Distorted liners? Really?
Discussion
At the start of this year I bought a 'remanufactured' top hat linered 96mm bore block that did not come cheap.
I also bought an offset ground tuftrided crank and forged rods and Pistons.
The engine was built by myself, dyno tuned by Dale at Bailey Performance and ran what seemed perfectly. I drove the car thousands of miles and drag raced all season setting records and winning 2 championships.
At the last couple of meetings there was oil smoke on the overrun so season over I stripped the engine investigating to find a broken piston and 4 bores all on the left bank badly scored.
I have had the engine checked over at Chesmans and Andrew says that those 4 bores measure 1-2 though smaller at the botttom and he suggested they weren't finished properly when machined. The engine supplier has as good as accused me of distorting the block when I mistakenly tightened the main bolts once before tightening the cross bolts.
So I would like to know if the engine guys on here think this is feasible.
I also bought an offset ground tuftrided crank and forged rods and Pistons.
The engine was built by myself, dyno tuned by Dale at Bailey Performance and ran what seemed perfectly. I drove the car thousands of miles and drag raced all season setting records and winning 2 championships.
At the last couple of meetings there was oil smoke on the overrun so season over I stripped the engine investigating to find a broken piston and 4 bores all on the left bank badly scored.
I have had the engine checked over at Chesmans and Andrew says that those 4 bores measure 1-2 though smaller at the botttom and he suggested they weren't finished properly when machined. The engine supplier has as good as accused me of distorting the block when I mistakenly tightened the main bolts once before tightening the cross bolts.
So I would like to know if the engine guys on here think this is feasible.
i also can't see the block distorting in such a way by tightening the mains first. the block in my car [95 5 litre] is basically the same as yours as in the main caps are recessed into the block just like a cross bolted block but mine isn't cross bolted so are they saying all rv8 engines that aren't cross bolted are distorted in such a way? i think i would ask them to explain how this torque sequence has resulted in one bank of cylinders distorting as they say.
I'd say thats total tosh... is the bore undersize all the way around or has it gone oval?... If it's undersize all the way around it's not been bored correctly... If not, I can't see why doing the mains would twist anything.. they have their own seats and are torqued up against these?.. how does that induce any twist on the block.. and as said.. why only 1 side....the cross bolts should be lined up so there is no side load once torqued....
Where is the block supplier based?....
Where is the block supplier based?....
The cross bolted blocks can nip the crank up tight until the cross bolts are fitted. I've experienced this before on rovers and chevy's. Bare in mind that bearing clearance is tiny and all 5 have to line up correctly in order for the crank to rotate freely.
I'd take some accurate bore measurements and look at any wear patterns on the pistons and liners. This may allow development/improvements for the future depending on what's concluded. Did the OP measure the bores when he sorted his piston/bore clearances? I assume the OP's not trying to get a refund from whoever built the engine?
I'd take some accurate bore measurements and look at any wear patterns on the pistons and liners. This may allow development/improvements for the future depending on what's concluded. Did the OP measure the bores when he sorted his piston/bore clearances? I assume the OP's not trying to get a refund from whoever built the engine?
Edited by Boosted LS1 on Friday 11th November 15:25
TVR Beaver said:
I'd say thats total tosh... is the bore undersize all the way around or has it gone oval?... If it's undersize all the way around it's not been bored correctly... If not, I can't see why doing the mains would twist anything.. they have their own seats and are torqued up against these?.. how does that induce any twist on the block.. and as said.. why only 1 side....the cross bolts should be lined up so there is no side load once torqued....
Where is the block supplier based?....
Some of this is interesting. It's tempting to tighten the cross bolts on one side of the block before tightening up the others side bolts. Most manufacturers have a correct procedure just like when you torque a cylinder head down.Where is the block supplier based?....
The boring comments above are reasonable enough. It would be interesting to see how the blocks liners have worn.
Out of interest OP, what has caused the scoring in the 4 bores? Is it piston debris from the broken piston? I've seen debris that's found it's way to other cylinders via the inlet manifold. Or have the pistons been scuffing their skirts?
I've just realised that the bottoms of the bores will be smaller then the regions above where there has been thrust on the faces. It's an easy job to check with a dti.
I've just realised that the bottoms of the bores will be smaller then the regions above where there has been thrust on the faces. It's an easy job to check with a dti.
