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2.8 Pistons in a 2.9

Posted: Sun Jun 08, 2014 1:05 pm
by tekatlarge
This topic has been tossed around for years. Theoretically using 2.8 Pistons in a 2.9 Block will yield a higher compression Ratio. The stock 2.9 Piston has a dish in the top. This dish is about 14cc. A 2.8 Piston is Flat.

I have read specs till my eyes are bugged out! It looks like this will work. I bring this up now as I just acquired a 2.9 Short block that has been punched 1 over and has 2.8 Pistons fitted. This is a Block,Pistons,rings,rods, and a crank. The only thing that is fitted to the block is the pistons. After mulling all this over I am going to build this motor and see how it works. This will be a "As time allows" build. Not a priority in the shop but as time allows. I have on the build sheet to use a Cam I got from Charlie over at Cam Craft. It is a Cam he designed for Lots of low end grunt. I also have a set of Stage 1 World heads,pacesetter Headers, and the Ignition will be almost Stock and will be driven by Mega squirt. There are some other things in the valve train that will be reveled in time. This looks to be a fun project. I will give more details Later.. :cool:

Re: 2.8 Pistons in a 2.9

Posted: Mon Jun 09, 2014 7:53 pm
by drofman
Interesting. I think I would be worried about valve relief. Hope you have some playdough around to check it.

Re: 2.8 Pistons in a 2.9

Posted: Sat Jul 12, 2014 10:33 am
by tekatlarge
The Block has been washed and cleaned and yesterday I masked everything off and Shot a couple of coats of VHT Ford Grey on it and today I plan on starting on the glyptal coating and hope to finish that before the weekend is over.

I sent the rotating assembly to a buddy for Balancing and I will have that back on Monday! Then the real fun begins.

So far so good. Oh and Drof I had the clay already and NO reliefs need be machined for valve clearence


Re: 2.8 Pistons in a 2.9

Posted: Wed Jul 23, 2014 9:30 pm
by tekatlarge
Progress is slow but steady. The block is now painted and prepped. I will start laying in the crankshaft tomorrow or maybe Saturday or Sunday. I had a bit of a panic over a perceived problem with the cam bearings. :eek: That is all figured out now so No Worries. I had a valve train parts come in today and I can move on with working over the World heads. Everything is coming along. :D I am getting deliveries and I been returning money to these companies for the simple chore of lining their pockets. on a grand scale so I guess I am helping the economy in my own special way. :angel:

I just picked up a 7.5 and a Dana 28 Pinion install kits and I have the gears ready to go into the New to this rig Dana 28. I can't remember if I said what I am using in axle department.
Axle wise I have the 7.5 rear and I am going 4:10. with a ford track lock to go in to the 7.5 The front will be stock Dana 28 with a Lock Right locker. Of course ratio will be 4:10. This will be a 2WD conversion to a 4X4. using a manual BW transfer case.
Oh so many things to do and so little time to do them. I have added a Page 3 on my site on Project BII. It has some pictures and some info on cam bearings there that is a good read if you are thinking about building a 2.9L . check out the progress in the Current Projects section. I am sure finding a lot of little parts I thought I had in stock that I didn't and the bill is spilling over on my recreational Capital.

So off I go back to the grind. I will ad more content to my Webpage as I get more done. If you have any comments or questions ask away. :cool:

Re: 2.8 Pistons in a 2.9

Posted: Tue Jul 29, 2014 9:29 pm
by tekatlarge
Well here I am. Making slow but steady Progress. The block is done and ready for assembly. I have it wrapped up in a garbage bag to keep it clean till I finish all the grinding and sanding on the heads.

I am now about 75% through the porting and smoothing of the ports and combustion chamber. The World heads are actually a lot nicer or cleaner than the Ford OEM head. The exhaust ports got a smoothing of the walls and floors and the valve cover bolt nub was ground away. the exhaust ports got just a little straightening of the port by some material removal but so far it is looking good and feels like glass.

