Toyota 4AGE into Eleven will go (one way or another)

[allymally]

Hi Charles any figures yet ?

[erictharg]

Hmmm. Well. Saw 144 hp briefly at 6500 on the first baseline power run (promising) and then the bottom end seized. All held together fortunately, but subsequent stripdown showed melted and spun big ends, badly worn mains, scored piston skirts from the bearing debris, and worst of all the low oil pressure had resulted in the cams and cam bearings starting to pick up.

So, all the bits at the machinist for their view on what is salvageable. First view is that the pistons skirts will polish out. Crank is re-grindable. Rods may not be salvageable. Block just needs a good clean out and touch with the hone to refinish. Cams should polish out and cam bearings should be honeable. If the rods are scrap I do have a set of both 40mm and 42mm stock rods that would work OK to 8500 with ARP bolts. I've already bought a new oil pump and oil cooler - neither safe to re-use.

It's also given me the chance to replace all the gearbox seals and I've bought a new 7.25" Helix clutch cover with a sensible spring as opposed to the used one that came with the engine bits that was way too heavy.

Big question is what was the root cause? Machinist thinks the big ends were where it all started so they were likely tight on assembly and gradually failed from there. I should have dry fitted them to the crank and plastigaged them before fitting into the block with the pistons. On reflection it seems that the rod and cap markings that I assembled with the i.d. markings to the same side may have been incorrect (even though that's how you'd expect them to fit). So much for the very pretty but un-branded billet rods.

So, bit of a bummer but that's what happens when you build modified engines and don't double check everything. You'd think I'd learn by now!

[Splat]

Hugely annoying, but nothing that can't be overcome for what sounds like a very promising final outcome!

[jonclancy]

Oh bugger!

Makes my #2 rings unbedded problem look mild.... Sorry to hear this, Charles. Hopefully, you'll be back up and ragging it on the dyno soon.

[erictharg]

Spoke to the machinist today and he thinks the rods are salvageable, and also confirmed that I fitted the caps correctly - so root cause still uncertain. Piston skirts will polish out and re-coat. Crank can be re-ground. Block will need a light re-hone. Cams and bearing bores need cleaning up. So just a question of time and money... and this time both he and I will be double checking everything! Meanwhile I'll do some more research on brakes. And establish for sure if I need to use a frontal head restraint this year for racing. Hope not as that's another £400 or so. MSA say pre '76 cars don't need to use one. Can't be certain until the first event. One of those things you don't want to ask about in too much detail as their fall back position will always be to use one.

[Westfield 129]

Sorry to hear about your misfortune.

I always do a full "blueprint" of the engine block, crank, and rods. This includes re surfacing the deck, line boring and removal of the oil gallery plugs for complete cleaning. This gives me a pretty accurate engine build kit that has served me well through numerous engine builds.

I know a lot of people who have to do two rebuilds. One that blows up in the first 5 hours, and a second, that lasts. Generally, the first is just a standard rebuild. with perhaps only a crank regrind but no truing, no rod resizing and no line boring. Usually, the only block work is a "hot tank". In most cases, the builders didn't take the brushes, detergent and water to the oil galleries ("cause they didn't remove the main gallery plugs for a good clean out). All to save money, I suspect.

While there have been many enthusiasts who think I am crazy to have the rods resized and bushed in ALL my engines, I have found the cost to be of little consequence when the total cost of the engine is figured. Of course, along with the rod resizing and balancing, I also true the crank, and regrind if necessary. Oil holes are chamfered or cross drilled if necessary. My experience with the BMC A series cranks is that I usually don't have to grind them, polishing the journals and re assembling with standard sized bearings. Note: If you replace rod bolts, the rods must be resized using the new bolts. I always replace the bolts with ARP fasteners.

Then, I have the deck height set. Since I am truing the block surfaces (I always resurface the block as well), the crank has to be dropped into the block on the new bearings, along with the resized rods and new pistons. This makes the machinist to check his work, and make sure that the rod and crank bearings are properly matched and fitted.

When I get the block back, the oil galleries are opened, and the new access plugs are threaded. These I install with Hondabond or similar sealer on the plug threads.

By having my machinist check the clearances (well, he is matching all the parts), I eliminate the clearance issues (of course, your machinist must be reliable), and by opening up all the oil galleries, the likelyhood of grit ruining my machinist's work.

And even then, I check the work, and use lots of assembly lube, along with a fresh oil pump that I pack with oil to ensure a quick oil pressure rise.

In the case of your block, I would definitely line bore it, true the deck, give the crank a thorough inspection, and resize the rods.

As for the "frontal head restraint" or HANS, get one. If you are racing, it doesn't matter how old the car is. If you run into something, it is the only thing that will keep you from snapping your neck. Like your roll over protection, helmet and driving suit, the HANS is becoming mandatory everywhere, and its saving lives and preventing serious injury. If a roll bar is required, get a HANS, even if it is not required. Stuff happens...

[jonclancy]

Off topic, but I was looking at the Simpson Rage restrain device a while ago. Protects against side impact too, where a HANS device apparently does not.

[erictharg]

The argument about HANS in club level motorsport is that of risk versus cost. Fortunately serious accidents are very rare. Injury levels are way less than most popular amateur sports. I'm much more likely to be seriously injured riding my mountain bike than when racing my car.
As with most things in life it has to be about compromise. Given unlimited funds would I buy a top spec HANS? Of course I would. Club level motorsport is dying out due to cost. It is increasingly becoming the domain of kids with rich dads who fantasise about being a pro driver. Or middle aged wealthy men who want to live out childhood fantasies (not that there is anything wrong with that).
So as most "ordinary" competitors like me struggle to get to each event and keep our car on the track, the decision to spend a significant amount of money to mitigate a small risk should be ours. To enter the most basic form of club level circuit racing costs a driver £1500 just in basic mid range safety equipment. All of which is lifed very conservatively (driven by manufacturers lobbies). So if you are in a position to buy a HANS and top range suits and helmets good for you. But I'm not and I resent anyone telling me what risks I can and cannot take with my life. If I have to run with HANS I'll buy one as I'm committed to racing for a few more seasons yet. But it will mean one or two less races I can afford do this year.

[erictharg]

Good news is that everything is salvageable. My machinist has also done a better job of the valve seats / ports with a 5 angle exhaust seat finish and a full radius for the inlets. When he took a good look at the crank he discovered the likely root cause of the problem. The blind oilway drillings were filled with a mixture of bearing debris and glass beads. Seems at some point the crank was bead blasted (god knows why) and either the bearings and oilways not masked well or at all. I pipecleanered the cross drillings before assembly but there was likely blasting media sitting in the blind oilway drillings just waiting for some oil to come along and mix with it into a lovely grinding paste. Should get the head and cams back Monday to shim the valve clearances then the rest by end of the week.

[Splat]

That's great news. We're enjoying following this!