Engine weakness

Tiapan · 19-04-2009, 01:17 AM

I thought i would start this thread to share differant findings or popular knowledge about differant engines and there factory weaknesses, when modded or not, its interesting to know and is also great pub ammo

may also help correct many beliefs or rumours

ill start...

Boss 5.4's sintered metal oil pump gears, fail with high rpm or hp, need billet oilpump gears

Nissan SR20, rocker arms jump off the lifter in high rpm applications, need to use rocker arm stoppers

Cleveland, oiling system can starve the bottom end, can be corrected with oil restrictor kit,
core shift in many blocks

Windsor 302 - prone to splitting due to thin webbing, aftermarket blocks have corrected this.

Boxer - cracking piston skirts in stock application when being thrashed in cool weather

Holden v8- might be quicker to list the pro's? lifter bore alighnment to cam, always on the , needs brass lifter bores installed

Holden 202- Shreading cam gear when pushed too hard

ill add more later, see what you can thing of

Falc'man · 19-04-2009, 02:36 AM

Here's info on the ticking problems with the pre '05 Boss.

CAMS290 · 19-04-2009, 08:10 AM

Quote:

Originally Posted by Tiapan

Holden v8- might be quicker to list the pro's? lifter bore alighnment to cam, always on the , needs brass lifter bores installed

Punching pushrods through rocker arms, wearing camshafts out because of lack of oil on lobes, factory single row timing chains stretching or even breaking.

66 coupe · 19-04-2009, 09:29 AM

thats only when they have oil pressure, usually the pickup is all sludged up = no oil pressure

yift · 19-04-2009, 11:06 AM

5.4 boss motors prone to ovaling bores.

**CAT600** · 19-04-2009, 08:02 PM

Quote:

Originally Posted by yift

5.4 boss motors prone to ovaling bores.

Got a link?

Never heard of that one before, Cast Iron modular blocks are usable up to 1200rwhp without issue. The only thing that kills a 5.4L mod block is the connecting rod coming through the side with factory sintered rods at 6500rpm+

Daniel

yift · 19-04-2009, 10:47 PM

Quote:

Originally Posted by CAT600

Got a link?

Never heard of that one before, Cast Iron modular blocks are usable up to 1200rwhp without issue. The only thing that kills a 5.4L mod block is the connecting rod coming through the side with factory sintered rods at 6500rpm+

Daniel

that was an issue with the early 5.4's when ford did a recall for supposed piston rings. no links for this info, just a ford engineer who i know.

**CAT600** · 19-04-2009, 11:04 PM

Quote:

Originally Posted by yift

that was an issue with the early 5.4's when ford did a recall for supposed piston rings. no links for this info, just a ford engineer who i know.

If there was ever an ovality issue with 5.4L blocks, I have never read about it, and it would be an issue that was present when the block was machined from new....... those blocks just dont give any trouble at all.

If you said piston ring pack issue, well, we all know that the early 290 engines had a problem with the combination of Mobil 1 and FPV's ring pack choice.

Daniel

Dezza · 19-04-2009, 11:28 AM

3.9/4.0 litre straight 6, particularly in EA-EL - prone to blowing headgaskets - Everyone know EAs blow them, but not everyone know EB-ELs are just as bad for it.

**Bluehoon** · 19-04-2009, 02:03 PM

BA XR6T - Rods & Valve Springs. Prone to throw the leg when pushed.

VN-VR Buick 6 - dare comment?

bcr2734 · 19-04-2009, 03:10 PM

Quote:

Originally Posted by Dezza!

3.9/4.0 litre straight 6, particularly in EA-EL - prone to blowing headgaskets - Everyone know EAs blow them, but not everyone know EB-ELs are just as bad for it.

yes they do, Every mechanic i know does aswell as do the owners.

Dezza · 19-04-2009, 03:15 PM

Quote:

Originally Posted by bcr2734

yes they do, Every mechanic i know does aswell as do the owners.

But the consensus I get from some people is that EAs blow head gaskets every few 1000kms but EBs are perfect. I know most know the real story, but some don't and are just oblivious to the fact they're pretty much the same engine.

Windsor220 · 19-04-2009, 08:31 PM

Quote:

Originally Posted by Dezza!

3.9/4.0 litre straight 6, particularly in EA-EL - prone to blowing headgaskets - Everyone know EAs blow them, but not everyone know EB-ELs are just as bad for it.

I thought EF-ELs were the worst actually.

Dezza · 19-04-2009, 10:46 PM

Quote:

Originally Posted by Torxteer

I thought EF-ELs were the worst actually.

True. My uncle's EL did about 3 of them, and it's done roughly as many kms as my EA which has only done one.

yift · 19-04-2009, 07:43 PM

dezza they are bad ea-bf. ba/bf not as bad but still prone. no ford ohc motor is safe from this kind of weakness.

stevepet · 19-04-2009, 07:47 PM

Nissan TB42 prone to cracking heads especially if using LPG.

Mr Hardware · 19-04-2009, 07:58 PM

Quote:

Originally Posted by yift

dezza they are bad ea-bf. ba/bf not as bad but still prone. no ford ohc motor is safe from this kind of weakness.

