Special getting closer...

[Gary71]

Fix it properly, or you will be wasting your time again. Even if you have to scrap that head off and start again.

[MdR]

Sorry Graham but my tuppence worth is in agreement with the others - you really need to sort that valve/head out now.

[911hillclimber]

TBH really cannot imagine I can get it better and it is all back together now. Really fed-up with the whole engine.
As long as it runs on 6 it will be fine.

A friend in the class below me has a mega bike engined sports racer with around 505 leak down issues on the engine. he won the Midland Championship last year...

If the engine is dow by a bit it won't make a difference to my results.
I would imagine if we all did leak-downs on our engines we might be 'surprised'

In the past, engines I've done i've simply lapped the valves, checked I have a nice grey even line and finished the engine, no fluid or light checks at all.
I certainly know which machine shop to steer well clear of, but doubt I'll do another 911 engine!

It has cost a fortune to return the engine from the bang. It will be replaced by an injected boxster engine/box next time for £3K. All I need are water rads and a bit of welding....to hell with nostalgia, dizzies, carbs, air cooling.

This rebuild has cost more so far and I'm not done yet. Imagine if i had to pay a specialist to do the lot!

To get a 3.2 head is £250 (ebay), it will need machining to suit the height of the refaced others and I'm at risk with the guides/seats.
It will be another £500 and I run the risk the cam will bind!
Why else was the engine broken up if it was a good one?

If the simple task of fitting a new guide, reaming and reseating was done right then all would be well. I paid for this work and it was sub-standard and that has cost me anorther strip-down to try to correct things.
The 574 sealant had not even hardened when I stripped it down....

I'm down to the very bone marrow on this engine.

[johnM]

Graham

When you fit new guides you need to recut the seats. It would take an epic amount of lapping to sort this.

Kind Regards

[911hillclimber]

Indeed. The inlet in #4 head was damaged and was re-guided/reseated as was the exhaust.
#5 inlet was also done by the same company who I had a bit of grief with about the substandard work and even got a £100 refund from the 1000+ spent with them.

Getting another head or finding a shop to do the engine work is not what I wanted.

I think it will be ok.

[Dingbat]

Hi
I like the others think you ought to get the valve issues sorted now rather than have another season of misfires and aggrevation if the valve is leaking now all that will happen is the burning gasses will get past it and burn it out further, and to fix it later will mean more stripping and having to clean everything up again not to mention the expense and brain damage off trailering the car to an event onl to have it act up again, with modern valve seat cutting gear if the job is done right valve lapping is pretty much uneccessary, I still have a go but only to reaasure myself all is well. You shouldn't have to buy another head, at worse you may need another seat fitting but this is not megabucks, as for Boxter engines they have issues with cylinder wall failiure etc so there not without their problems none of which are cheap to fix. With jobs like this there are not many short cuts to be had and when you do try and take one to save a few quid it normally costs you a bunch later, you have built up a neat car so why spoil it now after all it can't help it if the machine shop you used was a bit crap, or you have had a few hiccups during reassembly, buck up and have a cup of tea.

[911hillclimber]

I will do a leak test as before and if #4 hisses back at me in the inlet I will tear that side down and that head off.
I don't know who to go to for the seat machining...I thought it had gone to a good shop before.....and will not go back there ever again.

If it does not hiss then the leak must be small (!). I do not have the hearing of a Fruit Bat but with the carbs off you can get VERY close to the valves!
Maybe a little soapy water will do and look for bubbles!! (kidding)

People on another forum are saying the same, ie reface the seat. Sometimes I wish I didn't have all this on the internet.

The light shows a 30 deg area on one side of the valve and certainly not anything a feeler guage could entre. The grey lapped face is constant round the valve but also the seat.

Tiresome.

I'm good at timing 911 engines now and scraping 574 off surfaces.

[haasad]

Hi, If the seat isn't both concentric and at a perfect 90 deg to the guide centre line in all planes it will never lap flat. It is correct that with modern valve seat cutting gear and perfect valve lands lapping is (nearly) redundant..

I would be happy to recommend a route to a superb machine shop.

Andy

[911hillclimber]

Andy:
Please pm me with a good machinist who will take the head and cut the seat or even replace the seat and cut afresh. I hope the shop you have in mind is not who I went to.
If have to strip the one side of the engine I will, I can do it in my sleep now....

Just why am I bothering I'll never know.
Wife asks me the same thing....

[johnM]

Hi Graham

Mike Bainbridge can install guides and cut seats in house.

Kind Regards

[Mike]

Best of luck with it all, hope it works out ok!

[911hillclimber]

Thanks Mike. I can only marvel at that RSR engine of yours, all the more frustrating that this stupid bog standard 3.2 is such a pain. Might be the engine 'builder'...and a duff machine shop.

John:
I didn't know that!

I want Mike to up-rate my Lola box so a trip to Kendal with box and head may be a very good idea.
God, wish I'd known that before (or thought to ask...)

Lakes are nice this time of the year, so is a pint of Dent!!
I feel better already.

[911hillclimber]

#4 hisses like an adder, #5#6#1#2#3 quiet.
Stripped 4/5/6 side off in 40 minutes.
I hate 574 sealant...
I hate engine oil even more...
Calling Mike Bainbridge tomorrow to post the head up for a new seat and a lap.

Oh how I love this engine.

Thanks to all for keeping me focused.

[Mike911scrs]

HI Graham

"God, wish I'd known that before (or thought to ask...)

Lakes are nice this time of the year, so is a pint of Dent!!"

the offer was on the table!!!!!!!

will need both valves with the head

regards mike

[911hillclimber]

Posting the total head to you Mike as discussed tomorrow, should be with you Friday.
Graham.

I'll have this engine yet.