- SHORE A
- ±5 pts against the specified hardness
- TENSILE
- Per compound datasheet, tested to ASTM D412
Pads, Stoppers & Caps · Made to order
Cylinder Head Cover Insulator — Engine Noise Damping
A moulded rubber cover that sits over the cylinder head cover and damps the noise it radiates — the cam cover is one of the loudest surfaces on an engine, and a large thin panel is exactly what broadcasts it. Compounded for the oil mist and heat of the engine bay, not for weather.
- HARDNESS
- 40–60 Shore A typical, set from the damping required
- TEMPERATURE
- −40 to +160 °C in AEM, continuous
- THICKNESS
- Cover wall thickness — to your drawing
- MEDIUM
- Engine-bay heat and oil mist
- NOISE REDUCTION
- To your specification
- RETENTION
- Clipped, bonded, bolted or interference fit
- MADE TO ORDER
- ISO 9001:2015
- 09111526A
Product gallery
Visual Reference
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Cross section viewSection through the cover and its standoff — on request under NDA
- Max width
- Cover footprint — to your drawing
- Thickness
- Wall thickness — to your drawing
- Standoff
- Air gap held between cover and head cover
- Noise reduction
- Target attenuation, and the frequency band
- Retention
- Clipped, bonded, bolted or interference fit
- Clearance
- Space to the bonnet with the engine on its mounts
Section drawing available on request. Send the head cover outline, the attenuation you need and the space you have under the bonnet — or a sample cover and the engine it fits — and we will return a dimensioned drawing.
Technical specifications
Engineering Data
- Product Family
- Pads, Stoppers & Caps
- Material
- AEM standard; silicone where temperature governs
- Hardness (Shore A)
- 40–60 Shore A typical, set from the damping required
- Tensile Strength
- Per compound datasheet, ASTM D412
- Elongation at Break
- Per compound datasheet, ASTM D412
- Operating Temperature
- −40 to +160 °C in AEM; −60 to +220 °C in silicone
- Compression Set
- Tested to ASTM D395 Method B
- Density
- Per compound datasheet
- Colour Options
- Black standard, custom RAL on request
- Lead Time
- Confirmed with the quotation, from approved drawing and approved sample
- Medium compatibility
- Engine-bay heat and oil mist. Not for EPDM, which swells in oil
- Damping
- Selected for loss rather than resilience
- Noise reduction
- Target attenuation and frequency band, to your specification
- Standoff
- Air gap held between cover and head cover
- Retention
- Clipped, bonded, bolted or interference fit
- Electrical properties
- Not tested. This is a thermal and acoustic part
- Certifications
- ISO 9001:2015 — certificate 09111526A, valid to 21 February 2027
- Minimum Order
- 10,000 pieces per part number, per compound, or quoted against the part where geometry or tooling makes that unrealistic. Prototype and first-article lots sit outside the minimum.
Dimensional reference
- Max width
- Cover footprint — to your drawing
- Thickness
- Wall thickness — to your drawing
- Standoff
- Air gap held between cover and head cover
- Noise reduction
- Target attenuation, and the frequency band
- Retention
- Clipped, bonded, bolted or interference fit
- Clearance
- Space to the bonnet with the engine on its mounts
Available materials
Rubber Compound Options
Select the compound best suited to your operating environment and application requirements.
| Rank | Compound | Temperature | Why, on an engine cover |
|---|---|---|---|
| Recommended | AEM | −40 to +175 °C continuous to +160 °C | Formulated for hot oil and oil mist, with the temperature headroom a cam cover needs. The compound this part should be quoted in, and it is on no selector on the site |
| Recommended | Silicone | −60 to +220 °C | Where temperature alone governs and the cover is not oil-wetted. Excellent heat stability, and it damps well soft. Tears more easily and swells in hot mineral oil |
| Suitable | NBR | −30 to +120 °C | Good oil resistance at lower cost, but the temperature ceiling is the limit on a hot engine |
| Suitable | Neoprene | −40 to +120 °C | Moderate oil resistance and good general durability, with the same temperature ceiling as NBR |
| Available | FKM | −20 to +250 °C continuous to +200 °C | Handles anything an engine bay produces, at 2–3× the cost of NBR and with no damping advantage |
| Not recommended | EPDM | −40 to +140 °C | Swells in mineral oil, and a cam cover lives in oil mist. |
| Not recommended | SBR · natural rubber | See the compound table | No oil resistance and no temperature headroom |
Not sure? Send the medium, temperature and load
COMPOUND
AEM
hot oil mist to +160°C
Key advantages
Why Specifiers Choose Margo
The cam cover is a drum
A large thin panel over a running engine radiates noise, and the insulator is what stops it. Damping is what you are buying — the compound is chosen for how much energy it turns into heat, not for how tough it is.
