Ducman82

i was using my ipad to type that. i had to go pick up a deep socket to get a better angle of attack on that bolt. once i get the block apart, and see whats up, ill have a better idea what way to go. seems i cant loose either way.

danglerb

Harbor Freight sells a nice cheap 24" breaker bar, you will need some torque to get the heads off, but also some control. I like to break loose in a cross pattern, then do each nut a couple turns in the same cross pattern.

I would wait on deciding until after you know the condition of the 5.0L block, cylinder walls, and pistons.

OTOH if its all good I don't see any disadvantage except cost to more displacement. For myself I don't have any plans to build anything smaller than 5.0L.

Ducman82

so here is what i found in the 5.0 number 6 spun a bearing. now here is the million dollar question.... it it worth getting the crank fixed (im sure the machine shop can), and get a new rod, and cut the pistons (greg can do that, i dont trust my self) OR get a new rod for the 4.7, and get that one together?????

choices.... ugh....

Hilton

Its beginning to sound like you should just buy a stroker crank, custom rods, 968 pistons and get the 5;0L block bored..

In your shoes, I'd take the path of least resistance to getting a running 928.. put the 4.7L Euro together with a replacement straight rod, and plan a new engine build using the 5L block at your and your wallet's leisure.

mark kibort

find a good 5 liter 85 block and get the pistons cut. dont even take the crank out. re-ring it and be done with it. (with new rod bearings as the only mod). that way, you will know what you have is going to work well.

BC

Honestly Jake - for what you are going to get from just .3 LESS (BTW - you can use the rod from that 5L in the 4.7) liters, you should just continue with the 4.7. The expense of the valve reliefs, etc was going to get expensive.

The 5L BLOCK itself may be of use to you over a longer period of time.

Ducman82

I just got back from dropping the blocks and cranks off at the machine shop. going to get everything tanked, cleaned, checked. i could not get the dampener bolt out, so im going to let them do that, along with the old head studs. Mark, this block is an 85. the 4.5 i have now has no major issues at all so im going to run it whilst i build one of these bad boys.... or both!

FBIII

It doesn't look look like the crank got hot, but the cases would need to be split and the crank turned. Plus you need a new rod and that rod balanced to the other seven.

Roy928tt

Uh am I missing, surely the complete, crank and rods from the 4.7can be used with the 5.0 pistons and block, No? To repair the 5.0, I thought all rods and cranks except 5.4 were the same.

Puzzled Roy

danglerb

How do the cylinders look on the 5.0L block?

I am a BIG fan of get one running ASAP, and diddle with the dream motor at your leisure.

GlenL

Umm... Yes. No.

The rod and cranks (except for 5.4 "stroker") have the same specs. The same bearing sizes, the same lengths, etc. There are differences in details of their construction that make for incompatibilities. The crank counterweights come to mind. Open the PET and compare P/Ns, or just do inspections and trial fittings.

There are a lot of spare cranks out there. If you think you want to machine a journal and use and undersized (thicker) bearing then get a different crank. You'll be money ahead after getting the machine work and sourcing the bearings. IIRC you can get 0.25mm smaller bearings but not the 0.5mm undersized ones.

I'd chuck the crank with the damage and try for the other one.

Ducman82

i need to do some research on what i REALLY want. SC charging sure sounds nice, but is very expensive. i will have a better idea of what i want when the machine shop gets back to me this week. if the 5.0 crank is done, then its a 4.7E build. but there is that old adage, "there is no replacement for displacement"...

GlenL

That's catchier then "there's no substitute for cubic inches" but the forced induction guys would disagree in any case.

No problem with looking ahead and building it with 9:1 CR instead of 11:1. Some power loss now but more viable if you do go SC later.

Ducman82

here is a question. i had a big block dart with 10.5:1 compression and i had to run high octane and booster to run right. what about in a higher comp porsche motor/.?

GlenL

Same and depends. CIS has no knock sensors, nor does the '85/'86 US engine. It takes full LH-jetronic (E.g., S4) to get that. Without that you need to run high octane to prevent destructive knocking.

I run a mix of race gas and premium to get 95+ octane as my engine is near 11.5:1 CR and has just CIS. A genius might be able to tune the mix and spark to be safe with pump gas but he's not showing up in my garage.