Tap Tap Tap

[Kane 34]

Got out tonight after my new gunson tester arrived in the post. Readings were:

 

Cylinder 1 (flywheel end) : 190PSI (13Bar)

Cylinder 2 : 190 PSI (13Bar)

Cylinder 3 : 190 PSI (13Bar)

Cylinder 4 : 180 PSI (12.5Bar

 

From looking at those and comparing them to what I've seen online they look not too bad, if a little bit on the low side. What's peoples opinions?

 

I know Mei mentioned previously that slightly bent valves might not show up on a compression test and have read elsewhere about doing a leakdown test to confirm. What would be the easiest way to perform a leakdown test? Would fitting the compression tester on, turning the car over and then waiting to see if the pressure dropped do the job?

 

Next job on the list is to strip off the cams to get to the lifters and see if I can see any issues with them. I have a spare set of lifters and valves from an old duff head I've got at my old mans so will pick that up while i'm down that way over the weekend just in case.

[unariciflocos 49 1 Cars]

Depends if you did the test with the throttle open, if you have performance cams, but similar values across all 4 cylinders usually indicates a healthy engine.

 

In the meantime you could have already taken the top cover off and poked the lifters . Get the spares, put them in and see if the sound goes away, changes or moves.

[Kane 34]

Oops, only did it with throttle closed after letting her warm up for 10 minutes. Standard cams as far as I'm aware.

 

Ah so will it be noticeable enough with the cams still in if you give them a poke? I thought the cams would have to come out before I checked

[unariciflocos 49 1 Cars]

Try sliding some feelers between the lobe and the tappet, in theory there should be no space between them especially after running the engine a bit. (mind you, this is only my uneducated assumption, don't know how mechanics do it)

Edited December 5, 2014 by unariciflocos

[kyepan 291]

0.4mm off the deck you say, that could be a factor, i totally feel your pain here, having been in a very similar situation twice!

 

It does unfortunately sound an awful lot like a bent valve, same as mine did when i installed a cam the wrong way round, i bent 6.

I've also had problems refurbing lifters and filling them with too much oil and got zero compression.

 

when you take it apart, my advice would be to remove and inspect all the valves very carefully for contact marks (where they might have hit a piston) take them to your engineer to be checked for straightness, it probably won't be visible with the naked eye.

 

 

If the lifters were pre-filled during the refurb, it's more likely a valve has held off the seat and clipped a piston, especially with the 0.4mm reduced height, which would tighten the clearances up to a gnats whisker. I pre-filled mine too much, and would have bend them had it not been for the standard clearances.

 

This seems a much more likely than incorrect assembly and lack of lifter pressurisation, especially considering you seem sure about the assembly order.

 

Know you probably don't want to hear this but i would take it apart and find out what the cause is.

 

a bit of effort and it will be sorted and you'll be happy with your fully working build!

Get some cams and throttle bodies to make yourself feel better about it.. man maths.

 

ps it took visibly bent valves on mine to affect the compression test by 10psi, so i would say a leak down test is a far better test of cylinder sealing than compression test.

Edited December 5, 2014 by kyepan

[Kane 34]

Been in touch with my old man he's got some plumbing kit at the house that I should be able to make into a leak down tester so will do that while I've got time off from work over the Xmas period. Just need to get the motor back to his.

 

I'm going to have the spare valves I have sent off for checking and a clean just as a precaution so at least I can fit them if need be. I'll also refurbish the spare set of lifters I have, or at least the ones that are salvageable.

 

What's the most likely cause of bent valves to look out for when I am assembling again?

 

Valve clearance - how to check?

Belt correctly fitted - how to tell if you are not one tooth out?

Anything else obvious to look out for?

[Kane 34]

Could someone confirm the assembly procedure once I've stripped down the head? Would this be correct:

 

Rotate bottom end and secure with locking pin.

Fit valves etc in head

Fit head to block

Fit cams

Fit Belt (best method to ensure it's fitted correctly?)

Rotate by hand to ensure everything is clear (best method for this? Clockwise or anti-clockwise?)

Then start up.

 

What is the recommended way to check valve/piston clearance? Would rather make sure that there isn't any issues so I'm not having to do this all over again.

 

Thanks for your help

 

Kane

[unariciflocos 49 1 Cars]

Looks good, as kyepan says, don't prime the lifters too much.

 

Mine has had 0.6mm taken from the block and liners + head skim with no issue.

 

Maybe you can do a dummy build with some putty or get a cheap USB cylinder endoscope to check the clearance.

 

Before you plan for all that might as well whip the rocker cover off and have a look at the lifters, it will take 30 minutes and you may find something obviously wrong.

[Kane 34]

I had thought about using putty, might be an idea to put my mind at ease before starting her up again.

 

Got the car back go the garage over the weekend so just need to organize some fittings to make up a leak down tester. When doing the leak down test what figures should I be looking for in terms of pressure loss and time period for it to drop?

 

I've had the cover off once already to have a look but couldn't see anything obvious but didn't physically test each lifter so will have a go at that as well when I get some time off.