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ptjs1.I THINK that I would be minded to put the best matched tolerance A-spec Piston and Liner of the ones you have, to replace that damaged B one.
If I cannot find a B spec piston within the near future, that will be the action I will take as a last resort.
The 0.0001 variance between the A spec and B spec is not all that much when you really look at it.
Having said that, I now have to look at making a tool to extract the liner if they are really stuck.
I have yet to pull the heads of Engine #1. I bought 2 sets (4)head pullers from "Jaguar Preserve"($350.00 US) see photo but the pullers failed to pull both heads. The mild steel bolts kept bending so every time they bent, I had to stop, go to the hardware store to purchase bolts. I had to purchase 6 sets of stainless steel bolts (48) @ $3.03 a piece to pull the heads. Very costly indeed. One head came out OK but the other stalled about 3/4" up and I had no choice but to cut 4 studs in order to get the second head off. I have since removed the cut studs. I have to try to get the proper head puller to do the job. I joined my local Jaguar Club affiliated with JCNA to get the loaner tool but that is turning out to be a dud. I would not be able to get my membership number until the end of August which I need to get the loaner. Cost for the loaner. Shipping both ways plus a refundable deposit.
Cost of buying my own tool to save time = approx $600.00 US. Is this worth it? Jaguar Preserve head puller. A total waste of money as far as I am concerned
I am awaiting word from a seller in Sutton, UK who told me he may have some B spec pistons. If all else fails I will be doing the A spec piston and liner swap.
That will give me 11 B spec pistons and liners and one A spec piston and liner. Anything detrimental about doing this?
Sanchez
If the Uk guy does not work out, I will send you a B spec piston FOC if you pay the freight cost to the Salvation Army in your area and you pay the import charges if any at your end; BUT it has the experimental green anti friction coating as shown in an earlier photo. PM me if interested. They are brand new/maybe use for an hour on an experimental engine.
Last edited by Greg in France; 07-10-2024 at 02:35 AM.
Speculation time is over. This morning I did the preliminaries to get to the connecting rod and as recommended I locked down the liner on the other side and removed the B1 piston from the engine. As mentioned by jal1234, the ring lands were damaged and there is a fracture on the piston running through the piston crown and the second compression ring land.
The piston is a B spec. The connecting rod bearing is good (babbitt is still intact and no signs of scoring). Even without removing the piston, I knew it was damaged. The liner is in perfect condition. cylinder head Liner is in good condition this is what I used to lock down the liner on both sides piston fracture in red circle Top of piston con rod bearing
I need a B spec piston PERIOD.
I read through all of the info Greg posted regarding the differences between the A spec and B spec pistons and liners and I do not want to put an A spec piston and liner with 11 other B spec pistons and liners because of the 0.0001 variance between the two. So, I am in the market for a used B spec piston. I have 12 good A spec pistons on the other engine.
In a quandary:
If I put an A spec piston and liner in, I will have a different CR relative to the other 11 cylinders.
If I put an A spec piston in a B spec liner I would have piston slap on that cylinder( as per Greg) Come on Greg. Are you ever going to use those 12 B spec pistons and liners during this century? Madame will be happy if you make some space for her LOL.
ON another note, I am going to post a wanted ad to see what's available out there. Maybe contact Mahle and see what's available.
The short answer is no! If you check a perfectly running V12’s compression the variance between cylinder’s will be far more than the difference between A&B pistons.
One other thing. The tolerance between A&B is .001 the first number past the point is 10ths the second is Hundredths the third is thousands.
That’s an indication of the tolerance between pistons at the factory. Rather than waste 1/2 the pistons they batch them together. Even the factory has tolerance of + or - .0005.
The factory cylinder to bore variation ( to be inside of specification is .0012-.0017).
If the engine has miles on it the bores will be outside ( bigger) than factory specs.
Yet engines with well over 100,000 miles will still run fine.
Seeking perfection is fine but you can drive yourself nuts overdoing things.
Grab a shop manual and read the tolerances.
As long as you’re close to those you’ll be fine.
Not looking for perfection. Just want to do the right thing.
@mguar: Are you saying that I could put an A Spec piston in a B spec liner and it would be OK or put an A spec piston and liner in and all will be OK.
Greg In France states "Several engines left the factory with a mix!) also seems to think that using a A spec piston and liner on the engine should be OK as the factory also mixed A and B spec pistons and liners.
ptjs1.I THINK that I would be minded to put the best matched tolerance A-spec Piston and Liner of the ones you have, to replace that damaged B one.
