Another 4.6 Build

[John]

Those are indications that you need a new machinist.
John

[dwg86]

You are so right. I will never use them again.

[4point6]

I've been thinking about reusing the existing camshaft (from a 1997). It has 194k miles on it, so I measured up all the lobes and journals and compared to original. Journals check out right on. Lobes have some wear:

1: 0.007 loss (Exhaust), 0.006 loss (Intake)
2: 0.004 (E), 0.007 (I)
3: 0.006 (E), 0.007 (I)
4: 0.001 (E), 0.004 (I)
5: 0.002 (E), 0.004 (I)
6: 0.005 (E), 0.003 (I)

Above #'s are measured at the lobe

There still is about 0.0005-0.001 difference across the lobes, so I think the lifters should rotate. My question is, would you reuse this cam? I had been planning on using a replacement that I got with a rebuild kit (Melling I think), but it is the narrow lobe type, and I'm worried about the new cam failure problems.

-edit-

Another thought I had was to regrind the stock cam. Since I had to deck the block about 0.040, would regrinding help with the shim/pushrod/valve geometry issue? I figure it would. Any idea what it costs to grind a cam?

[4point6]

After a long hiatus, here is the latest update…

Stroker is done! Finished it about 2 weeks ago, so far I have about 1200 miles on it, and it runs great so far (fingers crossed).

Here is a write up on how it all went together, picking up from my last post:

So I decided to go with the new 87-95 camshaft, and keep the original one in storage just in case. So with that decision out of the way, I got going on putting everything back together. With the cam installed, the crank was next. The crank I ended up with was 20 under on the mains, 30 under on the rod journals. The machine shop I used was having a hard time tracking one down that was in decent shape. They got a crank kit from somewhere in NC, it is the lighter weight one (87-90). I should have just gone with one from an old block I could have picked up a while back. Clearances were all plastigauged at 0.002 to 0.0025, so that was good. Rear seal installed no problem with some anaerobic sealant. Journals were lubed up with some red assembly lube from Autozone. I was going to some gray graphite (I think) assembly lube from Napa that was supposed to be for this purpose, but the machine shop guy said no-no, that can clog up the oil passages. Just use the gray stuff on the cam journals and distributor gear.

Anyway, dished KB2229 pistons went in next, with the shorter 258 rods already attached by the shop. When I got the assemblies back from the shop, the caps were on pretty tight (new arp bolts). I had to slip each one over a wooded dowel, loosen the nuts so they were right at the end of the bolts, put a socket on the bolts, and tap the socket to get them off. Plastigauged the rod bearings , these were ok also. The machine shop went too far with the decking, as far as I could measure with my tools, pistons were only about 0.001 or 0.002 in the hole instead of 0.007 I had wanted. I ended up cc’ing the pistons in the hole; piston dish and ring land volume was around 24 cc. That combined with the cc of the head (58.5 cc or so after the head was planed), and the 0.043 gasket I was going to use left me with a CR of like 9.39:1, so I ended up using a 0.052 head to get the CR down around 9.20:1. Quench is right around 0.052 or so. Looking back, I should have had them dish the KB2229 pistons a little deeper so I could get a little tighter on the quench (I had him go to 0.180” total depth for the dish).

With that out of the way, assembly continued. Installed the timing chain and oil slinger – line up the dots on the crank and camshaft gears. Noted two things here – the FSM and also the Haynes says to count the links between dots, it should be 15. I counted 20. Their picture showed like 50 something links total (I think). I counted like 60 something on my new chain, also on the the old chain. I figured the dot alignment was correct. I also noted that the crank bolt is different between the 4.0 crank and the 258 crank. Next was the timing cover, in which I had installed the new crank seal. The FSM said to use some custom tool to align it with the crank, I ended up using the vibration damper to get it centered. Which is a pain, because you have to take it back off again to get to 2 or 3 of the timing bolts. Cover was sealed up with some RTV black and new gasket.

Oil pump and gasket were next. I used a regular volume pump. The hardest part here was getting the new screen on the pump – I used a crescent wrench (5/8” I think) around the base of the screen tube, and tapping in each side with a hammer until it seated. When I was about half way, I put a thin bead of RTV black on the outside of the tube, just to be sure. I wiped up the excess RTV after it was all the way down.

