Technical Valve Clearances on a Twin-Cam

[HooHar]

Hello all Twin-Cam Tipo owners, this one's for you!

I am trying to tune the 1.8 8v twin cam engine and was wondering if anybody out there could advise me on how to check my valve clearances. The engine is hard to start when hot (starts well when cold) It has a crazy idle speed of between 1000 and 2000rpm, up and down like mad! It uses a lot of fuel and has run-on once or twice recently. In the last two weeks the cam-belt, oil and filter and spark plugs have been renewed.
I have found out what seems to be the gap range:
Valve clearance - inlet: 0.40 0.05 c mm (cold)
Valve clearance - exhaust: 0.40 0.05 c mm (cold)

I have read that a gap on the larger side of the range might possibly increase power due to valves opening and closing a little faster/smoother. Don't know if it's as easy as that. Also something about a shim remover tool?! Maybe I should leave it to the pro's! What do you think?!

 

[sumplug]

Hello all Twin-Cam Tipo owners, this one's for you!

I am trying to tune the 1.8 8v twin cam engine and was wondering if anybody out there could advise me on how to check my valve clearances. The engine is hard to start when hot (starts well when cold) It has a crazy idle speed of between 1000 and 2000rpm, up and down like mad! It uses a lot of fuel and has run-on once or twice recently. In the last two weeks the cam-belt, oil and filter and spark plugs have been renewed.
I have found out what seems to be the gap range:
Valve clearance - inlet: 0.40 0.05 c mm (cold)
Valve clearance - exhaust: 0.40 0.05 c mm (cold)

I have read that a gap on the larger side of the range might possibly increase power due to valves opening and closing a little faster/smoother. Don't know if it's as easy as that. Also something about a shim remover tool?! Maybe I should leave it to the pro's! What do you think?!

Ok, i would only run a slightly loose exhaust valve. You can use a cycle "C" spanner to remove the shims or a bent screwdriver plus another one.
Your problem is possibly the coolant temp sensor which has failed and so engine is running very rich all the time. This would be my guess as when its hot, its overfueling. Get it checked by a Pro though. This would be the cost effective way. Valve clearance rarely needs doing.

Andy.

 

[HooHar]

Cheers Andy,

Thanks for your thoughts. My friend drain67 has suggested other sensors to check/clean as well like the Idle Air Control Valve and the Throttle Position Sensor. I will check Coolant Temp Sensor as well. The Temp gauge performs normally by the way, it is off when car just started and starts to light up gradually until it reaches half way and stays put. You say that Valve Clearance rarely needs doing, I always thought it was done as part of a 9-12mth service?

 

[Hellcat]

Crank position sensor is often at fault for issues starting while hot.

As for hunting (fluctuating revs) that sounds like the idle control valve as your friend suggested.

 

[drani67]

If crank position sensor is fault, ther is no chance to start engine. I had very bad experience with this sensor on my 1.8 running on LPG.
Dave , check injectors , maybe You have the same situation as mine was.

 

[HooHar]

Thanks Hellcat

Since starting the thread I have now replaced ecu and ignition coil and module (worth a shot as I have the spares!) with no difference. Next I tried new CP sensor, no change. I tried to start engine without sensor, no start drani67! The idle speed is still too fast, between 1500 and 2000 rpm after a run of say between 2750 and 4000 rpm. It does eventually settle down to 1000 rpm but it takes forever! Still need to check Idle Air Control Valve and Throttle Position Sensor but not sure where they are and what to do when I find them! Remove, clean and replace I guess!

Injectors seems like a bit of a nightmare drani67!

What do all you 2 ltr guys do? Haynes never covered the 1.8 and 2ltr models. I want to keep my 1.8 on the road but its getting hard without a manual or any data and I don't want to have to shell out £300 for a copy of the Guy Croft Moding and Tuning.......!

 

[drani67]

I told You ... after several weeks of :bang:we found second hand injectors from Renault Bacara V6 !!!! ( first by hand with same case as original !! ) , we put them instead of original and voilla! , now I'm proud owner of 1.8 IE with 800rpm without erratic idling and with max 12 lit per 100 km in city mode. Bacara's injector are still in fuel rail for almost one Years,without problems :worship: .

We were check old injectors with 3.0 bar classic air compressor and bottle with fuel . 3 of them , when they cold , make adequate fog of air and fuel , but after 5 minutes cooking in the pot with bolled water they work like jet with much more consumption of fuel from bottle. This can explain why we can not start hot engine , because we have too much fuel without air in the cylinders ( do You have a big black smoke cloud after engine start when engine is hot ? ) .
For IAC and TP , see there http://www.es.co.yu/DOC/KIF_0333jpg.html , and here is small photo album : http://www.es.co.yu/DOC/index.html .

 

[Hellcat]

For info we 2.0 drivers/owners have to bundle together info from Fiat Workshop manuals (coupe 16v) and other sources - I think the Lyndsay Porter manuals cover the 1.8 and 2.0 tipos.