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

[Westfield 129]

If the cams, rod bearings are OK, it is unlikely that abrasives are the problem. Abrasives in the oil would grind up everything. Wear to the cam and followers and cylinders would be evident as well as remains in the oil pan and filter.

Without the vibration damper, cranks twist and bend, failing the main and rod bearings while hammering the thrust bearings. Why was the damper omitted? Even race engines have dampers. I use competition, high RPM Romac or MED Engineering dampers on my A Series engines.

Incorrect clutch or flywheel installation can also cause problems.

Cranks are straightened (not reground) to correct any bend (the specialist crank shop that did mine preps cranks for NASCAR and other pro series teams). Most of the BMC A cranks that I get are out about a degree prior to truing. I have yet to grind an A series crank. The journals have all been to spec, requiring only polishing after the crank has been trued.

As for your 90K engine, you might just leave the short block well enough alone. Just inspect the inside of the oil pan and install it. Do a leak down test to check the rings and valves (unless you have a fresh or improved head, then install that). Leave the damper in place if it is in good condition. If it has slipped or is out of true, replace it.

My experience with the replacement of "just the shells" usually results in a failure requiring a rebuild. Leave it alone, or do everything. Feel free to freshen the cylinder head and install the cams, but leave the short block alone if it is not showing signs of stress (sparkly oil in the pan, excessive sludge indicating overheating).

If the thing has clean oil, no chunks or mud in the pan, and good cylinder leak down readings, leave it alone for the moment while you develop the rest of the car. It could be that a 90K engine might be just loose enough to make its best power with your improved cylinder head and cams.

[erictharg]

Worked out that if this used engine was good I might just have time to dress it with my head and cams and get it in the car in time for the Silverstone race on the 20th Aug. I was sure I needed to run a damper this time to eliminate one possible contributor to the previous failures. I mocked up the front end using my old engine and a stock but damaged damper I had. Because the damper pulley diameter was bigger than the aluminium one I'd been running I also needed to use the bigger stock water pump pulley to avoid overspeeding the pump. This also meant shifting the alternator bracket rearward slightly to get the three pulley to align. Then I measure up the resulting length of 4 rib belt and ordered one from an on line bearing company. I also ordered yet another oil cooler.
Drove up to Biddulph (just north of Stoke) Monday to collect the engine from a specialist Mk1 MR2 breaker. Back to the workshop by 3pm and stripped all the stock hardware and cylinder head of the used engine. Looked promising. Genuine Toyota oil filter fitted, cams unmarked. Bores were perfect - no wear ridge or scoring. Decided not to disturb the bottom end so didn't even remove the sump. Ordered a stock head gasket from my local Toyota dealer.
Tuesday after work (fortunately a short day delivering beer!) built up the front end and fitted my flywheel and clutch. As I didn't have my new head gasket I loose fitted the head to facilitate installing the engine and gearbox as they need to go in together, and the head provides the best lifting points. By the end of the evening the engine and box were all in place awaiting the head gasket. Big delivery day Wednesday so no more car work but I did manage to collect the gasket on my drayman's rounds.
Had to drive up to Leeds Thursday am to collect my new daily driver (2007 Cayman) and found the poly v belt had arrived when I got back home. Rest of the day saw the head back on and all ready to fire up.
Friday early I fired the engine up and it sounded and looked good. Great oil pressure! Did a couple of runs down the bypass to check it would rev out OK and then set to loading up the 110 and trailer ready for an early start Saturday (0820 scrutineering means leaving home 0615 'ish...).
Unloading the car at Silverstone I noticed an ominous ticking from the engine. The noise that says either head gasket or exhaust manifold leak. Manifold please god! No time to investigate before practice. Practice went well gradually stretching the engine to over 7000 rpm and full throttle. Track was wet so a lot of "oh shit" moments but no complete spins. Started backfiring on over run suggesting a manifold leak and sure enough when I got back to the garages you could see the signs of the manifold gasket leaking. Soon fixed with a dab of high temp RTV. Phew.
First race went well on a dry track. Hitting just over 7000 rpm at the end of Hanger Straight. Not quite as crisp as my previous build but then it is a 9.5:1 CR vs. 11:1 on the earlier engine. Water temp good at 75 deg with 20 deg ambient. Oil pressure brilliant staying between 55 and 75 psi hot. Still around 1 to 1.5 seconds a lap off the times of the group of cars just in front of me (GT40 replica, D Type replica and IMSA styled 240Z) but I was a little rusty and still being careful with the engine.
A check over back in the garages showed all to be well apart from an oil leak from the rear crank oil seal. Not terrible but enough to coat the tunnel and floor with oil. As always with oil leaks you couldn't notice it on the dipstick - a little oil goes a long way.
Second race I was going harder and time was close to the cars I was chasing. Then things got messy. Oil at Stowe (D Type engine blown) so cars spinning all over the place. Missed them OK and made up a few places in the process. A couple of other corners were noticeably slick also and then coming down Hangar Straight a Mustang Mach 1 got past me and as I followed him he caught yet more oil exiting onto the start finish straight, fishtailed and then into the pit wall hard. Ouch! Race was red flagged and game over.
So, mission accomplished. One more race this season at Donington, a circuit I like. I won't change anything before then except for a new exhaust manifold gasket and the carb balance needs re-setting. And all the leaked oil needs cleaning up.
So my 90,000 mile engine now has some 50 race miles on it. Do I just build up a stock of old engines to swap out as necessary, or re-build this one over the winter? Given it was hitting over 7000 rpm at the end of Hangar, that is likely to be over 7500 at Kemmel, Spa, the longest straight I'm likely to see. So I think a good bottom end re-build with decent rods and pistons is wise to ensure reliability. Plus, I really don't want to have to carry a spare used engine with me to every race.
In hindsight I think there was dirt or debris somewhere in my old block that the machinists washer did not get to. The scoring of the old piston's skirts says big bits of grit / metal from somewhere. Will have to sell my bike to pay for another build but it doesn't get used anyway when I'm racing. Anyone want a very modified track focussed 2002 Ducati Monster or a tidy 2005 MX5?

