a_florida_man said:Rings siezed, but not broken. 2 Piston lands broken.
Theory....
Looks like water in the cylinder promoted a little corrosion.
Later heating cycles jammed the rings in tight and the corrosion kept them from popping back.
This also caused excess lateral pressure on the lands....
That's a lot of piston destruction for not a lot of bore damage. Not sure why would you want to save the rings that are stuck if you can get used pistons easy enough.
In reply to Stampie :
Challenge reasons?
Stampie said:In reply to a_florida_man :
That's a lot of piston destruction for not a lot of bore damage. Not sure why would you want to save the rings that are stuck if you can get used pistons easy enough.
?
Was not planning on using THESE rings, and if additional rings are used, used rings will be used.
ha
that's funny.
we will see what the other pistons need as they come out.
Pistons can be had, but there are a lot more n/a pistons as opposed to s/c pistons out there.
Different CR.
Piston rings from Jaguar are $100/ piston.
Piston rings for a lincoln 3.8 (same bore - different stroke) are $11 / per piston.
But still need to verify that they are indeed the same thicknesses.
In reply to Mr_Asa :
There's Challenge and there's beating your head against the wall.
Good news
the other 7 look like this
that's coming right out of the block, no cleaning!
now I go on a parts journey...
the oem exhaust had 5 mufflers and was routed over the axle.
this one is 2 mufflers and runs under the axle
Just bought a set of 8 pistons and rods.... $200 no shipping.
Supposed to have come out of a car with 60k ish miles. I believe it, they look good.
But thats the difference here.
For a Jag this is a good deal.
For a SBC $200 is a running engine with accessories lol....
In reply to a_florida_man :
If your bad pistons have good rods attached, then you self-trade the rods and only hit your challenge budget for the price of the number of purchased pistons you actually use. If pistons and rods are equal value (an easy argument to make), then $200/16 = $12.50 is the price per piston or rod. Now you just need dimensions on the Lincoln rings. I'd have to bet they're identical.
In reply to AngryCorvair (Forum Supporter) :
Thanks for the budget tip....I'll probably use all 8 as most of the wear is on the pistons due to the nikasil liner. My engine has 168k on it:)
and yeah I'm going to order a set of rings (they come in sets of rings for two pistons for $22). I'll just measure those and order 3 more if they check out.
In reply to a_florida_man :
Is there a difference in the pistons between the Normally aspirated engines and the Supercharged?
Shop is now ready for production!
Its a lot easier to ge progress at this stage.
Even at 20 to 30 minutes a night and progress still happens!
Indy - Guy said:In reply to a_florida_man :
Is there a difference in the pistons between the Normally aspirated engines and the Supercharged?
Yes, s/c pistons are dished. Hopefully they share the 1.5 1.5 3.0 mm ring set with the n/a.
I have an idea for part of the car's theme...
Supurrrrrcharged.
How many r's are too much?
Do be sure to get a ring gapper. No a powered one is not needed. I do 12 cylinders all of the time. It's not tedious work.
Do match the current ring gap rather than factory specs. It's tempting but, too much tension will be hard on those boses.
frenchyd said:Do be sure to get a ring gapper. No a powered one is not needed. I do 12 cylinders all of the time. It's not tedious work.
Do match the current ring gap rather than factory specs. It's tempting but, too much tension will be hard on those boses.
Absolutely.... always gap and be certain the ends are square!
I finally found some printed specs on Lincoln rings, and I can of course measure my own, so now we know that
the Jag 4.0 S/C piston rings are 86mm x 1.5mm x 1.5mm x 3.0mm, aaaaannnnnddddd that the Lincoln LS 3.9 rings are 86mm x 1.2mm x 1.5mm x 2.8mm.
I think the difference isn't 3.9 vs 4.0 or Lincoln vs Jaguar, is S/C vs N/A.
The S/C rings are bigger and the oil control ring is a design similar to a diesel oil ring where yeah its an oil ring but it's still helping compression a little on the top I think.
