G'day,
just been pondering this for about a month now. i wanted to know what makes a jp block different from the standard issue? and were talking block here, not parts
what makes a jp block different
Started by
_judgelj_
, Oct 25 2010 08:21 PM
63 replies to this topic
#2
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Posted 25 October 2010 - 08:31 PM
Nothing..... I think the 73's had some cut outs but otherwise essentially just a very expensive chunk of cast iron in today's terms !
#3
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Posted 25 October 2010 - 08:36 PM
G'day,
just been pondering this for about a month now. i wanted to know what makes a jp block different from the standard issue? and were talking block here, not parts
G/day judgelj
Probably nothing much different other than the engine number prefix JP.
I've heard different stories about higher nickle content or silicone content in the cast iron and thicker webbing around the rear main bearing etc but who really knows if its true or not
. I'm sure there is someone out there who will be able to fill us all in on the details.
Dave
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Posted 25 October 2010 - 08:38 PM
calling mike73......copy??? ...over ????
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Posted 25 October 2010 - 09:41 PM
Hi
We should make a list of all the 'urban myths" about the JP and NP blocks. Don't forget the one about them being cast in the Government Aircraft Corp foundry. Having said that, I have read that the Repco Brabram V8 engines were cast there.
Personally I don't think there is any difference in the blocks except for the changes that applied to all.
Cheers
Bazza
We should make a list of all the 'urban myths" about the JP and NP blocks. Don't forget the one about them being cast in the Government Aircraft Corp foundry. Having said that, I have read that the Repco Brabram V8 engines were cast there.
Personally I don't think there is any difference in the blocks except for the changes that applied to all.
Cheers
Bazza
#6
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Posted 26 October 2010 - 07:10 AM
From what I understand the F5000 and L34 blocks were cast at CAC. Remember GMH was the majority shareholder at CAC and the plant was right next to GMH's engine plant at Fishermans bend.
Early JP blocks are the same as HQ 202 blocks. Go and have a talk to Dave McLean or Ian Tate about the later blocks (both JP and NP). Apparantly you can tell them apart from normal 202 blocks, but I don't know how. Apparantly you cannot pick them externally but it is something in the crankcase area. Dave is still adamant that they had picked up blocks from CAC, even before valve clearances existed in the later blocks. It was from suggestions from himself, Ian and another (name escapes me) that the blocks were changed for XU-1 use.
Early JP blocks are the same as HQ 202 blocks. Go and have a talk to Dave McLean or Ian Tate about the later blocks (both JP and NP). Apparantly you can tell them apart from normal 202 blocks, but I don't know how. Apparantly you cannot pick them externally but it is something in the crankcase area. Dave is still adamant that they had picked up blocks from CAC, even before valve clearances existed in the later blocks. It was from suggestions from himself, Ian and another (name escapes me) that the blocks were changed for XU-1 use.
#7
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Posted 26 October 2010 - 11:04 AM
how about 3100x and ck blocks, does the same apply here?
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Posted 26 October 2010 - 01:13 PM
how about 3100x and ck blocks, does the same apply here?
As far as I know there were just standard 186 blocks, as were the 3 x replacement engines (blank, 3100N and NK). Someone else may have further/better data on them though. From what Dave had told me, the early XU-1 202 motors were basically just a HQ short motor with LJ sump, XU-1 cam and XU-1 (161 style) head. I assume stuff earlier than LJ were the same (but in 186S guise). What I'm not clear on though is that when the last of the LC XU-1's were released there was no longer a "standard" 186S as such, so it is quite probable the CK/NK engines were different to their earlier siblings. Again someone here with much more knowledge than me on this can answer that.