If I cannot find a B spec piston within the near future, that will be the action I will take as a last resort.
The 0.0001 variance between the A spec and B spec is not all that much when you really look at it.
Having said that, I now have to look at making a tool to extract the liner if they are really stuck.
I have yet to pull the heads of Engine #1. I bought 2 sets (4)head pullers from "Jaguar Preserve"($350.00 US) see photo but the pullers failed to pull both heads. The mild steel bolts kept bending so every time they bent, I had to stop, go to the hardware store to purchase bolts. I had to purchase 6 sets of stainless steel bolts (48) @ $3.03 a piece to pull the heads. Very costly indeed. One head came out OK but the other stalled about 3/4" up and I had no choice but to cut 4 studs in order to get the second head off. I have since removed the cut studs. I have to try to get the proper head puller to do the job. I joined my local Jaguar Club affiliated with JCNA to get the loaner tool but that is turning out to be a dud. I would not be able to get my membership number until the end of August which I need to get the loaner. Cost for the loaner. Shipping both ways plus a refundable deposit.
Cost of buying my own tool to save time = approx $600.00 US. Is this worth it? Jaguar Preserve head puller. A total waste of money as far as I am concerned
pulling heads is a problem because of build up of calcium and possibly rust. ( dissimilar metals).
I’ve found that prior to pulling heads I use a good radiator flush. ( and sometimes 2 ) until the water flows out completely clean.
Then you need to be hyper critical about pulling it up equally.
If the head gets stuck use a dead l blow hammer to get it back down and start over again. As you already found out, it does no good once wedged. The good news is that the first time it cleaned off the studs at least to the part where it got stuck. So that part will go smoothly. But make sure it’s level.
To put radiator flush in an engine that’s been removed, tip it up on the back side pull off the water pump and then pour boiling hot water and the flush into both water passages.
Let it soak for longer than recommended then flush it out. You might have to do that a couple of times.
On the engine which had the dropped valve I did the above four times in about 2 weeks. That failed. I also used plasticine to create dams around the studs and filled it with a mix of 50/50 acetone and Marvel Mystery Oil topping it off every time the acetone evaporated. That also failed.
Next week I will start to work on the engine that has the two heads I need. Hopefully this time I will be lucky. Actually, I only have to pull the B side head. The A side head on the first engine came out OK.
Not looking for perfection. Just want to do the right thing.
@mguar: Are you saying that I could put an A Spec piston in a B spec liner and it would be OK or put an A spec piston and liner in and all will be OK.
Greg In France states "Several engines left the factory with a mix!) also seems to think that using a A spec piston and liner on the engine should be OK as the factory also mixed A and B spec pistons and liners.
in all probability, yes! I’d feel better if I knew approximately how many miles it has. I mean less than 20,000 I’d get out my equipment to measure to be sure. But I wouldn’t even bother checking if it’s got 50,000 or more.
Pistons wear. And even if the engine has had frequent oil changes as you get over that 20,000 mile range the wear negates any real difference.
As far as the factory goes, while it’s entirely possible A&B would be mixed by the factory, I never looked at the 50V12’s I took apart to scrap.
So I can’t confirm that. I can understand it happening. Most of the equipment used in building engines, was left over from existing stuff dating back to WW2. Jaguar purchased castings and I know Sir Lyons was commendably thrifty.
To be clear, A and B spec liner/piston sets were occasionally mixed up in factory engines, but the individual sets were eitherr A or B.
It was not unknown to find an A piston/liner set in a B spec engine, for example.
My own view is that it would not matter at all if a A spec piston was used in a B spec liner in a road car engine that had, as Mguar says, 50,000 miles or more on it.
Last edited by Greg in France; 07-11-2024 at 11:13 AM.
This is getting very interesting. Both engines have more than 50,000 miles on them.
I have to pull the heads on Engine #1 to use them on Engine #2.
