Well, did not take long to hit a snag with my new build...

New top hat sleeves bored to 3.702 (high end for B pistons).

B pistons.

Ended up with piston to cylinder wall clearance of about 0.0017

Standard Hastings ring set from AB (P/N 2C 4998) is too small. Top ring gap is consistent at 0.030 (pic attached). Spec calls for 0.010 to 0.020.

Hastings tech support is telling me they do not have a file to fit set for the 4.6L.

I would imagine someone else has had to run into this in the past. If so, what rings have others gone with? Brand / P/N?

Thanks in advance!

 

Rimmerbros https://rimmerbros.com/Item--i-STC1427020P might not be file to fit

 

Thanks, Richard.

Hastings also has a +0.020 set (P/N 2C 4998020). I have Grade B pistons and my bore is 0.002 larger than the low end of Grade A. The Hastings tech support person is advising against going with the +0.020 - "You can use only the compression rings after filing. The oil rings cannot be filed or modified. Hence suggested a set from Total seal. They can build you a custom ring set and you can return the STD set to the dealer."

Not sure that a custom set of rings is required for what I'm looking to do.

Bore spec for grade A pistons is 3.700 to 3.701.

Bore spec for grade B pistons is 3.7014 to 3.702.

The machinist is helping me source the right set of rings.

 

send an email to turner engineering....i'm sure they can point you in correct direction

 

Thanks. I did last night and they responded with this

“There is only 1 part number of piston rings available for the standards size STC 1427 which is suitable for all grades. The ring gap will depend entirely on the cylinder size and will generally give the correct gap or close to at 3.7008 bore size. The rings will not malfunction with a slightly larger gap. The ring manufacturers make to the minimum bore size likely to be encountered . Simply fit and forget.“

Does not sound right. I’m afraid that if I go with a standard set, my ring gap will be at 0.030 again.

 

sounds like a mixed set then..oversized top , and standard 2nd and oil. Filing rings is not hard using a simple rig gap tool. I like hastings rings, too bad they dont have what you need. I have used them in many rebuilds and they seat very well with standard crosshatch hone and standard oil. I usually used a moderately revving break in for them, but this was on v6s and IL4s. alternate the ring gap on the stack when installing. You will probably be fine with standard B rings (2nd compression and oil) but you could buy one set (one piston worth) of OEM A rings and check gap and file as needed...

are these new pistons too? I see you can get A pistons with rings for 40$ each in england...

 

here:
https://www.johncraddockltd.co.uk/er...4-6-litre.html

so they probably have the rings too...but their website sucks unless you have a part number...

 

I have the same setup bottom end - 4.6 w/ 4.0 "B" pistons. I used the stock size hastings rings, no problems.

 

Yep - was already thinking mixed set.

Hastings +0.020 for top and file to fit.

The Grade A pistons (standard ring set) are slightly smaller than Grade B. Block is already bored to high end of Grade B (3.702”). I have refurbished Grade B pistons. Maybe file to fit 2nd ring too - if that can be done? As for the oil rings, how critical is gap spec?

Thanks!

 

What was your ring gap at?

Spec is 0.010 to 0.020. Personally, I think 0.010 is too tight.

On the other hand, 0.030 is too much.