Engine Improvements Recommended?

[PatGalvin]

I'm just wrapping up the brake lines on my TR3A and getting ready to pull the greasy engine out of storage and start tearing into it. I have no idea what shape it may be in but it doesn't turn over - appears frozen.

What is the list of "must dos" while I've got this torn down and at the machine shop. My goal is to improve the engine a little and make it run slightly better than new; however, I do not want to build a high revving race engine. I love the low end torque that I remember so well from my college days.

I'll have the machine shop go through the block, head, crank, and rods and check for cracks or structural problems. Will have the crank modified for modern rear seal. Will take machinist recc's for align bore/hone and resizing big end of rods. Will probably regrind cam with mild street grind.

What about heads? Head is probably set up for leaded gas so can fit new hardened valve seats. Should I replace all guides, springs, and valves? Is it worth having these guys clean up the compression chambers and intake/exhaust ports for better flow? What compression ratios are favored for a "fast road car?"

Any tips on things that are "must dos" or other recommendations are much appreciated.

Pat

 

[TR3driver]

I would certainly replace the valve springs. If you're looking for a bit more power, I would also suggest converting to the TR4A style exhaust valves with the smaller stems (which requires special 'conversion' guides, available from the usual suspects).

Port work is risky, IMO. From what I've been told, it's easy to make it flow worse, rather than better! Even just polishing and port matching can have a negative effect. Pick up a copy of the Competition Preparation guide to see what does work.

Of course, I assume you'll be going for at least 87mm liners. You might consult your wallet and see if 89mm are in the budget (available from BFE). Might also be worth consulting Larry Young, to see if he has any cams left or would be willing to have yours ground.

 

[Mickey Richaud]

What Randall said.

And don't forget: Balance, balance, balance. Best thing you can do for the parts that go "whirr".

 

[Bremer]

Ditto on the 89 mm bore kit.
Besides internal engine work, you can pick up quite a bit of horsepower by replacing the stock exhaust manifold with tube headers and fitting a free flowing exhaust system. Also, the mechanical fan is a power thief at higher rpm, consider converting to an electrical one.
There's more to be had, if you're interested you can look into Kas Kastner's books and/or his forum.

 

[tdskip]

You might consider taking a small bit of weight off the flywheel as well.

 

[PatGalvin]

Thanks for the replies. Herman van den Akker (HVDA Toyo tranny conversion) gave me a drawing and showed me how to remove about 7 lbs from the flywheel so that will be in the machine shop work order.

Does anyone have any experience with 89mm pistons/liners? Basically, any problems with reliability? I know they aren't cheap but probably cheaper than significant head work. The small stem TR4 exhaust valves sounds like a good move too.

Any good source for tubular exhaust manifold and low restriction exhaust system? I'd don't prefer the Monza exhaust with the dual tip exhaust pipe. I like the looks of the single pipe exhaust behind the car.

 

[TR3driver]

I don't have my 89s in yet, but according to Ken @ BFE the only issue is keeping the bigger motor cool. More displacement = more power = more heat. Based on past experience, I don't expect to have any serious trouble, but if so, I'll cross that bridge when I come to it. I will be installing my stock radiator that has been recored with a modern Modine core & no crank hole; plus a Hayden electric fan configured as a puller and a 10 psi cap. The wrecked 3A had no trouble running 90+ mph through the desert in 100+F heat with that setup, so I expect it will work again.

If you are interested in going lighter on the flywheel, Joe Alexander made some new ones from billet steel. I don't recall the weight offhand, but they are pretty light compared to stock. Of course the alloy Fidanza I'm running is lighter yet

But lightening the flywheel does reduce apparent low end torque to some extent (making it easier to kill the engine when launching), so it's your call.

Sorry, no help on the header. Moss used to sell a nice 4-2-1 setup in mild steel, but AFAIK it's no longer available. (I bought mine because I heard they were closing them out.) And I plan to keep my copy of the factory exhaust, two Cherry Bomb seamless glass packs. I might add a chrome tip, but then again I might not.