Jump to content


  • Content Count

  • Joined

  • Last visited

  • Days Won


gerg last won the day on March 1

gerg had the most liked content!

About gerg

  • Rank
    Advanced Member
  • Birthday 04/21/1976

Profile Information

  • Gender
    Not Telling
  • Location
  • Interests
    My workmates have a saying when I've tampered with something... "it's been Gergified!"

Recent Profile Visitors

14,500 profile views
  1. gerg

    FMX dipstick?

    Ford did some funny things back in the day, they developed the FMX from the BW and used a Ravigneaux planetary set, but produced that box alongside the C4 and C6 which used a completely different Simpson planetary set. Then, when they were done making the FMX in the late 70s, they developed the AOD from it while the C4 and C6 were phased out. So in a roundabout way, the FMX design predated, then outlived the other gearboxes that were supposed to replace it. Sent from my CPH1920 using Tapatalk
  2. Agree on the ATF, it's pretty foolproof stuff. We even used to use it on plant equipment as a hydraulic oil. Sent from my CPH1920 using Tapatalk
  3. gerg

    Changing diff ratio?

    Ok that makes sense, use one as a spacer against the face of the chuck, makes it easier to true it up Sent from my CPH1920 using Tapatalk
  4. gerg

    Changing diff ratio?

    Yeah I looked at that and thought they'd be as hard as a dog's forehead, also hard to grip in the chuck. Unless there's an easier way of grabbing them? Sent from my CPH1920 using Tapatalk
  5. gerg

    Changing diff ratio?

    The halves of the hemisphere can be machined internally a bit to allow cone engagement again, what happens is the tapered friction surface wears in the housing and the cones sit deeper and deeper into the taper as it wears. Eventually they bottom out on the internal face (where the axle comes through), which prevents the cones from biting in the taper. Machining this flat internal surface a couple of mm will allow the cones to bite again, but now the spider gears (which rely on the cone depth to set backlash) now need to be shimmed up by the amount that you machined off the housing, so that backlash is back up to spec. I think mine needed 20 thou machining and shimming each side. You'd be surprised at how much difference there is with a 5 thou shim. Where I stuffed up first time round, I actually shimmed the cones up too much, and when I put the two halves together, the spider gears bottomed out on each other before the housings touched. That's right, the hemisphere faces actually didn't meet, the two were held apart by the spider gears! So I bolted it all together and thought "jeez this limo is tight" but it was because it was all bound together and the spider gears could barely move, and the two halves were driving purely on the 8 little bolts. They all broke off eventually, and carnage ensued. So next time I did one, I made sure that the spider gears had backlash with the halves butted together. So far, so good. The limo's nice and tight too, but actually works. There's either a build thread on it somewhere or it's buried in my gergwagon thread. Sent from my CPH1920 using Tapatalk
  6. gerg

    Changing diff ratio?

    2.92s are apparently getting harder to find now, as everyone used to just chuck them when upgrading to 3.45s, etc. Sent from my CPH1920 using Tapatalk
  7. gerg

    Changing diff ratio?

    My diff came out of an XG and all the old gear swapped over, but spot-on Dean about the annoying parts randomness of Aussie BW diffs. My original diff build had a 25-spline LSD centre out of an EA, put into said XG housing that originally came with 28-spline open centre and axles. I had 3.27 gears but felt they were too short, so late went over to 3.08s when I had to replace the centre with one from an XD. I'd made a mistake when assembling the first build by shimming out the clutches too much, and the bolts broke that hold the halves of centre together. They came out and one got caught in a couple of gear teeth and bang! Still drove fine, but the centre was mangled from having no bolts holding it together. Only the carrier bearings were holding the diff centre halves together. It wasn't pretty. So the current setup has an XG disc brake housing, 25-spline 2-pinion LSD centre from an XD, and Commodore 3.08 gears. This is behind a 302 so the pissy axles are what I always think about when tempted to launch hard. Being XF, yours should have the same internals as XB. So I'll say a tentative "yes" to them being interchangeable. The usual setup with shims and preload needs to happen though, don't fuss hugely about tooth pattern, just as long as your coasting contact patch is ok and backlash isn't way out (aim for less than 10 thou at the crown). The drive contact pattern matters less because that will lap in over time. You really need a diff housing spreader if doing the carrier bearing preload properly. If you've got fresh carrier bearings, you need preload on them otherwise they will wear out quickly once you put power through them. If you can slide the carrier in without spreading the housing, you have no preload. Some like to get the preload close, and hammer the shims into place but that just knocks the crap out of them and that's the reason why good ones are hard to find now (diff bloke told me that). Do it once, do it right. Sent from my CPH1920 using Tapatalk
  8. gerg

    302 to 351c, help a young fella

    Yeah it sucks that engine reconditioning has become a niche industry, as opposed to the old days when a vehicle would go through 2 or 3 engines in its life and there were plenty of mobs around that would do that work. Nowadays, the only machinists/builders left can pretty much name their price. $880 is an insane amount. There's probably a couple of hours max in that job, I've worked at a reco place and the crank grinder would pump out cranks all day long. Also, consider just carving a bit out of each chamber where the quench area meets the open bit. You could take outba few ccs there. Costs you nothing and no piston thickness to worry about. Sent from my CPH1920 using Tapatalk
  9. gerg

