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A2B, I think a leak down test would be preferable. A compression test will require cranking the engine. I don't think he should crank the engine until he is sure the timing is correct. Once timed a compression test would be ok.
The intake system has already been destroyed once by a backfire. Not a good idea to give it a second chance.
Originally Posted by BobRoy
Yes. That is the correct timing kit.
Originally Posted by BobRoy
A2B, I think a leak down test would be preferable. A compression test will require cranking the engine. I don't think he should crank the engine until he is sure the timing is correct. Once timed a compression test would be ok.
Thank you Gents for that, will report back on findings.
A small point # on this bore wash scenario, will it effect the Leak Down Test or the Compression test,
and would putting a small amount of oil in the bore help the test, if it is affected by Bore Wash, although nasty mess on startup when it happens !
Cheers
Last edited by Jagger98; May 24, 2021 at 03:50 AM.
BobRoy,
I think either test would be sufficient. The OP said he’s spun the engine over several times so whatever damage prior to and/or during the cranking process thus far has already been done. I know that a compression test would be far easier to perform than a leak down test unless the valve covers are already off.
BobRoy,
I think either test would be sufficient. The OP said he’s spun the engine over several times so whatever damage prior to and/or during the cranking process thus far has already been done. I know that a compression test would be far easier to perform than a leak down test unless the valve covers are already off.
Hi I hope "OP" is an endearing term,
I have looked up the leak down test, as i'm unfamiliar with this, it appears I need a compressor to put air into the chamber at TDC, minimum 80psi and then read the pressure loss, 10 - 15% being acceptable, is this correct.
I have a compressor but its mullered, so, as A2B has suggested, and I haven't heard anything that sounds like crunching valves, and if the head is damaged now, I think it'll be going to the car angels in the sky!
I have bought a Leak Test kit, I would have to get a compressor from somewhere, but it would be easier to do the compression, what do you think!
Just do the compression test. You've turned it over several times, so not likely to do further damage. The compression may be low due to bore wash, so put a little oil in the plug holes if it reads below 100 on all cylinders.
Just do the compression test. You've turned it over several times, so not likely to do further damage. The compression may be low due to bore wash, so put a little oil in the plug holes if it reads below 100 on all cylinders.
Thank you RJ, you said 100, whats the best reading to expect.
Please correct me if I'm wrong. Wouldn't he be better timing the engine first. If you do a compression test and the engine is lets say 1 tooth out of time. When the piston in a cylinder is at TDC a valve may or will be open giving you an incorrect or possibly a zero compression reading.
Another idea to see if the engine is even close to being timed correctly. Take the valve covers off and see if all the flats on the cams align.
You may have a point there. I assumed he had the cams in alignment, but going back to the beginning I realize that was not checked. But doing a compression check is a quick process and if there is a problem on one bank the coils are already off.
Please correct me if I'm wrong. Wouldn't he be better timing the engine first. If you do a compression test and the engine is lets say 1 tooth out of time. When the piston in a cylinder is at TDC a valve may or will be open giving you an incorrect or possibly a zero compression reading.
Another idea to see if the engine is even close to being timed correctly. Take the valve covers off and see if all the flats on the cams align.
Originally Posted by RJ237
You may have a point there. I assumed he had the cams in alignment, but going back to the beginning I realize that was not checked. But doing a compression check is a quick process and if there is a problem on one bank the coils are already off.
thanks for the pointers, If i remove the cam covers and line up the flats on the cams of one head, the other heads cams should be flat also ?
is that what you are saying, and this would show if the timing is correct or out by a tooth or more ?
Right, removed Cam Covers and this is what I have found, this is the right bank lined up on one side!
There seems to be a bit of follow on and Backlash on the tensioners, but that might be to do with the car not being run properly, so the tensioners are not hydraulically primed.
This is the Left Bank
I also looked at the Sprocket setup on the Camshaft Flywheel Sprocket and Secondary Chain Tensioner Sprocket, best picture I could find!
So, the amount of gap that is on each bank of camshafts is definitely not 15.652 degrees out, I dont think its jumped a tooth, what do you think ?
Compression Test Next !
Last edited by Jagger98; May 28, 2021 at 01:18 PM.
Ok, here’s where I am, compression tests done, have readings, will put them on here.The oil, 2 or 3 squirts from an oil can filled with engine oil in the spark plug holes definitely made a difference to compression test.
But, I wonder if someone can tell me what the thread size is externally and internally for the shrader valve, bought a kit to test fuel pressure and it doesn’t have a compatible adapter, any ideas?
or should I just start buying Schrader brass bicycle adapters (not with rubber hoses of course) and hope for the best!
I come up with 1/8" NPT or 4AN.
I got mine from Harbor Freight. I'm sure you don't have
any there. Seems you should be able to find something from an
auto supply store.
