12 Valve Tappet Covers - Competition Diesel.Com

Boosted Bulldog · 11-17-2019, 09:10 PM

Should I stay with a stock tappet cover or go with an aftermarket? The engine is going to have 4000 valve springs and a little timing. If aftermarket what do you recommend? Thanks Brent

joefarmer · 11-18-2019, 12:47 PM

It's easier to keep the oil on the inside of a 12valve with an aftermarket cover, but either will work. The OEM rubber seems to disintegrate after a few years.

Destroked 450 · 11-22-2019, 05:53 PM

I'm a firm believer in the dual vented valve covers.

Bersaglieri · 12-16-2019, 09:21 PM

I put a new seal on my stock cover, but now that the motor is opened up I am thinking billet might be the way to go to keep things from leaking.

Begle1 · 12-16-2019, 09:24 PM

I just rebuilt mine and couldn't keep the stocker from leaking. What's the trick?

A weak point on an excellent engine.

I went to a billet one and it's been good for the first 100 miles...

2wpuller · 12-17-2019, 03:43 PM

I don't have any problems with leaking with the 93 12valve in my 72 Chevy.The side tappet cover needs replacing it's leaking bad.Going to make a aluminum one to replace it.

Dale

Mark Nixon · 12-17-2019, 05:58 PM

Keep in mind, the OEM tappet cover is supposed to have a slight bow from the middle out to the ends.
It's NOT perfectly flat.

Mark.

2wpuller · 12-17-2019, 09:17 PM

I have made a few of them.I use 1/8 " aluminum with a spacer welded on between the bosses and and cover.and use permitex tuff stuff never had one leak are warp.and put breather fitting in just have to make sure their not inline with pushrods because of oil could come down and could go breather.There's a picture of one in our build thread in the 2wd pulling section.

Red Sleeper · 12-18-2019, 06:43 AM

On my 91 12v I replaced the tapper gasket and reused the stock cover with success. No leaks from that gasket for almost a year.

I did use aviation sealant on the engine side of the new gasket. Upon first install the gasket fell off the cover near bottom rear area. I then coated the bare cover with aviation sealant, allowed it to set up, slipped the gasket on, installed the cover to the block. This is basically a stock power level engine.

11-17-2019, 09:10 PM	#1
Boosted Bulldog Name: Boosted Bulldog Title: Rookie Status: Not Here Join Date: Oct 2018 Location: Saxonburg PA Member`s Gallery Posts: 24	12 Valve Tappet Covers Should I stay with a stock tappet cover or go with an aftermarket? The engine is going to have 4000 valve springs and a little timing. If aftermarket what do you recommend? Thanks Brent

11-18-2019, 12:47 PM	#2
joefarmer Name: joefarmer Title: MR. Supreme Overlord Status: Not Here Join Date: Jul 2006 Location: ohio Member`s Gallery Posts: 6,137	It's easier to keep the oil on the inside of a 12valve with an aftermarket cover, but either will work. The OEM rubber seems to disintegrate after a few years. __________________ brandon'); DROP TABLE Users;-- 1948 Dodge 1.5t 12v RH swap \| 99 F250 12v RE test rkt \| 11 X5 'no soup' \| 08 F250 CR RE swap \| 05 2500 CR 68 standalone firepunk.com

11-22-2019, 05:53 PM	#3
Destroked 450 Name: Destroked 450 Title: Too Much Time Status: Not Here Join Date: Mar 2015 Location: Harned,Ky. Member`s Gallery Posts: 340	I'm a firm believer in the dual vented valve covers. __________________ Mine: 04 F-450 sc 4x4 fb drw 5.9 12v 215 ppump, zf6, kdp fixed, 3k gsk, AFC Live, super b single, pusher intake, d-celerator ebrake Hers:2018 F-150 sc 4x4 5.0 Farm trucks: 01 Z71 ext cab, 95 S10, 93 F-800 8.3 Cummins, 87 AM General 5 ton

