There's the culprit. Dropped intake valve seat as viewed through the intake port. Looks a little like someone lost their wedding ring in there.

Here's what a healthy one looks like.

Whose doing your heads? These are the things you hope you only read about. I had a friend who always spoke highly of a place called Head Flow Masters. They were supposed to be very Type 4 savy. Are just doing the upper end?

It will be a full rebuild. 1st step was getting the engine out and stripping it down to at least the longblock. Haven't decided for sure what to do from there. Looks likely that I will go further and try rebuilding it myself. Not sure on who to go to for the heads.

Demick

Hi Demick,

Post pics as you go...i'm going to do the same...this is going to take a while...

I'm kinda having withdrawls already not being able to run the car.

Bill P.

It got hot....

Find out why it got that hot before you fire it back up again...

Seats don't drop unless the heads are overheated.

Demick, I seem to recall you mentioning something about a missing wedding band after the WCC...

Jen

All respect due Jake, but heads that are 30+- years old can drop seats without specific overheating problems... but having nice cool parts always helps!

Yep. Do you think it's a coincidence?

Wow. I didn't realize that when a seat drops, it drops into the intake/exhaust port. I have never seen pictures of a dropped seat before.

It doesn't really drop in. It drops out of the head but is still capured by the valve head. Sometimes it lodges in a way that the piston smacks the valve and/or seat and can punch a hole in the piston or break off the valve. Once those things are loose in the cylinder, a lot of damage can occur. Luckily (sort of) in my case it doesn't look like any major damage occurred. Not that it matters what damage occurs to the piston and cylinder since those get replaced, but it looks like minimal damage to the head.

Demick

It doesn't hurt much

I remembered when that happened. I cant believe we made it home.

Seats don't drop unless the head is overheated... Thats true for the old terriable seats that VW used...

The head being 30 years old doesn't have any impact on it at all, unless someone else overheated it years ago..

TIVs don't drop seats unless they are overheated, or unless a really shabby machinist installs them way out of whack.

This is why every aircooled car on the planet needs a CHT gauge installed.

Demick generates considerable heat with the high rev's occuring during autocrossing. Sorry to see it happen to you chief! Gonna build a Euro spec motor with tricked out components now?

No trick parts, but yes, planning on using Euro pistons and a #73 webcam for the rebuild. I thought about 96mm pistons to make a 2056 but that would put me in Bill P's class which I can't be competetive in with a stock car. Even so, that'll put me in Bp - so you'll have Bi all to yourself Rob!

Demick

Autocrossing uses lower gears and higher revs... that cools HEADS BETTER!! The lower gears create LESS load on the engine which generates LESS heat in the heads.. The high RPM spins the fan fast and generates plenty of charge over the heads to keep them cool...

5th gear is the engine killer in these cars, with a CHT gauge you can see that, especially with a stock cam.

Now that wouldn't be any fun. I'll have to put headers on or something.



Good info Dr Smartypants... I guess I'm not a friggen engine builder! j/k

Jake, how hard on an engine is idling on the grid for 10 minutes between runs?

Buy a CHT gauge and see!

actually, idling doesn't build heat... Oil temps stay low because revs are low and head temps stay down because there is zero load on the engine..

idling for 10 minutes on the grid is good for the engine, as the oil is thinned out and heads are warm before you go thrashin all over the course.

The only engines I have seen heat up at idle had 911 cooling fans on them, they have zero velocity at idle and cannot force any air where it needs to be- nearest the exhaust ports!

Plus see how long the oil temp takes to warm up at idle.

Stock cam for stock, improved, or production class. Then again, the Kap'n tells us the D-jet really only works with the stock cam anyway, so if it's got D-jet it must be the stocker, right??

Until they re-structure the classes, of course! When is that supposed to happen, next year or the following one? Or later? Aaaah, whatever.

--DD

Awww Crap. I just read the rules and anything but the stock cam puts you all the way up to Street Modified (that's Fm for 914's). That's race car territory!

I hope the new rules go in for next season. If they look like they will maybe I'll be more agressive on my rebuild.

Demick

Cam, what cam? Who said anything about a cam? I didn't swap cams! What you talkin' bout Willis?

Say IF I were to use a 911 cooling fan, what is the best way to get the cool air to the exhaust ports? I have the type-4 engine cooling peices, but they are just flat plates and do not wrap underneath the heads...

-Britain

OK, Jake,

I know you are a 4 cyl guy, but you said "all aircooled engines should have a CHT."

How does one do that with a 6? Special sender? A specific gauge?

The common VDO gauge uses a ring shaped sender that you place under a spark plug. The wire is routed out from under the sheetmetal to the gauge. On a T4 most people use the #3 cylinder, since this is generally thought to run the hottest. I have no idea which cylinder to use on a six.

#3 on a type 1 I can understand, but #3 on a type 4 doesn't make sense to me unless it's the diversion of air to the oil cooler.

anyone know the best cylinder for a six? what should the proper temperature range be?