M30b35 low engine vaccum. Suspecting valves are too tight

[kapicarules]

I’m trying to chase down a rough idle on my car. I checked for vaccum leaks (none found) and a vaccum gauge says 12-13 inches of Mercury in park at idle and 10 in drive. I had the headgasket and head redone and I’m suspecting the valve lash is off. When I’m driving car runs great minus a small hesitation on takeoff. Before I did the headgasket the car ran smooth as glass. Any ideas? I got 201,000 on it

[Tre0Tre34]

Only time I have experienced a stumble coming off idle, was after installing a parts store distributor cap. The damn thing had a hairline crack in the plastic housing, and would arc externally periodically.

The Bosch replacement (and its Bosch replacement) have been flawless in their operation.

I could hear the arc much more readily than I could see it.

Maybe your dizzy cap was dropped and cracked?

[kapicarules]

Dizzy is new

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Dizzy is new

[Tre0Tre34]

Mine was too. Hopefully yours is of better quality than that piece of garbage was. I know I will only use OEM parts myself.

If you suspect valve lash, you could always verify to rule it out. Take a couple hours, but not difficult.

[ross1]

Then check the valve lash.
In my experience they like the looser end of the range. Too tight will cause rough running and in some cases burnt valves.

[kapicarules]

That’s what I’m doing Monday at a shop I don’t feel confident trying it myself

[kapicarules]

Shop did the valve lash yesterday. The engine does tick a little bit which is not a big problem for me but now she runs like a top and it has more power

[ross1]

Shop did the valve lash yesterday. The engine does tick a little bit which is not a big problem for me but now she runs like a top and it has more power

It is sometimes tough to get it right with older engines having worn lash adjusters. I've found measuring at the cam rather than at the valve stem as is customary makes adjustment easier.
A tick won't hurt it.
Curious as to who did the job as I am local to you.

Even thirty plus years ago a very few engines required this sort of maintenance so sadly it gets neglected more often than not.

[kapicarules]

R&M auto performance auto care in Palatine. It’s located on rand road across the street from the Palatine Walmart on rand road. Their phone number is 847-907-9855. I paid 180 but it depends on what motor you got and how difficult the job is.

[ross1]

R&M auto performance auto care in Palatine. It’s located on rand road across the street from the Palatine Walmart on rand road. Their phone number is 847-907-9855. I paid 180 but it depends on what motor you got and how difficult the job is.

Thanks, I'm not familiar with them but know the spot.