the lvferraripilot engine rebuild thread

Well, they need to be 81mm and almost 81mm won't do so they will need to come out and go to the shop to be honed to size.

 

I was taught by an old guy many years ago to always take three measurements. If any one of the three dont match, you start over and take three more. Cylinders are hard because the bore guage is difficult to get into dead center. Any lateral tilt up or down makes your readings higher, any horizontal swing left or right makes them lower. Then there is the physical accuracy of your mic, and your accuracy measuring the guage. A mic should always bottom at zero, and I usually check them against my proofs before each session. Also, all tools and parts being measured should all be at 70 degrees. Just handling a light piston can rise its temps enough to make slight changes, which is why you see guys in measuring labs wearing gloves. An example might be a cylinder thats maybe 50 degrees, and a mic thats at 80 degrees. Is it enough to make a .001 inch change? More? Less? Now add in human error's.

Obviously you cant have a cylinder smaller than the piston, and all that measuring with a bore guage, then a mic, etc., adds so much potential for small errors, there has to be a better way. And there is. Slide your new piston into the cylinder, and start slipping feeler guages in between until you find the "real" piston to cyclinder clearance. That doesnt lie. As long as your well within the specs in the OWM......

Another thing to loos at are the wear patterns in the old cylinders and its matching piston. As long as they are all about even to one another and nothing looks wierd, your in good shape. These motors are far more plastic than many may realise, and the cylinders distort in varying degrees through each and every heat cycle. IOW,they are never, and can never be perfectly straight and true. But none of it is enough to matter much, as we see each time one is torn down; very minimal wear, nice patterns, etc..

See you have dirty mess too. I wonder how long it really takes for these cars to get that nasty. Probably not as long as we would like to imagine.

 

3.0L is 172 cu inches....

I'd keep the charcoal canister and associated tubing, that's tank vent system. The air pumps and rails,......not so much!!

 

If you are using a spring loaded T type bore gauge, they are real easy to use and get accurate readings.

The secret is to put the gauge in at an angle, tighten the spring loaded rods and then rock the gauge out , it will compress to actual bore size during rocking and you won't get any undersize or oversize readings, as during the rocking process, the gauge finds the widest part of the bore,a nd once it snaps free, it had reached minimum measurement on the widest part of the bore.

Doug

 

BTW, you are quite motivated for only 20 HP. Though if your car is visible blowing some oil smoke, I would get motivated also.

I would personally be more interested in getting rid of the hard corner carb stumble than adding 20 HP, given the choice, but I am not sure it is possible to eliminate the stumble without going to EFI and throttle bodies.

Good luck.

Doug

 

When I got my QV it ran fine but leaked oil everywhere so I decided to pull the engine to re-gasket it. Basically nothing inside was any good but it ran fine…..sometimes its best not to look.

 

Brings back memories. Keep up the good work. Looking good. You know how it goes, as long as you are in there ,,,,,,,,,,,,,,,,,,, Hard to stop once you get going. I ended up with all new parts. I'm not sure how that happened. LOL I think all we reused was the castings and crank. Funny thing was the car ran great before we started. Oh well.
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A good design works with large component tolerances. You didn't want to just change the cams anyway did you?

 

When I got my car it was leaking everywhere and burning more than a bit of oil. We jokingly called it the "Enzo Valdez". The PO was a good friend and wanted to pay for any repairs so we yanked the motor and had it looked through. All the oil issues were in the heads. The bottom end looked good and showed leakdown at the block of less than 1% on all holes. But that started a long journey on a road that you started down.... Here's a look just before it went back in a month ago.

Rick
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As others noted, the two motors ive torn down looked simular. What I hate seeing though, and we see this all the time, is filthy black oil and black internal engine parts and castings. Anyway you want to play it, its a sign of someone running extended oil change intervals. This doesnt 100% mean the cause of wear, but it sure doesnt help.

My first engine was black inside like that, but I ran some motor flush and MMO through it and it cleaned it up very nice. The second engiine was so dirty that even after 2000 miles and 4 oil changes, etc., it was still dirty.

I hope you stay on course and are able to get her back up and going soon. As you can see by the previously posted motors, "while your in theres" can take over and can really slow you down. But a lot of that becomes justified as the costs spiral upward. Its far easier to slap a motor back together without everything being 100% when you only have a few bucks wrapped up in it. But when the parts bill starts exceeding $$$$$$, you start thinking different. I certainly am not able to justify putting an engine back together after blowing almost $10K in parts unless its fully done. Yet in reality, as noted by how well these engines run in marginal condition, we probably dont need to be so damned anal. Long as its pretty on the outside and runs like a scalded cat, who cares?

 

Over heating is the normal cause of black internals....I needed paint remover to degrease the inside of my QV engine and I know that was cronically overheated.

 

That and your engine blackness can often both be attributed to fuel dilution of the oil. You really need a good 50 mile or more drive fairly regularly to get the fuel out of the oil.

Short drives on carb'd cars tend to accumulate unburned fuel from start up, in the crankcase.

Doug

 

Wasn't implying you did it, but this highlights that a low mileage car can have trashed motor.

A 30 year old car car with 5K miles on the motor can have more wear than a 70K mile motor, due to being driven only a few miles each month, or worse yet, being started every week and idled for 5-10 minutes without a chance to thoroughly warm up and evaporate the water and gas out of the oil.

Doug

 

Very true. And some people think the ones with less than 1000 miles in 30 years are even better. What a waste.