Rebuilt engine won’t start

[timpress]

1 hour ago, Waldi said:

Remove the thermostat and try again (with front lifted as far as possible). Since the geysir did not occur in the first 5 minutes, I feel it is cooling related.

Waldi

Waldi

I took thermostat out, back filled it and raised front as high as possible but it still geysered after about 5 mins. I’m going to retighten the head later when cool and give another go along with a compression test.

[PodOne]

Just a few thoughts from someone with no experience with starting one on these engines following a rebuild yet but if the above fails again is it worth a "sniffer test" just to confirm if it's the head gasket at fault before you tear anything apart?

Also anyway to confirm if the water pump impeller is actually turning and not spinning on the shaft.

Andy 

[Waldi]

Hi Tim,
if you have the thermostat removed and start it you should see some circulation in the radiator, do you?

(Do not take the cap off when engine is warm)

Waldi

[ntc]

You will never bleed the system without the stat correctly end of.And no need to jack the car up.

[Peter Cobbold]

The CR block uses a different gasket than the CP, designed to fit the slight depression around each cylinder. But you have had the block decked. Were the recessese re-machined? If not, a CP gasket might  be needed to seal properly.

Peter

[timpress]

I had the CR block decked but the recesses were not machined back in and am using the unrecessed flat silver gasket from Rimmers. Are there alternatives that maybe better? .

I did a compression test and all cylinders were between 175 and 185 so good there. I have retorqued the head down to 108nm and will give another run tomorrow.

I do have water flow with cap off but will get and fit another pump as it’s an easy job along with a new radiator. Then it is literally all I can do and replace and I will need specialist help.

Disappointing when it’s so close to being on the road.

[FatJon]

Retarded timing and/or lean mixture can also cause fairly rapid overheating. Usually you would notice either as it would be running rather roughly. 

 

[Mike C]

When the radiator  overflowed, was there any reading on the temperature gauge?

[timpress]

8 hours ago, Mike C said:

When the radiator  overflowed, was there any reading on the temperature gauge?

Yes, it kept creeping up to the maximum though I shut it off before it got fully there. it started gushing out as I switched engine off and on other occasions during running.

[Mike Herlihy]

Tim, was the block decked sufficiently to remove the recesses completely? If not then the CP type flat gasket fire rings may be leaking when the engine gets hot. The cooling system will then get pressurised and cause your issues. A CR stepped fire ring gasket can also hold the head off in this situation. It’s worth using ARP head studs if you haven’t already. We’ve had issues with customer supplied new head studs going plastic as the upper limit of 80 lb ft is reached. The quality can be dubious. 

[Mike C]

3 hours ago, timpress said:

Yes, it kept creeping up to the maximum though I shut it off before it got fully there. it started gushing out as I switched engine off and on other occasions during running.

The radiator core is clean?

[FatJon]

I my experience a leaking head gasket tends to lead to a very fast overheat. Far faster than you would get with a coolant flow problem. I had a couple of blown head gaskets and both would go from cold to spewing coolant in 5 minutes. A stuck thermostat or air lock usually takes rather longer as you not blasting super hot products of combustion into the coolant.

Also check for signs of one or more cylinders looking WAY cleaner that the others which usually results from them getting steam cleaned. 

In the picture you can see the effect of a seeping head gasket on cylinders 3/4 of our Maestro turbo. This wasn’t steaming noticeably from the exhaust but was boiling up in 5 minutes and then doing a fair impression of vesuvius. 

 

[Andy Moltu]

If it’s boiling up so rapidly you would expect a low compression in one or more cylinders.

You can get this with a CP gasket fitted to a CR, but as you have had the block decked and the grooves fully machined out your block is effectively a CP.

Fitting a CR head gasket to a CP leads to the coolant pouring out of the head. Had this on. Spitfire, when I was supplied a head gasket for a grooved  block when mine was flat.  Took a bit of figuring out in pre internet days.

There were some rogue head gaskets in the past  that blocked the waterways so look closely when you take it apart.

[timpress]

If I did have a head gasket leak I would expect to have poor compression on one or more of the cylinders but they are all solid. I’ll report back when I’ve changed the pump and radiator for anyone interested.

I could have done them during the build but they both looked good and pump felt fine and spun freely.

[ntc]

Don’t waste your money as I said you have a airlock 

[Waldi]

Hi Tim,

Have you checked ign. timing, static and/or with a strobe?

Waldi

[timpress]

32 minutes ago, Waldi said:

Hi Tim,

Have you checked ign. timing, static and/or with a strobe?

Waldi

I did the static timing to help get running (with bleeding injectors) but haven’t done strobe though I can. Would timing cause it to overheat in such a manner just on idle ? Maybe under heavy load but just sat there?

[timpress]

44 minutes ago, ntc said:

Don’t waste your money as I said you have a airlock 

I have bled it, have hot water through heater and hoses so surely if it’s doing that it doesn’t need bleeding. Took drain plug out of block, lots of water, took pump off, water came out there as well. I don’t see much ‘flow’ with cap off radiator and after a while it just geysers out.

with pump off and blowing on rad cap with upper hose blocked off I do get good water out of it so no physical block.

Not sure how else to bleed except the suggestions on this post. Other thoughts please.

Edited June 5, 2022 by timpress

[timpress]

On 6/3/2022 at 11:42 PM, Mike C said:

When the radiator  overflowed, was there any reading on the temperature gauge?

It gradually climbs up, it does hover mid point and slightly above and then goes upwards to the high point at which point I shut off and then it geysers.

[ntc]

29 minutes ago, timpress said:

I have bled it, have hot water through heater and hoses so surely if it’s doing that it doesn’t need bleeding. Took drain plug out of block, lots of water, took pump off, water came out there as well. I don’t see much ‘flow’ with cap off radiator and after a while it just geysers out.

with pump off and blowing on rad cap with upper hose blocked off I do get good water out of it so no physical block.

Not sure how else to bleed except the suggestions on this post. Other thoughts please.

And when it finished spouting what do do then ?

[timpress]

1 minute ago, ntc said:

And when it finished spouting what do do then ?

It just steams and gurgles after I switch the engine. I do see the levels rising and falling (mainly rising) when engine is running ahead of the geysering.

[ntc]

It will as you are only circling around the front cylinders as I said let water stop coming out leave the engine running and refill slowly then replace cap

[timpress]

11 minutes ago, ntc said:

It will as you are only circling around the front cylinders as I said let water stop coming out leave the engine running and refill slowly then replace cap

Even when my temp guage is heading to maximum? Not sure I have had the bottle to leave it running when the temp is so hot. 

[Waldi]

1 hour ago, timpress said:

Would timing cause it to overheat in such a manner just on idle ? Maybe under heavy load but just sat there?

Hi Tim,
not sure about that but easy to check. Target for 10-11 degrees BTDC at idle (800 rpm).
Waldi

[Martin50]

Tim, it sounds like an air lock at best or a blockage at worst in the water system. With the engine cold do you have hose from domestic tap that you could connect and try to run thru with cold water to drain on the block? Again just a thought to try simple option before any bigger works.