The Intake ports just gets smoothing and casting line cleaned up. I have to still do a little bowl work especially where the valve seat and head meet. Last on the first head is combustion chamber smoothing.

That's it for now..

Re: 2.8 Pistons in a 2.9

Posted: Thu Jul 31, 2014 9:24 pm
by tekatlarge
Was I an eternal optimist! I must remind myself that I got what I asked for when I thought this head porting thing was fairly quick. My memory of the many tedious hours I have done port work in the past must have all been tainted with age.

I am still working on head #1. I now have 3 intake ports and 3 exhaust ports done I just need to do a final polish and then I can Start the combustion chamber work. All that is happening to the combustion chamber is just smoothing the chamber as it looks like an orange peel right now. I thought about UN-shrouding the intakes but that is a lot more time involved than I want to spend. Actually all this work is in reality is not really worth much in the way of adding HP. However, what I am doing is what the original plan was to be so I am just going through the process.

It is sad to think that when all of this is over nothing will be visible outside to remind me of the mindless hours I spent working on these heads. I will say it looks kool so that has to be worth at least a 100 HP gain.... Yeah right.

Re: 2.8 Pistons in a 2.9

Posted: Wed Sep 03, 2014 8:10 pm
by tekatlarge
I reached a milestone in the 2.9 Build today. I finished the porting and polishing on Head #2. This has been one pain in the ass. I have had to share my free time between a major landscaping project, The building of 2 garden sheds and a host of little details. Head #1 is ported polished and Glypped. All that is left to do for head #1 is do a 3 way grind on the valve seats, Clean, Glypping Exterior Paint, and assemble with all brand new parts.

Head #2 is now ported and polished it needs glyptal painting, 3 way valve grind, Ext Paint, and assemble. I am pleased as can be that all this grinding sanding and polishing is done. That is one dirty job and I have lived in my respirator mask more than enough in the last month.

Oh yeah after assembly I will be doing a head combustion chamber cc measurements. When I get that number I can finally figure my calculated Compression Ratio.

Now I can clean the shop of grit and get ready to assemble the Lower end. I want to make some progress on this project as I am chomping at the bit to get the 27 Coup project underway.

I have done a lot of measuring and calculating on my T project and ordered up some parts and during the upcoming cleanup in the shop I will get the chassis jigged up so I can work on both projects at the same time. Finally progresssssssssssssss.

Re: 2.8 Pistons in a 2.9

Posted: Tue Mar 03, 2015 7:48 am
by Phillippi
Any updates on either project?

Re: 2.8 Pistons in a 2.9

Posted: Wed Mar 04, 2015 7:14 pm
by tekatlarge
Ah shucks, I knew I would be found out eventually..

To tell the truth about progress......... Ahhhhhhhh NO!

I really don't have an excuse cept, Life in general and of course my TCoupe project. I really want to get the frame up to a roller condition so it don't take up so much room in the shop. I was actually setting looking at the heads yesterday wishing they were done and telling myself I gotta get it done.. If ya want to see the latest progress on the coupe go to my webpage under latest projects..

Re: 2.8 Pistons in a 2.9

Posted: Wed Mar 04, 2015 11:26 pm
by Lance Skene
Well at least Im not the only one not getting projects done. Lol

I keep bringing more home tho.... two more garden tractors, a Harley golf cart, and an Explorer Sport... I need a bigger shop maybe. Lol

Re: 2.8 Pistons in a 2.9

Posted: Fri Mar 06, 2015 10:59 am
by Phillippi
I am the same way. My bronco was started 8 years ago with a V8 swap, that turned into front and rear axel swap, 5.0L swap, and AOD swap. I am about 40% completed and stalled. Its just sitting gathering dust in my garage. At this moment I have my sons 95 FS bronco town apart replacing the extended radius arms. What a pain in the ass those bolts and studs are to get off of the axle. No fun.