356B T5 engine rebuild question

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Marc Walz
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356B T5 engine rebuild question

#1 Post by Marc Walz »

I will start to rebuild the engine of my 1960 356B T5 Coupe. The engine is the 60hp version.

I would like to upgrade it with a NLA or AA big-bore kit 86mm/1720cc with forged JE pistons and Biral cyclinders at least if you guys have no other recommendations. Can you guys also recommend a matching cam? I would like to have a bit more torque and power in the lower/mid rpm‘s, the car is used just for the street, no track use. Should I go with the SC cam?

As mentioned above I would go with the light JE pistons, so I can keep the stock 50mm crankshaft. Is this something I can do or should I upgrade to the 55mm crankshaft to be safe?

I would rebuild the heads to the stock specs with stock valves. As a preventative measure I would weld the heads on the spots where they usually crack. Any concerns?

I‘m not sure to stay with the stock carbs, as on all my 911 I run Weber‘s which I‘m very familiar with.

Do you guys have any other helpfull suggestions which I should add to my setup list?

Looking forward to hear your thoughts.

Thank you
Marc

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Doug McDonnell
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Re: 356B T5 engine rebuild question

#2 Post by Doug McDonnell »

Marc When I rebuilt my 356C I wanted low end torque rather than high end HP and it sounds like you are thinking like me for your rebuild. You will need to have your Normal Zeniths rebuilt to later Super or C specs. If you do so they will provide more torque than Solex or Webers below 4500RPM which is where most of my driving is done. At the time of my rebuild Vic Skirmants was selling his "High Torque street Cam" which was an Elgin 66508 very close to the current 66509 that Elgin still sells. https://elgincams.com/porsche356-912/
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Mike Wilson
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Re: 356B T5 engine rebuild question

#3 Post by Mike Wilson »

Great advice by Doug and welcome, Marc.

Mike
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Marc Walz
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Re: 356B T5 engine rebuild question

#4 Post by Marc Walz »

Thanx Doug for your advice, so Elgin 66509 is the cam to go. Did you also upgraded to 1720cc?

Are there Zenith Super/C spec rebuild kits available, or what exactly are the Super/C specs? 8)

Did you ever dynoed your engine btw?
Last edited by Marc Walz on Sat Jul 30, 2022 4:34 pm, edited 1 time in total.

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Ken Tuvman
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Re: 356B T5 engine rebuild question

#5 Post by Ken Tuvman »

Hi Marc - mine is a 61 Super - bought cam, pistons cylinders from Leonard @ Shasta Designs & a forum member Dick Weiss assembled case - case was ultrasonic cleaned, he overhauled oil pump & rocker arms. Oil cooler sent to pacific oil cooler in CA & cleaned, pressure tested & painted. 356 CR overhauled carbs & BR18 distributor & fuel pump kit to overhaul it.
Bearings from Stoddard - crank was inspected & cleaned,
Getting bottom end right is key to good oil pressure & so important!
Heads also cleaned up / new valves & springs (mine had been raced & has Oversized valves - I believe to SC specs.

Lotsa good advice/ experience here - welcome & good luck!
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Marc Walz
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Re: 356B T5 engine rebuild question

#6 Post by Marc Walz »

Ken, thanx for the shared experience.

So no needs for an external oilcooler?

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Doug McDonnell
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Re: 356B T5 engine rebuild question

#7 Post by Doug McDonnell »

Yes I used an AA 1720 kit No I never dynoed the engine. Since the C has the larger valve size (same as SC and 912) Jetting was slightly different on the C carbs. Seems to work well out of the box with the 1720 kit. I have owned 63 Super with Zeniths 65 SC Big Bore and 912 Big Bore with Solex carbs and now 1720 C with Skirmants High torque cam. Very nice low end torque.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Re: 356B T5 engine rebuild question

#8 Post by Jay Darlington »

I rebuilt my 1600 A with a big bore kit, an SC wide lobe cam and 40mm Dellortos. i set my comp. at about 8.5/1 and run an aftermarket exh. and the 123 dist. we ran it on a friends dyno to do some jetting and adjustments, it put out 100hp at 5500. the engine runs real good very happy with it, its just a cruiser.
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Doug McDonnell
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Re: 356B T5 engine rebuild question

#9 Post by Doug McDonnell »

If you keep everything the same you will feel a slight increase from stock Normal with the 1720 kit since the Normals had lots of low end torque. So were you happy with the Normal or do you want more power across the rev band? 1720 kit with the rest of your engine unchanged would probably give you a 5% bump in power. If you want more then more changes will need to be done. Desires and wallet will at some point come into conflict the higher the power you want.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Re: 356B T5 engine rebuild question

#10 Post by Don Gale »

When you choose your pistons, make sure you match the piston top angles to the head, 22 degree vs. later C/912 30 degree chambers. Also if you're changing the cam, it's a good idea to temporarily assemble the long block without the rings, install the rockers, and clay the heads and rotate the crank by hand a few revolutions. .040-.050" minimum clearance between pistons and valves.
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Re: 356B T5 engine rebuild question

#11 Post by Dave Erickson »

Make sure the pistons and heads match. If your heads are original then they are machined at a 22 degree angle, so you need 22 degree pistons.

Welding the heads where they usually crack does not seem like a fruitful exercise. They usually crack between the spark plug and the intake valve seat, and the repair requires removing both the spark plug helicoil and the seat, grinding out the crack then rewelding and remachining. If your heads are uncracked, I suggest that you leave them as is. If they are cracked, good new or used heads are available for less than the cost of the repairs.

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Doug McDonnell
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Re: 356B T5 engine rebuild question

#12 Post by Doug McDonnell »

Excellent point Dave. I am biased because I started with a C which has the low end torque of a Normal and the high end power of a Super engine and the larger valves. Which is why I previously stated "Desires and wallet will at some point come into conflict the higher the power you want."
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Re: 356B T5 engine rebuild question

#13 Post by Martin Benade »

If you keep the Zeniths (a good idea) along with jetting them like a C don’t forget the larger venturies. Shasta p&c are well respected, medium priced. As for A&A most people would choose plain iron over the biral. Sometimes simpler is better. I think the lower cost ones from Stoddard are A&A.
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Ken Tuvman
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Re: 356B T5 engine rebuild question

#14 Post by Ken Tuvman »

Marc Walz wrote: Sat Jul 30, 2022 4:38 pm Ken, thanx for the shared experience.

So no needs for an external oilcooler?
I chose to stick with stock setup - others here are big on external oil coolers.
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Jules Dielen
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Re: 356B T5 engine rebuild question

#15 Post by Jules Dielen »

I would go for an aluminum cooler. Much more efficient and invisible.
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