#9
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Posted 26 October 2010 - 03:28 PM
the only problem with that yel327, there seems to be no one here with more knowledge on this subject than you...
i can tell you all the lc xu1 3100x and ck 186 engines are the same, the only diffrence between them and a standard is the build dates, thats why i started a thread some time ago trying to work the 3100x motors out, but i seemed to be the only one that would bring the numbers to the table,,, with the ck thay only built 2 lots of them F231 and G191 NK,JP,NP, im not sure on,,,, if there is anyone on the forum with more knowledge on this subject than yel327 please stand up.
ps i know that the 73 blocks had 3 ribs down the side under the block cast date, some say the jp had x in between the cyl inside the block, but to be hounest with you all i know frOck all about them.
cheers gong
i can tell you all the lc xu1 3100x and ck 186 engines are the same, the only diffrence between them and a standard is the build dates, thats why i started a thread some time ago trying to work the 3100x motors out, but i seemed to be the only one that would bring the numbers to the table,,, with the ck thay only built 2 lots of them F231 and G191 NK,JP,NP, im not sure on,,,, if there is anyone on the forum with more knowledge on this subject than yel327 please stand up.
ps i know that the 73 blocks had 3 ribs down the side under the block cast date, some say the jp had x in between the cyl inside the block, but to be hounest with you all i know frOck all about them.
cheers gong
Edited by BATHURST-32D, 26 October 2010 - 03:34 PM.
#10
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Posted 26 October 2010 - 05:38 PM
hrm interested reading some of the responses. im guessing they are sought after because of the prefix mostly, would be good to get someone who is an expert
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Posted 26 October 2010 - 06:05 PM
Hi,
I agree with Gong, how about a few more poeple standing up and helping us work this out?
I have been looking at XU-1 engine for a while now and am starting to work it out, though I still have a way to go.
Firstly with the X marks in the crankcase internal area, most do have these but there are also those that do have the = markings
I have records of both.
It seems that all the 186 9.7 compression Holdens used the same pistons as the LC XU-1, the blocks come up a different number as I recall maybe it was the colour or the engine prefix taht is responsible for this, but I can't think what else would be different?
Short motors will obviously be different numbers due to cams and sumps etc.
It could be that replacement engines in the 1970- 71 period are different to replacement engines for the LC XU-1 in the 1973 era too as these would be in the N series replacement era when Holden started to make different pistons.
LJ blocks and pistons started off sharing the same pistons as the HQ but when those pistons started failing on a regular basis due to faulty pitons, on the 14th of July 1973 C.A.M.S recognised new pistons so I am guessing about this time XU-1's changed more from a HQ engine, then of course by the 14th of August even more changes took place.
There may have been a engine number range change to reflect an up grade of replacement engines at this time also.
The changes that occurred from the 1st of August at the engine plant would match the production changes that started to filter through to the production plants on the 14th of August, I have the earliest build sheet known of which sets the change over engine number and it is not 386598 as was generally believed, this number would be correct as the engines were built but they were not put into XU-1's in that order.
If anyone has a XU-1 produced between the 14th of August and the 22nd of August with a lower engine number than JP 389265 please prove me wrong! if you have a XU-1 produced after the 21st of August this does not apply to you. ( there was an overlap )
Engine part numbers and other changes for the last XU-1's produced were covered in the 23rd of August Flash Bulletin firstly then confirmed in the Service letter in October 73 it wasn't until a new parts book was printed in mid 1975 that very late 1972 and 1973 XU-1's had a parts book that would cover those cars, but by then it seems development work had naturally progressed and some parts like pistons that were the first to have the steel strutts deleted in July or August had again apparently changed if the part numbers can be believed.
One of the other parts that had changed between 1973 and 1975 that the readers will be interested in, was the engine blocks I have records of NP blocks ( which is all that would have been available for XU-1's ) having changed by Aug 1974 to include external strengthening ribs behind the oil filter, though this may have been earlier, I do not have evidence of this in late 73 Bathurst 20 H 3 blocks so it could just be a NP improvement. ( these ribs are present in all blue Holden engines )
As far as the myth of Bathurst 73 blocks being cast at the Commonwealth Aircraft Factory, like some myths is could be confusion of facts and dates.
The valve releifs in the bore tops for the 166 final spec XU-1's is quite likely something that Holden would contract out as it represented a deveiation from standard engine machining practices at that time, it would be quite possible for small batches of fully machined "Holden blocks" to be sent across to the nearby factory for the final touches, and for that matter anyone with enough cunning might have even have been able to slip a couple of 186 blocks in for the same modification if that is what gong was referring?