Yeah I don't think so mate. I looked after a fleet of cabs and we never, ever took a head off an AU. Each of the 20 odd cabs did half a mil each while i looked after them too. The AU head gasket is a steel one as opposed to the paper one found on the e-series. The reason they blow is because of an iron block and alloy head, and the steel head gasket avoids this problem.

yift · 19-04-2009, 10:44 PM

Quote:

Originally Posted by Mr Hardware

Yeah I don't think so mate. I looked after a fleet of cabs and we never, ever took a head off an AU. Each of the 20 odd cabs did half a mil each while i looked after them too. The AU head gasket is a steel one as opposed to the paper one found on the e-series. The reason they blow is because of an iron block and alloy head, and the steel head gasket avoids this problem.

how often do cabs sit around switched off for more than 3 hours? head gaskets on these sixes blow because of the cooling off diferences between iron and aluminium. steel gaskets do help but cabs should never be competed with private vehicles or used as a real world example. i have seen taxi autos last 300,000+ km before needing replacement whereas a 4speeder in a private car like mine or yours may only last 150,000km. i have done a few headgaskets on the ohc motorsea - el are by far the worst but like i said no ohc motor is safe.

**CAT600** · 19-04-2009, 08:04 PM

Quote:

Originally Posted by yift

dezza they are bad ea-bf. ba/bf not as bad but still prone. no ford ohc motor is safe from this kind of weakness.

There are 600+ rwkw XR6T/F6's out there using stock heads/head bolts and blocks. There are 400+ rwkw ones still using stock head gaskets as well.

Daniel

yift · 19-04-2009, 10:51 PM

Quote:

Originally Posted by CAT600

There are 600+ rwkw XR6T/F6's out there using stock heads/head bolts and blocks. There are 400+ rwkw ones still using stock head gaskets as well.

Daniel

like i said ba/bf not as bad but still prone.

another thing i forgot to mention was early barra sixes cracked their blocks too. most ford dealers, that had these failures come through, thought it was a headgasket problem when infact is was cracked blocks. it had something to do with the casting of the early blocks from memory but cant remeber 100%.

nugget378 · 19-04-2009, 08:05 PM

Quote:

Originally Posted by Tiapan

Cleveland, oiling system can starve the bottom end, can be corrected with oil restrictor kit,
core shift in many blocks

The biggest issue with a cleveland is getting the valvtrain/geometry correct for any high rpm work, by far the most common cause of breakages, IMO the oiling issues are over rated, and easily fixed with a well designed sump..

BJ · 19-04-2009, 09:28 PM

Quote:

Originally Posted by nugget378

The biggest issue with a cleveland is getting the valvtrain/geometry correct for any high rpm work, by far the most common cause of breakages, IMO the oiling issues are over rated, and easily fixed with a well designed sump..

Yep i'll second that one Tony.

svo347 · 19-04-2009, 11:19 PM

Quote:

Originally Posted by nugget378

IMO the oiling issues are over rated, and easily fixed with a well designed sump..

Im sure im goin to get trampled here but i thought the idea with Clevo oiling systems was to add a restrictor kit to limit the volume of oil pumped into the heads at high rpm and the oils slow return to the sump. I remember seeing breathers extended up fairly high in a mates sprint car engine as everytime he went around the track, oil used to spew from the right hand r/cover, restrictor kit fitted and it was all good

**CAT600** · 19-04-2009, 11:21 PM

Quote:

Originally Posted by svo347

Im sure im goin to get trampled here but i thought the idea with Clevo oiling systems was to add a restrictor kit to limit the volume of oil pumped into the heads at high rpm and the oils slow return to the sump. I remember seeing breathers extended up fairly high in a mates sprint car engine as everytime he went around the track, oil used to spew from the right hand r/cover, restrictor kit fitted and it was all good

I can only assume that the bigger and better baffled sump must prevent oil starvation due mainly to the extra volume?

Daniel

svo347 · 19-04-2009, 11:37 PM

Quote:

Originally Posted by CAT600

I can only assume that the bigger and better baffled sump must prevent oil starvation due mainly to the extra volume?

Daniel

I do agree mate, but all i see is more oil being available to the top end and still not being able to return quick enough. Anyhoo better get my head back into the Terri forum lol

nugget378 · 20-04-2009, 12:17 AM

Quote:

Originally Posted by svo347

Im sure im goin to get trampled here but i thought the idea with Clevo oiling systems was to add a restrictor kit to limit the volume of oil pumped into the heads at high rpm and the oils slow return to the sump. I remember seeing breathers extended up fairly high in a mates sprint car engine as everytime he went around the track, oil used to spew from the right hand r/cover, restrictor kit fitted and it was all good

I usually fit a restrictor kit also, but alot of guys dont and they dont seem to have problems, In my experience a good baffled high capacity sump will solve 99% of it, sure its a band aid, as is the restrictor kit, but it works, (if the pick up is always sitting in oil there is no problem) the proper fix is bushing the lifter bores, as the restrictor only does one bank anyway.

madmelon · 19-04-2009, 09:05 PM

The Holden/Buick 3.8's tend to stretch timing chains over time (more than most cars anyway), causing the cam timing to get progressively worse. Results in poor performance and economy. Can't recall the source of this information.