    302 to 351c, help a young fella

    Most cam companies quote cam timing at 0.050" lift because that's the point where any appreciable flow starts to occur. Before that, it's negligible and 0.006" specs are only given to take into account pushrod and rocker flex, oil clearances, etc . Also to demonstrate the amount of cam ramp up; the 0.006" duration will be a lot longer than at 0.050" if it's a stock-type, flat-tappet grind. You'll notice on hydraulic rollers that the advertised vs 0.050" figures are much closer because the ramps can be made much more aggressive. So to answer your question, you'd enter your specs at 0.050" lift (if you have them handy). You can calculate the intake valve closing event at 0.050" from the other calculators on that page (assuming the cam is a symmetrical pattern), inputting LSA, etc. After a lot of reading about dynamic comp, an ideal figure for a street engine is around 8:1, getting up around 8.5 for a well-prepped, closed-chamber engine, up to 9:1 with an alloy head and racey fuel. Going too high in comp is an exercise in diminishing returns. Once you get up to the ideal, going higher only causes more problems for very little gain in HP. In my opinion, you should start with a camshaft and build the engine around it. If you want to use the cam you pulled out, make sure you keep every lifter in order so they're going back on the lobe they ran on. If you've mixed them up, throw the whole lot in the bin. One wiped lobe will mean a full engine pulldown to get all the shavings out. Trust me on this one, I've wiped 2 cams in 70,000km. If going for a new cam, Thom's recommendation is sound, as well as some offerings from Elgin (low-end and OEM spec cams) which some folks on here have used and have had good results with. I've used Crow and Precision's house brand (forgotten the name) but to be honest, I wouldn't mind an upgrade soon as I was a bit disappointed at the HP I got from the 208/208 I'm running. Great torque, just falls on its face after 5000. Some good rules of thumb: * Stock rockers and springs don't like lifts much above 0.5" * If you want to take your engine past 5000, or upgrade the cam, or go up in lift, you need to upgrade the valvesprings. * a narrow LSA will give a narrow powerband, a wide LSA will give a wide powerband. That's why towing cams have a pretty tight LSA. They're made for midrange. * The small parts will be what cost the most. The engine itself is pretty simple. Carb, coil, dizzy, plugs, leads, gaskets, nuts, bolts, water pump, alternator, all add up. Sent from my CPH1920 using Tapatalk
  10. gerg


    Oh dude.. sounds like your next project will involve those mounts, but I also heard that 429/460 drops straight in where a clevo goes, mounts and all. Sent from my CPH1920 using Tapatalk
  11. gerg


    There's about 12 kg going from 351C to 400, probably a few in the wider manifold, heftier 400 crank worth a few more again, the block is taller of course but all done, for the sake of less than an extra cement bag over the front axle, 50 extra cubes is well worth it. Going up to a big block is a massive jump in weight. 351C - 550lbs 400/351M - 575lbs 429/460 - 720lbs Sent from my CPH1920 using Tapatalk
  12. gerg

    302 to 351c, help a young fella

    Ok you got me bear [emoji23] All good advice here... I can vouch for that cam being a baby one. Good midrange punch with the narrow LSA, easy on rockers and springs with such low lift. I have that exact spec cam in my 302 but advanced 4 degrees (to give it better low down torque) but yes as mentioned, will nose over very sharply just after 5k. I would gather that you'd get 250 HP at the treads with this cam on a 351. My 302 got 196hp through a manual, on a mainline dyno (not as "happy" as other dynos generally) 40 thou is getting iffy on a clevo, most will advise never to go past 30, and on blocks this old, to get them sonic checked. It's extra expense, yes, but no point in doing even a light freshen-up if it's going to split a bore. 12.5 comp doesn't sound right to me. I know it will go up a bit with closed chambers vs open, but I think it's more like 10.5. You need to add in deck height, as most hypereutectic rebuilder pistons sit down the hole quite a bit so you add that to the effective chamber volume. Also piston dish has to be added. I have noticed that mine likes E10 the most out of all the fuels. It hates 91 (pings its arse off). 95 and 98 it runs ok, but drinks shitloads of each. We have to remember that fuels these days are 100% designed for fuel injection, and in the fuel companies' eyes, carburettors don't exist. Mine loves heaps of timing so I think a bit more comp will be ok. Mine sits at about 10:1 with a 0.025" head skim. If going up in cam size, comp will be even less of an issue for you. http://www.wallaceracing.com/cr_test2.php Have a play with that compression calculator. It's from a Pontiac specialist website but it works and their other calculators are pretty useful too. The dynamic comp calculator is great, this is what you build your engine around (using cam specs). Sent from my CPH1920 using Tapatalk
  13. gerg

    ball bearing in brake caliper?

    One of those "unexplainable" head fk moments... But maybe at some stage, for some reason, somebody mashed one into the flared seat to block that caliper off? I have come across some jobs where people have blocked off an air line going to a brake chamber on a truck, a "get you home" measure strictly and probably not a good idea in these days of transport safety regulation Sent from my CPH1920 using Tapatalk
  14. gerg


    Here's another angle: a 408 stroker 351W bottom end with clevo heads. Stroker kits were comparable to buying and getting the stock bits machined, haven't priced them lately though. Sent from my CPH1920 using Tapatalk
  15. gerg

    Old XC Crossflow engine...

    Yeah we used to have one back at the buses. You attach a water hose to fill the reservoir, and an air hose with a pressure reducing valve to charge it, and a release valve to punch it through the system at high speed. It attached to one of the heater hoses from memory. You leave the bottom rad hose off and watch the s*** come flying out. Sent from my CPH1920 using Tapatalk