Oil pan was next. I cleaned this out with brake cleaner and a lot of rags to get all the crud out. Installed a magnetic plug to pick up any metal bits and pieces. New one piece gasket on the oil pan, also some RTV black. Torqued all the bolts to spec. Note – before you take your oil pan off, mark where the studs are vs. the regular bolts. I didn’t do this, and just guessed at every other one or so. You need these studs to attach the transmission coolant lines and O2 sensor wire support.

With the bottom end all done, flipped it over to start on the top end. Water pump was next with new gasket and some more RTV.

My stock head was too warped to reuse due to overheating (machine shop said like 0.025 to get it straight again), so it ended up being the guinea pig for my mild port and polish job. Machine shop had a 7120 head that they sold to me which I ended up using. I basically cleaned up the casting flash and smoothing things out. Also narrowed down the valve guide areas, and cleaned up the short side radius, and gasket matched the intakes only. Cleaned up the chambers a bit. Sent that back to the shop for the 3 angle valve job.

Installed new lifters, with the graphite stuff on the bottom, red assembly lube on the sides and top. Cc’d the combustion chambers as noted above. I put the 0.052 gasket on, and then the 7120 head. Minor note – my stock head had alignment pins, 7120 doesn’t. I used two pieces of threaded rod at opposite corners to help align the head as it was installed. Torqued all the bolts down to spec, with the sealant on bolt #11.

Next step was to check the lifter preload. I had drawn some things up in cad to try to figure out what happened with all the decking, and I ended up buying shorter push rods (9.594” I think, the ones for an older 258) based on my drawing. In the real world, I measured a little too much preload even with the shorter rods, so I also installed some thin shims (I know, I know, not the best solution). I got the preload around 0.035”. After I did all of that, I ended up taking the rockers off, and checked and recorded the cam lift at each lobe. I plan to track these measurements every 5k miles or so to see if I am losing any of the lobes, as many have before. Then put the rockers back on. Before putting the valve cover with a new valve cover gasket, I screwed in the heater tube into the water pump.

Thermostat housing and new thermostat (180*) went on next, then some of the miscellaneous brackets and mounting hardware. 99+ intake (with bored 62mm TB, sensors, stock 23.2 lb injectors, and fuel rail already installed) went on next, along with the new header. Finally ready to put back in the XJ.

Reinstallation was pretty straight forward. Once it was in and all the sensors hooked up, I filled it up with Delo 400 and a bottle of EOS, and primed the oil using a drill with a flat head screwdriver with the handle cut off. Oil pressure was good.

Next step was to install the distributor, spark plugs and wires. Next I filled it up with coolant. I had a little bit of a scare here. As it was filling, I could hear fluid leaking to the ground from the rear of the engine. Not good, since there are no hoses back there. Turns out the 7120 head has an extra hole for a sensor (not required for my 97) that I left open. I found a short bolt with the right thread (I have no idea what size), coated it with sealant, and installed it. After that, no more leaking fluid. So I finished filling the coolant.

Double checked everything, and went to start it up. Cranked nice, but would not turn over. Not good. Double checked everything again, and then decided to check the distributor. Turns out I had installed it 180* out of phase. The trick, from the FSM, is to feel for pressure on the spark plug hole, then rotate the crank until the mark on the vibration damper lines up with the 0* advance mark on the timing cover. Set the slot in the oil pump at 11:00 (looking at the engine from the passenger side). Set the distributor shaft to the correct position – there is a hole in the housing, and a hole in the rotating plastic piece inside – place a dowel through both to lock the rotating assembly in place. Then drop the distributor in with the hold down tabs at about 1:00. The whole assembly will rotate clockwise as the drive gear engages the camshaft, and the hold down tabs should end up exactly in the right place for the hold down screw on the block. If you are 180* out, these don’t line up exactly right – I had wrestled with getting the tabs and the hole lined up when I first installed it. I think maybe there are an odd number of teeth in the cam which causes that.

