BBi engine rebuild

This engine is pretty original other than the usual EO services over the years. Reliability was the main concern so the goal was to replace the exhaust valves as a preventative measure before a head falls off one, perform the service and clean it up, detail etc.

Leak down numbers showed 38% past an intake valve (lash setting was fine) and 8-10% being a combo of other valves and ring seal. Oil consumption was another symptom.

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Every cylinder wall had pitting you could feel with your finger and some had scuffs. Number 7 had the most scuffing so it was decided we should refresh the engine while we're this deep.

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Going to do pistons cams and valves?

 

How many miles? Was all of the pitting at the "bottom" surface of the cylinders (condensation drops rolling down and sitting at the "bottom")?

 

Looks like moisture, reminds me of one I did that lived in Hawaii and had a lot of pitting, oil consumption.

No cams. Doing pistons of course and valves.

 

and sleeves of course?

 

Boring them oversize not replacing

 

but for this you have to take them out. I once tried to bore them to oversize ( had at that time the machines). first was working, but the second one started to turn. so I took them all out and put in new ones with std.
would it not be cheaper to take new ones? labor is the same.

so put in higher compression pistons?

 

They have to be taken out to properly rebuild the engine but they get put back in and machined in the block with a torque plate and a head gasket to simulate an installed cylinder head. The sleeves change shape when under compression so for the best results they need to be machined under those conditions.

I'll up the compression ratio a little bit for an increase in torque.
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you are right paul. but I bored the sleeves outside, put them in then and honed them inside.
good idea with the headgasket and a torque plate

 

Out of curiosity, about what would this cost?

 

much much money - but worth every cent when doing right

 

but only with very low "pressure" that the sleeves will not turn

 

I would guesstimate $40k? Hopefully it will be a long time before my TR needs an overhaul.

 

New main bearings? Another 'while you're in there' event?

 

How do you torque those nuts for the mains? Looks like limited space.

 

Diff carrier?

 

It already has one of my diffs in it but it was set up incorrectly wherever it was installed. Backlash is .012" and no preload by the feel of it so I'll tighten that up and check the pattern.

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Here's one I took out of a car, didn't look broken until I undid the left side support and it spread open. I'm making another batch of diffs because I've had some requests.
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I have a tool I made that's 2" long with a box end wrench end and a 1/2" drive for the torque wrench. It changes the actual torque setting I use because of the 2" added length.

 

Agreed - my 78 had rust on the bottom of a few cylinders. It ended up being more cost effective to buy 12 new cylinders at stock bore size and install quality HC pistons. The car is as quick as my TR now.

 

Memories. I can vouch for Newman’s differential carrier. Installation in the TR was easy and the pattern was perfect, once Romano sent me a shim. Thanks again to both of you.

 

Like the new wall art!

 

Before pulling the engine I noiced the 2 groove a/c pulley which isn't right for a boxer. Check out the misalignment.

I need a single groove, if anyone has one shoot me a pm please.

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Down to the block. Liners, crank, heads, all at the machine shop and pistons on order.

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If they are not honed with full torque on the torque plates it is pointless. BB cylinders balloon in the middle when under full pressure and will never seal well. One of the reasons for their well known smoke and oil consumption issues. That and the terrible rings and pistons used back then.

 

Do you remember about how much the distortion was in the middle? Half a thou or so? Just curious for documentation purposes.