...and I got myself 800 $ worth of JE Flat-Top Pistons for exhibition.
Turns out while honing, that the bores are distorted some. Can't get it out unless we get too much clearance. @#FS%
At the time we ordered the pistons, it was the machine shop owner who measured the bores to decide if boring over or not.
Unfortunately at that time I did never take the measurements myself. Another lesson learned...
Well - new pistons ordered today at .020 over.
To properly describe what had happened, I'll have to define the directions of measurements. "Across" the piston pin is between the bore wall inside the "V" where the lifters are to the outside, where the outer wall of the block is. "Along" the piston pin is between the bore wall forward and aft seen in driving direction.
What was wrong:
The bores are perfect with very little wear across. Even when measuring 60 degrees left and right of the "across" line, well within limits.
Only the middle cylinder has a bore "along" which is 0.800 mm (0.030") tighter than the others. Seems from the hone and wear marks that this is the case since new. Despite the honing stones being able to cut mostly at the tightest part in a bore, it will still shave some off at the lower (wider) parts too. This led to the bore opening up just so much, that the clearance is now 0.17 - 0.18 mm (0.006 - 0.007") which is too much.
The narrowing bore can only be detected when measuring exactly "along" and from about 1/3 down the bore to 1/3 from the bottom of the bore. Measuring half an inch above or below that area and it seems normal. Looks like it's the area where the bores are closest to each other.
I have taken a full set of measurements on all cylinders. This afternoon I'l go and pull the torque plates and re-measure. Will be enlightening on how much torque plates change the bore.
So it will be 3 or 4 more weeks until I can assemble my short block.
The next time I'll measure it myself the same way I did now. 4 measurements on 3 levels for every cylinder. Makes 72 measurement points on a V6. When taking the "along" line as 0 degrees I will measure at: 0, 45, 90, 135 degrees at about 3/4" from the top about half way down and 1" from the bottom of the bore.
...and I got myself 800 $ worth of JE Flat-Top Pistons for exhibition.
Turns out while honing, that the bores are distorted some. Can't get it out unless we get too much clearance. @#FS%
At the time we ordered the pistons, it was the machine shop owner who measured the bores to decide if boring over or not.
Unfortunately at that time I did never take the measurements myself. Another lesson learned...
...
Oh man! So sorry to hear that. Adds a whole new meaning to "Measure twice, cut once."
For my sailboat, I ordered new stainless steel cable for new standing rigging (the wires the hold up the mast). Well, even after measuring not just twice but three times, I still cut one of the wires too short by 4". Argh. Good thing I purchased some extra cable when I placed the parts order. Otherwise it would have been another week or more to finish the job. My experience was much less of a frustration than yours but you are not alone!
Well up to now this is the first mistake and can be corrected. I'm already looking to what I could do with the 6 pistons. One will probably be used together with the extra set of 1.6 rocker arms and the spare couple of valves for display.
I've set the budget in a way to tolerate some of these mistakes. So it is 800 $ for a lesson in check-and-double-check. Machine shop said they will pay for it and I said: We cut the loss in half as I had a bore gauge in the cylinders as well but did not properly measure as well. So 400 $ for some nice exhibits.
Couple things arrived from Summit today.
Hopefully I have the correct size cam bearings now. Also the MLS head gaskets arrived at .027" and .030" thickness.
Once done the final cuts on the heads and re-checked piston to head clearance I'll know which one to use.
Going at a snails pace at the moment. While the machine shop is still open we are waiting for the pistons form JE. Seems the guy who was in charge forgot to put the re-order into the production line. Now that we found out we have been given second week of May for delivery.
In the meantime I'm getting slightly excited about the Megasquirt EFI projects side. Ten days ago with Phil from extraefi in the U.K. I've finalised and ordered the ECU and several items and a 10feet harness. The plan is to slowly work out the ECU and the tuning software, then build the electrical part for the Blazer and finally mount the MS (Megasquirt) actually a fully loaded MS3X ECU into the Blazer. At first without any active drivers. I'll make the ECU sniff all possible data from the stock engine. At the same time I'l get data I can get used to the software and figure out all the quirks with the wiring and sensor data.
A lot of stuff will be involved on the electrical side. Such as:
figure the best reluctor wheel for a crank sensor (VR sensor) 60-2 seems reasonable
figure out how to fix it to the damper/crank
figure out how to make a drawing on freecad and have it laser/water cut.
then there is the cam sensor needed for a fully sequential injection/ignition setup (I still have my old distributor - too expensive to ship the core back to the U.S.) So I have a distributor do disassemble and look on how to fix a cam signal, probably with a Hall-Sensor, maybe optical-sensor.
find a way to fit an LED to the stock ECU knock signal (Then we will know if the 1st gen engines are knock limited somewhere)
after that, figure if the MS3X does detect the same knock signal (Important for the new engine)
Then there is that MAF idea of mine - I have to figure that one out. (Just so to get a means of VE for future tuning.)
And as I'm writing - the doorbell rings - and the loom, COP's, O2 sensors and controllers has arrived.
Seems that all my builds are working in a specific order. The last thing that I need is the first thing to be ready - LOL.
Sorry to hear about the piston clearance issues. Can't wait to see how it works out with the MegaSquirt. I've been reading a lot about them lately, and would definitely love to use one to run some ported vortec heads along with the sequential injection someday.
With how strict you said they are over there with modifications, I'm surprised you can get away with running that setup.
The Megasquirt thingy is more my personal R&D project. First I have the Blazer being available at this time with an engine being built. With this opportunity I will explore what can be done with the MS ECU.