Edited by Boosted LS1 on Friday 11th November 19:39
^ Ah, I get you but after all the racing, driving and nitrous abuse together with a grenaded piston the clearance issues are probably irrelevant as far as the engine failure's concerned. It would have failed much sooner if the clearance was to small.
It's still an interesting anomaly if one bank has unusual measurements at the bottom of the cylinders though. Certainly worth exploring.
It's still an interesting anomaly if one bank has unusual measurements at the bottom of the cylinders though. Certainly worth exploring.
PhilH42 said:
Boosted LS1 said:
Only on one bank of cylinders :-)
yep I agree from a practical point of view, but I was looking at it as irrelevent if the cert was missing or had possibly expired 
Maybe worth asking for a copy...only if the OP was sure he was being fleeced of course.I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Edited by portzi on Saturday 12th November 08:04
What is the diamentional tolerance for a honed machine bore, l would have estimated between at least + or - 0.0005", or 0.0127mm which is a tight tolerance.
+ Or - 0.001", or 0.0254mm is a tolerance which is still pretty hard to get within, in any long bore machining.
I would have thought the same tolerance for being parallel.
+ Or - 0.001", or 0.0254mm is a tolerance which is still pretty hard to get within, in any long bore machining.
I would have thought the same tolerance for being parallel.
Boosted LS1 said:
^ Ah, I get you but after all the racing, driving and nitrous abuse together with a grenaded piston the clearance issues are probably irrelevant as far as the engine failure's concerned. It would have failed much sooner if the clearance was to small.
It's still an interesting anomaly if one bank has unusual measurements at the bottom of the cylinders though. Certainly worth exploring.
It's still an interesting anomaly if one bank has unusual measurements at the bottom of the cylinders though. Certainly worth exploring.
your not wrong there....if you're seriously trying to test an engines integrity then the OP has given it b****y good go this season. Bearing in mind the sustained stress the engine has been put under the detinated piston doesn't suprise me or possibly score marks if debris is flying around and reading between the lines I think the OP would accept some partial rebuild may be required after such a damn good thrashing. But yes surely if bolts were torqued out of sequence or incorrectly the whole cylinder would distort? The fact its on one bank is strange and you wonder whether the base of the cylinders are distorted or a consistent taper? Plus you would expect increase in cylinder size with piston rock. Wonder which way the bores are narrowing and the difference from original machined/stock narrowest point to current narrowest point...they won't get smaller with use??
portzi said:
If their PME has not used a TMEC to Cal it every 12 months then all the pistons would have measured small at the ends of the bores? As it would give the same measurement for all 8 of them?
I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Yes agree you would certainly expect consistency across the 8....if the same equipment (as you say difficult to say how precision it is) has been used across both banks?! I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Edited by portzi on Saturday 12th November 08:04
Also who knows (Outside the organisation) the company protocols or if there was a delay between both banks or change of personnel mid process.
All assumptions of course, might be a million miles away.
PhilH42 said:
portzi said:
If their PME has not used a TMEC to Cal it every 12 months then all the pistons would have measured small at the ends of the bores? As it would give the same measurement for all 8 of them?
I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Yes agree you would certainly expect consistency across the 8....if the same equipment (as you say difficult to say how precision it is) has been used across both banks?! I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Edited by portzi on Saturday 12th November 08:04
Also who knows (Outside the organisation) the company protocols or if there was a delay between both banks or change of personnel mid process.
All assumptions of course, might be a million miles away.
portzi said:
PhilH42 said:
portzi said:
If their PME has not used a TMEC to Cal it every 12 months then all the pistons would have measured small at the ends of the bores? As it would give the same measurement for all 8 of them?
I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Yes agree you would certainly expect consistency across the 8....if the same equipment (as you say difficult to say how precision it is) has been used across both banks?! I don't know what PME they use as never been to that company, but l would suggest they would be using a dial test comparator and a set of ground and honed set of standards to zero the comparator.
If they are using spring loaded telescopic bore gauges!! , they are classed as a posh vernier caliper and are rubbish for precision work. Only a turner would use telescope bore gauges as it's roughing out compared to honing and boring.
Edited by portzi on Saturday 12th November 08:04
Also who knows (Outside the organisation) the company protocols or if there was a delay between both banks or change of personnel mid process.
All assumptions of course, might be a million miles away.
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