Rough cold running

This forum is specifically for engine and gearbox posts, please try to keep on topic in any thread to make things easy to find

Moderator: Board Moderators

User avatar
Alan_M
Senior Poster
Posts: 807
Joined: Sat Aug 12, 2017 01:17
Model: Excel SE, Excel SA, Elan SE
Colour: Red, red, white
Location: South Wales

Re: Rough cold running

Post by Alan_M »

A quick way to test for an air leak is spray some thing like damp start, easy start or brake or carb cleaner around the joints with the engine running. If revs rise you’ve found your leak.

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

Hawaiis0 wrote:
Fri Nov 19, 2021 15:32
How does the crank case breather fit in? Is it still secure and together?
The green filter thing is in good condition. Will recheck the connections again.
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

Alan_M wrote:
Sat Nov 20, 2021 00:05
A quick way to test for an air leak is spray some thing like damp start, easy start or brake or carb cleaner around the joints with the engine running. If revs rise you’ve found your leak.
Good idea. I have some brake cleaner so will give it ago.
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
Crowman30
Junior Poster
Posts: 32
Joined: Sat Feb 27, 2021 15:38
Model: Excel SE
Colour: Calypso Red
Year: 1987

Re: Rough cold running

Post by Crowman30 »

Hi,
Hope this might help.
Image

Image

Image

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

Thanks for the info Crowman30

Tried to find a leak today but no joy. Disconnected the brake servo pipe at the manifold and blocked it off to take the servo out of the equation.
Image
This made no difference so I guess I can dismiss the brake servo as a problem. Also clamped the pipe that goes to the green breather filter using a brake hose clamp - this also made no difference.
Then I noticed that next to the distributer on a 'ledge' on the engine block there was a small pool of coolant. Seemed to be coming from the inlet manifold. Coolant passes through the middle of the manifold and feeds the rail that the thermal valves are in.
Image
If water is leaking from there then so must air. Also there is some black gunge visible in the joint between manifold and head as if a previous owner had sealed it with high temp sealant. I happen to have a gasket in stock so intend to remove the manifold with carbs attached and replace the gasket. Fingers crossed this might be the answer - watch this space :)
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
shaunw
Senior Poster
Posts: 1324
Joined: Sat Jul 10, 2010 19:19
Model: Excel SE
Colour: pacific blue maghide
Year: 1990
Location: Hants

Re: Rough cold running

Post by shaunw »

Have you checked the brake servo one way valve Phil? When that fails it makes weird sucking noises. Mine had an air leak from the valve and it affected running though not the same symptoms as yours. Could also be the hose or hose connection at either end?

Edit: sorry Phil, didn't read your last post! Obviously not servo related.

Shaun

Pete Boole
Senior Poster
Posts: 3157
Joined: Tue Apr 04, 2006 21:28
Model: Elite
Colour: Monaco White
Year: 1974
Location: Nottingham

Re: Rough cold running

Post by Pete Boole »

Be prepared to see some corrosion around the coolant transfer holes Phil - manifold may need skimming (but hopefully not the head).

Pete

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

Pulled the manifold off this afternoon. There was a proper gasket in place. Just got to make sure nothing drops into the head when I scrape off the old gasket.
Second picture below just about shows the small pool of water near the distributor that was there before removing the manifold.
Interesting that along the bottom edge of the mating face on the block, there is a long distance between studs. The gasket has two holes in it along the bottom edge that are not used.

Image

Image
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

About time I updated this thread. Pete Boole was right. There was a bit of pitting on the head and manifold but nothing deep enough to feel with your finger. So I scraped some sealant over both surfaces and dragged it off with a flat blade in the hope some of it would stay in any pits or depressions. Fitted a new gasket and bolted back together. Good news and bad news. The water leak is fixed. I've been driving it around for a month and no sign of any water leaks. However the cold starting problem remains. Tried looking for vacuum leaks again. I removed the vacuum pipe from the manifold and then attached it to a bike pump and pressurised the system to see if there were any leaks. The system held the pressure very well and no sign of any leaks. I'm starting to wonder if the problem lies with the Aldon ignition that I have fitted. It's been on the car for over 10 years - starting to clutch at straws now!
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
Hawaiis0
Senior Poster
Posts: 3763
Joined: Sun Jun 30, 2013 18:39
Model: Excel SA (No 3); Elite 504
Colour: BRG; Dirty White
Year: 1986
Location: West Oxfordshire

Re: Rough cold running

Post by Hawaiis0 »

Would a stuck open thermostat affect cold start at all?

User avatar
robertverhey
Senior Poster
Posts: 785
Joined: Tue Nov 01, 2005 10:54
Year: 0
Location: Sydney
Contact:

Re: Rough cold running

Post by robertverhey »

Have you checked the markings on the camshaft sprockets at tdc? Just wondering if one might be a tooth out.
Robert Glacier Blue '87 SE

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

Hawaiis0 wrote:
Sat Jan 29, 2022 23:48
Would a stuck open thermostat affect cold start at all?
Wouldn't have thought so but worth checking. I have circumnavigated the problem slightly by making the idle mixture slightly richer and advancing the ignition to 12 degrees but I still have to spend 10 minutes with my foot on the accelerator to make the car tick over until it warms up a bit so I can pull of the drive. When warm it drives great.
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
Tanz
Senior Poster
Posts: 1894
Joined: Thu May 03, 2007 22:05
Model: SE
Colour: Calypso Red
Year: 1988
Location: Wolverhampton

Re: Rough cold running

Post by Tanz »

robertverhey wrote:
Sun Jan 30, 2022 09:36
Have you checked the markings on the camshaft sprockets at tdc? Just wondering if one might be a tooth out.
Yes Robert - I pulled the cam cover off and set the crank pully to TDC and the dots on the cams were perfectly aligned.
Cheers, Phil
Never take life seriously, nobody gets out alive anyway!

User avatar
Alan_M
Senior Poster
Posts: 807
Joined: Sat Aug 12, 2017 01:17
Model: Excel SE, Excel SA, Elan SE
Colour: Red, red, white
Location: South Wales

Re: Rough cold running

Post by Alan_M »

Tanz wrote:
Sun Jan 30, 2022 21:28
robertverhey wrote:
Sun Jan 30, 2022 09:36
Have you checked the markings on the camshaft sprockets at tdc? Just wondering if one might be a tooth out.
Yes Robert - I pulled the cam cover off and set the crank pully to TDC and the dots on the cams were perfectly aligned.
It is possible for dots to appear lined up, but be 1 tooth out. I discovered this sorting mine out after purchase to find just this. Obviously previous cambelt replacement wasn’t done correctly. So, just to check - did you use a straight edge through the bolt centres and dots in cams line up against the straight edge?

Also have you checked compression, both cold and hot and dry and wet? In the early stages of loosing some compression this tends to show up more when cold.

User avatar
CID
Junior Poster
Posts: 77
Joined: Mon Apr 29, 2013 20:15
Model: Excel SE
Colour: White
Year: 1988
Location: Belgium

Re: Rough cold running

Post by CID »

I would suggest to check your spark plugs?

They mostly tell you a story. :shock:
This engine is quite prone to Spark fouling when not properly adjusted and especially when running idle on choke for some time.
They also indicate if you running rich/poor etc....

See this pdf chart from Autolight [url]https://www.autolite.com/docs/default-s ... ps.pdf/url]

Rgds Curt

Post Reply