Compression Test Results

[Guest simonb]

Hi Guys,

 

Have just done a compression test on the donor car (2L 1983 Pinto running carb).

The results are as follows:

 

1 = 138

2 = 165

3 = 70 !!!

4 = 185

 

I haven't done a wet test yet, but noticed a very white coating through the spark plug hole on cylinder 3.

 

I'm hoping it's just a dodgy valve, but your thoughts would be much appreciated. The head is going to be rebuilt soon anyway.

 

Ta

[Guest daveg]

Simon

 

Check the head gasket...

 

I would get the head and block skimmed anyway. Also...check for cracks

 

I must be a big enough crack to spot with that loss of compression

 

Dave

[Guest simonb]

Will do.

Hope it isn't cracked though. Are the heads on the old pinto alloy or cast iron?

 

PS. Head won't be coming off just yet, going to lift the whole engine in one and still need the car mobile as I have a few more things to sort out in the garage yet.

[Guest daveg]

I think the head is cast iron...I didn't even strip the engine as it went while in the donor so...it should still work! I didn't even check the compression!

 

I want to get on the road, sva etc, then I might try a different engine. I was unemployed at the start of the build...otherwise how could anyone even start such a thing while working full time?????

 

Dave

[Guest rizla]

the head is cast iron and it is very rare for them to crack or warp....the problem is more likly to be a valve or rings to find out do a wet test , if the compresion goes up its a ring problem if it doesnt then its a valve

[Guest simonb]

Cheers Rizla,

The engine came out today and went without many problems (apart from the alternator mount breaking apart when taken off). Going to buy a tank so that I can de-gunk it before I start stripping the head etc. Still have to remove the g/box and rear suspension yet.

 

I'm just hoping that it is a knackerd valve, although I will probably rebuild the bottom end aswell as there doesn't seem to be much point having to do it again later.

 

Does anyone know the best place for new parts such as valves etc? I don't really want to pay Ford prices if I can help it.

 

Cheers

[Guest Ianz]

Simon

Looks like you've bought a lemon!!!!

Cheers Ian

[Longboarder]

The compression test suggests problems in two or posibly three cylinders. Now would be a good time to get the block rebored out to 2.1L, a lightened flywheel and the bottom end balanced. Its not going to cost much more than a standard rebuild would. You could put a standard head back on and/or add a modified head and cam now or later as funds/time allows.

 

Nigel

[Guest simonb]

I agree,

Here's what I plan to do over the next few months:

 

1. New valves / guides

2. 3 angled/hardened valve seats to run unleaded.

3. kent/piper cam

4. Head skim to raise comp ratio.

4. Head polished/ported ???.

 

With regards to the bottom end, I'll have to wait till the head comes off

so I can have a good look. I'm sure it's not too bad and will hopefully not take too long to get the engine running sweet again.

 

My dad and I will be doing most of the work ourselves to keep the cost down.

 

PS. what cam do you guys recommend. I have a kent 270 in my Pug but have a feeling that may be too rorty for the Pinto.

 

Ta

[Longboarder]

I run a piper 285 with twin forties on mine and it pulls easily from 1500 rpm and is docile in traffic. Doesn't feel over-cammed at all. I think you can go up one level from what you might run in a tin top because the Hood is much lighter.

 

Nigel

[Peter Bell]

Hi Simon, I have a 285 with a 38 DGAS, its is fine, I think much wilder then you may start regretting. Instead of modifying your head get an injection one, it already has the valve inserts in for unleaded and flows better, then flow that if you wish. Look at the Dave Andrews site downloads for the information on head flowing and just about everything else.

Peter

[Guest Angel Boy]

Ditto Peter B's comments.

 

Read the Dave Andrew's articles.

 

Any further questions ask here

 

Andy.

 

ps just read your note again. I seem to recall that the Dave suggests that polishing does bugger all for your head (other making it look nice). I would chek it when you read the articles.

[Guest simonb]

Cheers guys,

285! - Cool, thought it may be too much but you learn something every day.

 

With regards to the head, does the carb inlet manifold bolt straight on or are the ports different. If that's the case then I'll get an injection head as 10-15 BHP more is a big difference in tuning terms.

 

Ta.

[Guest simonb]

Just tried the Dave Andrew's site, but not all the links to the articles work.

[Guest Phil Slater]

Check out the download section of the RHocar site (the old one not the new one) I think you'll find the article, by Dave Andrews,you want there.

 

Phil Slater