LDS427 Head gasket help

[just weldit]

My wife picked them up from the shop but they talked to me on the phone. They said that they failed a vacuum test but when I told them I didn't think I would be able to find parts they recommended moroso ceramic seal and that was about as far as the conversation went.

 

[gringeltaube]

.... I may do that tomorrow.....

Here a late update to my post #7: I thought I had the heads from a stock LDS427-2 which I took apart years ago... But those turned out to be from an early LD465, so I must have sold the other pair... (... bummer!)
Reason enough to move on to Plan "B" and pull the heads off of another (Continental)LDS427-2!
(This one was actually my first Multifuel engine, a 0-hour '89 "Tooele"-rebuilt engine which I used to convert one of my M35 gassers, back in 1997.) This engine has always been a good starter/runner but after so many years and at least 50K-miles the gaskets were leaking oil bad now, so they had to be replaced anyways.

What I found was interesting... and not too surprising after all:
1) The heads on that Depot-rebuilt LDS427-2 engine are identical to the ones I had pulled from an (unmolested?) LDT465-1C (!!). All share the part#11641633 plus the casting number #FSCM28265, in raised letters, on the pass.side. (pics)
2) Both engines still had the old style head gaskets (second generation, still with separate fire rings). And the fire rings are exactly the same size, for both engines! That actually answered one of my long-time questions: if a LDT465 gasket set could be applied for the LDS427: ... YES!
3) Valve part numbers from both model engines are as shown in TM 9-2815-210-34P, May'74: intake #11668493 and exhaust #11668445. (pics)

Conclusions:
1) I still have no idea what the difference would be between heads #11641632 ( => LSD427-2) and #11641633 (=> LDT465-1C); according to the parts book, and if that is not a mistake...?
2) A LDS427-2 engine can be perfectly rebuilt- and run by using the most commonly available LDT465-heads (and gaskets)


On a side note: the valves I found in those early style LD465 heads have different part numbers, but only the intake valve coincides with what the TM shows for the LDS427-2: #10935205. They have the same basic dimensions but the shape of the head is different (first pic, left side...)


To the OP: I concur with WillWagner in that your heads are ready to be retired (= scrapped).
You should be able to fix that engine "in-frame", if the pistons and everything else is OK.
Let me know if you can't find a pair of good take-out heads in your area.


G.

 

[just weldit]

I was wrong. All the pistons have cracks. I took the pictures in order but the computer decided to put them in a random order.

 

[just weldit]

Thank you gringeltaube for going through the trouble of pulling the heads and finding that information. It will be helpful information when others work on these less common engines. .

 

[WillWagner]

Well, believe it or not, in older engines that I have been a part of for the past 25 yrs, the factory said that cracks were OK for reuse as long as they did not extend over the crown of the piston. All of the pistons pictured, IMHO, and if it were mine, would be reusable from that , but, from pase experience, any piston that shows the edges of the machined part of the crown, like the area where the bowl transitions to the crown and the crown makes the turn over the edge to the ring lands, melted from excessive cylinder tems, is NOT reusable, they like to continue to errode until a failure happens. To my eye I would say pics 3, 4 and 6 show the errosion associated with way too high temps, and wouldn't reuse them. But, it could be just the pic. You need to look close at them. If the edges are crisp, sharp, look like they were cut with a tool, they are OK. If they look like there are pits or look melted, If they were mine, they would not be reusable, only 'cause I see what happens...well, happened, cylinders are different now a days. But, there are other things to consider, How is it loaded when driven, how often is it driven? The reuse guidelines were written to be applied to a truck that works daily, puts 100k miles a year on the engine and uses the horsepower the engine is built to. The way you operate your truck might dictate that the parts are reusable.

 

[brianp454]

Good info! You think you can find a local multifuel pull at a reasonable price?

 

[just weldit]

I haven't found any heads close by yet.
I'll have to take a closer look at the cracks after these storms pass. That one trip of hauling my gear is the only time I've ever loaded it down so the damage might have been done while it was still a tanker truck for the fire department.