Once I got the distributor all set, went to start it again – nothing. Turns out I forgot to plug the coil wire back into the distributor. Tried again - it started right up this time. No CEL’s. Oil pressure looked good. A bit of smoking as all of the residual fluids burned off, but otherwise good. I brought it right up to 2000 rpms, and ran it for about 10 min until I noticed that the coolant temperature gauge hadn’t moved, so I shut it down to investigate. The plug connection housing for the sensor fit like it was connected, but the wires in the two housings were not connected. I had the wrong sensor. Once I got a new one of those, I started it back up and watched the temp – it leveled off right above 210. So I ran it for about 20 more minutes at 2000k, then shut it down and changed the oil.

Replaced the oil and filter, this time with Rotella T and another bottle of EOS. No particular reason for the switch from the Delo 400, that’s just what was available. With the oil changed, it was ready for a test drive and engine break in. I also reset the computer at this time.

The engine definitely has more power than the 4.0 – low end torque is good. But what really makes it nice is the extra power at speed. There are a few hills on the highway near my work, that pretty much slow everyone down as you get near the top of them. I could maintain 70 going up this hill, whereas before I would have to move over to the slow lane, and be at like 50-55 by the time I got to the top. I had same problem with my Explorer (4.0L SOHC).

Also no pinging! And so far I am getting around 19 mpg, with about 80% highway driving at 75 mph. I’m keeping track of that also.

I’ll put together the build list and price, some pictures, and some more thoughts when I get some more time.

[4point6]

Some additional thoughts regarding my build:

When upgrading to the newer 99+ intake, I had to extend the intake air temperature sensor leads and also one of the small vacuum lines to reach the fittings on the new manifold. Also the one I got had an extra small vacuum fitting which I had to block off (Autozone sells caps that do this).

When installing the bored TB, I matched the opening in the intake manifold to the TB – there was about 1/16” or less of material to be removed from the intake. This is to provide a nice smooth flow from the TB to the intake. I used a dremel to remove this.

If you are dishing your pistons, make sure you are confident in your machine shop. The dishes on mine were ok, and done partially by hand, so I am sure the dish volumes are a little different between the pistons. I think Oleshot on the board does them, also there is another guy (or maybe its the same person?) Jeff Leigh Machine that has a CNC set up to get your dish to the right volume. He did my TB, it came out really nice. I think my guy ate some dollars dishing my pistons, because I told him I could get them done for $120 elsewhere, and he matched the price. Also remember there is a little volume in the piston ring lands, maybe 1 cc or so.

If you are doing a build like mine (decked 0.045+), plan on getting new push rods, probably better to get custom length ones once you measure the preload. I’m not crazy about the shimming I did, but it works for now.

Have your shop mock up the crank and pistons to measure true deck height before figuring how much to take off the block. Otherwise you might get into trouble. I think I lucked out since I was planning on the 0.043 gasket, and I could fall back to the 0.052 gasket when the deck height was too low for my desired CR.

Camshaft – personal preference. I would have gone with my stock 96+ one if it wasn’t for the difference in lobe wear. I think this one will give more low end torque, based on some computer simulations I did. The 87-95 one has (theoretically) higher torque, but it is in the upper end, and I’ll probably get to 5k rpms rarely to actually see the add’l torque and HP there.

Make sure your head checks out ok before doing any porting. Luckily I had the shop check out the original one first before I got into the porting. I had to get a new one. Also, one tip they had, that worked out well for me, is not to hot tank it until after porting. The black carbon makes a good contrast to the areas you already hit with the grinder, so you can easily see where you still need to smooth out.

[4point6]

Update:

About 2,000 miles on the stroker, still runs well. Still getting around 18-19 mpg. I just installed rusty air tube with the K&N filter. Seat of the pants dyno: seems to have more power in the 2000-3500 rpm range. I'm monitoring the mpg's with the new tube. I'll probably change the oil this weekend, also I want to install an map sensor adjuster. I already built one but wanted to see how it worked without it, so I haven't installed it yet. I have gotten a few pings at WOT on hot days, but very minor. Any idea if adding the map sensor adjuster will add power (assuming I increase voltage)?