If a racing team did in fact go to the Aircraft Factory to pick out which block they wanted, there will have been several sorts going through the earlier ones and the reinforced ones, they would naturely pick the stronger reinforced ones.
There is no evidence found so far to suggest that XU-1 blocks went through any different casting or machining stages as normal HQ engines also shareed all the same characteristics to the XU-1 engine with the exception of the valve reliefs.
Both the XU-1 and the HQ blocks in 1974 could have either the X marks or the = marks and equally the August 74 block rib changes also applied to both the HQ and the XU-1's
I also agree with Gong that the block cast dates are likely to be in batches and December was a time that low production blocks seemed to have been produced, I have information on replacement blocks being cast around this era and even change over engine types as early as the early 186 X2's having December cast dates. The Feb 73 XU-1's also had a December 72 cast date!
Of course there would have been several times through the year that batches could be made.
The only exceptions to this block information would be race specials that Holden made, I have heard of one which has extra external block markings but it still has Holden cast into it!
Don't ask who has this car as I will be respecting the persons privacy and security.
If anyone has additional information to this posting, please prove me wrong! but try to use documented information where possible.
Mike
I agree with Gong, how about a few more poeple standing up and helping us work this out?
I have been looking at XU-1 engine for a while now and am starting to work it out, though I still have a way to go.
Firstly with the X marks in the crankcase internal area, most do have these but there are also those that do have the = markings
I have records of both.
It seems that all the 186 9.7 compression Holdens used the same pistons as the LC XU-1, the blocks come up a different number as I recall maybe it was the colour or the engine prefix taht is responsible for this, but I can't think what else would be different?
Short motors will obviously be different numbers due to cams and sumps etc.
It could be that replacement engines in the 1970- 71 period are different to replacement engines for the LC XU-1 in the 1973 era too as these would be in the N series replacement era when Holden started to make different pistons.
LJ blocks and pistons started off sharing the same pistons as the HQ but when those pistons started failing on a regular basis due to faulty pitons, on the 14th of July 1973 C.A.M.S recognised new pistons so I am guessing about this time XU-1's changed more from a HQ engine, then of course by the 14th of August even more changes took place.
There may have been a engine number range change to reflect an up grade of replacement engines at this time also.
The changes that occurred from the 1st of August at the engine plant would match the production changes that started to filter through to the production plants on the 14th of August, I have the earliest build sheet known of which sets the change over engine number and it is not 386598 as was generally believed, this number would be correct as the engines were built but they were not put into XU-1's in that order.
If anyone has a XU-1 produced between the 14th of August and the 22nd of August with a lower engine number than JP 389265 please prove me wrong! if you have a XU-1 produced after the 21st of August this does not apply to you. ( there was an overlap )
Engine part numbers and other changes for the last XU-1's produced were covered in the 23rd of August Flash Bulletin firstly then confirmed in the Service letter in October 73 it wasn't until a new parts book was printed in mid 1975 that very late 1972 and 1973 XU-1's had a parts book that would cover those cars, but by then it seems development work had naturally progressed and some parts like pistons that were the first to have the steel strutts deleted in July or August had again apparently changed if the part numbers can be believed.
One of the other parts that had changed between 1973 and 1975 that the readers will be interested in, was the engine blocks I have records of NP blocks ( which is all that would have been available for XU-1's ) having changed by Aug 1974 to include external strengthening ribs behind the oil filter, though this may have been earlier, I do not have evidence of this in late 73 Bathurst 20 H 3 blocks so it could just be a NP improvement. ( these ribs are present in all blue Holden engines )
As far as the myth of Bathurst 73 blocks being cast at the Commonwealth Aircraft Factory, like some myths is could be confusion of facts and dates.
The valve releifs in the bore tops for the 166 final spec XU-1's is quite likely something that Holden would contract out as it represented a deveiation from standard engine machining practices at that time, it would be quite possible for small batches of fully machined "Holden blocks" to be sent across to the nearby factory for the final touches, and for that matter anyone with enough cunning might have even have been able to slip a couple of 186 blocks in for the same modification if that is what gong was referring?
