Lock Washers on Exhaust Manifold Bolts?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=42949
Printed Date: November-15-2024 at 7:54pm
Topic: Lock Washers on Exhaust Manifold Bolts?
Posted By: Wisky Badger
Subject: Lock Washers on Exhaust Manifold Bolts?
Date Posted: June-13-2018 at 1:06pm
| Should I install lock washers on my Exhaust Manifold Bolts? Will the heat of the engine allow the lock washer to work (lose there spring tension)? The original bolts had lock washers on them. I order new manifolds and a manifold service kit and it didn't include washer for the manifold bolts. It did include lock washers for the riser bolts. |
Replies:
Posted By: KENO
Date Posted: June-15-2018 at 11:29am
|
The PCM illustrated parts manual has no lock washers shown or listed for the allen head bolts holding the manifolds to the heads. Just like your kit, there are lock washers shown for the riser to manifold bolts. Here'a a link to the manual, it comes in handy for lots of things Page c5-1 has the manifold stuff https://www.marinepartsguys.com/wp-content/uploads/ILLUSTRATED-PARTS-MANUAL-PCMcompressed.pdf" rel="nofollow - link |
Posted By: Hollywood
Date Posted: June-15-2018 at 12:23pm
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There is water transfer between the riser and manifold. There is no water transfer between manifold and head. When you have water transfer, especially with gas transfer across the same plane, you need a good seal. |
Posted By: TRBenj
Date Posted: June-15-2018 at 12:54pm
| You still want a good seal at the manifold to Head connection... I have seen plenty of those bolts loosen up over time (to the point of falling out entirely), I don’t know why Pcm didn’t use lock washers originally but I can’t think of a good reason not to use them either. I have used plenty of bolts with lock washers on other manifold types without issue. |
Posted By: Hollywood
Date Posted: June-15-2018 at 1:20pm
| Well yea any seal you seal is worth sealing good. Not all are critical though. |
Posted By: TRBenj
Date Posted: June-15-2018 at 1:24pm
| Agreed that the water/exhaust boundaries are more critical (the exhaust to Head connection won’t allow Water to leak into the cylinders if it fails) but an exhaust leak at this location is not a desirable condition either. |
Posted By: Hollywood
Date Posted: June-15-2018 at 2:04pm
| A seal that doesn't seal is no seal at all, and certainly undesireable. |
Posted By: Gary S
Date Posted: June-15-2018 at 2:19pm
|
Don't be messing with seals--- A vacationing penguin is driving his car through Arizona when he notices that the oil pressure light is on. He gets out to look and sees oil dripping out of the motor. He drives to the nearest town and stops at the first gas station. After dropping the car off, the penguin goes for a walk around town. He sees an ice-cream shop and, being a penguin in Arizona, decides that something cold would really hit the spot. He gets a big dish of ice cream and sits down to eat. Having no hands he makes a real mess trying to eat with his flippers. After finishing his ice cream, he goes back to the gas station and asks the mechanic if he's found the problem. The mechanic looks up and says "It looks like you blew a seal." "No no," the penguin replies, "it's just ice cream." ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: phatsat67
Date Posted: June-15-2018 at 3:24pm
|
I would presume lock washers probably won't hold their properties too well when heated up to 600+ degrees. Spring metal probably wouldn't like being heated and cooled to extremes over and over and probably negates any locking abilities it has. Most likely why I have never seen lock washers on exhaust fittings in automotive or marine environments. Probably not worth the thoughts you have already spent on it, Check the bolts once a year and you should be fine, I haven't had one I have installed back out ever. Most importantly recheck the torque after your first full heat cycle (operating temp then cool off over night). Also, I prefer to use the steel cored graphite coated gaskets, I have never had one of those fail and generally they are reusable if you don't tear them up taking them off. I don't care for the old aluminum crush style perforated/paper gaskets. |
Posted By: 8122pbrainard
Date Posted: June-15-2018 at 10:32pm
I agree. They won't hold up and I feel is the reason locks aren't used. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
phatsat67 wrote: