for my tranny and knocked a plug wire up and my whole arm went numb in a split second.

by the book as it gets.

i would add, to double check and verify that all of the marks and pointer is not damaged and in the correct position. thats another thing easy to overlook.

 

[drgrcr]

if you suspect something is wrong with cam timing, do a compression test. That engine should pump at least a 125 psi @ 4000' elevation.

Another method to set timing, old drag racing trick. Disconnect vacuum advance, connect a timing light, tricky part, while watching the timing with the light start bringing the rpm up until the timing quits advancing, usually around 3k, note what the timing advance is. The 2.8 that I beat around like's 38' max advance, I don't know what the timing is while at idle, because it runs really good using this method. The elevation where I drive most of the time is around 3700', no pinging. I have another 15' of vacuum advance all in @ 10'' of vacuum, you adjust that with a hand held vacuum pump connected to the vacuum pot on the dist. Use the pump to pull a vacuum and check the timing, to adjust it stick a 1/8" allen wrench in the hole where the vacuum line connects, you will feel the wrench fit into a hex, turn the wrench clockwise to reduce and counter clockwise to increase. This is for a duraspark dist. of course.

I run 42 main jet, idle speed set @ 700 rpm, idle screws adjusted for smoothest idle. Usually can squeeze 15 to 18 mpg around town, and I'm not nice to it. The carb is a 1.08 with the metering rod idle system.

I am getting real close to rebuilding the engine in this truck, just got the heads back from the machine shop. They are 78 Mustang II heads with 2.9 valves, harden exhaust seats, moderate porting, cooling holes drilled, combustion chamber volume is 37 cc's. Piston deck clearance will be .010'' with a .057'' head gasket compression ratio will be 10.5 to 1. and it will run on 87 octane fuel....

 

[MadMax_636]

Hello,

It has been a while since I have posted on TRS, but I think this is probably the best place to ask about my 2.8L.

My 2.8L was pressurizing the crank case about a year ago and blowing oil out about as fast as I could dump it back in. In addition, it was pretty gutless, and had some pretty good valve noise going on.

I got tired of trying to nurse it along, and decided to rebuild it. This was the first engine I had rebuilt on my own, but I got through it all right. The engine was bored out .030, and the crank was turned .010 under. I put new pistons, rings, lifters, cam, and bearings in it. I essentially did a stock rebuild on it.

I have been driving it for about 3000 miles now. It doesn't leak a drop, and it is a lot quieter now, but it did not seem to pick up any power over when it had a bad cylinder and was blowing oil everywhere. If anything it seems like it has a little less power now. This is very disappointing, but I was wondering if anyone might have an idea of what is going on. I have trouble getting to 65 mph!

I know this is OLDER post/thread but Im planning on doing a rebuild on my 2.8 soon. Could you PM me on a guide or book I should get/follow on the process? Ive never rebuild a engine but I have on small engines. Any help would be appreciated!

 

[alwaysFlOoReD]

I know this is OLDER post/thread but Im planning on doing a rebuild on my 2.8 soon. Could you PM me on a guide or book I should get/follow on the process? Ive never rebuild a engine but I have on small engines. Any help would be appreciated!

 

[MadMax_636]

View attachment 37436

I have that already, The only thing that made me ask the question was because I heard on other forums that it wasnt as much of a guide on how to rebuild the engine....Im only going off of what others have said. Trying to do the most research and get the most amount of INFO I can before undertaking this project.

 

[alwaysFlOoReD]

@PetroliumJunkie412

 

[Jim Oaks]

I know this is OLDER post/thread but Im planning on doing a rebuild on my 2.8 soon. Could you PM me on a guide or book I should get/follow on the process? Ive never rebuild a engine but I have on small engines. Any help would be appreciated!

I'm not aware of any books or guides that will tell you how to rebuild your Ford 2.8L. I know somewhere I have a book that's pretty much a step by step guide to building a Ford V8. You can find articles online on how to do it as well. Here's a quick example:

Small-Block Ford Rebuild Guide: How to Assemble the Short Block

Small-Block Ford Rebuild Guide: How to Assemble the Short Block - Covers 221, 260, 289, 302, Boss 302, 351W, 351C, 351M, and 400M Small Block Ford Engines.

www.diyford.com

The principals to building an engine are basically the same where you're building an 8-cylinder, or a 6-cylinder. The biggest thing is knowing the torque specs for everything when you put it back together. You should be able to find those here:

Ford Ranger 2.8L V6 Engines - The Ranger Station

About The 2.8L V6: The Ford Cologne 2.8L V6 is a 60° cast iron block V6 engine built by the Ford Motor Company in Cologne, Germany. The 2.8L engine in the Ranger is the same design as the 2.8 V-6 … Continued

www.therangerstation.com

If you buy a rebuild kit, it may come with the torque specs.

In the past, I've sent my bare block out to get it cleaned, inspected, bored, honed, and any other machine work that may need done. I've also sent them the rods and pistons. I've sent the heads out and had them cleaned, inspected, and a valve job performed. I had the machine shop install my camshaft bearings for me. Then I installed new freeze plugs in the block and assembled the engine.

There's really not that much to your 2.8. If you're patient and mechanically inclined, it will probably turn out to be easier than you expect.

For anyone that doesn't know, we have the .pdf version of 'How To Build And Modify Ford V6 Engines' here:

https://therangerstation.com/tech_library/pdf_documents/How-to-build-and-modify-Ford-V6-engines.PDF

 

[MadMax_636]

I'm not aware of any books or guides that will tell you how to rebuild your Ford 2.8L. I know somewhere I have a book that's pretty much a step by step guide to building a Ford V8. You can find articles online on how to do it as well. Here's a quick example:

Small-Block Ford Rebuild Guide: How to Assemble the Short Block

Small-Block Ford Rebuild Guide: How to Assemble the Short Block - Covers 221, 260, 289, 302, Boss 302, 351W, 351C, 351M, and 400M Small Block Ford Engines.

www.diyford.com

The principals to building an engine are basically the same where you're building an 8-cylinder, or a 6-cylinder. The biggest thing is knowing the torque specs for everything when you put it back together. You should be able to find those here:

Ford Ranger 2.8L V6 Engines - The Ranger Station

About The 2.8L V6: The Ford Cologne 2.8L V6 is a 60° cast iron block V6 engine built by the Ford Motor Company in Cologne, Germany. The 2.8L engine in the Ranger is the same design as the 2.8 V-6 … Continued

www.therangerstation.com

If you buy a rebuild kit, it may come with the torque specs.

In the past, I've sent my bare block out to get it cleaned, inspected, bored, honed, and any other machine work that may need done. I've also sent them the rods and pistons. I've sent the heads out and had them cleaned, inspected, and a valve job performed. I had the machine shop install my camshaft bearings for me. Then I installed new freeze plugs in the block and assembled the engine.

There's really not that much to your 2.8. If you're patient and mechanically inclined, it will probably turn out to be easier than you expect.

For anyone that doesn't know, we have the .pdf version of 'How To Build And Modify Ford V6 Engines' here:

https://therangerstation.com/tech_library/pdf_documents/How-to-build-and-modify-Ford-V6-engines.PDF

Thanks for the LONG indepth response! I appreciate it a LOT!

I will probably have the machine shop (One I find one in my area) Ill probably get them to do all of the stuff you mentioned.
For the torque specs, I have noticed they are there but the patterns are not. Which in the past of rebuilding anything and torqeing stuff down it needs a pattern not to warp anything.

I do have the PDF, Im confident that I can do it. Hopefully I can save up enough money for everything!