If a racing team did in fact go to the Aircraft Factory to pick out which block they wanted, there will have been several sorts going through the earlier ones and the reinforced ones, they would naturely pick the stronger reinforced ones.
There is no evidence found so far to suggest that XU-1 blocks went through any different casting or machining stages as normal HQ engines also shareed all the same characteristics to the XU-1 engine with the exception of the valve reliefs.
Both the XU-1 and the HQ blocks in 1974 could have either the X marks or the = marks and equally the August 74 block rib changes also applied to both the HQ and the XU-1's
I also agree with Gong that the block cast dates are likely to be in batches and December was a time that low production blocks seemed to have been produced, I have information on replacement blocks being cast around this era and even change over engine types as early as the early 186 X2's having December cast dates. The Feb 73 XU-1's also had a December 72 cast date!
Of course there would have been several times through the year that batches could be made.
The only exceptions to this block information would be race specials that Holden made, I have heard of one which has extra external block markings but it still has Holden cast into it!
Don't ask who has this car as I will be respecting the persons privacy and security.
If anyone has additional information to this posting, please prove me wrong! but try to use documented information where possible.
Mike
#12
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Posted 26 October 2010 - 06:52 PM
Hi Mike
I don't know if this adds to the body of knowledge or confuses matters, but I have a 14H3 NP block and a 21H4 202 - both have no external ribs.
Cheers
Bazza
I don't know if this adds to the body of knowledge or confuses matters, but I have a 14H3 NP block and a 21H4 202 - both have no external ribs.
Cheers
Bazza
#13
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Posted 26 October 2010 - 07:40 PM
here is one for you,,, my F231 ck block has the valve reliefs, i dont have proof now as i never took any pics of this but i did have many of forum members over here while i was building my ck,, i think for one could WHITEA9XS please cut in, as you was the man that told me,,, race motor 4 sure,,,,
now mike73,,, dont take every thing to heart man, this forum is a place for all to come and learn about our belovered cars, not every one is out to prove people wrong, some people might think im one to be talking and yeh i know i have been guilty of this as well, so mate drop your defence shield and injoy what others have to offer and at the same time give back what you think is right, dont be affraid to be wrong as we have all made that mistake as well.
we have lost alot of knowledgble members over the years, because people have had to much pride to amit when wrong or slang to much shit when thay have been right,,, it cuts both ways mate
LETS INJOY WHAT WE HAVE HERE
cheers gong
now mike73,,, dont take every thing to heart man, this forum is a place for all to come and learn about our belovered cars, not every one is out to prove people wrong, some people might think im one to be talking and yeh i know i have been guilty of this as well, so mate drop your defence shield and injoy what others have to offer and at the same time give back what you think is right, dont be affraid to be wrong as we have all made that mistake as well.
we have lost alot of knowledgble members over the years, because people have had to much pride to amit when wrong or slang to much shit when thay have been right,,, it cuts both ways mate
LETS INJOY WHAT WE HAVE HERE
cheers gong
#14
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Posted 26 October 2010 - 08:02 PM
Hi Mike
I don't know if this adds to the body of knowledge or confuses matters, but I have a 14H3 NP block and a 21H4 202 - both have no external ribs.
Cheers
Bazza
Not confusing at all because both ribbed and unribbed were in manufacture at the same time, I guess you were lucky if you got the ribbed one, though engine balance was likely a greater issue as the normal HQ and XU-1 engine I suppose were not well balanced, actually there was no sustancial changes to the crankshaft from 1963 till the Blue 202's
I am not counting the change from forged to cast cranks that the HK Holdens had I am talking counterweighting which was obviously needed because Holden eventually changed this in the blue engines.
Mike
#15
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Posted 26 October 2010 - 08:17 PM
I think the difference is................. they have JP stamped on them?
R
R
#16
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Posted 26 October 2010 - 08:25 PM
yeah and $5000 more expensiveI think the difference is................. they have JP stamped on them?
R
#17
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Posted 26 October 2010 - 09:18 PM
Not all. Some had NP!
#18
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Posted 27 October 2010 - 06:40 PM
what's the importance of the 'X' markings in the bore? lots of engines have this?