[Splat]

Brilliant news! So glad to hear of success. Finally!!!

Would there be any sort of "economy of scale" in having two good "race" engines built in parallel over the winter? A deal to be struck on eight rods and Pistons, not four? two heads flowed rather than one? (Yeah, I realise you've already got one of them!)

When's Donington?

[Westfield 129]

Excellent!

I have raced several stock short blocks with heads and cams (Ford and Chevy V8s, Alfa 1750s, Renault R5T2s), backed up by improved cooling, lubrication, and a better, high RPM race crank damper (the stock started to come apart after one event. Fortunately, I was able to drive the thing home without incident). It's one way to go, and a lot of successful racers do it (and have to do it in the showroom stock classes).

I have also built quite a few of my own engines, with success and no failures or regrets.

In order to get the best out of yoru cams and head, you need the extra compression that a rebuild would require. In addition, the blueprinting of the block can extend its life at high RPM and stress levels.

Starting with a running engine with a known history (even the short history you have with your successful 90K mile engine) is always a good thing to do. You know that your current engine doesn't have any shrapnel in it, so grit wont be a problem. The crank is likely fine, requiring only polishing and balancing. Same for the rods, which should be resized with new bolts. Truing and setting the deck height, line bore the mains, unplug the main oil galleries for a flush and isntall threaded plugs if appropriate. Replace the freeze plugs. Bore to suit. Short blocks are pretty simple, really. Select some good pistons.

It would be better to rebuild the engine you have now, prior to breaking it, to eliminate any of the usual variables, such as pieces of pistons in the main oil galleries and bent cranks. it is likely that this rebuild will be successful.

Meantime, find another engine that runs and put it in the car so you can continue to enjoy the sport. You might not have to sell your Ducati (Which I would like to purchase, had it been in my neighborhood).

Oh, and don't forget the crank damper. Make sure that it is true and not on the verge of failure, or find a competition version.

[erictharg]

Thanks guys. Crank damper is in good shape and will carry over. I will as you suggest acquire another spare engine, just in case. Current engine feels a little soft vs. the previous two - because mainly the CR is lower (as y'all know - a major factor in engine performance).
Again, as you say, this engine's pedigree is known, and it will be the basis for a be build with forged hi comp pistons and some decent rods to give me a bullet proof bottom end.
Donington is 1st Oct. Love to see any of you there...