Engine rebuild parts

[Jrhendo]

It started out as a timing chain replacement...

While it was apart, it seemed like a good idea to rebuild the engine. Oversize pistons seem to be a challenge. Can anybody suggest where to get them?

[Bartman4800]

https://www.precisionintl.com/Engine.as ... &EID=12339

Regards, Bart

[Jrhendo]

Thanks Bart, knew about them but they’re only showing a standard size. If I run standards, it will need sleeving and the dollars creep up.

[CraigB]

Oh dear..... I've been down this road..... haven't actually got to the end yet!

I gather this is for 450 M117 engine? You have to be careful with precision international site - a lot of the stuff on there they no longer have and prices not correct - they have closed down their Adelaide operations and I think just operating out of Melbourne. Its still a good site for working out what you need though.

But pistons are crazy price wise and hard to get. I swapped a pair of good 3.5 heads to get a set of oversize 3.5 pistons.... but then I can't get rings for them..... absolutely anywhere. I asked Thomas in Germany and got some contacts, Metric motors in US, ring manufacturers in US (forgotten their name) and nobody interested.

What are your old pistons like? Have you thought about sleeves? That's what I ended up doing on another motor, but I did it myself with my cousins help and don't know what sort of charges are involved. If done properly you wedge them between bottom of bore and head and bond them in there with interference fit and shouldn't give any trouble.

The other option that springs to mind is to contact Kimrh- Kim Holmes - might catch him easier on facebook - or search his posts on here, but I think he had new pistons made in the US. Lots of money from memory but no worse than genuine price.... if you can get them.

but if you do find a ring supplier I am very interested. It is for Lurch, the 350slc and i do have lots of other distractions, but it has put a stop to that advancing for now.

[Jrhendo]

Yes, the 450SLC. I’m not sure exactly what the problem is, but I gather at least one cylinder could use a little help. I’m amazed that over-the-counter oversized pistons just don’t seem to be available. Ultimately it looks like whatever is cheapest will be the answer: standard pistons plus sleeves vs custom pistons.

I’ll keep an eye out for oversized 350 rings. Sounds like it’s the same problem as the 450. If I’d realised it was going to be like this, I’d have given more serious thought up a 560/4speed swap.

And all this started with a simple timing chain/guide swap. And that was well worth doing: one of the guides had broken.

I’ve got my US 450SLC booked in for a timing chain/guide job when I return next year. I hope it doesn’t turn into this.

[CraigB]

If the other cylinders measure up ok and its just one cylinder with a bit of damage, and the pistons are ok, I would definitely just sleeve the one cylinder. Have you had a quote on sleeving? Maybe ring around. The sleeves aren't that expensive and its just a matter of boring it to interference fit but you leave a lip down at the base. Then you knock the sleeve in with the right loctite on it, then hone it all and skim the face of the block - the head locks it all in place if everything else doesn't. It shouldn't be that expensive, especially just one.

Honing with new tight rings will make a huge difference if it is a tired motor.