In any case it's looking like used pistons, 7 sets of reused rings (ill check end gap for wear and cross compare uncompressed gaps for evidence of collapse.) and 1 $100 Jag set.
Unless I can find an alternate.
I looked at ring sets by size and found several sets from Hastings (such as 2M4601) that were dimensionally correct, but had differences in ring designs.
Probably need to formally inspect the other 7 old sets and confirm that they can be reused within tolerance.
I really like the idea of used pistons and used rings. I don't have enough experience with Nikisal (sp?) to know but I should imagine there are some real knowledge involved in the rings.
In reply to frenchyd :
News got a little better. SNGBarrat lists an OEM Jaguar ringset for $110, and a MAHLE (OEM supplier) set for 49.50. And that is interesting because MAHLE does not list an application for a 4.0.
Add to that the MAHLE set is in the US ready to ship.
slow and steady.....
a_florida_man said:In reply to frenchyd :
News got a little better. SNGBarrat lists an OEM Jaguar ringset for $110, and a MAHLE (OEM supplier) set for 49.50. And that is interesting because MAHLE does not list an application for a 4.0.
Add to that the MAHLE set is in the US ready to ship.
slow and steady.....
I'd be sure and use the part number search at Rockauto to see if they have the Mahle's in their system somewhere. Might save some money.
SNGbarratt should have a forum discount code on jaguarforums.com. In the customer comment section of your order just mention jaguarforums for a discount.
Jagbits, it's "Jagforums-10%" or -5% I forgot which.
Cousin_Eddie (Forum Supporter) said:a_florida_man said:In reply to frenchyd :
News got a little better. SNGBarrat lists an OEM Jaguar ringset for $110, and a MAHLE (OEM supplier) set for 49.50. And that is interesting because MAHLE does not list an application for a 4.0.
Add to that the MAHLE set is in the US ready to ship.
slow and steady.....
I'd be sure and use the part number search at Rockauto to see if they have the Mahle's in their system somewhere. Might save some money.
I don't see anything engine wise:
Other than the common timing stuff and odd bits.
What about a used engine and then part out what you have?
In reply to a_florida_man :
I think he meant to try the mahle part number in the search box. They may carry the part but not have the cross reference info correct. Maybe?
dculberson said:In reply to a_florida_man :
I think he meant to try the mahle part number in the search box. They may carry the part but not have the cross reference info correct. Maybe?
Right , my mistake.
Reading is fundamental!
The Mahle part number is not known
Final engine post mortem:
The engine was ok untill it was last majorly overheated.
When it was overheated, it blew the head gasket at the outside edge of #8 to the water jacket.
When it was parked immediately after overheating, some coolant entered the #8 bore.
After that point it was towed and not driven for a period of time.
That coolant actually caused the carbon between the rings to swell, and it also caused some rust on the top and 2nd rings.
That caused the rings to sieze in a fully compressed cold condition.
Next time it was driven, the rings did not seal properly, causing hot blow by at the top of the piston crown, under the sprak plug and flame front.
That further weakened the piston, causing the two lands to fracture.
That led (mercifully lol) to a loss of compression that was sufficient to keep the cylinder from firing any longer.
CEL - #8 misfire!
So, in the end I can't fault this engine design at all (aside from the old timing tensioner design, this engine has been upgraded).
In fact I have to praise it.
The cylinder bores are ALL 0.002" over 86mm.
Top.
Bottom.
Below the wear line in the bore.
Above the top compression ring wear.
0 and 90 deg to the crank.
EVERYWHERE.
So much for 'NIKASIL = BAD"
The pistons (so far) exhibit 0.0005 to 0.001 overall wear.
186k miles.
Amazing.
A little bit of service and this car would have lasted MUCH MUCH longer.
But that's ok, this is how I get to enjoy them, lol.
It will live again.
Reasonable diagnosis! Thank you for sharing all the details of this teardown as you go. It's fun for us to follow along.
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