Friends F7p turbo Conversion non starting prob & low com

[James5]

I am posting this on behalf of a good friend and am after some advice as to things to look into. The engine is a new fresh build F7p with new rings, bearings, honed bores, skimmed OE piston etc..

I will add the engine has only been started once and the rings haven't bedded (not sure what sort of comp results he should get with new unbeeded rings).

This is his problem which i have cut and pasted - (this is not my engine mine works).


OK, since my F7P started & revved up a little high, (deffo no more than 4 or 5k & deffo didn't hit the limiter, prob started for 3 or 4 secs max) it won't start.
It's got fuel, it's got spark as I've checked this numerous times, checked leads & plugs, they all spark, swapped leads got a backfire a couple of times but it's deffo not catching.
Today I went over to try again thinking it could have been flooded, no such luck so I did a compression test..................

1. hardly registered
2. 45 psi
3. 45 psi
4. 10 if I was lucky

Now I am assuming that this probably means I've slipped the cambelt as those are woeful even for a block that the rings haven't bedded in on
I have had the pistons skimmed by 1.9mm so I'm hoping the valves should be clear & it's just a case of re-timing the belt, I wasn't able to check as my torx bits were at home so couldn't get the cover off.
I can't see any other reason why it won't start now either, it all seems to point to cam timing ?? ?

[kj16v]

Hi, On a side-note, it would have been better if he had dished the pistons instead skimming them.

First thing: did he definitely hold the accelerator full-throttle when he did the compression test?

[James5]

Hi, On a side-note, it would have been better if he had dished the pistons instead skimming them.

First thing: did he definitely hold the accelerator full-throttle when he did the compression test?

Hi KJ, I am just waiting for him to come back to me with answer but yeah dished would have been better he got a well known RTOC member to skim them down 1.9 mm to flat top them and bring compression down to 8.5:1 and is going to be running low boost fastchips setup (we are both planning on getting our cars up to yourself in the future for live mapping)

With results that low I can only assume belt has jumped a few teeth and timing it out or belt jumped further than expected and has bent a couple of valve's hence the almost non existent comp test result's.

[James5]

OK he said he forgot to do it WOT but he has been and tested timing and it's spot on

[kj16v]

See what is says the comps are with the throttle WOT

[James5]

See what is says the comps are with the throttle WOT

I am popping over tonight afterwork to give him a hand and make sure comp test done properly this time

[James5]

Ok I popped down and we done an WOT compression on all cylinders and no change at all, timing is all spot on aswell??

We also done wet test and results didn't change This is a new build so hasn't even been bedded in yet. The car was started once and then turned straight off.

All I can think is that the H/G hasn't sealed properly?

Any other idea's

[chip]

tow it up the road to make the engine turn over at 3-4krpm for a good few seconds, might just be the lifters.

[volymmannen]

tow it up the road to make the engine turn over at 3-4krpm for a good few seconds, might just be the lifters.

Dont think that the lifters make bad compression, a new engine should have compression

[Wobba]

This might be a really daft question but are you sure you are testing the compression with the correct adaptor screwed in? Test it on another working car in on one cylinder and see what the results are.

Was the tightening sequence for the headbolts done correctly and were they the right type?

If it's definitely the compression it's head off time. Was the head rebuilt as well?

Other than that look at MAP sensor, crank sensor and the ECU itself (open it up and look at it or try another ECU).