It has to live in oil mist
A cam cover is surrounded by oil vapour and the occasional weep, at engine-bay temperature. We quote AEM for that duty — hot oil to +160 °C — because the general-purpose weather compounds swell in it.
An air gap does the work
An insulator clamped hard against the panel conducts the vibration straight through. The standoff is what makes it insulate, so we design the mounting and the gap with the cover rather than after it.
This is not an electrical part
The name says insulator and it means thermal and acoustic. We do not test dielectric strength or volume resistivity and we make no electrical claim — if you need an electrically insulating component, tell us and we will say plainly whether we can supply it.
Industries served
Global Applications
Automotive
cylinder head cover insulation, and acoustic covers elsewhere in the engine bay
Generator sets and compressors
acoustic covers on stationary engines, where noise limits are a site condition
Agriculture
tractor and harvester engine covers, where the operator sits close to the engine
Heavy industry
acoustic covers on plant with exposed engines and drives
Manufacturing process
From Compound to Certification
Material compounding
Polymer blending, additive integration and batch QC in our in-house lab. The compound is chosen for damping and for hot oil-mist resistance, which is why AEM leads rather than a general-purpose weather compound.
Mould Design & CNC
Mould design and CNC tool manufacture, in-house, held as a controlled record. The standoff and the mounting features are cut with the cover, since an insulator clamped flat against the panel does not insulate.
Compression Moulding
Compression moulding.
Post-Cure & Trimming
Post-cure and trimming. AEM and silicone are oven post-cured, which is what delivers their published temperature performance.
Quality inspection
Dimensional check, hardness, and compression set on batch samples. Fit is checked against the head cover profile rather than to the drawing alone.
Export packaging
Industrial packing with documentation. Covers are packed nested and unstacked so the standoff features are not crushed. ISPM-15 treated pallets where timber packaging is used.
Quality assurance
Certified to International Standards
Every product leaves our facility with a documentation package — material test reports, dimensional inspection sheets and a certificate of conformance — giving traceability from raw material to finished part.
ISO 9001:2015 · Certificate 09111526A
Integral Certification Ltd · Valid to 21 February 2027
Scope: rubber moulded components — quality management, not a product approval
IATF 16949 — upgrade in progress, certification targeted by end 2026
ISO 14001 and ISO 45001 — targeted 2027
This part is a thermal and acoustic insulator. It is not an electrical insulating component, and we do not test dielectric strength or volume resistivity. Rubber is not electrically insulating by default.
Certification detailProduction metrics
- Since 2005
- In operation
- 60+
- Active clients
- 3–4 weeks from approved sample
- Avg. lead time
Downloads
Technical Documentation
Dimensioned drawings and 3D models are issued on request, under NDA where required. Send the head cover outline or model, the attenuation you need and the clearance you have, and we will return a proposal.
Request a drawingFAQ
Technical & Commercial Questions
Answers to the most common questions from engineering teams and procurement managers worldwide.
What is the minimum order quantity for this part?
We supply in bulk. The minimum run is 10,000 pieces per part number, per compound, or quoted against the part where geometry or tooling makes that unrealistic. Prototype and first-article lots sit outside the minimum.
Can you match a competitor specification or reverse-engineer an existing part?
Yes — send the head cover as well as the insulator if you can. The fit has to follow a casting, and a cover copied from a used sample reproduces whatever distortion the heat has already put into it. We work from the casting and the clearance you have.
What file formats do you accept for drawings?
PDF, DWG, DXF and STEP. A 3D model is worth more than a drawing on this part — the cover follows a casting and has to clear the bonnet with the engine moving on its mounts. Mark the attenuation you need and the surface temperature at the cover.
Do you provide material test reports with each shipment?
Yes. Material test reports, dimensional inspection sheets and a certificate of conformance ship with every consignment. Hardness, tensile to ASTM D412 and compression set to ASTM D395 Method B are tested in-house. We do not test electrical properties — this is a thermal and acoustic part.
What are your payment and delivery terms for international orders?
TT and LC accepted, discussed per order. Ex-works Nashik or FOB Nhava Sheva. Commercial invoice, packing list and certificate of origin are issued with every consignment. Covers ship nested and unstacked.
Same compound
Other parts we mould in the same compounds
- Silicone Rotary Shaft Seals — High-Temperature, Low-Speed Service · Silicone
- AEM Insulation Bush — High-Temperature · AEM
- Rubber Oil Filler Cap — Push-In, Sealed or Vented · AEM, NBR, Neoprene
- Compression Pump Inlays — Moulded Elastomer Inserts · AEM, Silicone, NBR
- Oil Filler Cap O-Rings — Moulded to ISO 3601 Sizes · AEM, Silicone, NBR
- Air Extractor Flap — One-Way Cabin Pressure Relief · Silicone, Neoprene
Need this part quoted?
Send the head cover model or outline, the attenuation you need and the surface temperature at the cover. We confirm compound, damping and the standoff, then quote against your annual quantity. We respond within 48 hours.