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what have i done to my locost race engine
swampy - 14/11/10 at 07:37 PM

Hello, this is my first post as i am very green when it comes to engines.
Usually like to drive hard and call the pros in when it goes pear shaped, but being in the financial situation that we are all in i need to start doing my own engine work.

HELP and ADVICE NEEDED PLEASE

Today at Cadwell in my Locost race car when going up through the gears i mistakingly whent from 3rd into 2nd.. twice

This led to a nasty noise at high revs so i immediately slowed down and headed for the pits.
At first i thought the noise was coming from the rear axle/diff area and thought i had sheard some metal, but after stopping i realised that when i increase the revs a load poping was coming from the carb/air filter so obviously an engine problem and not a diff.

I am hoping it is something simple as i have been unfortunate to blow a big end in an MR2 turbo before now and the noise is very different. ( i appreciate 2 very different engines)

as i am going to have to try fixing or rebuilding the problem as a very green spanner hand any indepth advice or advice on where to seek it would be greatfully appreciated....

Cheers

DRC INDY 7 - 14/11/10 at 07:45 PM

Sounds like the piston have hit the valves and bent some hench the loud popping noise just take of the rocker cover and check the valves all sit a the same height when you rotate the engine or just do a compression test

Angel Acevedo - 14/11/10 at 07:49 PM

Bent/broken valve from over rev?
Sagging spring?
Perform compression test to check for leaking valves or better yet, remove head to check for signs of valve to piston contact.

TOO SLOW...

[Edited on 11/14/2010 by Angel Acevedo]

swampy - 14/11/10 at 07:50 PM

Il give it a go but thanks.
What would be necassary if i find there is a problem, is it just a case of re-seting things up?

rallyingden - 14/11/10 at 07:51 PM

If compession OK it could just be that the timing has moved or possibly bent a push rod / rocker arm. I am assuming this is a 1300 X flow.

RD

locost750mc - 14/11/10 at 07:58 PM

Realistically, if you got yourself a haynes manual for the engine, the x-flow is a very easy engine to strip down, as removing the head is very simple as none of the timing is upset and would be a lot easier to physicaly see any damage that has been done. Thats assuming this is a x-flow tho :O

swampy - 14/11/10 at 08:03 PM

just taken the rocker cover off first 4 springs at same height then 2 out of the remaining 4 are slightly lower and the rocker is not tight to it it has about 10mm of play in the last 1...


do they do a specific haynes for the engine alone or would it be foe an old escort or something..

DRC INDY 7 - 14/11/10 at 08:06 PM

Head of time you have bent valves just need to check there is no big damage to the piston crowns

Angel Acevedo - 14/11/10 at 08:08 PM

quote:
Originally posted by swampy
just taken the rocker cover off first 4 springs at same height then 2 out of the remaining 4 are slightly lower and the rocker is not tight to it it has about 10mm of play in the last 1...


do they do a specific haynes for the engine alone or would it be foe an old escort or something..


Head removal is in order,
New vlves and guides most likely to be needed.
Good timing for Porting job as winter Mod?

perksy - 14/11/10 at 08:18 PM

As above, looks like head off time for inspection

*If* its bent any of the valves, replace the valve guides aswell

Some folks leave them and get away with it, But alot don't

LBMEFM - 14/11/10 at 08:48 PM

Welcome to the site, as already posted the head will have to come off, but a reasonable easy job on your engine. By the way it is nice that you have come around to the fun of cars at last following all of your by-pass protests in the 80's.

swampy - 14/11/10 at 08:52 PM

cheers guys much appreciated..

Will i need to take the head to a machine shop to get the new guides inserted?


o by the way it wasnt me in the trees around melton mowbry all those years ago. but if i had a quid for every time etc etc i bet i could pay someone to do me engine for me

rusty nuts - 14/11/10 at 09:26 PM

Unless it has already had them fitted the x flow guides were bored straight into/through the head . If they have been retrofitted then any decent engine reconditioning company can sort it out and recut the seats for you. Might be a good idea ro put your location in your profile as someone local to you may be able to help. Welcome to the forum

ShaunB - 14/11/10 at 10:10 PM

quote:
just taken the rocker cover off first 4 springs at same height then 2 out of the remaining 4 are slightly lower and the rocker is not tight to it it has about 10mm of play in the last 1...

In short, valves have hit pistons and something has bent/broken most likely the pushrod or the valve itself, but if you are unlucky you may have broken a cam follower (like I did earlier this year!). The 2 that are slightly lower sound like the valve heads are bent and hence no longer able to seat back on the head, the one with 10mm play, if the valve is fully up sounds like a very bent pushrod or a broken cam follower - I hope it's the pushrod as cam follower replacement means a full engine strip down

First step is to remove the rocker gear and pull out the pushrods (keep them in order). Very bent ones are obvious, but check any that appear straight by rolling them on a flat surface. Next remove the head and look at the piston tops, you should see marks where there has been contact. Again, even if the valves look fine try grinding them back into the valve seat and checking that you are getting full contact all the way round the valve - I had 2 valves that looked fine until I did this. If you still have not found the cause of the 10mm gap, the aftermath will probably be laying in the sump...

quote:
do they do a specific haynes for the engine alone or would it be foe an old escort or something..

Mk2 Escort manual - I have both Haynes and Autodata, not much between them.

Shaun.

Hammerhead - 15/11/10 at 09:34 AM

might it be easier and cheaper to bolt on a second hand head instead of repairing yours?

procomp - 15/11/10 at 10:29 AM

Hi

When this situation crops up you need to basically strip the majority of the engine down and check everything. It has happened many many times to drivers within the formula and the common problems such as those listed above and others such as cracked / damaged camshafts damaged crankshafts etc are common. The pistons will need to be fully checked around the crowns gudgeon pins and skirts. Pushrods will have to be checked for straightness / damage. Timing chain will need replacing for certain.

All in all there's an awful lot that need to be checked to make sure that the engine will not just fall apart when reassembled and used again. If you fancy having the whole lot checked over and evaluated as to the whats recoverable Etc give me a shout and ill look at the whole lot FOC. IF you just require parts Etc i stock and supply all the parts for less than they can be brought else where to all 750Mc locost registered drivers.

You are not the first to do this and certainly wont be the last. Main problem for this usually happening is sloppiness in the gear selection IE gearbox / gearstick arrangement.

Cheers Matt