My 109 Build with Cost, Oil Pressure and Clearance Results


Gearhead/Engineer/GN Addict
Apr 29, 2011
A couple of years ago I asked this group for some advice on how to build my GN and I thought I would post the results in case someone else had some similar ideas in mind. My goal then, and surprisingly still now, is to have a low 11sec GN capable of reliably cruising virtually anywhere and still pulling down 20mpg on the highway with ice cold AC.

Late last year I completed my 109 engine build and have been driving the car around as often as I can. I thought I would post my results to help others with their budget and ideas to return the favor of those that have helped me plan this build.

With an engine budget of five to six thousand dollars, a bunch of searching to find some good deals and even more searching to select a good machine shop in central Florida, here is how I spent it: (Details in picture since I couldn't get formatting to work the way I wanted)


Labor: $1326 Parts: $4189 Total: $5516

I want to say I am very pleased about the work that Robert and his guys at Central Florida Machine did for me. The work was by far the best of any of the other machine shops I have used on other projects and Robert was real good to call me when stuff came up like noticing my stock crank was slightly bent.

While the engine was away at the machine shop I used that time to powder coat and freshen up as much stuff under the hood as possible including powder coating the front core support, sway bar, transmission lines, various engine brackets, and a host of other parts. Eastwood makes a pretty inexpensive powder coating gun and IR Lamp that is pretty easy to use. If you haven’t checked these out in a while it might be worth another look. If there is interest in how some of the results turned out I can post some pictures.

Once the machine work was done I assembled and installed the engine myself. I have assembled a variety of engines over the years but this was my first 231. After doing some reading and finding out how important the bearing clearances are on these engines I ended up with main bearing clearances between 0.0016” to 0.0018” and the rods a little looser at 0.0020” to 0.0022” (factory journals cleaned up with minor polishing so we elected to not turn the crank). My original plan was to use a new timing cover, oil pump repair plate, standard volume oil pump kit and do the oil pump mods myself thanks to the write up by Earl Brown. The cover and pump clearances turned out great, but sadly this cover had the cam sensor bore machined incorrectly and would not let me position the cam sensor once the cover was installed on the engine. Of course I found this out after I powder coated the cover and installed the engine. Since my factory cover was in decent shape and the clearances checked out I ported and powder coated that one and got a perfect fit.

Final oil pressure readings using 30HD Castrol at 750 RPM idle in Drive netted 50 psi cold and 20 psi hot. The engine is making 50 psi hot by 1800 rpm, and max oil pressure is 60 psi as expected. I had a biggie oil filter kit on the shelf that I installed a few weeks later and picked up another 3 pounds at an idle hot. Final compression ratio ended up at 9.0:1. No oil leaks of any kind so far, including the notorious rear main seal ;)

I bought my heads directly from Champion as they are only an hour or so away. Tom was nice enough to show me around the shop some and give me some pointers on some other parts I have been eyeing so I thanked him by dropping off my old heads to add to his collection of cores. Perhaps they will see some more use on someone else’s project sometime soon. As part of the assembly, I had Champion install a set of Comp 26918 beehive springs and hardware for a small upcharge. For what it’s worth I used the factory rocker arms and shafts with upgraded hold-downs knowing that I will be upgrading to a set of T&D’s eventually. By using shims under the shafts, my final lifter preload ranged from 0.044” to 0.056”.

If you have any questions or comments please feel free to ask. I am sure there are others out there that may have done this a different way but I figured that at the very least this may help someone else in much the same way my researching on our forums has helped me.


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Thank you for this post! This is the kind of information I was looking for. Very good read! Sticky????
Is the alternator bolt touching the MAF pipe? Might want to put a rubber nipple over it just in case. :)
Thanks all. Earl- Good Eye! In that picture it shouldn't be touching but it takes a little "fine tuning" to avoid rubbing the alternator bolt. Since then I have revised the mounting and it no longer tries to hit. Thanks again for your write up on oil pumps as well. Good laughs and great oiling ;)
That's why I wrote it! :D That sucks about losing all that work on the chinese cover. I was hoping that would be common knowledge by now to avoid those If if helps, you aren't the only guy to fall down that rabbit hole. lol

It's pretty common for that to be a touchy spot with the S-shaped MAF pipes. You can't move away without getting interference from the up pipe or the IAC plug.

If you don't like the idea of cutting the stud shorter and capping the nut, you can get a vacuum nipple kit (seems like 3/8" is the right size) fill the bottom with a little RTV and stick it one. It'll look like it's kinda meant to be there.

Or just get on old section of thick rubber like a radiator hose, cut a square out and glue it to the MAF pipe. Either one should get you safe from unmetered air and/or a squeak that only happens and odd times under speed.