Cheers Blake
Cheers Blake
#19
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Posted 27 October 2010 - 08:19 PM
what's the importance of the 'X' markings in the bore? lots of engines have this?
Cheers Blake
G/day Blake
The markings he is talking about are inside the crankcase not in the bores. My take on these markings is that they are sandcasting mold identification marks for quality control purposes and are of no real significance outside of GMH.
Casting and or production dates would be a similar deal. They would help GMH identify when a particular part was cast/manufactured so as to help track problems with parts or batches of parts if warranty problems or safety issues arise.
Others may disagree with my prognosis but what the hell they're entitled to.
Cheers
Dave
#20
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Posted 27 October 2010 - 08:26 PM
I'm guessing all the same urban myths apply to the JP as the 179 HP
#21
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Posted 28 October 2010 - 02:49 PM
Hi,
My understanding from the wise words of the doctor that there is no connection or similarity between 179HP and JP other than they had P in the prefix.
The 179 HP was a higher performance than a 149 and that would not be difficult!
If you are confused with the 179X X2 engine this is a different matter as they did at least have two carbies and headers, but the HP on those was just because they used the same block and did not directly refer to this performance version.
The JP of course used the same block, crank, rods and pistons as the stock HQ Holden which also scored some late improvements to block strength.
That is where the similarities between JP and QL engines end as everyone knows ( I am generalising ) Heads were different, carbies were different, manafolds were different, sumps were different and the last ones scored different pistons, extractors, and rods.
Mike
My understanding from the wise words of the doctor that there is no connection or similarity between 179HP and JP other than they had P in the prefix.
The 179 HP was a higher performance than a 149 and that would not be difficult!
If you are confused with the 179X X2 engine this is a different matter as they did at least have two carbies and headers, but the HP on those was just because they used the same block and did not directly refer to this performance version.
The JP of course used the same block, crank, rods and pistons as the stock HQ Holden which also scored some late improvements to block strength.
That is where the similarities between JP and QL engines end as everyone knows ( I am generalising ) Heads were different, carbies were different, manafolds were different, sumps were different and the last ones scored different pistons, extractors, and rods.
Mike
#22
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Posted 28 October 2010 - 03:18 PM
Hi,
My understanding from the wise words of the doctor that there is no connection or similarity between 179HP and JP other than they had P in the prefix.
The 179 HP was a higher performance than a 149 and that would not be difficult!
If you are confused with the 179X X2 engine this is a different matter as they did at least have two carbies and headers, but the HP on those was just because they used the same block and did not directly refer to this performance version.
The JP of course used the same block, crank, rods and pistons as the stock HQ Holden which also scored some late improvements to block strength.
That is where the similarities between JP and QL engines end as everyone knows ( I am generalising ) Heads were different, carbies were different, manafolds were different, sumps were different and the last ones scored different pistons, extractors, and rods.
Mike
Don't quote it as gospel, but I think you'll find that the HP cast mark was gone before HD release. Or at least early in HD. Same HP cast mark appears on early HT Brougham engines, and the odd other HT for a few months too (but mainly Brougham as it was the only HT to get a 308 when the rest got a 307 until significantly into the HT series). The 308 HP mark also attracts similar stories, although one of them has what appears to be some truth - some very early HT 308's seem to have cranks cast from different material.
#23
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Posted 23 September 2011 - 11:12 AM
Nothing..... I think the 73's had some cut outs but otherwise essentially just a very expensive chunk of cast iron in today's terms !
Hello Mike here again,
I would be happy to donate a chunk of my December 73 NP block if someone knows where it can be microscopically or metalurgacally analized at a reasonable price as I am not loaded with money.
Mike
#25
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Posted 29 September 2011 - 04:22 PM
I had a JP block in the early 90's and recall it had valve cut outs at the top of each cylinder bore. From what I recall that was required for the higher lift cams? I'm no mechanic but thats what I remember. I seem to recall it may have also been mentioned in that GTR XU1 book by Fiv Antinou.
cheers, Trent.
cheers, Trent.
Edited by Trentm, 29 September 2011 - 04:24 PM.
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