12-16-2019, 09:21 PM	#4
Bersaglieri Name: Bersaglieri Title: Ron Swanson's Brother Status: Not Here Join Date: Jan 2008 Location: Ohio Member`s Gallery Posts: 1,957	I put a new seal on my stock cover, but now that the motor is opened up I am thinking billet might be the way to go to keep things from leaking. __________________ 2013 - ISBe - Aisin - AAM 1997 - 6BT - G56 - Dana "Overworked and Underpaid" 2002 - 6BT - 47RH - Sterling [Excursion] 1994 - LT1 - 4L80e - Moser

12-16-2019, 09:24 PM	#5
Begle1 Name: Begle1 Title: Too Much Time Status: Not Here Join Date: Nov 2007 Location: Kihei, Maui Member`s Gallery Posts: 4,143	I just rebuilt mine and couldn't keep the stocker from leaking. What's the trick? A weak point on an excellent engine. I went to a billet one and it's been good for the first 100 miles... __________________ 1990 D-250 Regular Cab: Automatic transmission, turkey air horn, wires.

12-17-2019, 03:43 PM	#6
2wpuller Name: 2wpuller Title: letting the smoke fly Status: Not Here Join Date: Dec 2006 Location: Washington,Missouri Member`s Gallery Posts: 2,894	I don't have any problems with leaking with the 93 12valve in my 72 Chevy.The side tappet cover needs replacing it's leaking bad.Going to make a aluminum one to replace it. Dale __________________ 1975 f250 6.0 Perkins,twins,2006,6sp allison 1972 C10,5.9 5sp 2007 Dodge 2 WD pulling truck Sponsors GoerendTransmission Haisley Machine MCS MidwestPerformanceDiesel ShowMePerformance Snow Performance

12-17-2019, 05:58 PM	#7
Mark Nixon Name: Mark Nixon Title: No Savior among the flesh Status: Not Here Join Date: Feb 2009 Location: Brownville, Nebraska Member`s Gallery Posts: 8,676	Keep in mind, the OEM tappet cover is supposed to have a slight bow from the middle out to the ends. It's NOT perfectly flat. Mark. __________________ If you or I did business like the PEOPLE in government do business, we'd be put in jail. Government is coercive. Anarchy: The state of existence where there are no masters & no slaves. Therefore, Anarchy means the ABSENCE OF SLAVERY, or, in other words, FREEDOM.

12-17-2019, 09:17 PM	#8
2wpuller Name: 2wpuller Title: letting the smoke fly Status: Not Here Join Date: Dec 2006 Location: Washington,Missouri Member`s Gallery Posts: 2,894	I have made a few of them.I use 1/8 " aluminum with a spacer welded on between the bosses and and cover.and use permitex tuff stuff never had one leak are warp.and put breather fitting in just have to make sure their not inline with pushrods because of oil could come down and could go breather.There's a picture of one in our build thread in the 2wd pulling section. __________________ 1975 f250 6.0 Perkins,twins,2006,6sp allison 1972 C10,5.9 5sp 2007 Dodge 2 WD pulling truck Sponsors GoerendTransmission Haisley Machine MCS MidwestPerformanceDiesel ShowMePerformance Snow Performance Last edited by 2wpuller; 12-17-2019 at 09:32 PM.

12-18-2019, 06:43 AM	#9
Red Sleeper Name: Red Sleeper Title: Too Much Time Status: Not Here Join Date: Aug 2009 Location: Lone Star State Member`s Gallery Posts: 4,597	On my 91 12v I replaced the tapper gasket and reused the stock cover with success. No leaks from that gasket for almost a year. I did use aviation sealant on the engine side of the new gasket. Upon first install the gasket fell off the cover near bottom rear area. I then coated the bare cover with aviation sealant, allowed it to set up, slipped the gasket on, installed the cover to the block. This is basically a stock power level engine. __________________ Nick J '14 Silverado LTZ 5.3 4wd '05 Cummins QCSB 4wd 48re '91 Cummins w350 5spd