Hi all,

I asked a question a few months ago about spacing a 1 1/2" SU onto a minisport manifold. The manifold doubles for Hi44 carbies, so the hole on the manifold is actually 1 3/4". I just cut the gasket to this size, and used the spacer.

All works well, and has been for months. But I recently got sick of the huge amount of engine noise, and decided to put the under-bonnet sound insulation back in. But now it won't fit - the carby is too close to the firewall.

So, what is the spacer actually for? Is it to reduce heat transmission from the engine to the carb or something? What would happen if I removed the spacer and cut the studs back, and attached the carby straight to the manifold?

On a side note, anyone know what compression (PSI) I should be getting for a 998?

the spacer improves low-end torque, and may also be there to stop the carb from hitting on something, and the float bowl from being too close to the extractors

nothing to stop you machining it down a bit narrower, but as long as it doesn't hit anything, you can bolt it straight up to the manifold

Well, I went out to have a look today, and it looked like there was plenty of room without the spacer. So I took the carby off and removed the spacer, and then found that the thread of the studs doesn't go far enough - if I were to cut them short enough, there wouldn't be any thread left to put the nuts on. Looks like I might actually have to buy some :(

There's really not enough space even if the spacer is machined down - if it were 1/4" the sound insulation would fit, but any engine movement would push the air filter up against the firewall.

My other question: anyone know what I should be getting with a compression test for a 998?

You can screw those long studs out and replace them with bolts, of whatever length you need.

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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.

...duh. Why didn't I think of that?

anywhere above 120 - main thing is consistency across all 4

Good-o. I got between 140 and 148. I understand that within 10% is sufficient, right?