172 Track Car Engine rebuild tips

[Gixerdom]

Hello Everyone ,
This is my first post, after alot of work on the track car, fitting a replacement engine that had cat cams and a few other bits on, I got it tuned by Chris at EFI and manged to get 200bhp. Absolutely spot on great drive on track and after a few other jobs it was brilliant. Afternoon session not going mad then bang, the fatal throwing a leg out through the block. Right on the oil filter housing. Nothing to do with the remap of course as Chris is a legend of the tuning world just unlucky it went on me outon track. A few of my mates race Clios and its a common thing apparently.
I'm going to have to rebuild the engine ( my mechanic mate will be mainly) , I have a bottom end, I've been advised 197 pistons and rods , polish the crank shaft, king racing bearings etc, not looking at any more power than it has, heard that the bigger oil pump helps also and possibly a baffled sump.
Any other suggestions to hopefully prevent it happening again.

 

[Struggler]

How common is this problem and what is the consensus on the root cause?

I am following a similar path but with ITBs as well, hoping for ~210, worried I'm going to throw a rod out the casing on my first trackday.

 

[Gixerdom]

How common is this problem and what is the consensus on the root cause?

I am following a similar path but with ITBs as well, hoping for ~210, worried I'm going to throw a rod out the casing on my first trackday.

Seems very common, my mate races and he has ITBs and his thrown a rod on sighting lap, forged rods definitely if affordable, I get told they can be a ticking timebof regarding throwing Rods, I've gone 197 rods and pistons and uprated bearings , shells and the all important upgraded oil pump .

 

[R3k1355]

Prolonged high rpm, oil starvation etc. Could well be worth having a good look at the breathers and oil flow back to the sump, if too much oil is accumulating in the head and not flowing back fast enough you'll starve the bottom end.

I know a while back some people were just running standard unopened engines, when it went pop they threw another in. Back when you could get 10x stock lumps for the price of one fully built unit.

 

[Struggler]

I'm planning on using a stock block for now. Perhaps I will just keep my eye out for a replacement as early as possible and go forged when it (enevetably) goes pop.

 

[NorthloopCup]

The reason they let go is because the oil pressure on the f4r is absolutely dire.

The cranks flex, centre main spins and goodnight vienna.

There are many reasons for them to fail, which I’ve listed many times before. But as far as being a ticking time bomb, I’m afraid I disagree.

 

[Brigsy]

The reason they let go is because the oil pressure on the f4r is absolutely dire.

The cranks flex, centre main spins and goodnight vienna.

There are many reasons for them to fail, which I’ve listed many times before. But as far as being a ticking time bomb, I’m afraid I disagree.

What do you reckon to the diesel oil pump? I see a few places selling it as an upgrade.

 

[NorthloopCup]

What do you reckon to the diesel oil pump? I see a few places selling it as an upgrade.

I have no data on oil flow from the pumps, so difficult to comment tbh. But just closing up the tolerances on the original oil pump works very well, but it’s an ‘in combination with’ kinda thing.

It’s got the potential to be the same story as the diesel boxes having ‘bigger bearings’ in them. Which of course, in the world of the jc5 is absolute and utter horse s**t.

 

[Mr Trailer Man]

Fit ARP rod bolts while you're there.

Could be one of the causes for letting go, especially at high rpm.

 

[Gixerdom]

Fit ARP rod bolts while you're there.

Could be one of the causes for letting go, especially at high rpm.

Believe it or not it had arp bolts fitted, but 100% a new set are going on, just got 197 rods and pistons also.

 

[npt]

When did it fail, 7k rpm, 4krpm, on a downshift etc?

 

[Gixerdom]

When did it fail, 7k rpm, 4krpm, on a downshift etc?

I was on track at Oulton not reving too much going around Druids, it had been tuned a few weeks ago so when though fine all the high revs etc, until I strip down the engine who knows. I was with my lad so it was more of a shake down I was taking it easy.

 

[Yarp]

I spun a bearing on engine number 1 in the 182. Came off a roundabout and up a slip road with a sweeping left hander and that was it. My failure was just a death knock though, nothing quite that dramatic! Lasted long enough to drive it home anyway. My guess was it was too long and I was going a bit too hard and starved the pump with it being on the left. No way to prove/disprove though.

As before though, you could pick the engines up for 300 quid so wasn’t worth the hassle of trying to do anything better. Just throw it away and stick a new one in.

Although given my engine is currently still sat sump off post rebuild, I’d be keen to listen to any ideas that make it less likely to throw rods 🤣

 

[npt]

I was on track at Oulton not reving too much going around Druids, it had been tuned a few weeks ago so when though fine all the high revs etc, until I strip down the engine who knows. I was with my lad so it was more of a shake down I was taking it easy.

Nightmare, yeah you'd need to see what went/is going wrong for them to throw rods out, whether its oil pressure related, bearing failure etc, I try and keep away from the limiter for this reason on my 172, read a few similar stories 🫣😂