Please controll my work
Discussion
As You may know it, I have recently built 2 nice and very expensive A-series "smoke generators". I have done many things to solve the problem, without any success.
Now I have recived my new pistons - slightly modified version of the original AE - and started my work again.
I try to document everything, and publicate here. Please controll my work, and help me with advices if You think I do anything badly.
Thanks in advance!
Now I have recived my new pistons - slightly modified version of the original AE - and started my work again.
I try to document everything, and publicate here. Please controll my work, and help me with advices if You think I do anything badly.
Thanks in advance!
I have installed the rings in the bores (1 inch from top), and measured the ring end gaps. I use new rings.
The gaps were:
- compression ring: I-0.35 II-0.3+ III-0.35 IV-0.35
- oil scrapper ring: I-0.35+ II-0.35 III-0.35 IV.-0.35
- Oil controll ring(s): I-0.4 II-0.35+ III-0.4 IV- 0.4
The gaps were:
- compression ring: I-0.35 II-0.3+ III-0.35 IV-0.35
- oil scrapper ring: I-0.35+ II-0.35 III-0.35 IV.-0.35
- Oil controll ring(s): I-0.4 II-0.35+ III-0.4 IV- 0.4
Edited by camelotr on Thursday 1st July 22:32
After this I have lubricated the pistons slightly and installed them in the block.
Now turned onto the crankshaft.
I have installed the main bearing shells, torqued them, and measured them dry with telescope gauge+micrometer, and controlled this by using plastigauge.
It looks like I have the following clearances:
I-0.04 II-0.045 III 0.05. About +0.005 with plastigauge
.
Now turned onto the crankshaft.
I have installed the main bearing shells, torqued them, and measured them dry with telescope gauge+micrometer, and controlled this by using plastigauge.
It looks like I have the following clearances:
I-0.04 II-0.045 III 0.05. About +0.005 with plastigauge
.Edited by camelotr on Thursday 1st July 22:56
Edited by camelotr on Thursday 1st July 22:58
Edited by camelotr on Thursday 1st July 22:58
Edited by camelotr on Thursday 1st July 22:59
As the camshaft has run 500kms recently, I have kept the followers in order. Cleaned, lubricated and fitted them, together with the camshaft (after inspection, It had no bad wear marks on it). The camshaft is rotating free, and has not much radial play.
Edited by camelotr on Thursday 1st July 23:02
Edited by camelotr on Thursday 1st July 23:22
My Hero 
You're doing the bearing clearances all wrong. I've already told you in the previous thread how to measure the housings and the shell thicknesses separately. You don't do it in one step with the bearings installed and anyway bearings are so soft you'll mark them with a telescopic gauge.
Measure all the main housings in the vertical plane. Polish the caps down on wet and dry paper on a flat surface until all 3 are the same size if there are any great differences. To be honest I doubt if telescopic gauges are accurate enough for this but maybe your dial bore gauge will fit with the smallest extensions on it. Mine goes down to 2 inches which is fine for main housings.
For the conrods you have to bolt them up and measure in both planes to check for ovality. If any have stretched they'll need the caps ground and the bores rehoned.
The crank journals should be the same within 1 or 2 tenths of a thou. Once you have worked out the nominal clearance between just the housings and the journals you can select the shells to minimise any differences. Fit the thickest shells in the journals where the housings are largest or the journals are smallest etc.
Hopefully you can then get all assembled clearances near as dammit the same.
Rest the crankshaft in just the two end bearings and check the centre journal with a dial gauge to make sure the crank is straight.
I know it's a pain but you should really unplug the oilways in the block and clean them with test tube brushes. Unfortunately on the A series the plugs are press fit brass rather than screw in ones but you can buy a kit of plugs cheaply enough. If you're really keen you can drill and tap the oilways for threaded plugs to make it easier to clean things in future.
I hope you followed my recommendations on the diameter of the ring land area of the pistons and if so what size are they?
Have you chamfered both the tops and bottoms of the bores properly? I bet you haven't even thought about the bottom ends but the sharp edges left after boring can be very damaging to piston skirts. I chamfer every block with a 1 inch porting stone on my flexible drive shaft equipment but I guess you won't have any of that. A fine file and then some coarse emery paper should suffice just to remove the cutting edge.
Before you ever fit piston rings take a fine engineer's oil stone and knock the sharp edges off the outside corners of the ring gaps. These can dig into a bore and mark it with vertical lines as soon as you start the engine up. All it takes is a few strokes with the oil stone just to break the sharp edges.
I also break the sharp edges at the split line of every main and big end housing, both the caps and the other side of the bores so they have no burrs and don't damage or scrape the bearing shells when you fit them.
Now take it all apart again and do it properly!
To be honest if you could watch me build a race engine you'd be staggered at the number of fine detail jobs I do on every part of the engine to improve the original machining and ensure everything is a perfect fit.
Measure all the main housings in the vertical plane. Polish the caps down on wet and dry paper on a flat surface until all 3 are the same size if there are any great differences. To be honest I doubt if telescopic gauges are accurate enough for this but maybe your dial bore gauge will fit with the smallest extensions on it. Mine goes down to 2 inches which is fine for main housings.
For the conrods you have to bolt them up and measure in both planes to check for ovality. If any have stretched they'll need the caps ground and the bores rehoned.
The crank journals should be the same within 1 or 2 tenths of a thou. Once you have worked out the nominal clearance between just the housings and the journals you can select the shells to minimise any differences. Fit the thickest shells in the journals where the housings are largest or the journals are smallest etc.
Hopefully you can then get all assembled clearances near as dammit the same.
Rest the crankshaft in just the two end bearings and check the centre journal with a dial gauge to make sure the crank is straight.
I know it's a pain but you should really unplug the oilways in the block and clean them with test tube brushes. Unfortunately on the A series the plugs are press fit brass rather than screw in ones but you can buy a kit of plugs cheaply enough. If you're really keen you can drill and tap the oilways for threaded plugs to make it easier to clean things in future.
I hope you followed my recommendations on the diameter of the ring land area of the pistons and if so what size are they?
Have you chamfered both the tops and bottoms of the bores properly? I bet you haven't even thought about the bottom ends but the sharp edges left after boring can be very damaging to piston skirts. I chamfer every block with a 1 inch porting stone on my flexible drive shaft equipment but I guess you won't have any of that. A fine file and then some coarse emery paper should suffice just to remove the cutting edge.
Before you ever fit piston rings take a fine engineer's oil stone and knock the sharp edges off the outside corners of the ring gaps. These can dig into a bore and mark it with vertical lines as soon as you start the engine up. All it takes is a few strokes with the oil stone just to break the sharp edges.
I also break the sharp edges at the split line of every main and big end housing, both the caps and the other side of the bores so they have no burrs and don't damage or scrape the bearing shells when you fit them.
Now take it all apart again and do it properly!
To be honest if you could watch me build a race engine you'd be staggered at the number of fine detail jobs I do on every part of the engine to improve the original machining and ensure everything is a perfect fit.
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