Engine #2 had the dropped valve seat which means that it probably overheated more than once. So I do not want to use the A bank head from this engine for obvious reasons. OFF TOPIC:
Engine #1 according to the PO only overheated this one time. He owned the car for years. He told me that he changed the oil on the car every three months without fail. To quote the PO; "had an oil change done. Within a few miles of the shop the oil light started to flicker and engine started to shake violently and smoke was pouring out of the car underhood and behind and with the engine temp rising I pulled over and called to shop that did the oil change" When I got the car, My examination found that the B1 con rod let go from the crank and destroyed the block. I surmised that either the mechanic forgot to put oil back in the car or it just threw a rod and that caused the oil to leak out hence all the smoke he was seeing. The other thing I saw was that the oil filter was full but the oil was thick and black as tar. The condition of the oil I saw did not indicate that this car had frequent oil changes even though he said the he had the oil changed "every 3 months without fail"
When I spoke to the PO, he told me that he knew very little about cars ( He is a practicing doctor by profession) and that he entrusted his mechanic to do whatever was necessary to keep the car in good condition. He told me he spent thousands of dollars to maintain his car. He sent me a spreadsheet of the expenses for the car together with more work receipts. ( I always ask for documentation when I acquire a used Jaguar) My inspection of the car says otherwise. The work done based on the spread sheet and receipts is not apparent when you get under the car. This guy was ripped off by his mechanic on a regular basis. He was paying for work that was never done to the car. How do they sleep at night? I hate when this happens.
BACK TO THE TOPIC AT HAND:
So the heads of the Engine #1 will be used on Engine #2.
I have to look at the Camshafts and Journals on Engine #1 to make sure they were not damaged because of lack of lubrication.
If they are, I will swap over the Camshafts and boxes from Engine #2 to the Cylinder heads of Engine #1.
I will assemble the Cylinder heads and check the valve clearances before installation.
This will be a total mix and match job.
I ve done exactly that. Then went on to use the engine for Vintage sports car racing. I have one set of reground ( racing) camshafts that allow me to run the engines up to 7000 rpm. + or - some. Using E85 and leaving everything else stock I’m almost competitive with the V8 guys who have $20,000+ in their engines.
The trick is those engines trade everything for big top end power. My power curve is a lot flatter than theirs keeping me around them except when they get ”on the camshaft” at peak revs.
Back to your matter,
I know similar happened many times. I started acquiring “junk” Jaguars in the 80’s and some had pristine engines while many had been butchered. Living in the rust belt the early cars had body cancer all over and a 10 year old car was pretty bad. ( unless parked for the winter).
Some of the engines I acquired were from a Jaguar repair shop that didn’t know how to trouble shoot EFI. So when they came in dead the owner talked them into a Chevy swap. ( much more profitable than fixing a wire or hose). A fair number of cars that were supposed to get a factory crate engine got a junkyard engine that was cleaned and repainted with a set of chrome valve covers to dress them up.
I removed the B side head from Engine #1 and was not happy with what I saw. the cylinder head had some deep pits and I decided not to use them. I won't even bother to remove the A side head.
I was fortunate enough to find a pair of never used OEM Cylinder Heads from a seller on Ebay US. It comes with valve seats and valve guides. Should be in my hands on July 23.
I removed three cylinder heads from the engines I have so I will remove the best valves and springs and install them on the new heads. I will see how much work it will be to lap the valves or whether it has to go to a machine shop.
I will be using the cam boxes, camshafts cam buckets and their shims from the removed heads and install them on the new heads.
I am hoping that by using the above parts on the new heads will keep the valve tolerances within specs.
Besides contacting David Manners, I was looking for the gasket sets (Bottom End and Cylinder Head) but I am only coming up with gaskets for the Pre HE and E type 12 cylinder engines.
Will keep looking.
It may be too late, but hopefully you do know the early pre HE head are vastly superior than the HE heads don’t you?
Jaguar even tells you so. There is no horsepower gain between the PreHE heads. With 7.8-1 compression ratio and the HE horsepower with 11.5-1 compression.
That was only done to clean up emissions. ( ask I’ll go over the whole story).
Yes the early head fit on the HE engine. But the HE pistons don’t work. If you use the stock 9.0-1 compression pistons you will pick up 20 hp more.
If you can find the 10 -1 pistons you go from 262 horsepower to 299 horsepower and slightly better fuel mileage. (1980 only)
@Mguar Yes I thought of that but I am doing this on the cheap. Using the earlier heads would mean I have to change all the pistons and with that comes new rings and con rod bearings.
That would be beyond my budget. I am a cheapskate at heart. I have a small parts budget for this car, but every time I turn something else needs attention. (Think Head Studs).
I am just going to make this engine as reliable as I can. I am not fixing it to sell. With the help of the forum members, who have never failed me in the past, I will get this car going and enjoy it while I can.
07-09-2024, 01:05 PM
