I'll get the guides fitted when they arrive, but then I'll need to find a shop to hot tank it, fit the valves and have the seats recut. I don't think it'll need facing -- or rather, I seriously hope it doesn't need facing as it's pretty thin already at 2.65".

Open to recommendations, I've never needed a head shop this side of town...

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Simon

The adventures of an owner builder in the Tallarook Ranges

Anyone?

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Simon

The adventures of an owner builder in the Tallarook Ranges

I toss them out once they have more than .001" wear (relative to the original diameter at the end of the stem).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Cheers, thanks Doc. I'll measure and toss as appropriate

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Simon

The adventures of an owner builder in the Tallarook Ranges

You could try these guys? Never used them myself, but you won't get one much closer.

Total Flow Cylinder Heads
175A Stephen St, Yarraville, VIC, 3013

Madmorrie

Sigh.. it's never easy, is it?

(Thanks for the pointer Morrie, I'll have a chat and suss them out).

The guides and stem seals arrived from Karcraft today, great service as usual

However.

Trial fitting them reveals that about half are a very easy fit in that I can push them into place easily with a thumb; one so easy it fell out . Two are almost impossibly tight, and the rest seem ok.

So.

What to do about the guides? Are these safely Loctite'd into place, or is there another way other than trying different ones with no guarantee of a closer fit? The ones that came out were knurled.. I wonder if this meant something...?

As for the valves, seems I'll be buying new exhaust valves all around. None of them are a particularly smooth fit in the guides, and all have build-up around the poppet end which when removed with a wire brush reveal pitting in the stems. For the $$, I'll just bin them.

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Simon

The adventures of an owner builder in the Tallarook Ranges

Hey mate, don't spose you markd which guide came from where?

When you Knurl a part, it grows in diameter. I think you might be onto something. Its not uncommon practice for fitters to use knurling to ""Adjust"" the fit of a part.

Nah, they were stuffed so I didn't bother. I do know that #1 exhaust was the only one not knurled, but its one of the ones which is a good fit to the new guides.

I think I'll fit the ones which are a good fit, then ask the head shop to have a look at the loose ones. I strongly suspect the old ones were knurled, as you say to "grow" them in diameter slightly.

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Simon

The adventures of an owner builder in the Tallarook Ranges

The head has had a hard life in the past and as PK said, someone has knurled the guides up to give an interference fit.
I would knurl the new ones rather than relying on Loctite there- exhaust guides get pretty hot.
Any engine reco shop (or a 1/2 decent machine shop) could do it..

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Bummer.

Best option is to ensure the holes in the head are actually round and then have some guides made. I wouldn't advocate knurling and pressing them in again, especially the ones for the exhaust valves as a far bit of heat is transfer from the valve head through the stem, to the guide and then into the head. Reducing the surface area contact might have adverse effects.

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couldn't agree more. Why you would use loctite on something exposed to BLOODY HOT exhaust gases is beyond me.. just asking for trouble.

nah I hear what your saying, but there is still plenty of contact between the guide and the head. Enough for cooling. Just talking about a fine or medium knurl... nothing over the top (otherwise they WON'T fit).... To prove what I'm driving at... Sgc, did you ever have a problem with any of your valves sticking?

<edit> if the knurling is over the top, can always turn it back down to the right diameter

Nup, never. Prior to the rebuild 10 years ago I knocked a corner out of a valve though!

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Simon

The adventures of an owner builder in the Tallarook Ranges

And were they new valves 10 years ago? (Just thinking, old valves, smaller diameter, not going to stick anyway)

Sounds like it will be alright to knurl... Its a legitimate fix (the doc I think would back that). Short of making custom guides I reckons its a safe bet... and not hard to do either

I'd start digging around for another head.... at least get that one tanked and crack tested before you spend any money on it. There could easily be other nasties lurking

grab a 202 and get stuck into it with a die grinder