Once running I'll have to decide on how to run the Blazer and in what context. There is ways to get it through our equivalent of CARB which will involve considerable cost. While this is one aspect we do have relatively strict rules in some aspects they are very loose in others. For emissions checks you just need to be as good as the vehicle had been certified by the manufacturer. That said, the MS setup should meet the OEM emissions.
Finally the MS project is just taking advantage of the availability of an already fuel injected car together with an engine build. On this I can solve all the problems arising with a fully programmable aftermarket fuel injection. I'm kind of preparing Plan B ahead of Plan A. Once I have the MS running I may use it on my Alfa Romeo inline 4 engine which is a much more simple approach. But hey - I've never gone for the easy stuff.
What this fuel injection thingy is really all about? Simple, my hobby.
I'm a nerd! I like to go where others don't go. (Consider the effort to tune the 4.3 V6 in itself is something most won't touch.)
I'm an automotive fan since I've started to (successfully) tamper with engines at age 15. Before that time I was usually left with a not running engine and some parts left over.
I've been the guy with modest results and some highlights when it came to high end comparisons. At age 17 the others were asking me "why" their stuff would not work. I've been the guy at the public and university library spending an afternoon sifting through 2 stroke tuning, which at the time was available only in books.
Not much has changed since. Despite not being a mechanic I've been involved with automotive repairs and tuning for the last ... decades (gee - getting old). That said I've been working with some of the most interesting people of their trade. I got to learn stuff from them nobody else ever heard, they never told anybody else. Why? I don't know. Might be my interest to go into a subject and read and actively learn. I do this for fun. Research, learn. I do hang out in front of the TV but I get easily bored there. I'm absolutely not into sports, except of practicing myself, mainly MTB and bicycling and a fitness center in walking distance. That said, If you have all the time at your disposal that you do not waste watching sports and following events, you have a lot of time you can invest in other things. With all that time for myself and no marriage and no kids, guess what - time to play with cars and trucks.
Back to topic:
Plan A
Make the Blazer work with the modifications and the really tame camshaft with the OEM style TBI.
Pros:
Easy, no transformations, some tuning, new EPROM, new injectors may do the job. Retains all the OEM instrumentation, transmission control, and is legal if still meeting emissions.
Cons:
No direct control, no tuning, maybe not getting to the real potential of this engine build. Kinda boring, still interesting.
Plan B
Use the MS on the Blazer and pushing the limits of what is doable by aftermarket and own R&D. Hopefully not braking anything in the process.
Pros:
Keeps me busy developing the methods, the approach, planning and executing the required changes. Skill building in various areas of interest, such as 3D CAD drawing, electronics, analytics, electrical planning and wiring. Don't know if it may come in handy in the future as economy doesn't look too great.
Cons:
Complex. A sh...load of work - but then, that's the one thing I've never been afraid of. Costs a lot of money.
The driving reason behind is simply my wish to see where I can get with the help of my friends and others willing to assist and see if we can come up with something running decently. The whole will be an R&D effort using what I have at the moment and see where it will lead me.
Maybe one day it will run on a nice lightweight V8 racecar for some trackday racing.
I love how you think through all this. I can see why you are leaning towards Plan B even thought is is more work and money because you obviously are a person who enjoys the process as much as the final product.
...and I got myself 800 $ worth of JE Flat-Top Pistons for exhibition.
Turns out while honing, that the bores are distorted some. Can't get it out unless we get too much clearance. @#FS%
At the time we ordered the pistons, it was the machine shop owner who measured the bores to decide if boring over or not.
Unfortunately at that time I did never take the measurements myself. Another lesson learned...
Well - new pistons ordered today at .020 over.
To properly describe what had happened, I'll have to define the directions of measurements. "Across" the piston pin is between the bore wall inside the "V" where the lifters are to the outside, where the outer wall of the block is. "Along" the piston pin is between the bore wall forward and aft seen in driving direction.
What was wrong:
The bores are perfect with very little wear across. Even when measuring 60 degrees left and right of the "across" line, well within limits.
Only the middle cylinder has a bore "along" which is 0.800 mm (0.030") tighter than the others. Seems from the hone and wear marks that this is the case since new. Despite the honing stones being able to cut mostly at the tightest part in a bore, it will still shave some off at the lower (wider) parts too. This led to the bore opening up just so much, that the clearance is now 0.17 - 0.18 mm (0.006 - 0.007") which is too much.
The narrowing bore can only be detected when measuring exactly "along" and from about 1/3 down the bore to 1/3 from the bottom of the bore. Measuring half an inch above or below that area and it seems normal. Looks like it's the area where the bores are closest to each other.
I have taken a full set of measurements on all cylinders. This afternoon I'l go and pull the torque plates and re-measure. Will be enlightening on how much torque plates change the bore.
So it will be 3 or 4 more weeks until I can assemble my short block.
The next time I'll measure it myself the same way I did now. 4 measurements on 3 levels for every cylinder. Makes 72 measurement points on a V6. When taking the "along" line as 0 degrees I will measure at: 0, 45, 90, 135 degrees at about 3/4" from the top about half way down and 1" from the bottom of the bore.
Can't you sell the pistons on ebay or something to recoup part of the cost?
01-28-2020, 03:28 AM
Turns out while honing, that the bores are distorted some. Can't get it out unless we get too much clearance. @#F
, I ordered new stainless steel cable for new standing rigging (the wires the hold up the mast). Well, even after measuring not just twice but three times
, I still cut one of the wires too short by 4". Argh. Good thing I purchased some extra cable when I placed the parts order. Otherwise it would have been another week or more to finish the job. My experience was much less of a frustration than yours but you are not alone!
